Andrew D. Clark, Dominik Deffner, Kevin Laland, John Odling-Smee, and John Endler (Jan 2020)
A meta-analysis of selection gradients shows that niche construction affects the variability and strength of selection
“Niche construction affects the variability and strength of natural selection”
Posted on
Niche construction influences selection in the wild
That organisms modify their local environments (i.e. nest-building in birds, dam-building in beavers) has long been known and studied by evolutionary biologists. However, it is less certain how animal-built artefacts and choices (a.k.a. ‘niche construction’) influence the natural selection that they experience. In this study, Andrew Clark, Dominik Deffner, Kevin Laland, John Odling-Smee, and John Endler conduct statistical analyses of data from published studies measuring natural selection in the wild to test whether such organismconstructed environmental elements differ from non-constructed environmental components in the strength and variability of natural selection generated. Such a difference is expected because organisms partly control and regulate their environments by building and modifying conditions in nests, burrows, and mounds, and also choosing habitats, resources, and foraging locations. These activities typically act to ensure that the environmental variables they experience remain within suitable tolerance ranges. As predicted, the analysis reveals an overall lower magnitude of selection, and reduced temporal and spatial variation in selection, associated with constructed elements of the environment. The study confirms that organism-manufactured or chosen components of environments may have qualitatively different properties from other environmental features, and highlights how the activities of organisms may shape selection in a manner not yet fully appreciated.
Abstract
Consideration of the properties of the sources of selection potentially helps biologists to account for variation in selection. Here we explore how the variability of natural selection is affected by organisms that regulate the experienced environment through their activities (whether by constructing components of their local environments such as nests, burrows, or pupal cases, or by choosing suitable resources). Specifically, we test the predictions that organism-constructed sources of selection that buffer environmental variation will result in (i) reduced variation in selection gradients, including reduced variation between (a) years (temporal variation), and (b) locations (spatial variation), and (ii) weaker directional selection, relative to non-constructed sources. Using compiled datasets of 1045 temporally replicated, 257 spatially replicated, and a pooled dataset of 1230 selection gradients, we find compelling evidence for reduced temporal variation and weaker selection, in response to constructed compared to non-constructed sources of selection, and some evidence for reduced spatial variation in selection. These findings, which remained robust to alternative datasets, taxa, analytical methods, definitions of constructed/non-constructed, and other tests of reliability, suggest that organism-manufactured or chosen components of environments may have qualitatively different properties from other environmental features.