Mr Thomas Kaveney
Manager, Environmental Assessment and Trade
Wildlife Protection Authority
Australian CITES Management Authority
Nature Conservation House
GPO Box 636
CANBERRA ACT 2610
Dear Mr Kaveney,
The enclosed document provides information on issues raised by you 9 September 1996 concerning a request to AQIS to permit importation of bumblebees into Australia. It is being forwarded directly to you at the request of Mr I. Peebles, Veterinary Officer, AQIS.
We have endeavoured to the best of our ability to respond not only to concerns raised by you but also those of other stakeholders whom we solicited for information and comment. We believe that we have addressed all the issues; however, should there be any additional points raised, please contact us for clarification or further information.
Yours sincerely,
Dr Stephen Goodwin
Marilyn Steiner
Gosford IPM Services
GOSFORD
NSW 2251
encl.
A SUBMISSION TO AQIS AND
ENVIRONMENT AUSTRALIA
DR STEPHEN GOODWIN AND MARILYN STEINER
GOSFORD IPM SERVICES
OCTOBER 1997
(i)
TABLE OF CONTENTS
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1.2. The potential benefits of importing bumblebees into Australia |
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1.3. People and agencies contacted for information concerning the proposal |
2. Information gathered in fulfillment of ANCA queries
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2.2. Taxonomic relationship to Australian native bee species |
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2.3. Similarity of habitat and habit to bee species in Australia |
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2.3.5. Potential for habitat competition with native bees and honeybees |
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3. Other issues relevant to the importation proposal.
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3.1. Issues raised by the scientific community for and against the proposal |
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3.1.1. Chances for establishment of a feral population of B. terrestris once introduced |
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We would like to thank the many people who contributed to the discussion on the merits and risks associated with importation of bumblebees into Australia. Their names, affiliations, and contributions are detailed in the document. In particular we would like to thank Dr Rod Macfarlane, Christchurch, New Zealand, who placed a wealth of published and unpublished data at our disposal and acted in a consultative capacity.
A request to import bumblebees (Bombus spp.) from New Zealand into Australia was made to AQIS in February 1996. The applicant was Dr Stephen Goodwin, representing Gosford IPM Services, Green Point, NSW and their clients. A copy of the application was forwarded by AQIS to ANCA for consideration in August 1996. ANCA responded to AQIS on 9 September 1996 with a request for additional information.
The reason for the original request was to make available a commercial supply of bumblebees from specialist insectaries for crop pollination. Bumblebees are reared commercially in North America, New Zealand, Canada, Israel and Europe to improve pollination in greenhouse crops such as tomatoes and capsicums, in field crops such as strawberries, zucchini, beans and aubergines, and in tree crops such as almonds and stone fruit. Estimated sales of commercial bumblebees are worth about $50 million per annum, and they pollinate crops worth $5 billion. They are used in over 2,500 ha of tomatoes in Europe alone.
Australia is one of the few countries in the world that does not have either naturalised or native bumblebees. The technology for rearing bumblebees in captivity on a year-round basis has been available since 1989, and demand for the bees by growers has been very high. Bumblebees are very efficient pollinators and hard workers, even under adverse weather conditions, and their use can result in substantial benefits in terms of increases in yield, fruit set, weight, and quality of fruit. Use of bumblebees has had the additional benefit of obliging growers to adopt environmentally friendly pest management practices, as bees are killed by many pesticides.
Pollination in Australian greenhouse tomatoes is presently assisted by electric vibrators. Their use is a time consuming and laborious process, and Australian greenhouse tomato growers are very keen to have bumblebees do the work for them. There are several other horticultural crops where bumblebees would improve pollination, and support from the relevant producers has also been received.
The current proposal has been restricted to Bombus terrestris, a northern European species. It is the most commonly available and efficient pollinator in commercial production.
The earlier application to AQIS to introduce Bombus spp. into Australia proposed to import on an ongoing basis pre-established commercial nests for direct use by growers. This was on the basis of the availability of a commercial production operation then being established in New Zealand by the Belgian company BioBest Biological Systems. BioBest has since withdrawn its interests from New Zealand. Because of concerns about possible transfer of pathogens and parasites with each shipment, we now consider it advisable to establish a commercial rearing unit in Australia that would be founded with certified clean stock, probably originating in New Zealand. Nuclear material would be inspected for parasites and pathogens by AQIS or their designate before release to the commercial breeding unit.
1.2. The potential benefits of importing bumblebees into Australia.
These benefits were detailed in large part in the original proposal.
Benefits of bumblebees to:
(a) Applicant:
The applicant seeks to make bumblebees commercially available to Australian horticultural industries to facilitate pollination in crops, particularly tomatoes, as an integral part of integrated pest management (IPM) practices involving biological control agents and reduced pesticide use.
Currently, a NSW Agriculture research and development project funded by the Horticultural Research and Development Corporation is aiming to develop and implement a national IPM program in greenhouse crops, including vegetables, in Australia. This is being undertaken in Queensland, NSW and Victoria and has the support of industry. The availability of bumble bees would add further support to the efforts to reduce pesticide usage, and to use biological control as an alternative, as occurs overseas.
(b) Industry:
Bumblebees can assist in flower pollination in a range of crops grown in Australia, resulting in greater production and crop quality. The most significant contribution by bumblebees would be in tomatoes. This is the most important vegetable crop grown in Australia. In tomatoes, bumblebees can totally replace the use of manual vibration and hormone application to facilitate pollination under protected conditions, providing the plants produce viable pollen. Advantages to growers are less manual work, easier management, higher profit, and higher production of seeds which results in a larger and more solid fruit. A single bee colony will pollinate 1000-3000 m2 for 6-8 weeks. Reported yield increases in tomato range as high as 28% (Abak et al. 1995 (Turkey), Ikida and Tadauchi 1995, Koide and Hayashi 1993 (Japan),Vecchio et al. 1996 (Italy), Banda 1990 (UK)).
In capsicum, the use of bumblebees is not an absolute necessity to obtain fruit, but it is essential to maximising crop quality. Overseas, it has been found that with improved pollination, the fruit contains more seeds, resulting in a better shape and a thicker pericarp. A single colony of bumblebees will pollinate 3,000-10,000 m2 for 6-8 weeks.
In strawberries, bumblebees are used in California where the US crop is grown outdoors. They are used in Europe and the UK where the crop is grown under greenhouse conditions, and are particularly useful in periods during which honeybees do not pollinate well - in winter and spring, when adverse conditions can prevail. In Australia, this crop is also mostly grown outdoors, and the commercial availability of bumblebees would benefit fruit production and quality.
In melons, bumblebees are important for the production of fruit, because honeybees are insufficiently active during winter and autumn when the sky is cloudy. A single colony is sufficient for 1000-1500 m2 for 6-8 weeks.
In almonds, bumblebees are being developed to assist pollination in North America. Plant Sciences Inc., an agricultural service provider specialising in the provision of IPM services and commercially produced biological control agents to farms, is involved in this work. Colonies are being delivered just prior to blossom time to almond orchards in California, and are used in conjunction with honey bees.
In blueberries, Bombus is regarded as the principal native pollinator in North America, and far more effective than the honey bee. In Australia, there are 230 ha of blueberries grown on the NSW North Coast, and the farm manager is keen to have B. terrestris available to assist the pollination of his crops.
Other crops that benefit from bumblebee pollination include zucchini, aubergine, beans, cranberries, canola, sunflowers, kiwifruit, and crops grown for seed production. To this list Macfarlane (pers. comm.) adds plums, passionfruit, feijoa, blackcurrants and pastoral legumes.
(c) Australia:
Widespread use of commercial bumblebee colonies in protected crops and some field crops overseas (Appendices 3, 4, and 5) suggests that there is an obvious and substantial benefit to Australia in the same crops. Macfarlane (pers. comm.) considers that B. terrestris is the top priority option for improving alternative pollinator supplies for crop pollination in Australia.There is strong grower interest in the importation of bumblebees into mainland Australia. In Tasmania, where bumblebees currently exist only in the wild, tomato growers are lobbying their Minister for Primary Industries to have them commercially imported into that State for use in greenhouses. In mainland Australia, growers are aware of the economic benefits of having bumblebees for pollination, and are supportive of this application.
Advantages of bumblebees:
Tomato is the most popular vegetable grown in Australia and the demand on production is high. There is increasing pressure from supermarkets for guaranteed production and fruit quality of this crop. Woolworths, the major purchaser of fresh fruit and vegetables in this country, is currently investing a significant amount into the greenhouse crops industry in Australia to ensure production and fruit quality are guaranteed for their retail stores. They also plan to develop an export market.
Recognition by Woolworth of the need to improve greenhouse production practices through the latest technology, includes their support for the use of bumblebees. A letter of support for the importation of bumblebees into mainland Australia has been provided by Mr G. Andersen, Managing Director of Chisholm Manufacturing (a division of Woolworth), who is responsible for the current investment into greenhouse technology for vegetable production. The involvement of Woolworth will have a major influence on standards in greenhouse vegetable, particularly tomato, production in Australia in the future. This influence will also see a trend towards greenhouse production for salad vegetables, creating a large demand for bumblebees as pollinators. Australia is just about the only country not to have bumblebees present and not to have them available for use as commercial pollinators for the benefit of industry.
1.3. People and agencies contacted for information concerning the proposal.
In the interests of objectivity, contacts were made with several expert sources both overseas and within Australia for their input into the proposal. Apart from personal contacts, opinions were also sought through the BOMBUS listserver on the Internet (bombus-l@listserv.uottawa.ca) and through the International Bee Research Association (IBRA). These sources represent scientific and commercial experience in the fields of bee ecology, commercial rearing and importation. It should be noted that while the merits of Bombus terrestris use in crop pollination are not in question, scientific opinion on the risks of introduction of bumblebees as a group into Australia is divided. Every effort has been made to represent both sides of the discussion in this response (see Section 3.1).
Information was received from the following individuals:
Dr Rod Macfarlane, formerly of the DSIR and currently Vice Chairman, International Commission of Plant Bee Relationships, Christchurch, New Zealand;
Dr Barry Donovan, formerly DSIR, Lincoln, New Zealand;
Dr Mike Allsop, Protection Research Institute, Stellenbosch, South Africa;
Dr Mark Wright, Agricultural Research Council, Elsenberg, South Africa;
Dr Karel Bolckmans, BioBest NV, Belgium (commercial rearer and supplier);
Dr Richard Nelson, Plant Sciences Inc., California (commercial supplier);
Dr Terry Houston, Western Australian Museum, Perth, WA;
Drs M.P.Schwarz and K. Hogendoorn, Flinders University, S. A, and A. Hingston, University of Tasmania;
Dr Tetsuo Wada, Tomen Corporation, Tokyo, Japan;
Drs Jonathan Cnaani, Amit Einav, and Dan Weil, Pollination Services,Yad-Mordechai, Israel;
Dr Adriaan van Doorn, Koppert BV, The Netherlands (commercial supplier).
Dr Suzanne Batra, Bee Research Laboratory, Beltsville, Maryland,USA.
Dr Don Griffiths, Consultant to Bunting Brinkman Bees Ltd., The Netherlands.
Dr Ken Walker, Victorian Museum, Melbourne, Victoria;
Ray Hart, Tasmanian Department of Primary Industry and Fisheries, Devonport, Tasmania;
Roger Buttermore, Tasmanian Museum & Art Gallery, Hobart, Tasmania;
Dr Anne Dollin, Sydney, NSW;
Dr Graham Pyke, Australian Museum, Sydney, NSW.
The following bee scientists replied to the BOMBUS listserver enquiry:
Dr Chris Plowright, University of Ottawa, Canada;
Dr Madeleine Beekman, University of Amsterdam, The Netherlands;
Dr Barry Donovan, Crop & Food Research, New Zealand;
Dr Penelope F. Kukuk, University of Montana, USA;
Dr James Cane, Auburn University, Alabama, USA;
Dr Roger Buttermore, Tasmanian Museum, Australia;
Dr Katja Hogendoorn, Postdoc, Flinders University, Australia;
Dr Allan Spessa, Australian National University, Australia (representing a group of four scientists including Dr Hogendoorn).
Their contributions are detailed in Section 3.1. A special acknowledgment is made of the substantial contribution made by Dr Rod Macfarlane, to whom we are deeply indebted for providing us with very informative and detailed information, both published and unpublished, on most of the issues raised. His submission is appended to the proposal (Appendix 2).
2. Information gathered in fulfillment of ANCA enquiries.
2.1. Biology of Bombus terrestris.
Bombus terrestris has been studied quite extensively for many years, and its life history is well documented (Sladen 1912, Cumber 1954, Alford 1975, Donovan and Weir 1978, Prys-Jones and Corbet 1987, Macfarlane et al. 1994).
In northern Europe, solitary queens hibernate in soils in temperatures below 5oC and emerge in spring when ground temperatures reach about 6-7oC. Carbon dioxide also stimulates an end to hibernation and is used in commercial production to ensure a year-round supply of colonies. In northern Europe queens may spend 6-8 months underground, but in warmer climates such as coastal New Zealand, this period may be reduced to 3.5-5 months. There may also be a partial second generation in warmer areas, so prolonging the period of nest initiation (Macfarlane, Appendix 2). New queens feed and then search for nesting sites, for which there are specific requirements (see Section 2.3.4). After 2-3 weeks, the queen has prepared the site, and lays her first eggs on a bed of pollen. The eggs hatch after four days. Over the next 3-4 weeks, the queen must maintain the brood at the optimum temperature of 30-32oC, and forage for nectar and pollen to sustain the developing larvae. During this time she lays further eggs in wax packets close to or on top of the first packet; these develop alongside each other. Larvae pupate after 10-20 days, and workers (females) emerge two weeks later. Colonies therefore require 25-30 days before the first workers appear and another 3-4 weeks before new queens are produced.
Once the first young workers emerge the queen is relieved of her foraging duties and she devotes her time to laying eggs. The population of the colony rises exponentially to its maximum of 300-500 workers in the ensuing 3-4 months. Colonies selected for commercial rearing may be much larger and average 60-180 new queens and 800-1000 workers and males, with maximums many times larger. According to Macfarlane (Appendix 2), food requirements dictate that colonies that do not exceed 500-600 workers and males cannot produce any new queens (cf 150-400 workers in 'Bumblebees for Pleasure and Profit', Appendix 3). In any event, an adequate food supply is essential to initiate new queens.
Drones (males) are produced towards the end of summer, and new queens a few weeks later. The queens leave the nest and mate with males from other nests. Each queen normally mates only once, after which the drone dies. The new queen sets about stocking up her honey stomach with nectar and looks for a suitable site to overwinter, usually excavating a tunnel in soil. Over a 31 week period in an average colony in northern Europe, production of workers peaks in week 14, and declines to nil at week 31. Drones first appear in week 14, peaking to 70-80 during weeks 22-24, before falling off to nil by week 31. Production of queens commences about week 18, steadily increasing to reach about 50 by week 24, maintaining this number until week 31. The old queen does not survive a second season, so nests never build up like those of honeybees. There are several unique features in the bumblebee life cycle, which distinguish it from Apis mellifera and Australian native bee species:
2.2. Taxonomic relationship to Australian native bee species.
There are an estimated 20,000 bee species in the Superfamily Apoidea worldwide, of which approximately 85% are solitary. They are exclusively anthophilous and are regarded generally as the most important group of insect pollinators (Armstrong 1979). In Australia there are probably up to 3,000 bee species (Michener 1970), of which approximately 1,630 species in seven families have so far been described (Michener 1965). Taxonomic information on Australian native species has been drawn from Michener and Houston (1991) and Cardale (1993). Armstrong (1979) stated that Australia has the most distinctive continental bee fauna in the world, characterised by the marked radiation of the primitive Colletidae, and the absence or rarity of several distinctive groups that are otherwise almost worldwide.
The following families are represented in Australia (Michener and Houston 1991):
2.3. Similarity of habitat and habit to bee species in Australia.
An evaluation of the potential risk to the survival of native bee species and to native flower pollination by the introduction of Bombus to Australia requires information about geographic range, nesting habits and flower visiting records of both Bombus and native bees. The fact that nearly half of the approximately 3,000 native bee species in Australia remain undescribed, let alone studied, means that information on the latter is incomplete. However, we feel there is sufficient known about named Australian native species and data from New Zealand studies to enable an objective comparison with B. terrestris.
2.3.1. Geographic range and climate preferences.
Bumblebees are essentially northern Hemisphere temperate species, and this is reflected in their natural climatic range, in their annual activity cycle and in their foraging habits. Macfarlane (Appendix 2) provides detailed information on the natural and naturalised range of B. terrestris. He states that it is difficult to predict with confidence its potential coastal northern distribution in Australia, because there are no tropical areas adjacent to its natural southern distribution in Europe, the Middle East or New Zealand. In Europe the coastal northern limits are about 58oN in Scotland and southern Scandinavia. Arid, hot areas limit the distribution more than hot moist areas. The southern limits in the Mediterranean are 28-37oS, which includes the Canary Islands, Madeira, Italy, Sicily, Malta, southern Greece, Turkey, northern Israel, Afghanistan and Spain. It is not found in areas of Iraq and Israel where temperatures exceed 40oC. In New Zealand it occurs almost everywhere with adequate rainfall. Macfarlane (Appendix 2) concludes from the latitudes and climate restrictions that the likely northern coastal limit in Australia should be between Newcastle and Brisbane, more likely the former, and it might be capable of spreading into the southern uplands of Queensland. He suggests that ants and fungal infections in warm tropical zones may have a significant impact on survival, and that desiccation during overwintering or summer hibernation will likely have an impact in drier areas.
Hingston reports (1997) from a limited study in Tasmania that he observed B. terrestris actively foraging at 38oC, and from as early as 0550h to as late as 2030h; however, this is at odds with many other observers who state that their activity is restricted to early morning and late afternoon, particularly on warm days. In Italy in plastic tunnels they stopped foraging at 27oC (Koide and Hayashi 1993).
2.3.2. Floral hosts and preferences.
The common behavioural factor among bees (Apoidea) is the dependence on nectar from flowers as their chief source of carbohydrates, and on pollen as their source of protein. Many species obtain nectar from a wide variety of flowers, and some also gather pollen from many kinds of flowers. However, some restrict their pollen collecting to particular kinds of plants. Since most of the pollen gathered is used in provisioning cells for larvae, an activity in which only females engage, it is primarily the females that show the restriction in the kinds of plants they visit. However even in these species, the males and females may visit a variety of flowers to gather nectar (Armstrong 1979).
Floral preferences of native bees in Australia.
According to Armstrong (1979), Australia is the only continent where most bees are largely dependent on a single family of plants, the Myrtaceae. Genera of Myrtaceae attractive to bees include Angophora, Baeckea, Callistemon, Eucalyptus, Eugenia, Leptospermum, Melaleuca and Tristania. Most bees oligolectic on Myrtaceae will collect pollen and nectar from whichever members of that family are in bloom in the area. Many polylectic forms also include Myrtaceae among their pollen sources. Armstrong (1979) provides a comprehensive list of known pollen and nectar sources of Australian bees, including non-myrtaceous species (Appendix 7). He quotes Michener (1965) as emphasising that apart from the oligolecty of the Australian colletids to myrtaceous blossoms, there are many pollen- and nectar-seeking bees that visit a variety of flowers, including those of the family Myrtaceae. This is true of species of Allodapula, Exoneura, and Lestis (Anthophoridae), Chalicodoma (Megachilidae), Homalictus, Lasioglossum, Nomia (Nomia metallica has been observed to carry pollen from as many as 11 plant genera in a single pollen load (Hardy 1910)) (Halictidae), Hylaeus (Colletidae), and Trigona (particularly T. carbonaria) (Apidae). Some native bees apparently confine their pollen-collecting visits to blossoms of the Asteraceae e.g. certain species of the genera Hylaeus and Leioproctus (Colletidae), and Lasioglossum (Halictidae); others restrict their visits to flowers of the family Fabaceae e.g. certain species in the genera Amphylaeus, Euryglossa, Hylaeus, Leioproctus, Paracolletes and Trichocolletes (Colletidae), Ceratina (Anthophoridae), Lasioglossum (Halictidae), and Megachile (Megachilidae), while some species are narrowly oligolectic on the blossoms of Wahlenbergia (Campanulaceae) e.g. certain species in the genera Euryglossa, Hylaeus and Leioproctus (Colletidae) and Lasioglossum and Nomioides (Halictidae).
Floral preferences of native bees in New Zealand
New Zealand is the nearest neighbour to Australia, and the likely source of B. terrestris should approval to introduce this species be granted. Although it does not have the same diversity of native bee species as occurs in Australia, it nevertheless has a representation of families that provide evidence of the potential for interactions between native and introduced bees in Australia.
There are about 40 species of native bees in New Zealand, about 36 of which belong to the Colletidae, and four or five to the Halictidae. Macfarlane (pers. comm.) notes that despite the presence and presumed competitiveness for floral and nesting sites of the introduced honeybee and bumblebees in New Zealand, additional species of Australian Colletidae and Halictidae have since spread there, and become established.
Information on floral relationships from New Zealand studies (Donovan 1980, Macfarlane Appendix 6) provides further insight into the potential for competition with our own native bee species should Bombus be introduced into Australia. They are similar to those reported for Australian native bee species. Donovan (1980) noted that the Myrtaceae appeared to be the primary flowering host family of most colletids. Leptospermum, Metrosideros and Lophomyrtus are visited for pollen and nectar by many Leioproctus species, while other species visit primarily leguminous genera such as Carmichaelia, Chordospartium and Notospartium, and a small number of species visit native and introduced Compositae.
Based on flower visiting preferences, most Colletinae could be divided into three groups: those that visited Myrtaceae, Leguminosae, or Compositae. Species that visit flowers in one of these groups have rarely been collected on flowers of the other two groups.
The lengthy nesting periods of New Zealand Halictinae means that a demand for pollen and nectar exists through much of spring and autumn and throughout summer. As a result, Lastioglossum sordidum appears to be a generalist with no marked preferences, visiting an extremely wide range of native and introduced flowering plants, including Prunus, Pyrus, Ceanothus, Taraxacum, Achillea, Brassica, Daucus, Cucurbita, Cytisus, Medicago, Actinidia, Phebalium and others in the latter category.
Floral preferences of introduced bees in Australia
Bombus terrestris. Semmens (1996) recorded that in the limited time that B. terrestris has been recorded in Tasmania, flower visitation observations on at least 170 plant species (156 introduced and 14 native species) showed that introduced plants such as apple, blackberry, blackcurrant, boysenberry, cherry, kumquat, grapefruit, lemon, mandarin, orange, passionfruit, pear, raspberry, beans (broad and runner), pumpkin, herbs (bergamot, borage, comfrey, lavender, rosemary), plus a large number of flowers of trees, shrubs, bushes and grasses, were favoured over native plant species by as much as 9:1. This is similar to the situation in New Zealand, where it is reported that B. terrestris visited at least 400 introduced and only 19 native plant species (Donovan and Macfarlane 1984; Semmens et al. 1993).
Hingston (1997) reported that he has recorded B. terrestris in Tasmania as foraging on 65 species of native Tasmanian plants, in particular 17 Myrtaceae, 8 Fabaceae and 7 Epacridaceae, and he clearly views this with concern. Since the Tasmanian population originated just five years ago from perhaps only a single queen (Pomeroy et al. 1996), it is possible that the population he was studying was influenced by inbreeding and/or a phase or area where it is still expanding and therefore individuals are forced to take honey and nectar wherever they can. Hingston does not report any introduced plants that may have offered alternate sources of nectar and honey in the areas that he studied. These observations may be more of a reflection on the narrower habitat focus of his study. He also made particular mention of this species biting holes in the base of long-tubed flowers of Epacris impressa where it could not reach the nectar with its tongue, but failed to mention that Epacris spp. are normally bird-pollinated. Armstrong (1979) lists only Nomia spp. (Halictidae) as feeding on Epacridaceae under known pollen and nectar sources of Australian native bees. Hingston also quotes the paper by Dafni and Shmida (1996) claiming negative impact of B. terrestris on native bees in Israel as proof of a conflict; however, both Cnaani et al. (pers. comm.) and Griffiths (pers. comm.) commented independently that Dafni's methodology was seriously flawed. In his main study Dafni surveyed only one tree outside his laboratory window! As also claimed by Dafni and Shmida, both Israeli B. terrestris and the native Xylocopa spp. are known to nectar-rob, but the impact of this behaviour is not necessarily to the detriment of either the plant or other pollinators (see Section 2.3.3).
Apis mellifera. It is acknowledged that in part of its range, the honeybee is dependent on native flowering plants in Australia for pollen and nectar, and there has been some debate on the extent of competition with native bees. Braybrook (1983) noted that 80-90% of honey produced in Victoria is derived from floral resources on public lands, and that with continual land clearing in SA, National Parks were becoming the last refuge of floral resources for beekeepers. Despite this, Hamilton (1988) claimed that scientific evidence for competition between native bees and honeybees, or for damage to flowers by honeybees, is neither extensive nor rigorous. It is accepted that Apis and native bees share the same resources, but whether they compete, and if so, to what extent, remains uncertain. Manning (1997) adds further to the debate by criticising the methodology and conclusions of much of the previous published papers claiming a negative impact. He also points out that ants may eat nectar pre-dawn and no attention has been paid to their impact. Schwartz and Hurst (1997) also argue that the jury is still out on the subject of honey-bee/native bee competition. Present studies on bees at Rothamsted in the UK emphasise the need to be very careful with the way studies on bee-plant relationships are conducted because they can be very complex.
Megachile rotundata. This North American leafcutter bee was introduced from New Zealand with an application for further introductions from Canada to pollinate lucerne crops. It can also be used to pollinate other forage legume species such as clovers, milk vetch and birds-foot trefoil. It is the most important pollinator of lucerne in Canada, and increasing in importance worldwide. It does not pollinate native plants to any extent and so is not considered to compete with native bees.
Floral preferences of introduced bees in New Zealand
There are two introduced bee groups found in New Zealand; the honeybee, A. mellifera, and four Bombus spp.
Bombus spp. Donovan and Macfarlane (1984) provide a record of 419 flowering plant hosts for B. terrestris in New Zealand. More detailed information is in unpublished notes of flower visitations by over 35,000 bumblebees, collected between 1969 and 1990 (Macfarlane unpub. data) as part of field studies in eastern South Island and SW North Island (Macfarlane and Gurr 1995). Macfarlane gives the flower preferences and seasonal variation for feral B. terrestris and other bumblebee species found in New Zealand (Appendix 6). Seasonal variation in the species composition and abundance of bumblebees was found to occur from mid spring (October) onwards. These data were recorded from over 300 introduced species of flowering plants, and 53 species of a total of about 1,800 flowering native plant species. The relative flower usage of short-tongued B. terrestris declined as the season progressed compared with the long-tongued B. ruderatus and B. hortorum, increasing again as the populations of the smaller colonies of these bumblebees declined.
Gurr (1957) noted that differences in the availability of food sources in spring and summer also influenced the composition of the two bumblebee species in coastal Marlborough. During extensive studies on the biology and management of bumblebee colonies (Macfarlane et al. 1984, Macfarlane & Griffin unpublished), it was observed that gaps in food supply reduce the size of larval clumps that could result in the early demise of colonies. Conversely, colonies with an adequate sequence of food supply can grow rapidly and produce more new queens. Food stores in mature colonies during summer and autumn were found to strongly influence the survival of overwintered queens in spring prior to colony formation (Holm 1972).
Macfarlane's study confirms the dependence by bumblebees upon flowers of introduced plants for nectar and pollen requirements in New Zealand (Appendix 6). Australian plant species and Proteaceae have been marked in bold in the summary of flower visitations. Among the non-cultivated, introduced (Australian natives and Proteaceae) and New Zealand native flowering species, the study showed that the better nectar-secreting Proteaceae, notably the Australian Grevillea rosmarinifolia (red flowers), Dryandra formosa, and to a lesser extent Banksia species and the Chilean firebush (red flowers), are attractive to B. terrestris. For obvious reasons, this was not apparent in European literature on flower use by bumblebees. The record concerning red-flowered species is interesting as bumblebees cannot distinguish the colour red. B. terrestris also visits the white flowers of macadamia quite freely, and Hakea sericea rather reluctantly. The more important New Zealand native flowers used by B. terrestris are Fuchsia excorticata, Sophora microphylla, Meterosideros spp., Hebe spp. and Hoheria spp. Interestingly, although extensive records of native bees on Leptospermum (Myrtaceae) were obtained by Macfarlane (pers. comm.) and Donovan (pers. comm.), bumblebees do not appear to favour their flowers, even though they are an important source of honey in New Zealand.
Limited studies suggest, surprisingly given their colour, that the red flowering pohutukawa and two red flowering gum species are among the more attractive native flower sources for B. terrestris in New Zealand. It would appear that myrtaceous flowers with favourable nectar secretion are likely to be attractive to bumblebees, although the range used more intensively will be narrower than for the honeybee. It is unlikely that the Australian species of Leptospermum will be attractive to B. terrestris. Dark purplish and yellow flowered Pittosporum species are a quite valuable mid spring/early summer food source for honeybees in New Zealand, but these flowers have only been recorded as being used spasmodically by B. terrestris. The reasonably free use of the better purple flowering Hebe species in New Zealand by B. terrestris, and their preference for flowers with an uneven flower outline, suggest that any similar flowers in the Australian flora of the family Scrophulariaceae are also likely to be freely used. The blue flowers of Ceanothus are used to a moderate extent by bumblebees, although greater use is made of them by honeybees. The native matagouri, Discaria toumatou, is also well used by honeybees, as well as by native Lasioglossum and perhaps less frequently by bumblebees (Primack 1983, Macfarlane R.P. limited observations). Hence the better nectar-secreting Rhamnaceae in the Australian flora may be used to a moderate extent by the short-tongued B. terrestris.
The vast majority of bumblebees visiting the native myrtaceous and proteaceous flowers of New Zealand, Australia, and Chile, were B. terrestris. Kowhais, pohutukawa and ratas (Meterosideros spp.), puriri, Hebes and lacebark (Hoheria spp.) were also attractive to B. terrestris, while two B. terrestris were seen visiting flowers of the scrub weeds, kanuka and manuka (Leptospermum spp), but these species, and Pittosporum, were generally unattractive even when visits by honeybees, flies and beetles confirmed nectar was available.
Bumblebees see colour from ultraviolet through to orange, but not red. Red is an important colour on many flowers dominated by bird pollination. Deep, red flowers with low sugar concentrations like New Zealand flax, Phormium tenax, are hardly used by bumblebees though they are an important source for honeybees and are used by native Hyleaus bees. This might remove some of the concerns raised about competition between honey-eater birds and bumblebees.
From Macfarlane's study it might be concluded that the more important families of flowering plants for B. terrestris include Leguminosae (Fabaceae), Rosaceae, Proteaceae, Boraginaceae, Berberaceae, and perhaps less consistently Myrtaceae, Rhamnaceae, Salicaceae and Scrophulariaceae. Native flowers favoured by B. terrestris include Fuchsia excorticata, Sophora microphylla, Meterosideros spp., Hebe spp, and Hoheria spp. Foxglove and viper's bugloss are the most critical weeds that support the present populations of bumblebees in New Zealand.
Apis mellifera . Donovan (1980) stated that the honeybee probably has a greater floral range than any other species. This is driven by the needs of almost continuous breeding, and continuous adult activity, plus the drive to store surplus pollen and honey. A list of flowering plants visited by A. mellifera is given in Walsh (1978).
In summary, B. terrestris shows a distinct preference for non-native flowers. In the temperate areas in which it is likely to occur if it becomes feral, there is an abundance of such plants during the seasons (spring and early summer) in which it is actively foraging. The main competitor would likely be the honeybee, and both coexist across their natural range. The greatest threat to the survival of native bees is loss of native flowering plants through habitat loss, generally caused by land development and clearing.
One of the arguments against the introduction of Bombus terrestris (Dafni and Shmida 1996, Hingston 1997) is that as a short-tongued species it prefers shallow flowers, but has been known to rob nectar from flowers with long corollas by biting a hole in the base of the tube, thus circumventing the pollination process. Other bees such as the honeybee may use these holes secondarily. However, there are very few flowers of this nature in Australia (R. Worrall, pers. comm.), and most have evolved a relationship with bird pollinators such as honey eaters, which may still serve to pollinate the flower while looking for nectar legitimately, as may other bees and pollinators (Donovan 1980, Prys-Jones and Corbet 1991, Macfarlane, pers. comm.). The native Australian bee Xylocopa is also a nectar robber in the same fashion. Newton and Hill (1983) reported that in New Zealand, B. terrestris was found to nectar-rob field bean flowers but that this did not prejudice pod development nor pollination by other insects, similarly with seed set in red clover (Hawkins 1961, Gurr 1975).
It is often overlooked in the debate about the impact of various bees on native plants that Australia possesses a diverse pollen-vector fauna (Armstrong 1979) including other insects (moths, butterflies, beetles, flies, thrips, wasps), birds, flying foxes, bats and marsupials.
Bumblebees. Dr van Doorn (Koppert) and Dr Donovan (NZ) both stated that bumblebees have a requirement for dry cavities with at least some fibre. They also require drainage for faeces and ventilation (Donovan and Weir 1978). According to information provided by Koppert BV, 'bumblebee queens usually search for existing cavities as their nesting place-cavities that are large enough, or can be made large enough, to accommodate an entire colony. Bumblebee nests can be found in former mouse nests, between stones or twigs, in compost heaps or dense tussocks of grass, or in hollow trees. Sometimes they can be found closer to home: in cavity walls or sheds'. Bombus terrestris in Europe and New Zealand shows a preference for abandoned mouse nests; however, they also occurred on at least one island off New Zealand where there were no rodents (Macfarlane and Gurr 1995).
Australian native bees. Most Australian bees are solitary, with the female making her own nest without the cooperation of others. In these species there are no separate queen and worker castes. The female lays an egg in each cell of the nest and before sealing it provides the egg with pollen and honey; the adult female generally dies before her progeny reach maturity and emerge from the nest. Australian native bee species in the families Apidae, Colletidae, Stenotritidae, Halictidae, Ctenoplectridae, Megachilidae and Anthophoridae have a range of nesting habits, summarized in Table 1.
New Zealand native bees Donovan (1980) reports that Colletinae excavate in bare and semi-bare ground free of excess moisture, and in a substrate that lends itself to excavation. Most known nest sites of the majority of species have been made from the activities of man. Only a single nest site of Euryglossinae has been found in the tunnels of the house borer beetle Anobium punctatum. Nests of Hyaelinae have been found in insect galls in Meuhlenbeckia sp., in stems of Lupinus sp., Linaria sp., and Digitalis purpurea, and in grooved board nest holes of the lucerne leafcutting bee Megachile rotundata. In the Halictidae, the majority of Lasioglossum sordidum nest in fine-grained bare soil maintained by man's activities.
Introduced bees Apis mellifera nests in boxes provided by beekeepers, or, when feral, in hollow trees or rock crevices. In New Zealand, natural nest sites are commonly hollow trees, and to a lesser extent, hollows in rock formations. Cabbage trees (Cordyline australis), white pine (Dacrycarpus dacrydioides), and willows (Salix spp.) are frequently used.
Table 1. Nesting preferences of Australian native bees.
|
Nesting habit |
Bee families |
|
Ground nesting |
Colletinae (mostly), Euryglossinae (mostly), Hylaeinae (some), Stenotritidae (all excavate), Halictinae (most excavate), Nomiinae (mostly), Anthophorinae (mostly excavate), Megachilinae (pre-formed and excavated). |
|
Dead/rotting wood |
Colletinae (some), Euryglossinae (some), Halictinae (some excavate), Nomiinae (some), Megachilinae (some pre-formed and excavated), Xylocopinae (some pre-formed and excavated). |
|
Pithy stems |
Hylaeinae (common), Xylocopinae (mostly pre-formed and excavated). |
|
Pre-formed wood cavities |
Ctenoplectridae (related to the single Australian native species), Meliponinae (mostly). |
|
Insect borer holes |
Hylaeinae (common). |
|
Cleptoplectic |
Nomadinae (single genus on ground-nesting halictines or other species), Anthophorinae (Thyraeus on Amegilla (Anthophorinae), Xylocopinae (Inquiline on Exoneura (Xylocopinae), Megachilinae (Coeloxys on Megachile). |
|
Exposed on rocks or plants |
Megachilinae (some). |
|
Rock crevices |
Meliponinae (some). |
Bombus species. Of 28 naturally occurring nests studied by Donovan and Weir (1978), 50% were in abandoned rodent nests. Mature nests may reach 30 cm across by 12 cm high (Macfarlane 1976, Donovan and Weir 1978). They do not compete with native bees, most of which excavate in bare soil and make use of plant stems for nest sites.
2.3.5 Potential for habitat competition with native bees and honeybees.
Amongst the large amount of information accessed for this response, in particular on the issue of competitiveness with native bees, the detailed study on the interactions between native and introduced bees in New Zealand (Donovan 1980) provides the clearest objective comparison of the interrelationships of these bee groups in nature. It also offers an insight into an expected outcome should bumblebees be introduced into Australia. Kukuk (pers. comm.) suggested that New Zealand data could not be relied upon for a comparison with Australia as it had different weather and plant communities. Although there are few countries that have the diverse range of climatic conditions found in Australia, there are enough climatic similarities between New Zealand and large parts of Australia for this comparison to be valid and quite useful to this submission. Moreover, while some species of Bombus are found in warmer climatic regions, B. terrestris is found naturally in warm and cool temperate zones and would likely be restricted to regions with climatic conditions similar to those found in New Zealand.
Donovan (1980) concluded that while all bees exploit similar resources such as nest sites, pollen and nectar, the wide differences in the specific requirements among almost all bee species indicated that there was very little or no competition between native and introduced species for this resource except a slight overlap between large Hyaelinae and introduced Megachilinae. Donovan (pers. comm.) recently reaffirmed this conclusion, saying that native bees were competing very successfully, and that human actions had far more effect (many beneficial) on native bees than possible competition from introduced bees. Bumblebees are not aggressive, even when sharing flowers, unlike native bee species such as Trigona and several bird pollinators who defend favoured resources.
Corbet (1996) and others have pointed out that honeybees (and many native bees) can tolerate heat better than bumblebees so can forage in the hottest parts of the day when bumblebees are inactive. Moreover, Bombus are most active in the cooler seasons of spring and early summer, whereas honeybees are active all year round, Halictidae from September to May (spring to autumn) and Megachilidae summer to early autumn.
Donovan (1980) believed that competition from bumblebees was probably minimal because of their generally low numbers compared with honeybees, and their preference for flowers other than those visited by native bees. Some degree of specialisation for different flowers by most bee species, and the coincidence of peak numbers of most native bee species with abundant pollen and nectar production, further reduces the chance of competition for these resources between native and introduced bees. Bombus terrestris has an obvious preference for introduced flowers with data from New Zealand and Tasmania supporting a claim of a 9:1 ratio for introduced and native flowering plants (Semmens 1996). Extensive records of flower visitations involving more than 35,000 bumblebee observations collected between 1969-1990 (Macfarlane unpublished data) provide strong evidence of this claim. Native bees, on the other hand, have an obvious and strong linkage with native flora, particularly the family Myrtaceae, although other families are utilised e.g. Asteraceae, Leguminaceae, Campanulaceae and Compositae. Donovan (1980) makes the observation that native bees in New Zealand outnumber both honeybees and bumblebees on many native and introduced flowers in New Zealand after about 140 years of contact, so are clearly competing successfully. In a study of North American bumblebee species, Pyke (1982) found that in a stable community there was only one each of a short, medium and long-tongued species and in some cases a short-tongued nectar robber so that resource competition was minimized.
As outlined in Section 2.3.4, an analysis of nesting site requirements of Australian and New Zealand native bees demonstrates not only the diversity of needs, but more importantly the difference between the nesting requirements of bumblebees and those of native bee species. Donovan (1980) concluded that while basic data on many native bee species are scarce, wide differences in nest site requirements suggest that competition for this resource does not occur. Pyke and Balzer (1985), while examining the effect of honeybees on Australian native bees, stated that studies done outside Australia have found that nest sites did not limit the abundance of native bees.
Aside from competition with other bees, Paton (1997) argues that there may be interference with honey-eater birds. Again, this supposes that resources are limited and non-renewable. Bird-pollinated flowers are often red, which is not a colour seen by bumblebees.
2.4. Details of previous introductions, and the results.
Unsuccessful attempts to introduce Bombus into Australia were made in the early 1890's, and 1912 (Froggatt 1891, 1892, 1912) and again in the 1930's in Victoria (Rayment 1935) . In October 1891, releases of small numbers were made in parts of Sydney, Maitland, Kiama, Bodalla, Bathurst and Tenterfield, although autumn was the preferred time of year for this exercise. Sixty bees were imported at that time. In January 1892, they were thought to have established at Bodalla. Further releases were made in September 1892 in the 'Garden Palace grounds', although many were dead on arrival. In three boxes, 17, 7 and 10 were alive from 22, 42 and 40 shipped respectively. In 1912, it was reported that the NSW Department of Agriculture had imported bumblebees on several occasions from New Zealand, but though every care was taken in releasing them, and trying to establish them in suitable localities, not a single specimen was found a week after release in Cooma and Glen Innes. Rayment (1935) postulated that the solitary nature of establishment queens, their large size and comparatively slow flight making them easy prey for birds, and probably contributed to their failure to establish in this country during that period. However, accidental or subversive introduction of B. terrestris into Tasmania has led to its establishment and discovery in 1992 (Semmens et al. 1993). To date it hasn't been recorded outside of Tasmania on mainland Australia.
2.5. Importation of B. terrestris by other countries, and any problems experienced with release and pest populations.
Examples of approval to import B. terrestris into countries where the species previously didn’t exist include New Zealand, Japan, Iceland, South Africa and Finland. The experiences of Japan are worth particular attention, and considerable effort has been taken to provide accurate information on this example. Reasons for a decision not to import B. terrestris into North America are also given.
New Zealand Bumblebees were first successfully introduced into New Zealand in 1885 after four attempts (Macfarlane and Gurr 1995), with the release of two species. A further release was made in 1906. Overall, it would seem that at least six species were introduced; however, only four species ( B. terrestris, B. hortorum, B. ruderatus and B. subterraneus) appear to have established and have since been recorded (Gurr 1964). New Zealand is now a bumblebee exporting nation.
South Africa A permit to import a limited number of B. terrestris into South Africa was granted in 1996 to a grower group. A number of local academics expressed concern about the importations and had them stopped after two shipments. The government is still trying to arrive at a policy.
Japan Perhaps the most appropriate example of a recent introduction of a non-native bumblebee species was the approval to introduce B. terrestris, which was not previously present, into Japan. Given the well-known protectionist attitude of MAFF in that country, it probably surprised most people when approval was given.
Authoritative information has been obtained from sources within Japan involved in the preparation of the submission to import B. terrestris, and independently from a bumblebee exporting company in The Netherlands. The following information was provided by Mr T. Wada, IPM and Biological Pollination specialist, Tomen Corporation, Tokyo, Japan. It contains some commercially sensitive information, and it is requested that it not be divulged.
There are 14 Bombus species endemic to Japan; B. terrestris is not one of them. Prior to 1992, when importations began, B. terrestris was not recorded in Japan. Currently 20,000 to 30,000 colonies are imported from nine companies in five countries (The Netherlands, Belgium, France, England and New Zealand) to supply the needs of tomato growers (commercially sensitive information and not to be distributed).
Bombus terrestris has been imported to the island of Hokkaido over the past five years and has become established outside greenhouses. There has been no visible impact on the ecosystem on Hokkaido caused by the introduction of this bumblebee species. Japanese ecologists claim that Apis mellifera has a more significant impact on native bee ecology, and it is concluded that any B. terrestris influence is much less, if any at all.
The question of the potential for ecological impact was put to two Japanese bee specialists, Dr M. Matsuura, Mie University, and Dr F. Ikeda, Shizuoka Prefecture Agriculture Experimental Station, who were initially involved in the preparation of the submission to import B. terrestris into Japan. Dr Matsuura commented that any release anywhere would have some impact on the ecology of the release environment, but it is a matter of whether this effect is significant or not. For many years Japanese scientists had seen many releases of insects in many areas of the world, and while not all were harmless, 99% did not lead to any negative effects on the environment. This risk was weighed up against the potential benefits to the economy.
There has been no reported competition between B. terrestris and A. mellifera, and no decline in the population of the latter species over the five years since the introduction of B. terrestris into Japan.
Japanese scientists have been undertaking rearing experiments over the past four years with the endemic Bombus species, B. ignitus, B. hypocrita hypocrita and B. hypocrita sapporoensis. They have found them to be very difficult to compete with B. terrestris in rearing efficiency, and there are presently no plans for commercial production.
Japanese tomato growers are benefiting financially from the use of B. terrestris for pollination. MAFF, Japan, supported the introduction of B. terrestris because of strong claims made on the basis of economic benefit. For this reason importation of B. terrestris will continue.
Dr Adriaan van Doorn, Head of Pollination R&D, Koppert Biological Systems, The Netherlands, has also consented to provide information from his company's experience in obtaining approval for the importation of B. terrestris into Japan. Dr van Doorn stated that Japanese tomato growers applied pressure on MAFF for the introduction and release of B. terrestris at the earliest available date. He reported that the major quarantine concerns of the Japanese MAFF were the transfer of parasites and pathogens, the possibility of the bees establishment in the field, and the potential for competition with native bee species. However, in the end approval was quite rapid. It transpired that Japanese bumblebee researchers and advisers had given up their equivocation, on the one hand because they estimated the risks to be low, and on the other hand because it had become clear that there was not (yet) a Japanese alternative available. From consultations with many bumblebee researchers it was learned by both the authorities and Koppert that breeding of Japanese bumblebee species was not very advanced, and that most species wouldn’t be suitable anyway because they were pocketmakers and breeding of these species had not been very successful to that point. On that basis they supported the importation of B. terrestris.
There has been subsequent concern expressed by some Japanese researchers, some of whom had been involved in the original discussions on the importation of B. terrestris, about its establishment on Hokkaido. There have been no visible impacts on the Japanese ecosystem despite it having become established on Hokkaido. Wada (pers. comm.) said that its establishment was not a surprise. There were complaints from a plant ecologist, Dr Washitani, that her research on Primula japonica might be affected by this establishment, however there is no evidence of any adverse impact. Wada (pers. comm.) explained that the basis for her complaint was that the short-tongued B. terrestris would displace the longer-tongued B. diversus which she insisted was the ONLY pollinator of this plant. Wada disputed the claim that B. diversus could be the only native pollinator of P. japonica, and a study by Hokkaido University subsequently found that there were a number of other native bees, both solitary and Bombus species, which visit this plant. Several entomologists claim that A. mellifera has more influence on the ecology of native bee species than B. terrestris. Dr van Doorn believes it improbable that B. terrestris will ever become a problem for native bumblebee species in Japan. At the moment the discussion is focussing on the likely impact on the native species B. diversus on Hokkaido. Dr van Doorn said that this species differs from B. terrestris both in its floral and nesting site preferences, and he does not see any possibility of competition.
North America A request to import the non-native B. terrestris into North America was declined by the regulatory authorities. Circumstances in these countries were different from those in Japan. There was already quite a lot of experience with breeding of several North American species. In fact, Dr Chris Plowright in Canada had already started to commercially rear B. impatiens (later taken over by Koppert). In North America, the discussion focussed on the differences in bumblebee fauna between the eastern and the western part of the continent. It was decided that commercial breeding of B. impatiens would be permitted on the eastern side of the Rockies, and that B. occidentalis would be separately reared on the western side in California. However, since the initial decision was taken, regulations have been relaxed and another bumblebee rearing company, BioBest of Belgium, has obtained a permit to breed both species in the one location in Canada. The rearing efficiency of both these species is comparable with B. terrestris, unlike the situation between Japanese native bumblebee species and B. terrestris.
Nowadays, B. terrestris is used in every European country and in Russia and many other former USSR States, plus some North African countries such as Morocco. However, it should be noted that B. terrestris naturally occurs in most of these countries, though sometimes only in certain areas. Only Israel and New Zealand require local commercial breeding operations for B. terrestris. All other countries that make use of commercially-reared B. terrestris allow their importation from other countries.
2.6. Comparison with the methods and effectiveness of chemical pollination and details on the environmental effects of chemical pollination.
As far as we are aware, in Australia the only aid to pollination is in protected tomatoes where mechanical pollination by electric vibrator is used. Overseas, plant hormone preparations such as Tomatone and NAA are used in some crops. Both have been superseded by bumblebees in all countries where they are commercially available. There are currently approximately 25 different crops pollinated by B. terrestris in over 30 countries, with about 250,000 commercial nesting boxes produced annually (Griffiths & Robberts 1996). Koppert BV of The Netherlands, one of the largest suppliers of commercial bumblebees, lists recommendations for use of bumblebees in 25 different crops (see http://www.koppert.nl/english/pol.htm for details).
There is unequivocal evidence that the introduction of bumblebee pollination technology has greatly benefited production in many horticultural crops. Most notable of these successes has been in greenhouse tomatoes, where pollination needs to be assisted because pollen does not loosen easily from the stamens. In North America, less than four years ago most tomato growers had hardly heard of the success of bumblebees in European crops, yet today most growers in the US and Canada are using them for pollination of their crops. One of the largest greenhouse tomato growers in Australia, Eden Farms in Queensland, has 2.8 ha of production. Time taken to pollinate this area using the 'Electric Bee' has been calculated to take up to 3,360 hours per annum, which represents a considerable cost to the grower, and time away from other pressing duties.
Articles from three overseas trade journals providing supporting information on this issue are provided (Appendix 3). In one of these articles, The Zuider Zee Nursery in The Netherlands demonstrated the clear benefits of this biological approach to pollination. It previously employed the 'electric bee' on 22 acres of greenhouse tomatoes. The pollination process took 140 hours per week. It now uses bumblebees for pollination instead. Besides the obvious savings in labour costs, estimated at $26,000/ha/year in The Netherlands, the farm also has benefited from improved yields. Further evidence of the labour saving benefits of using biological pollination is demonstrated in the second article. Additionally, Chapter 4 ' Bumblebees as pollinators of glasshouse crops ', by Don Griffiths and Evert Jan Robberts, from a 1996 Symposium of the International Bee Research Association entitled 'Bumblebees for Pleasure and Profit' (Appendix 4), and a Technical File on Pollination of Strawberries, by BioBest Biological Systems (Appendix 5), provide considerable detail on crop pollination using bumblebees.
3. Other issues relevant to the importation proposal.
3.1. Issues raised by the scientific community for and against the proposal.
Extensive information was provided by Dr Rod Macfarlane, Canterbury, New Zealand in support of the introduction. Dr Macfarlane is a widely published, world renowned expert on bumblebees and crop pollination. His expertise covers areas such as management of bumblebees in field crops, identification and control of their natural enemies, implementation of commercial use in field crops, commercial rearing methods, ecology and bee-flower relationships. He provided a wealth of both published and unpublished information, the latter including perhaps the most comprehensive study of Bombus-flower relationships in New Zealand.
In his summary (Appendix 2), he states that 'B. terrestris should be of considerable value in field crop pollination in Australia in addition to its importance in glasshouse pollination of tomatoes and to plant breeders in screen cages....slight risks are identified in nectar and pollen depletion where areas are unusually bereft of honeybees. This may have a minor impact on native bee pollinators and some Australian nectar feeding birds....Overall, the proposal to import B. terrestris to mainland Australia is sound and economically worthwhile.'
Dr James Cane, Auburn University, Alabama, USA, opposed the introduction, suggesting that native bee species such as Exoneura or Xylocopa should be developed for pollination purposes instead. Dr Cane has worked with North American native bumblebees in a limited range of crops, and spent three months in WA looking at native bees. He based his concern on the risk that if B. terrestris went feral they could displace native bees through exploitive competition for pollen (in fact bumblebees generally seek nectar and only incidentally collect pollen). His concerns were based on the future of the sandplain heaths of WA, 'already under siege from massive incursions of agriculture, a $24 million cut-wildflower trade, fire suppression, rabbits, feral cats, habitat fragmentation and introduced honeybees'. In separate correspondence, Dr Cane reiterated his opposition because he believes the polylectic behaviour of bumblebees would compete with native bee species for floral and nectar resources of native plants.
Dr Penelope Kukuk, University of Montana, USA, opposed the introduction on the grounds that the Australian bee fauna is unique and should be valued and protected. She says that ‘any introduction of Bombus in Australia would have a very different effect than it had in New Zealand for a vast number of reasons including differences in weather, plant community composition and the like. In addition there are many native bee species that can be reared in captivity (and are now for research purposes) that would function very well in greenhouse situations.’ She said that she would like to see these species exploited for use in Australia so that the potential for disruptive impact on the native fauna is minimised. She also stated that 'many prominent plant species are known to be adversely affected by honeybee visits'.
Dr Katja Hogendoorn, postdoctorate from The Netherlands at Flinders University, opposed the introduction on the basis that it would lead to several problems concerning native bees. Recently she contributed to a joint submission with Dr Schwarz of Flinders University and A. Hingston of the University of Tasmania. The submission raised several concerns: Bombus spp. becoming feral, competition with native fauna, both vertebrate and invertebrate, negative effects on native pollination, nectar robbing habits, potential spread of pathogens and parasites, and alternative pollination mechanisms, including the use of native carpenter bees. These issues are discussed and dealt with under appropriate sections of this proposal; however, we would like to note here that no scientific references were provided to back up any of the contentions except that relating to bumblebee parasites and pathogens. In separate correspondence Dr Hogendoorn referred to a preliminary study she is undertaking on the ability of the carpenter bee Lestis sp. to forage in and pollinate tomatoes. While she claims to have obtained some promising results, she admits to being a long way off commercially rearing these bees. In particular she has not yet made any progress in getting the bees to mate in captivity, nor in encouraging them to be active at the time tomatoes need to be pollinated.
Dr Madeleine Beekman, The Netherlands, opposed the introduction, drawing a comparison with the experience with A. mellifera and citing the ‘debate’ going on in Australia about the impact of the introduced honeybee on wild/native bee species. She says the debate has revealed ‘possible negative effects’ of the presence of the honeybee on native bees in Australia. She would also not consider supporting B. terrestris introductions until it had been shown to be unable to establish outside the greenhouse.
Roger Buttermore, Tasmanian Museum, reported that an HRDC study on the Tasmanian population (HRDC Project HG 631) had confirmed that it was very inbred. Ray Hart, Tasmanian DPI, (pers. comm.) reported that it had probably originated from a single queen.
Dr Chris Plowright, a recently retired bumblebee researcher and breeder in Ottawa, Canada, noted that the most contentious precedent involving greenhouse importation of B. terrestris into other jurisdictions was that into Japan, with the discussion on his BOMBUS listserver mainly focused on the possible impact on resident bumblebee species. He was not aware of any problems relating to transfer of pathogens or pests with shipments into new areas, but advised extremely careful quarantine and inspection procedures should be in place if the application is approved, and recommended New Zealand as a source of the cleanest bees. He favoured rapid approval of the introduction on the grounds that there are no native bumblebee species with which to interact, that the New Zealand population likely to provide a source is clean, and that it is questionable that escapees would be able to survive in the wild.
Dr Barry Donovan, New Zealand, supported the introduction on the basis that he believes that it is inevitable that B. terrestris will reach the mainland, and preferable to introduce 'clean' bees from New Zealand rather than risk some enterprising grower taking over mite or pathogen-infected ones. He says that if there was concern about the effect of introduced bees on the environment, then surely the first step would be to eliminate honeybees, admitting that this was not possible. He suggested that it was entirely likely that bumblebees would establish in the wild if introduced, but that there had never been any suggestion that the native New Zealand environment had suffered from the introduction of bumblebees, though subtle effects may have been missed.
Dr Allan Spessa, formerly postgraduate at ANU, rang to express an objection on behalf of a group including Dr Hogendoorn (see above), Dr Michael Schwarz, Flinders University (his postgraduate supervisor) and Andrew Hingston, postgraduate student at the University of Tasmania. He supported the development of solitary native bees such as Xylocopa sp.
Dr Suzanne Batra, Bee Research Laboratory, Beltsville, Maryland, USA, wrote to support the development of solitary native bees for pollination purposes, while not opposing the introduction of Bombus. She was very supportive of the use of bees to aid crop pollination, mentioning that she had imported Osmia conformis and Anthophora pilipes from Japan for orchard use in the US. This was achieved following the usual precedents and procedures involving the importation of exotic solitary bees for pollination.
Dr Terry Houston, Western Australian Museum, suggested the common blue-banded-bee, Amegilla pulchra as a native buzz pollinator. He also advised caution against introducing bumblebees without a thorough environmental impact assessment.
Mr Tetsuo Wada, Biological Control Specialist, Tomen Corporation, Tokyo, Japan, reported on the situation relating to the approval to import B. terrestris into Japan (see Section 2.5). He believes importing B. terrestris into Australia would be beneficial.
Jonathan Cnaani, Amit Einav and Dan Weil (Pollination Services, Yad-Mordechai, Israel), wrote to say that Israel is the world's southernmost border for the distribution of natural populations of B. terrestris, although they were not reported in Israel before the 1940's. They are continuing to spread south, possibly because of the expansion of settlements with non-native plants. Commercial colonies have been reared and used in greenhouses since 1992. There is a possibility that the population may differ from the European one so imports from outside Israel are not permitted (information supplied by Dr Don Griffiths contradicts this). Also, Israeli bees are claimed to be free of any known parasites and diseases, so they do not want them contaminated. They are used in tomato (mostly), green pepper and strawberry crops.
The area where the bees are used in greenhouses is south of the natural distribution and is warm and arid. So far there is no evidence that escaped queens have established in the wild in such areas, and they do not think that they could do so.
There are at least 1,000 species of solitary bees in Israel; none has been commercialised.
Dr Mike Allsop, Honeybee Research Section, Protection Research Institute, Research Council, Stellenbosch, South Africa, commented on the recent importation of B. terrestris into South Africa. In the South African context, he believed growers should have tried honeybees first, then local bees, then if neither worked, a strictly controlled trial with Bombus, then a comprehensive environmental assessment, and then the importation opened for public and scientific debate.
Dr Adriaan van Doorn, Head, R&D-pollination, Koppert BV, The Netherlands, doubted that there would be any extinction of native bee species in Australia since B. terrestris is a generalist feeder. He did not believe native bees offered an alternative to bumblebees because they are difficult to rear, especially in confined areas, and not available all year. He stated that native bees would not be suitable hosts to bumblebee parasites and diseases because of their deviating biology. Regarding the situation in Japan, he understood the main concern was the potential impact on native Bombus diversus, but as this species differed both in nesting site and flower preferences, he could not see any relationship. Despite efforts to breed Japanese species, 'the results still are very meagre'. Concerning other possible pollinators in Australia, like Xylocopa, he believed it would be very difficult to find pollinators that would work in the same range of crops as B. terrestris, and not economically feasible to try to find different ones for different crops. Other comments concerning the use of native pollinators are considered under Section 3.1.3.
Dr Don Griffiths, formerly technical director to Bunting Brinkman Bees Ltd., The Netherlands (a major producer/supplier) and now a consultant to them, provided information on the Israeli situation. According to information supplied to him, a Turkish strain of B. terrestris from The Netherlands was brought into the country in about 1991 by a commercial producer and may also have been released into the wild. This strain is distinct from the indigenous one, which was first recorded in 1930 in the mountains of the Upper Galilee. In 1981 the latter strain was recorded on Mount Carmel and it is now found as far south as Tel Aviv and Jerusalem. Dafni and Shmida's study (1996), claiming negative effects on the native bee fauna, relates to this indigenous strain. Dr Griffiths was present at the meeting where this paper was presented and states that he was 'singularly unimpressed with Dafni's methodology' and openly criticised it at the time.
Dr Griffiths stated that it is possible to ensure that new queens would not develop during commercial use of managed hives but that this would be more expensive.
3.1.1 Chances of establishment of a feral population of B. terrestris once introduced.
Several previous attempts at establishing B. terrestris in Australia are recorded (Froggatt 1891, 1892, 1912, Rayment 1935). None was successful. Queens were released in different climatic zones including coastal NSW, tablelands NSW, NSW/ Qld border, southern highlands NSW, and Victoria. It is difficult to understand why there was a complete failure; however, from that it can be argued that this species will not readily establish in the wild, although the Tasmanian experience demonstrates that this is not impossible. Predation by native birds, rodents and ants, starvation or heat stress are some possibilities.
It should be noted that the aim of this submission is not to release bumblebees for establishment in the wild, but for growers to be able to buy, as needed, a commercial product with limited shelf life, subject to stringent quality control procedures. The bees come already established in special boxes, one colony per box. Each nest contains about 50 bees (one queen and the rest workers), which build up to about 300 before undergoing decline and eventual termination. After 8-12 weeks the nesting boxes are replaced with fresh ones from the supplier. Boxes are generally replaced before new queens are produced, lessening the chances of release into non-target areas. The nests provide reproductive sites and nutrition. They are entirely self-supporting and the bees can be shut in during adverse crop conditions such as during pesticide application. Growers can control the activities of the bumblebees in this way. The bees relate to the nesting boxes and return there every day after pollen and nectar collection is completed.
While it is not the intention to establish feral populations, it is anticipated that improper use or accident could result in bumblebees establishing in the wild. Should this occur, it is likely, given the known distribution of B. terrestris elsewhere, that the species would only persist in temperate zones without extremes of summer heat and in higher rainfall areas along the coast. In these areas there is an abundance of preferred introduced flowering plants. Macfarlane (pers. comm.) is of the view that B. terrestris could establish in parts of south east Australia and productive areas of Western Australia, based on its known distribution in Europe, Northern Africa, and parts of the Middle East through to about Moscow and the Caucus Mountains. Van Doorn (pers. comm.) also supports the view that it might be possible for establishment to occur in selected areas; however he doubts that this will lead to a problem for native bee species. Macfarlane (pers. comm.) stated that a lack of accurate mapping of its distribution in North Africa and Iraq make it difficult to be precise about the rainfall and upper temperature limitations that would prevent its northern and western spread in Australia. However, he believes that climates with between 200-250 mm of rainfall per annum would probably prevent the colonisation of B. terrestris. Consistent summer temperatures much over 30oC also pose a problem, because even in underground nest sites it becomes impossible for the colony to remain cool enough. Bumblebee wax melts at not much above this temperature. Adults can only fan and they do not bring water to the colony for evaporation, unlike honeybees. If the wax/pollen mix melts, and the larvae become more than slightly exposed, the workers discard the larvae and so new queen and male production becomes impossible, and only colonies started early enough in the season avoid this problem. In summer, the first generation of bumblebee queens are believed to aestivate for about 4-6 weeks before a modest second generation is attempted for mid-January to March. Queens in aestivation can probably resist summer temperatures up to about 35-40oC , provided they do not fly. At around 40oC any bumblebee that flies very rapidly dies unless it is a tropical species. Hence B. terrestris would not be expected to colonise much of coastal Queensland. Pyke (1982) stated that for North American species, they were only successful where the flowering season was more than 9-10 weeks (length of the life cycle).
Fire adds another dimension to the possible survival of feral colonies of bumblebees in Australia, possibly unique across their range. We were unable to find any studies relating to its possible effects or any competitive advantage that native bees might have. It is highly likely that natural bush fire phenomena, and man's hazard reduction burning, particularly the latter, could have a serious negative impact on nesting sites and populations of bee species in general.
3.1.2. The risks of introducing parasites and pathogens harmful to native bees and the honeybee, A. mellifera.
The risks of introducing pathogen and parasite problems with bumblebees was considered non-existent among respondents (Wada pers. comm., van Doorn pers. comm.), because there were no native bumblebees in Australia, and other native bees would be unsuitable hosts because of the differences in their biology. The leafcutter bee Megachile rotundata was subjected to rigorous tests for pathogens and parasites before introduction was approved. The same would be expected of B. terrestris nuclear material before establishing breeding colonies in Australia.
Macfarlane et al. (1995) reviewed bumblebee pathogens and internal enemies and summarised the records, distribution, incidence, impact and symptoms of viruses, bacteria, fungi, protozoa, nematodes, mites, conopids, sarcophagids and braconids found in bumblebees.
The following table summarises information from Macfarlane et al. (1995), De Wael et al. (1993), and Lipa and Triggiani (1992).
Table 2. Pathogens and parasites affecting bumblebees and native and introduced bees.
|
Type of pathogen/ parasite |
Specific organism |
Affects Bombus spp. |
Affects B. terrestris |
Affects Apis mellifera |
Affects solitary bees |
|
Viruses |
acute bee paralysis virus |
Yes, in US |
Not recorded |
Yes |
Not recorded |
|
|
entomopoxvirus |
Yes, in US |
Not recorded |
Not recorded |
Not recorded |
|
Spiro-plasmas |
Spiroplasma melliferum |
Yes, in US, pathogenicity unknown |
Not recorded |
Yes, causes pollen intoxication or May disease |
Recovered from solitary bees in the northern hemisphere |
|
Bacteria |
Various |
Yes, rarely associated with disease |
Not recorded |
Foulbrood, not recorded in bumblebees |
Not recorded |
|
Fungi |
Various, most have a wide host range and are not specific to bees |
1Yes, mainly Paecilomyces farinosus, Metarhizium anisopliae, Verticilium lecanii and Hirsutella |
Yes |
Not recorded |
Not recorded |
|
Yeasts |
Candida spp. |
Yes, in honey, low incidence |
Yes? |
Yes? |
Unlikely as affects stored honey |
|
Protozoa |
Apicystis bombi (sporozoan) |
Yes, in Canada, France, Finland, Italy and Switzerland |
Yes, not present in New Zealand, Israel or Japan |
Yes |
Not recorded |
|
|
Nosema bombi (microsporidian) |
Yes, in Europe, North America and New Zealand |
Yes, in Europe and New Zealand |
No, Nosema apis only, a different species |
Not recorded |
|
|
Crithidia bombi (trypanosomatid) |
Yes, in Europe |
Yes, in Europe |
Not recorded |
Not recorded |
|
|
Neogregarine |
Yes, in Europe |
Yes, in Europe |
Yes, in Europe |
Not recorded |
|
Nematodes |
Sphaerularia bombi |
Yes, in Europe, New Zealand and North America |
Yes, in Europe and New Zealand (restricted) |
Not recorded |
Not recorded |
|
Mites (tracheal) |
Locustacurus (Bombacarus) buchneri |
Yes, in Europe, North America and New Zealand |
Yes, in Europe |
Not recorded |
Not recorded |
|
Conopid flies |
Various species |
Yes, in Europe, North America and Japan |
Probably, not in New Zealand |
Yes, some species of conopids |
Yes, some species of conopids |
|
Sarcophagid flies |
Various species |
Yes, in North America and Europe |
Yes, in Europe, not in New Zealand |
Yes, in Europe |
Not recorded |
|
Braconid wasps |
Various species |
Yes, in North America |
Yes, in Europe, not in New Zealand |
Not recorded |
Not recorded |
|
Eulophid wasps |
Melittobia acasta |
Yes, in Europe |
Yes, in Europe |
Yes, in Europe |
Possibly, attacks range of bees and wasps |
1. Common entomopathogens used by growers to control various insect pests. Some of these naturally occur in Australia.
In general, far fewer pathogens and parasites are reported from Bombus species than the relatively domesticated honeybee. The major diseases of honeybees, such as internal mites (Varroa and Acarpis), bacterial foulbroods, honeybee viral sac broods, and fungi (Ascosphaera) have no widespread or common equivalents in bumblebees. They share some viruses, a restricted range of protozoa, and some parasitic flies, but not fungi and mites. The risks to Australian native bees would appear to be negligible. Macfarlane et al. (1995) state that 'nothing can be done about either the pathogens or internal enemies of bumblebees apart from devising sensible procedures to minimize the risks of spreading....to new countries or within continents'. For this reason we support controlled introduction from countries with the fewest problems and strict quarantine of individuals before release into breeding colonies.
Donovan (1990), in discussing selection and importation of new pollinators to New Zealand, recommends (i) transporting inspected larvae or adult bees free of their nests (ii) dipping pre-pupae in bactericide to remove surface contamination (iii) transporting young queens collected in fall instead of spring to avoid nematode infestation in queens during overwintering.
3.1.3. Possibility and implications of natural or illegal entry onto mainland Australia.
Besides the discussion about the pros and cons of the submission, the prospect that B. terrestris might find its way onto the Australian mainland regardless should also be considered. This point is raised by some of the scientists responding to the Internet discussion on this topic (Donovan pers. comm., Plowright pers. comm.). It is a possibility that B. terrestris could arrive either under its own steam or by illegal introduction. The distance between Tasmania and the mainland is not prohibitive for this species. There is evidence of regular mass migration of B. terrestris which demonstrates its ability to travel over large distances. Regular spring migrations of unmated Bombus queens along coastal routes in Europe were recorded annually in 1975-77 (Mikkola 1978), and again Bombus were recorded coming from the sea on to land in northern France, in southerly mass flights on theYorkshire coast of England, also flying along the Cumberland coast across 23 miles of sea at heights of up to 60 feet, and in southern Sweden (Johnson 1969).
Clearly the distance between Tasmania and the mainland, with islands at accessible distances, is unlikely to be an impediment to natural dispersal of this species of bumblebee. Donovan (pers. comm.) believes that this will happen. Macfarlane (pers. comm.) also considers that there is a strong likelihood that B. terrestris will spread naturally to the mainland. Besides this natural dispersal, there is a good chance of illegal importation and release by impatient tomato growers who would wish to enjoy the obvious benefits of bumblebee pollination of their crops. The latter was raised as a real prospect and concern by both Donovan and Plowright (pers. comm.). The fact that the horticultural industry in Australia is anxiously awaiting the outcome of this submission should not be overlooked.
In recognising these two possibilities, Plowright (pers. comm.) argued in favour of rapid approval of this application on the grounds that controlled introductions of healthy stock from New Zealand, where proper quarantine and inspection procedures could be followed, would be preferable to ending up with a bee population contaminated with parasites and pathogens. It should be noted that Plowright was actively involved in the development of commercial rearing methods for native N. American bumblebee species, that resulted in the rejection of the application to import non-native B. terrestris into the US and Canada. As a bumblebee scientific specialist, his support for the introduction of this species into Australia is significant, as he has an equal affiliation with native species where appropriate.
We believe that it is better to control the risks, however minor, and protect the valuable honeybee industry and the health of the native bee population in this country through stringent controls, than wait for a chance introduction.
3.1.4. Are there viable alternatives to the introduction of bumblebees for commercial crop pollination?
It was claimed by some bee specialists (Batra, Cane, Kukuk, Hogendoorn and Spessa et al.) that solitary native bee species such as Xylocopa, Amegilla and Lestris spp. should be developed as alternatives to B. terrestris for the purposes of crop pollination in Australia, particularly greenhouse crops such as tomatoes. While this sounds like an attractive proposition in theory, the practical reality is that this is very unlikely. Kukuk said that there are many native bees that can be reared in captivity (and are now for research purposes) that would function very well in greenhouse situations. The key point in this statement is the word 'research'. There is a great deal of difference between maintaining small research cultures, and being able to operate a year round, commercially viable operation. On the claim in general, it is interesting to note that Hogendoorn, who is undertaking a postdoctoral study on one of the key groups, the carpenter bee Lestris sp., admits that she has been unable to get them to mate in captivity, and to pollinate when the crop is in need of this function. Dr Adriaan van Doorn, head of pollination R&D with Koppert BV, and an experienced bee researcher, responded to this issue. He was not aware of any native alternatives to B. terrestris, and believed that solitary bees would be difficult to rear, especially in confined spaces, and could not be relied upon to provide year round supply. He said that one of the advantages with Bombus spp. is that the technology allowed the commmercial producers to completely control the production of queens, having overcome the diapause problem, so that they had year round production capability. Also, bumblebee species were able to pollinate a wide variety of crops. He felt that it would be very difficult to find other pollinators with the same catholic tastes in pollination. Using different bees for different crops would also be economically less feasible. He said that it was his understanding that Xylocopa had been demonstrated to visit tomato flowers and would buzz pollinate, and that they could be kept in field populations, but that the technology had not progressed beyond that stage. However, there were many unanswered questions such as how they might survive under in vitro rearing conditions in confined spaces, how to breed them in captivity, how to control diapause, what were the sex ratios and how might this influence the economics of a potential breeding operation, what was their longevity, their flower preferences, etc.? There are five species of Xylocopa in Australia, but four of these are confined to the tropical Queensland coast. The remaining one may be useful for passionfruit, kiwifruit, feijoa and red clover but these crops are outside its normal range. Dr van Doorn said that he believed solitary bees would prove to be inferior to Bombus in some of the necessary parameters for commercial rearing, and that it would take years to answer all of the necessary questions (Hogendoorn confirmed that the answers were a long way off). Van Doorn believed that solitary bees would be difficult to rear in captivity, and that a number of aspects or stages of the rearing operation would have to take place under less controlled conditions with a lesser degree of control and predictability, and a greater cost. Even if native bees could fulfill all the necessary criteria, the same argument would apply in moving a species into an area in which it was not endemic.
In Japan, one of the arguments that contributed to the approval to import B. terrestris into the country was that despite there being 14 native Bombus species, Japanese scientists undertaking rearing experiments with the endemic B. ignitus, B. hypocrita hypocrita and B. hypocrita sapporoensis over the past four years had found that they could not compete with B. terrestris in rearing efficiency. Further, that breeding research was not very advanced, and there were no plans for commercial production of any of these species. In the end approval to introduce B. terrestris was quite rapid. Batra has imported bee pollinators from Japan and is very supportive of supplementing crop pollination by this approach.
A strong case can be made for conservation and augmentation of native bees for pollination of orchard and field crops, but this is a separate issue from commercial rearing of one species on a continual basis, for primarily greenhouse crop use.
3.1.5. Comparison with the perceived adverse effects of A. mellifera on native bees
Many native bees and introduced A. mellifera forage on the same flowers (Donovan 1980), but this should not be seen as necessarily typical of the relationship between native bees and other introduced bees such as Bombus and Megachile. In any case, native bees frequently outnumber A. mellifera on native and some introduced plants. Peak native bee foraging occurs during the 'honey flow' when pollen and nectar are abundant, thus competition between species for food is reduced (Donovan 1980). Donovan (1980) in fact concluded that in New Zealand, where native bees have existed with introduced Bombus and Apis species throughout this century, they were competing very successfully, and that some human actions had far more effects on native bees (many beneficial) than possible competition from introduced bees.
The comparison of Bombus with Apis was made by some bee specialists (Cane and Beekman) in their opposition to the introduction. This is not a sound comparison. Bumblebees have different floral and nesting requirements, they are not active all year round, their requirements for nectar are far less as they do not store more than for their immediate needs, their colonies are much smaller, they have a different social structure, and they do not tolerate heat as well. For all these reasons, they would be far less obtrusive should they become established in the wild. Also, the argument that because A. mellifera requires native flora for the honey industry to flourish, it must therefore follow that it is having an adverse impact on native bee species is not proven. Beekman said that there was a debate in Australia that had revealed possible negative effects of the presence of honeybees on native species, but she didn’t say what it might be nor provide any scientific evidence to support this assertion.
There is recent evidence in the US that native bees can persist and rebound rapidly to exploit a resource where honeybees are absent. Following five consecutive years of the worst honeybee declines in history, experts predicted that pollinator scarcity could seriously limit crop yields in crops such as pumpkin, apple, cranberry, almonds and squash. The USDA reported in spring 1996 that in some parts of the country up to 90% of all honeybees had been killed. However, scientists from the Forgotten Pollinators Campaign, in compiling bee and crop estimates from more than eight States, found that reduced visits by honeybees through spring and summer, in many cases no visits at all, were compensated for by the increased prevalence of bumblebees, squash bees, gourd bees, sweat bees, leaf-cutting bees and other wild native species (Anon. 1996). There was no suggestion that bumblebees had occupied the void left by honeybees to the exclusion of native bees.
3.2 Introduction of the leafcutting bee Megachile rotundata into Australia.
In this discussion it is appropriate to mention the recent approvals to import the leafcutting bee Megachile rotundata into Australia for lucerne pollination (Peebles 1996, Winn 1988). Trial shipments of this species have been introduced into Australia, and an extensive study has been undertaken into possible parasite and pathogen contamination of source material in this species. None was found. Currently application is being considered to import larger numbers from Canada.
A paper presented by Mr R. Winn, SA Department of Agriculture at the Second Australian and International Beekeeping Congress, 1988 (Appendix 8), provides detailed information on the importation and release of leafcutter bees into South Australia. Details of the justification for, and steps taken in, the introduction of M. rotundata into Australia make an interesting supporting case study for this submission on B. terrestris, and provide a recent precedent.
4.0 Summary of the risks and benefits of introducing B. terrestris into Australia.
Table 3. A summary of the risks and benefits of importing Bombus terrestris into Australia
|
Risks |
Comments |
|
Competition for nectar and polle |