A Local Replacement of \u3ci\u3eBombus Ternarius\u3c/i\u3e by \u3ci\u3eBombus Terricola\u3c/i\u3e in Northern Wisconsin (Hymenoptera: Apidae)

During the last few years, the bumblebee Bombus ternarius Say has markedly decreased in numbers in Vilas County in northern Wisconsin while Bombus terricola Kirby has increased. The great ecological similarity of these species suggests that interspecific competition may cause or facilitate this replacement

The bumble bees (Hymenoptera: Apidae: Bombus) of Arkansas, fifty years later

Many species of bumble bees (Hymenoptera: Apidae: Bombus Latreille) are declining throughout their ranges in North America, yet detecting population trends can be difficult when historical survey data are lacking.  In the present study, contemporary data is compared to a 1965 survey to detect changes in bumble bee distributions throughout Arkansas.  Using county-level records as a point of comparison to look for changes in state-wide occurrence among species over time, we find that state-level changes reflect national trends.  Contemporary records of Bombus bimaculatus Cresson and B. impatiens Cresson have more than tripled, while records for B. pensylvanicus (De Geer) show a decline to 61% of historical levels.  Although B. fervidus (Fabricius) has been reported infrequently in the state, misidentifications may have led to an overestimation of the state’s species richness.  In addition to an updated assessment of the bumble bees of Arkansas, we also provide new, localized information on the seasonal phenology and plant preferences of each species that can be used to guide conservation efforts

Gyne and drone production in bombus atratus (Hymenoptera: Apidae)

For over a decade, our research group has studied the biology of the native bumblebee, Bombus atratus, to investigate the feasibility of using it to pollinate crops such as tomato, strawberry, blackberry and peppers. Traditionally, captive breeding has depended on the use of captured wild queens to initiate the colonies. The goal of the current work is to investigate conditions required to produce new queens and drones in captivity. In this study, 31 colonies were evaluated under either greenhouse or open field conditions over a 15 month period. A total of 1492 drones (D) and 737 gynes (G, i.e., virgin queens) were produced by all colonies, with 16 colonies producing both drones and gynes (D&G), 11 producing only drones (D) and 4 producing neither. Some of the D&G colonies had more than one sexual phase, but no colonies produced exclusively gynes. More drones and fewer gynes were produced per colony under greenhouse conditions with the highest number of drones produced by D&G colonies. The numbers of immature stages per cell declined in colonies as increasingly more resources were allocated to the production of gynes and the maintenance of increased nest temperature

Insects Associated with Michigan Bumblebees (\u3ci\u3eBombus\u3c/i\u3e Spp.)

(excerpt) Studies of insect associates of bumblebees are not new. For example, Tuck (1896, 1897) reported over 50 species of insects associated with nests of British bumblebees. Sladen (1912) discussed nest associates and parasites of European bumblebees, and Plath (1934) published similar data for American bumblebees. Postner (1952) published more detailed data. He listed over 60 taxa of insects associated with bumblebees near Erlangen, Germany

BumbleKey: an interactive key for the identification of bumblebees of Italy and Corsica (Hymenoptera, Apidae)

BumbleKey is a matrix-based, interactive key to all 45 species of bumblebees of Italy and Corsica. The key allows to identify adult males and females (queens and workers) using morphological characters. The key is published online, open-access, at http://www.interactive-keys.eu/bumblekey/default.aspx

Infection and transmission of Nosema bombi in Bombus terrestris colonies and its effect on hibernation, mating and colony founding

The impact of the microsporidium Nosema bombi on Bombus terrestris was studied by recording mating, hibernation success, protein titre in haemolymph, weight change during hibernation, and colony founding of queens that were inoculated with N. bombi in the larval phase. Infection with N. bombi was diagnosed in 36% of B. terrestris queens exposed to N. bombi. Mating and hibernation of queens was not significantly affected by N. bombi infection but colony founding was reduced significantly. Haemolymph protein titre of N. bombi diseased queens was reduced, possibly indicating a disturbance of the metabolism. It was demonstrated that N. bombi infection was transmitted to the successive age cohorts in a colony and to the adults that were already in the colony prior to the introduction of the infection. The study showed a significant negative impact of N. bombi on B. terrestris colony development and indoor rearing

Ambient air temperature does not predict body size of foragers in bumble bees (Bombus impatiens)

Bumble bees are important pollinators of crops and other plants. However, many aspects of their basic biology remain relatively unexplored. For example, one important and unusual natural history feature in bumble bees is the massive size variation seen between workers of the same nest. This size polymorphism may be an adaptation for division of labor, colony economics, or be nonadaptive. It was also suggested that perhaps this variation allows for niche specialization in workers foraging at different temperatures: larger bees might be better suited to forage at cooler temperatures and smaller bees might be better suited to forage at warmer temperatures. This we tested here using a large, enclosed growth chamber, where we were able to regulate the ambient temperature.We found no significant effect of ambient or nest temperature on the average size of bees flying to and foraging from a suspended feeder. Instead, bees of all sizes successfully flew and foraged between 16C and 36C. Thus, large bees foraged even at very hot temperatures, which we thought might cause overheating. Size variation therefore could not be explained in terms of niche specialization for foragers at different temperature

Conservation Conundrum: At-risk Bumble Bees (Bombus spp.) Show Preference for Invasive Tufted Vetch (Vicia cracca) While Foraging in Protected Areas

In recent decades, some bumble bee species have declined, including in North America. Declines have been reported in species of bumble bees historically present in Ontario, including: yellow bumble bee (Bombus fervidus) (Fabricus, 1798), American bumble bee (Bombus pensylvanicus) (DeGeer, 1773), and yellow-banded bumble bee (Bombus terricola) (Kirby, 1837). Threats contributing to bumble bee population declines include: land-use changes, habitat loss, climate change, pathogen spillover, and pesticide use. A response to the need for action on pollinator preservation in North America has been to encourage ‘bee-friendly’ plantings. Previous studies show differences in common and at-risk bumble bee foraging; however, similar data are unavailable for Ontario. Our research question is whether there is a difference in co-occurring at-risk and common bumble bee (Bombus spp.) floral use (including nectar and pollen collection) in protected areas in southern Ontario. We hypothesize that common and at-risk species forage differently, predicting that at-risk species forage on a limited selection of host plants. We conducted a field survey of sites in southern Ontario, using observational methods to determine bumble bee foraging by species. The results of a redundancy analysis show a difference in foraging between common and at-risk bumblebee species. At-risk bumble bee species show a preference for foraging on invasive, naturalized Vicia cracca (tufted vetch). This finding raises the question of how to preserve or provide forage for at-risk bumble bees, when they show an association with an invasive species often subject to control in protected areas.York University Librarie

The diversity and floral hosts of bees at the Archbold Biological Station, Florida (Hymenoptera: Apoidea)

A list is provided of 113 species of bees and their 157 known floral hosts at the Archbold Biological Station(ABS), a 2105 ha site on the Lake Wales Ridge in Highlands County in south-central Florida. This is more species than might be expected at a single site so far south in Florida, based on previous studies in the Miami area and Everglades National Park, but fewer species than would be expected in an upland area of similar size with open habitats in north Florida, the mid-Atlantic states, or the upper Midwest. The small size of the fauna might be correlated with the absence of species that require a cold period in their life cycle, those that require clay or other heavy soils, those that require mesic woodlands and those that require abundant host plants in certain groups that are poorly represented on the ABS, such as Rosaceae. The natural history of southeastern bees is not known in enough detail to ascribe these causes to the individual species that are missing from the ABS fauna. In terms of bee taxa, the relatively small diversity at this site can be mainly attributed to a very poor representation of the genus Andrena (3 species), a poor representation of the genus Lasioglossum (13 species), and a poor representation of the entire family Apidae (22 species). The bee fauna of the ABS is mostly composed of species that occur (or may be expected to occur) through much of the southeastern Coastal Plain, combined with species that are widely distributed in eastern North America. In addition to these elements, there appear to be at least a few species or populations that may be relics of the dry savannahs that stretched across southern North America in parts of the Pleistocene or in the late Pliocene. There is only one species that appears to have come up from tropical Florida or the West Indies. There is no evidence that there are plants that are dependent on single bee species at the ABS, but certain buzz-pollinated plants may rely on only a few species of Bombus. A few species of bees appear to be oligolectic; their host plants, however, are visited by a wide variety of bees and other insects. Bees at the ABS belong to four conspicuous mimetic complexes: metallic green; black with a red abdomen; black with red bands and spots; black with yellow bands and spots. Most ABS bees do not have any warning coloration that is conspicuous to human eyes. There is only one exotic bee on the site, the European honey bee. This lack of a large exotic component in the fauna contrasts with the situation in the ants, of which about one fourth are introduced. Honey bees are often extremely abundant, and possibly dominate nectar and pollen resources in ways that are disruptive to native bees. Although it is easy to observe individual honey bees displacing individual native bees on flowers, there are no data on the ecological effects of honey bees on native pollinators at the ABS. About one quarter ofthe bee species (26) are parasitic species that depend on other species to gather nectar and pollen. This proportion of parasitic species is similar to some other well-studied sites in temperate North America, and is higher than the proportion found in tropical areas

Heterospecific Hymenoptera found inside the nests of Bombus impatiens (Hymenoptera: Apidae).

The nests of social Hymenoptera are particularly attractive to species engaging in resource robbing due to their concentration of resources. Here, the identity of heterospecific intruders in Bombus impatiens nests are described, with a particular focus on intrusion by invasive species – Vespula germanica and Anthidium oblongatum. While V. germanica is well known as a resource robber, this is the first time Anthidium spp. have been documented entering the nest of a social heterospecific. Of 16 Bombus impatiens colonies placed in a field in Lansing, MI, eight had heterospecific intruders, including Apis mellifera, A. oblongatum, and V. germanica. Motivations behind entering a foreign nest are discussed