Bumblebees are important pollinating insects, but many species have suffered declines over the last century. Long-tongued bumblebees have been identified as particularly at risk, partly due to their more selective diet. Attempts to study these species in captivity have been impeded by stress-induced behaviours which cause queens to kill or abandon their brood. Here, we attempt to further develop techniques, using queen pairing and Bombus terrestris cocoons, to successfully rear two common long-tongued bumblebee species (B. pascuorum and B. hortorum ) in captivity. Approximately half of queens laid eggs and 29% produced workers. Although challenges remain, there is a great deal to be gained from optimising the captive rearing of these species.pocket makers / pollination / Bombus pascuorum / Bombus hortorum / Bombus terrestris / rearing / cocoon / queen pairing

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Bumblebees (Bombus spp.) are ecologically and economically important pollinating insects and nutritional stress is one of the most significant factors causing their decline. However, our knowledge of the nutritional requirements of bumblebees is largely limited to just a small number of species that can be easily reared in the laboratory, so there is an important need to understand the nutritional requirements of a greater range of bumblebee species. In particular, the long-tongued, pocket maker species that have been intractable to laboratory rearing, yet are often of greatest conservation concern. Here, we compare the development and success of incipient colonies in two species of pocket maker bumblebees (B. pascuorum and B. hortorum) when fed either a less diverse or more diverse pollen diet. Our results show that both diets were sufficiently good for queens of both species to rear workers, but they performed significantly better for some variables on the less diverse diet. Our findings support previous work that suggests that a less diverse diet can be as good as a highly diverse mix in some respects. We also observed significant differences between species, demonstrating why we must not rely only on one or two model species to understand the effects of nutritional stress on bumblebee communities.