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ARS Home » Pacific West Area » Logan, Utah » Pollinating Insect-Biology, Management, Systematics Research » Research » Publications at this Location » Publication #307075
Title: Nutritional regulation of phenotypic plasticity in a solitary bee

Author
item FISCHMAN, BRIELLE - University Of Illinois
item Pitts Singer, Theresa
item ROBINSON, GENE - University Of Illinois

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2017
Publication Date: 7/24/2017
Citation: Fischman, B.J., Pitts-Singer, T., Robinson, G.E. 2017. Nutritional regulation of phenotypic plasticity in a solitary bee. Environmental Entomology. 46(5):1070-1079. https://doi.org/10.1093/ee/nvx119.
DOI: https://doi.org/10.1093/ee/nvx119

Interpretive Summary: That larval nutrition plays a role in whether a larva goes into diapause (a period of quiescence) or continues to develop so that is becomes an adult without spending time in diapause is a proposed ancestral ground plan for the evolution of social insect castes (queens, workers, and drones). We performed comparative analyses of the solitary alfalfa leafcutting bee and the eusocial honey bee to explore this hypothesis. We investigated how larval nutrition affects developmental flexibility, gene expression, and female reproductive behavior in alfalfa leafcutting bees. Field surveys and laboratory manipulations of larval diet quantity demonstrated nutritional control of whether or not bees entered into diapause. Manipulation of larval diet quality through the addition of royal jelly, the caste-determining substance of honey bees, increased the probability of alfalfa leafcutting bee larvae entering into diapause. We also found a significant overlap between genes that respond to nutritional manipulations in alfalfa leafcutting bees and genes associated with caste determination in social bees. Finally, as in social bees, larval nutrition affected female reproductive behavior in alfalfa leafcutting bees. These results support the hypothesis that two striking forms of flexibility in developmental outcomes, diapause and caste determination, are evolutionarily related in bees.

Technical Abstract: Nutrition-dependent developmental plasticity for larval diapause is a proposed ancestral ground plan for the evolution of social insect castes. We performed comparative analyses of the solitary alfalfa leafcutting bee, Megachile rotundata, and the eusocial honey bee, Apis mellifera, to explore this hypothesis. We investigated how larval nutrition, a prominent regulator of social bee caste determination, affects diapause plasticity, gene expression, and female reproductive behavior in M. rotundata. Field surveys and laboratory manipulations of larval diet quantity demonstrated nutritional regulation of diapause plasticity in M. rotundata. Manipulation of larval diet quality through the addition of royal jelly, the caste-determining substance of A. mellifera, increased the probability of diapause in M. rotundata. We also found a significant overlap between genes that respond to nutritional manipulations in M. rotundata and genes associated with caste determination in social bees. Finally, as in social bees, larval nutrition affected female reproductive behavior in M. rotundata. These results support the hypothesis that two striking forms of phenotypic plasticity, diapause and caste determination, are evolutionarily related in bees.