Body size predicts ant worker longevity: A hierarchical analysis of field and laboratory survival across phylogenetic lineages

Lifespan is a key life history trait that shapes ecological strategies and
colony fitness in social insects, yet its drivers remain unclear. We
evaluated whether intrinsic traits—especially worker body size, a
principal pace-of-life axis, and phylogeny—predict survival across 18 ant
species from five subfamilies monitored in the field and in captivity.
Mark–recapture data analysed with hierarchical models accounting for
imperfect detection showed that larger workers lived longer in both
environments, highlighting intrinsic physiological properties as the
strongest determinant of longevity. Worker lifespans ranged from 23–394
days, and field and lab survival were positively correlated. Body mass
scaled negatively with colony size: small colonies invested in large,
long-lived workers, whereas large colonies relied on smaller, short-lived
workers. In captivity, survival was modestly higher for some clades and
comparable for others, indicating mixed lab–field differences consistent
with hazard reduction in certain lineages; Dolichoderinae and Myrmicinae
showed little to no improvement. Phylogenetic signal was weak, indicating
that lineage imposes little constraint beyond body size. These results
confirm body size as a strong—and phylogeny as a weak—predictor of worker
longevity. Laboratory assays capture relative field lifespans despite
environmental complexity, based on the first comparative survival dataset
for a local ant assemblage spanning multiple lineages.