RUI: Exploring neuromodulation of reproductive behavioral flexibility in biparental burying beetles

Successful parenting often requires that parents make flexible choices and stay attuned to the needs of their babies and their mates. Burying beetles, an insect species in which a male and a female will join efforts to raise young, exhibit such advanced form of care. Much like birds, beetle parents will coordinate tasks while taking turns in regurgitating pre-digested food to their young and tending their underground ‘nest’ for extended periods of time. This study seeks to understand how such complex organization of social behavior is controlled by the brain through changes in specific pathways, in particular those that involve dopamine, a neurotransmitter related to motivated behavior, decision-making and various aspects of reproduction. Because neurotransmitters are well-conserved from fruit flies to humans, this work will contribute new understanding about the fine-tuning of nervous system activity by dopamine and how that might enable flexible choices during care. The proposed work will provide Youngstown State University undergraduates from underrepresented backgrounds with an immersive research experience that will integrate DNA work and behavioral observations and facilitate access to advanced STEM research training to both undergraduates and a graduate student. These research experiences will be shared with the broader community through related outreach activities to stimulate participation in STEM research. As opportunistic breeders, facultatively biparental burying beetles, Nicrophorus orbicollis, have evolved remarkable quirks of behavior to quickly conceal and exploit a nutrient rich resource as food for their young. The ability to raise a brood with or without a partner and remain highly responsive to social cues during care is unusual among insects, with its neural basis largely unknown. This work takes advantage of the experimental accessibility and natural variation in beetle parenting behavior to ask whether dopamine, a monoamine broadly implicated in insect reproduction and behavior, can influence behavioral flexibility during care. This idea will be explored by 1) quantifying brain dopamine levels during sexual maturation and across several reproductive social contexts; 2) examining tissue and social context-specific expression of several dopamine-related genes between males and females; and 3) causally testing whether in vivo manipulation of dopamine signaling can interfere with care. The opportunity to combine neurochemical, molecular and behavioral analyses will help to more precisely define a neurophysiological mechanism for flexible care behavior in this species. These insights would add to findings from many studies in highly social honeybees, wasps, or ants, with work in the subsocial burying beetles potentially helping bridge the gap between solitary and eusocial insects in our understanding of the modulation of reproductive social behavior. The functional relatedness of monoamines could also render this work relevant to studies from mammalian models, ultimately testing the idea of convergent neurobiological mechanisms in species that evolved complex patterns of care. This project was co-funded by the Neural Systems Cluster and Behavioral Systems Cluster within Integrative Organismal Systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.