Eusocial Reproduction Selects for Longevity

Abstract

Naked mole-rats have exceptionally long lifespans and reproduce eusocially, with a single female, the queen, producing all offspring. Other eusocial species, such as bees, ants, and termites, also have long lifespans relative to their solitary kin. We propose that eusociality drives the evolution of longevity through three mechanisms: first, individuals in eusocial populations tend to be older than in non-eusocial populations, and thus genes favoring survival at later ages are more strongly selected; second, slower growth in eusocial populations reduces early mortality from resource scarcity, making longevity more important. Finally, the fitness benefits of long lifespan are stronger when the population\'s reproductive success rests on the survival of a single individual. Non-eusocial species reproducing in ways that partly access these benefits also have relatively long lifespans. We demonstrate these three mechanisms using mathematical models and computer simulations, highlighting longevity as an evolvable, selectable trait. Our results echo conclusions from Life History Theory but cast them in a new light.