Like their diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual informatio...

Pollinators such as bees are essential to the functioning of terrestrial ecosystems. However, despite concerns about a global pollinator crisis, long-term data on the status of bee species are limited. We present a long-term study of relative rates of change for an entire regional bee fauna in the northeastern United States, based on >30,000 museum records representing 438 species. Over a 140-y...

Certain species of bumblebees are difficult to distinguish based on morphology alone due to a lack of diagnostic characters and extensive intraspecific variation in colour patterns. The discussion concerning whether Bombus lapponicus and Bombus monticola are the same species or not, seems to be ongoing. We present a study of 16 speciemens of B. monticola/B. lapponicus from Norway, identified wi...

To assess the ability of traditional biological recording schemes and lay citizen science approaches to gather data on species distributions and changes therein, we examined bumblebee records from the UK's national repository (National Biodiversity Network) and from BeeWatch. The two recording approaches revealed similar relative abundances of bumblebee species but different geographical distri...

In bumblebees, the male secretion of the cephalic labial gland is species-specific. It is highly involved in the nuptial behavior, acting as a sexual attracting pheromone. Therefore, it is also used to accurately identify the species. In contrast to this common scheme, the secretions of Bombus mesomelas are found to be strongly reduced and do not include the most volatile compounds that are pre...

In the flight muscles of European bumblebees, high activities of fructose-1,6-bisphosphatase (FbPase) relative to phosphofructokinase (PFK) have suggested a thermogenic 'futile cycle' important for regional endothermy. We find generally low activities of FbPase (0.7-19.7 units g(-1) thorax) in North American Bombus species, with the exception of Bombus rufocinctus, where activity (43.1 units g(...

Megabombus bumblebees have unusually long tongues and are generally more specialised than other bumblebees in their choice of food plants. The phylogeny of Megabombus bumblebees shows that speciation was concentrated in two periods. Speciation in the first period (ca 4.25-1.5 Ma) is associated with the late rise of the Hengduan Mountains at the eastern end of the Qinghai-Tibetan plateau. Specia...

Social bees and other insects are frequently parasitized by a large range of different microorganisms. Among these is Crithidia bombi (Kinetoplastida: Trypanosomatidae), a common gut parasite of bumblebees, Bombus spp. (Insecta: Apidae). Bumblebees are important pollinators in commercial and natural environments. There are clear detrimental effects of C. bombi infections on the fitness of bumbl...

Bombus terrestris is one of the most commonly used insect models to investigate visually guided behavior and spatial vision in particular. Two fundamental measures of spatial vision are spatial resolution and contrast sensitivity. In this study, we report the threshold of spatial resolution in B. terrestris and characterize the contrast sensitivity function of the bumblebee visual system for a ...