Variation in endocrine signaling underlies variation in social life history

Gro Amdam, Kari Anne Nilsen, Kari Norberg, M. Kim Fondrk, Klaus Hartfelder

Research output: Contribution to journalArticle

75 Scopus citations

Abstract

Variation in endocrine pathways can be a major mechanism underlying life-history evolution. Yet it is unclear whether this insight, derived primarily from solitary species, explains the origins of complex life-history traits in highly social taxa. Thus, we here document and study variation in social life-history syndromes of female fecundity, behavior, and life span in selectively bred honeybee (Apis mellifera) strains. Associated variation in endocrine signaling was uncovered by RNA interference (RNAi) silencing of the juvenile hormone (JH) suppressor gene vitellogenin. High versus low endocrine reactivity in response to vitellogenin knockdown consistently correlated with rapid social behavioral ontogeny and short life span versus slow social behavioral ontogeny and long life span. Variation in JH reactivity, furthermore, was a function of variation in fecundity (ovary size and follicle development). A JH-mediated pleiotropy of female life-history traits, including fecundity, behavior, and life span, characterizes the distantly related solitary insect Drosophila. For the first time, we document a similar regulatory principle in a highly social species where most females are alloparental helpers (workers) that seldom reproduce. We conclude that variation in endocrine pathways of solitary origin can underlie variation and evolvability of complex social life-history traits.

Original languageEnglish (US)
Pages (from-to)37-46
Number of pages10
JournalAmerican Naturalist
Volume170
Issue number1
DOIs
StatePublished - Jul 1 2007

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Keywords

  • Endocrine pleiotropy
  • Insulin signaling
  • Juvenile hormone
  • Longevity
  • Social evolution
  • Vitellogenin

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

Amdam, G., Nilsen, K. A., Norberg, K., Fondrk, M. K., & Hartfelder, K. (2007). Variation in endocrine signaling underlies variation in social life history. American Naturalist, 170(1), 37-46. https://doi.org/10.1086/518183