Interactive effects of social environment, age and sex on immune responses in Drosophila melanogaster

J Evol Biol. 2019 Oct;32(10):1082-1092. doi: 10.1111/jeb.13509. Epub 2019 Aug 1.

Abstract

Social environments have been shown to have multiple effects on individual immune responses. For example, increased social contact might signal greater infection risk and prompt a prophylactic upregulation of immunity. This differential investment of resources may in part explain why social environments affect ageing and lifespan. Our previous work using Drosophila melanogaster showed that single-sex social contact reduced lifespan for both sexes. Here, we assess how social interactions (isolation or contact) affect susceptibility to infection, phagocytotic activity and expression of a subset of immune- and stress-related genes in young and old flies of both sexes. Social contact had a neutral, or even improved, effect on post-infection lifespan in older flies and reduced the expression of stress response genes in females; however, it reduced phagocytotic activity. Overall, the effects of social environment were complex and largely subtle and do not indicate a consistent effect. Together, these findings indicate that social contact in D. melanogaster does not have a predictable impact on immune responses and does not simply trade-off immune investment with lifespan.

Keywords: gene expression; infection; phagocytosis; senescence; sex differences; stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / physiology*
  • Animals
  • Bacteria / immunology
  • Bacterial Physiological Phenomena
  • Drosophila melanogaster / immunology
  • Drosophila melanogaster / microbiology*
  • Drosophila melanogaster / physiology
  • Female
  • Host-Pathogen Interactions / physiology
  • Male
  • Sex Factors
  • Social Behavior*