Investigating the effects of biogenic amines on the dominance hierarchy in the small carpenter bee, Ceratina calcarata

Authors: MILLER, RIYA - Quinnipaic University; REHAN, SANDRA - Quinnipaic University; COOK, CHELSEA - Marquette University; Brent, Colin; LAWSON, SARAH - Quinnipaic University

Submitted to: Insectes Sociaux
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2026
Publication Date: 3/16/2026
Citation: Miller, R.N., Rehan, S.M., Cook, C.N., Brent, C.S., Lawson, S.P. 2026. Investigating the effects of biogenic amines on the dominance hierarchy in the small carpenter bee, Ceratina calcarata. Insectes Sociaux. https://doi.org/10.1007/s00040-026-01086-w.
DOI: https://doi.org/10.1007/s00040-026-01086-w

Interpretive Summary: Biogenic amines are neurotransmitters that regulate many aspects of insect behavior and physiology. Within social insect species, biogenic amines are responsible for modulating traits associated with higher levels of sociality, such as division of labor. In Ceratina calcarata, a bee species that exhibits varying levels of sociality, mothers establish a dominance hierarchy over their eldest daughters by providing them with less pollen and protein, resulting in smaller, more submissive adults called dwarf eldest daughters (DEDs). We hypothesized that this dominance hierarchy is additionally modulated by biogenic amines. To examine this hypothesis, we first compared biogenic amine levels between mothers and daughters and found significantly higher levels of dopamine, octopamine and tyramine in the former group. To clarify the role of dopamine, which is often a driver of dominance behaviors, we topically administered the biogenic amines to DEDs, while the mothers were treated with a dopamine blocker. Mothers and DEDs of the same nest underwent behavioral assays to assess aggressive and tolerant behaviors. When dopamine was blocked in the naturally more aggressive mothers, they became more tolerant of DEDs, indicating dopamine plays a key role in modulating these behaviors. More work is needed to understand the different roles each biogenic amine plays in the development of a dominance hierarchy.

Technical Abstract: Biogenic amines are highly conserved across animal species and aid in the regulation of movement, behavior, motivation, temperature, blood pressure, and endocrine secretion. Within eusocial species, such as the honeybee Apis mellifera, biogenic amines are responsible for modulating traits associated with higher levels of sociality, such as division of labor. In Ceratina calcarata, a facultatively social bee species, mothers establish a dominance hierarchy over their eldest by providing them with less pollen and less protein, resulting in smaller, more submissive adults referred to as dwarf eldest daughters (DEDs). We hypothesized that this dominance hierarchy is additionally modulated by biogenic amines. To examine this hypothesis, we first compared biogenic amine levels between mothers and DEDs and found significantly higher levels of dopamine, octopamine and tyramine in the former group. To quantify the effects of these biogenic amine differences, dopamine was topically administered to C. calcarata DEDs, while the mothers were topically treated with the dopamine blocker cis-(Z)-Flupentixol dihydrochloride. Aggression helps to establish social hierarchies, so mothers and DEDs from the same nest underwent behavioral assays to assess aggressive and tolerant behaviors.. When dopamine was blocked in the naturally more aggressive mothers, they became more tolerant of DEDs, indicating dopamine plays a key role in modulating these behaviors. More work is needed to understand the different roles each biogenic amine plays in the development of a dominance hierarchy, especially in these species on the brink of eusociality.