Can recent evolutionary history promote resilience to environmental change?

Abstract

Principles of social evolution have long been used retrospectively to interpret social interactions, but have less commonly been applied predictively to inform conservation and animal husbandry strategies. We investigate whether past social selection can predict resilience to environmental change. Upon exposure to harsh novel environments, populations that previously experienced more benign social environments are predicted either to suffer fitness losses (the "mutation load hypothesis" and "selection filter hypothesis") or maintain fitness (the "beneficial mutation hypothesis"). We tested these contrasting predictions using populations of burying beetles Nicrophorus vespilloides evolved experimentally for 48 generations under harsh versus benign social environments through manipulation of parental care. We exposed sexually immature adults from each population to varying heat stress and measured the effect on survival and reproduction. The more benign the social environment previously experienced by a population, the better its survival under heat stress during sexual maturation. Although consistent with the "beneficial mutation hypothesis", it is also possible that populations evolved under the harsher social environment were more prone to dying during maturation, regardless of their thermal environment. Overall, stochastic genetic variation, probably due to founder effects, was a better predictor of resilience. We discuss the implications for translocation and captive breeding programmes.

Selection on the joint actions of pairs leads to divergent adaptation and coadaptation of care-giving parents during pre-hatching care

“…The strength of our conclusions is tempered by the fact that our experimental design lacked any control pairings within replicate lines (we had to sacrifice this treatment owing to logistical constraints). Nevertheless, from other data we have collected from these populations, we have no reason to suppose that the replicate lines, within either the NC or FC treatments, had diverged by this stage of experimental evolution [ 29 , 34 – 38 ] (but see [ 53 ]). If our conclusions are broadly correct, then our expectation is that the evolution of other group or pair-level traits in response to environmental change should be initiated unilaterally by the individual that takes that lead in shaping these collective actions, and that this in turn will provoke swift social coadaptation by other members of the pair or group.…”