Relatedness predicts multiple measures of investment in cooperative nest construction in sociable weavers

Abstract

Although communal goods are often critical to society, they are simultaneously susceptible to exploitation and are evolutionarily stable only if mechanisms exist to curtail exploitation. Mechanisms such as punishment and kin selection have been offered as general explanations for how communal resources can be maintained. Evidence for these mechanisms comes largely from humans and social insects, leaving their generality in question. To assess how communal resources are maintained, we observed cooperative nest construction in sociable weavers (Philetairus socius). The communal nest of sociable weavers provides thermal benefits for all individuals but requires continual maintenance. We observed cooperative nest construction and also recorded basic morphological characteristics. We also collected blood samples, performed next-generation sequencing, and isolated 2358 variable single nucleotide polymorphisms (SNPs) to estimate relatedness. We find that relatedness predicts investment in cooperative nest construction, while no other morphological characters significantly explain cooperative output. We argue that indirect benefits are a critical fitness component for maintaining the cooperative behavior that maintains the communal good.

Sociable Weavers Increase Cooperative Nest Construction after Suffering Aggression

“…Based on visual sightings of unbanded birds we estimate that ~70% of the birds were banded in across all three nests. Observation bouts of three hours were performed in the morning (08:30–11:30) or in the afternoon (13:30–16:30) following [ 33 ]. We performed observations during the months that are the beginning of the austral winter, and sociable weavers typically do not breed during this season.…”

“…Sociable weavers are a useful system for studying social evolution because individuals live in communal nests with multiple chambers present within the nest [ 30 , 31 ]. Recent evidence suggests that cooperative nest construction in sociable weavers is maintained, at least in part, by the acquisition of indirect benefits [ 32 , 33 ]. Since the communal nest is a public good [ 34 – 36 ], the benefits of nest building may be exploited by others in the nest [ 33 ]; cooperative individuals may still need to limit exploitation.…”

“…Recent evidence suggests that cooperative nest construction in sociable weavers is maintained, at least in part, by the acquisition of indirect benefits [ 32 , 33 ]. Since the communal nest is a public good [ 34 – 36 ], the benefits of nest building may be exploited by others in the nest [ 33 ]; cooperative individuals may still need to limit exploitation. Sociable weavers may rely on aggression to limit exploitation, and cooperative nest construction may therefore be maintained via multiple mechanisms in sociable weavers.…”

swinger: a user‐friendly computer program to establish captive breeding groups that minimize relatedness without pedigree information

“…Leighton et al . ). There is also pressure towards zoos to move their breeding programmes from focusing on exhibiting animals in captivity to conservation‐orientated maintenance in captivity and restoration to the wild (Conde et al .…”

“…The concerns of estimate reliability based on microsatellite data sets may soon become irrelevant due to the development of genomic data sets of thousands of SNPs (e.g. Leighton et al 2015). There is also pressure towards zoos to move their breeding programmes from focusing on exhibiting animals in captivity to conservation-orientated maintenance in captivity and restoration to the wild (Conde et al 2011;Conway 2011;Lacy 2013).…”