A worker-specific reproductive role for neuroparsin A in social bees

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Author:
Messner, Ella
Graduate Program:
Entomology
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
June 04, 2026
Committee Members:
Etya Amsalem, Thesis Advisor/Co-Advisor
Heather Hines, Committee Member
Gary Felton, Program Head/Chair
Fang Zhu, Committee Member
Keywords:
bumble bees
social insects
reproduction
division of labor
dominance
Abstract:
The reproductive division of labor between fecund queens and sterile workers forms the basis of sociality, but the molecular mechanisms that regulate reproduction in social insects are not fully understood. Specifically, the pathways mediating reproductive suppression in subordinate workers remain unresolved, and it is unclear whether these pathways represent conserved ancestral reproductive mechanisms or social-specific evolutionary adaptations. In this thesis, I examined the role of the neurohormone neuroparsin A (NPA) in regulating reproduction through gene expression analyses across bee species and RNA interference in Bombus impatiens. The relationship between NPA expression and reproductive state varied across non-eusocial species. In contrast, NPA was upregulated in non-reproductive workers of both eusocial species examined, Apis mellifera and B. impatiens. Detailed gene expression analyses in B. impatiens demonstrated that NPA is consistently upregulated in reproductively subordinate workers, regardless of whether they are inhibited by the queen or by dominant nestmates. Knocking down NPA expression increased ovary size in queenless B. impatiens workers but was not sufficient to induce ovary activation in queenright workers. NPA knockdown further reduced aggression in queenright workers. Together, my results suggest a social-specific role for NPA in regulating reproduction and dominance interactions among worker bees. NPA may have been co-opted to regulate worker sterility during the evolution of social insects.