Context‐dependent joint buffering of abiotic stress by parental care and sibling interactions

Abstract

Abstract Climate change represents one of the most complex challenges of the 21st century, increasing global temperatures and the occurrence of extreme events, such as heatwaves, cold snaps, floods or droughts. These changes exert significant pressure on biological systems, often resulting in altered behavioural patterns and impairments in fecundity, reproductive success and offspring survival. The evolution of parental care is hypothesized to represent an adaptive response to environmental challenges, with the potential to buffer offspring performance against stressors such as thermal extremes. While parental care is long regarded as the major evolutionary driver for family groups, an increasing number of studies highlight the beneficial effects of sibling interactions on offspring development, raising interest in sibling cooperation as an early driver of social life. Here, we tested whether the fitness consequences of sibling interactions depend on abiotic environmental conditions and whether sibling interactions buffer offspring against environmental stress, act synergistically with parental care or lose their beneficial effects under harsh conditions. To this end, we examined larval performance in the subsocial burying beetle Nicrophorus vespilloides . In two separate experiments, we manipulated the presence or absence of parents and siblings and exposed offspring to either temperature or soil moisture extremes. The capacity of cooperative behaviours to mitigate the effects of environmental stress depended strongly on environmental context, social constellation and the trait considered. Under low temperatures, parental care and sibling cooperation acted synergistically to buffer larval mass, whereas the benefits of sibling interactions disappeared in the absence of parents. In contrast, high temperatures reduced offspring performance when parents and siblings were present simultaneously but did not diminish the benefits associated with sibling interactions in the absence of parental care. Our findings demonstrate that the effects of social interactions under environmental stress are highly context dependent. Rather than consistently promoting or disrupting cooperation, abiotic stress modified the strength and expression of social effects across environmental conditions and social constellations. These results highlight the importance of sociality for resilience to environmental change, while showing that its buffering capacity is conditional rather than universal. Read the free Plain Language Summary for this article on the Journal blog.

The authors' abstract, as published at the source. Functional Ecology, 2026 · DOI ↗