Senescence in wild insects: Key questions and challenges

Abstract

Abstract Insects are key laboratory models for research on the fitness effects, genetics and plasticity of senescence. It was long believed that insects almost never survive long enough to senesce in the wild, but it is now clear that senescence occurs and can exact substantial fitness costs in natural insect populations. Yet, given the practical challenges of obtaining longitudinal field data on small, motile animals, we still know remarkably little about the evolution, expression and fitness consequences of senescence in wild insects. We argue that the study of senescence in wild insects is important because many insights and hypotheses based on laboratory experiments must be tested in natural populations. Examples of research areas where conclusions from laboratory studies could be misleading include the roles of candidate senescence genes, the effects of nutrition and dietary restriction on life span and senescence patterns, and the roles of viability selection and sexual selection in shaping senescence through trade‐offs and antagonistic pleiotropy. Several emerging model species (such as antler flies, crickets, damselflies, dragonflies and butterflies) offer opportunities for field research on senescence using a range of observational and experimental techniques, as well as new genomic approaches. Insects provide valuable and increasingly tractable models for research on senescence in natural populations. We believe that such work will shed light on many important questions in ecology and evolutionary biology. A free Plain Language Summary can be found within the Supporting Information of this article.