Winandy, L. | Search bioRxiv

bioRxiv2025

Quantitative genetics of lifetime growth curves in a lizard

Body size is an iconic trait in quantitative genetics. For species with indeterminate growth however, growth curve, a function-valued trait, is the actual trait of interest and requires a specialised framework to study its quantitative genetics. Here, we use such a framework in the common lizard (Zootoca vivipara), using two large datasets (wild and mesocosm populations) with pedigrees, decomposing the total heritability in growth dynamics into two components: the heritability of "intrinsic size" (being small or large across ages) and the heritability of the shape of growth curve. We found slower growth and larger asymptotic sizes in the wild population. We show very low to moderate heritabilities in the parameters of growth curves, varying across populations and sexes. We show a small to moderate heritability in the growth curves, with a stronger importance of the heritability in the shape of growth curves than on average intrinsic sizes. Genetic variation in growth curves differed between the two populations and sexes. Our results highlight the importance of discussing the full dynamics of growth by showing that there is more adaptive potential in the earlier ages for males and in the later ages for females, with differences between the studied populations.

evolutionary biology↗

bioRxiv2017

Bottom-up and top-down control of dispersal across major organismal groups: a coordinated distributed experiment

Organisms rarely experience a homogeneous environment. Rather, ecological and evolutionary dynamics unfold in spatially structured and fragmented landscapes, with dispersal as the central process linking these dynamics across spatial scales. Because dispersal is a multi-causal and highly plastic life-history trait, finding general drivers that are of importance across species is challenging but highly relevant for ecological forecasting.\n\nWe here tested whether two fundamental ecological forces and main determinants of local population dynamics, top-down and bottom-up control, generally explain dispersal in spatially structured communities. In a coordinated distributed experiment spanning a wide range of actively dispersing organisms, from protozoa to vertebrates, we show that bottom-up control, that is resource limitation, consistently increased dispersal. While top-down control, that is predation risk, was an equally important dispersal driver as bottom-up control, its effect depended on prey and predator space use and whether dispersal occurred on land, in water or in the air: species that routinely use more space than their predators showed increased dispersal in response to predation, specifically in aquatic environments. After establishing these general causes of dispersal, we used a metacommunity model to show that bottom-up and top-down control of dispersal has important consequences for local population fluctuations as well as cascading effects on regional metacommunity dynamics. Context-dependent dispersal reduced local population fluctuations and desynchronized dynamics between communities, two effects that increase population and community stability.\n\nOur study provides unprecedented insights into the generality of the positive resource dependency of dispersal as well as a robust experimental test of current theory predicting that predator-induced dispersal is modulated by prey and predator space use. Our experimental and theoretical work highlights the critical importance of the multi-causal nature of dispersal as well as its cascading effects on regional community dynamics, which are specifically relevant to ecological forecasting.

ecology↗