Queen biology
Bumble bees are eusocial insects, where females are divided into the queen and worker castes. The overwhelming majority of bumble bee research has focused on workers, but the queen caste is unique in several ways. Queens live longer (up to almost a year) and go through various life history stages that workers do not, such as an overwintering stage. Queens can also mate and produce female offspring, which workers are unable to do. Queen fitness is a fundamental component of bumble bee population dynamics because the death of a single queen early enough in the season precludes the production of a nest with up to hundreds of workers and new reproductives.
PhD candidate Erica Sarro's research is focused on queen behavior and physiology and its consequences for nesting success and population dynamics. This work follows in part from the finding that queen brood-feeding behavior is responsive to social conditions; queens reduce their brood-feeding activity when workers emerge in the nest, and they actively feed brood if workers are absent (Woodard et al. 2013, Sarro et al., submitted). Erica is using laboratory experiments with B. impatiens and field experiments with B. vosnesenskii to explore how and why queens make decisions about how they spend their time, their reproductive investment, and their foraging decision-making. She also plans to visit the Rocky Mountain Biological Laboratory in summer 2021 (postponed due to COVID) to study wild queens in this system. Erica is supported by an NSF National Research Traineeship.
Postdoc Claudinéia Costa is also examining the effects of diet on queen fitness during the pre-overwintering period. She has found that diet impacts the expression of detoxification genes in the fat body, the “liver-like” organ in insects (Costa et al. 2020). This work sheds light on the sublethal effects of inadequate nutrition, and builds on our previous research on how queen mortality is driven by food unavailability during the pre-overwintering stage (Woodard et al. 2019). Beginning in 2021, Claudinéia will begin working on an NSF-funded project that couples field studies in the southern Sierra Nevada Mountains with laboratory studies in B. vosnesenskii, to identify the nutritional drivers of early nesting success in bumblebees. This work is a collaboration with Shalene Jha (UT Austin) and Neal Williams (UC Davis).
PhD candidate Erica Sarro's research is focused on queen behavior and physiology and its consequences for nesting success and population dynamics. This work follows in part from the finding that queen brood-feeding behavior is responsive to social conditions; queens reduce their brood-feeding activity when workers emerge in the nest, and they actively feed brood if workers are absent (Woodard et al. 2013, Sarro et al., submitted). Erica is using laboratory experiments with B. impatiens and field experiments with B. vosnesenskii to explore how and why queens make decisions about how they spend their time, their reproductive investment, and their foraging decision-making. She also plans to visit the Rocky Mountain Biological Laboratory in summer 2021 (postponed due to COVID) to study wild queens in this system. Erica is supported by an NSF National Research Traineeship.
Postdoc Claudinéia Costa is also examining the effects of diet on queen fitness during the pre-overwintering period. She has found that diet impacts the expression of detoxification genes in the fat body, the “liver-like” organ in insects (Costa et al. 2020). This work sheds light on the sublethal effects of inadequate nutrition, and builds on our previous research on how queen mortality is driven by food unavailability during the pre-overwintering stage (Woodard et al. 2019). Beginning in 2021, Claudinéia will begin working on an NSF-funded project that couples field studies in the southern Sierra Nevada Mountains with laboratory studies in B. vosnesenskii, to identify the nutritional drivers of early nesting success in bumblebees. This work is a collaboration with Shalene Jha (UT Austin) and Neal Williams (UC Davis).
Taste and nutrition
There is accumulating evidence that bumble bees (like many insects) taste their food and base some of their feeding-related behaviors on this information. However, in the case of bumble bees, feeding can be either a personal or a social act. PhD candidate Kaleigh Fisher is working in collaboration with Naoki Yamanaka and Anupama Dahanukar to examine gustation in bumble bees, including some of the fundamental aspects of taste and also some of the complexities of how it operates in this social insect system. This work is supported by USDA-NIFA.
We are also examining the environmental processes that influence bee nutritional states and how these in turn influence foraging behavior. PhD student Natalie Fischer is using metabolomic approaches to explore how a primary stressor (neonicotinoid exposure) impacts the bumble bee metabolome, and also how it is shaped by social factors during early development. She will be returning to the Rocky Mountain Biological Laboratory in summer 2020 to continue her work on metabolomic states in wild bees. Natalie is supported by an NSF Graduate Research Fellowship and National Research Traineeship.
We are also examining the environmental processes that influence bee nutritional states and how these in turn influence foraging behavior. PhD student Natalie Fischer is using metabolomic approaches to explore how a primary stressor (neonicotinoid exposure) impacts the bumble bee metabolome, and also how it is shaped by social factors during early development. She will be returning to the Rocky Mountain Biological Laboratory in summer 2020 to continue her work on metabolomic states in wild bees. Natalie is supported by an NSF Graduate Research Fellowship and National Research Traineeship.
social and nutritional effects on larval development
The larval stage is an important period in early bee development. In bumble bees, this is the period when both caste (in females) and body size are determined. Previous studies have identified that caste and size determination are influenced by nutritional and social factors in bumble bees, but the specific mechanisms underlying these effects are almost entirely unknown. We are working in collaboration with Guy Bloch (The Hebrew University of Jerusalem) to explore social influences on larval development, including how brood-rearing by queens shapes offspring size and functional characteristics. This work is supported by funding from USDA NIFA, the US-Israel Binational Science Foundation, and the US-Israel Binational Agricultural Research and Development Fund.