Although absent from much of its former range, B. Below are findings from recent studies. Some scientists consider Bombus occidentalis the western bumble bee to be the same species as Bombus terricola the yellowbanded Bumble beewhereas others consider them to be two separate species. On this website, we treat these bees as two separate species.
Bumblebees are specialised pollinators of many agricultural weeds in the genus Solanum, including white horsenettle and buffalo burr. Some Solanum weeds are poisonous to livestock and children have died overseas after eating the fruit of buffalo burr . Bumblebees are also the major pollinators of impatiens, an invasive weed of riverbanks and lakesides in Europe, Britain, North America and New Zealand where it often grows so densely that it smothers other plants [3, 4, 5, 25, 27, 29, 31, 32, 33, 34].
In the absence of bumblebees on the Australian mainland, some of these weeds are now acting as relatively benign 'sleeper weeds'. However, if bumblebees became feral and spread through the Australian mainland, some of these weeds could become much more invasive and destructive new pests .
Research on the effect of bumblebees on weeds in Australia is only just beginning but is currently underway at the University of Tasmania and at Macquarie University. Goulson points out , 'If even one new major weed occurs in Australia due to the presence of bumblebees, the economic and environmental costs could be substantial'.
They have become established in the most remote areas of Tasmania including in four out of five national parks in the Tasmanian Wilderness World Heritage Area . Further surveys have shown that bumblebees are breeding in native vegetation in every region of Tasmania and active nests were found in National Parks .
One colony in Maria Island National Park, isolated from urban areas by 10km of sea, had produced at least new queen bees . European bumblebees have several competitive advantages over our solitary native bees: Bumblebees store food in their nests , while solitary bees do not, so they can better survive periods of food shortage.
Bumblebees can fly at least 4 km from their nests, while many solitary bees can only fly a few hundred metres , so they have a better chance of finding good food sources. Bumblebees can learn from their hundreds of nest mates about the discovery and scent of good food sources , while solitary bees must find all their food by themselves by trial and error.
Bumblebees can fly at much lower temperatures than most native bees, so they are able to forage much earlier in the morning . In situations where nectar and pollen are in short supply, bumblebees may exhaust the available supplies before the native bees begin to fly.
Native bees in the family Colletidae are the most likely to suffer competition from bumblebees because the flowers preferred by the Colletidae native bees are visited particularly heavily by bumblebees .
About half of Australia's native bees belong to the family Colletidae . Australian honeyeaters may increase their territory sizes and displace subordinate birds , lose weight [10, 23] and suffer increased mortality  when nectar supplies are reduced.
Of special concern is the endangered Swift Parrot, Lathamus discolor. Fewer than Swift Parrot adults remain in the wild. They are dependent largely on the nectar and pollen of Eucalyptus globulus and E. In Tasmania Andrew Hingston found that these flowers were virtually devoid of nectar when the introduced European honeybees and bumblebees were active.
However, the recent introduction of bumblebees appears to be closing this window because they are able to forage at much lower temperatures than honeybees . Bumblebees were established in a variety of vegetation types from coastal heath, through sclerophyll forest, and alpine shrubberies up to an altitude of m.
This shows there is potential for these exotic bumblebees to harm a wide variety of Australian native plants. Bumblebees also were foraging on some plant species that are not visited by European honeybees plant species previously free from the effects of exotic bees. Exotic bees may alter the seed production rates of native plants in various ways  such as: Exotic bees may increase seed production by providing additonal pollination services.
They may reduce seed production by removing pollen from flowers. They may reduce seed production by displacing native pollinators without properly pollinating the flowers themselves.
Much more research needs to be done. However, early studies in Tasmania have already shown that bumblebees may be affecting native plant seed production by robbing nectar from the native Common Heath Epacris impressa and displacing native megachilid bees from Gompholobium flowers [15, 16].A study of the feral bumblebees in Tasmania  showed that bumblebees were visiting at least 66 native species of plants from 21 families.
Bumblebees were established in a variety of vegetation types from coastal heath, through sclerophyll forest, and alpine shrubberies up to an altitude of m. There are approximately 30 bumble bee species in the Pacific Northwest region of the United States and the Western bumble bee was once the most common of these – its historic range spanned 14 states and western Canada.
B. occidentalis is known as a generalist . The Western bumble bee is a social insect that lives in very structured colonies. There are three classes, or castes, of Western bumble bees in any colony: the queen bee, worker bees and drones.
In the early spring, queen bees emerge from hibernation in overwintering sites and look for places to build nests for their new colony. COMPETITIVE INTERACTIONS BETWEEN THE INVASIVE EUROPEAN HONEY BEE AND NATIVE BUMBLE BEES.
Authors. Impacts on pollen-nectar resources and wild bee communities, Basic and Applied Ecology, , 17, 3, Local bumble bee decline linked to recovery of honey bees, drought effects on floral resources, Ecology Letters.
CEQA Initial Study: Bumble bee (Bombus impatiens) This paper serves as a study to determine the potential impact of the release of a non-native bumblebee, Bombus impatiens, into It can be classified as "Endangered" when its survival and reproduction in the wild are in immediate jeopardy from one or more causes, including loss of habitat.
To infer spill-over, studies need to examine the prevalence of DWV in managed Western honey bees and wild bee species across multiple sites, and couple this with proof that the pathogen in managed Western honey bees and wild bee species is the same, for example, by .