Developmental feedbacks and the emergence of individuality

Abstract

Behavioural individuality is a hallmark of animal life, with major consequences for fitness, ecology, and evolution. One of the most widely invoked explanations for this variation is that feedback loops between an animal's behaviour and its state (e.g. physiology, informational state, social rank, etc.) trigger and shape the development of individuality. Despite their often-cited importance, however, little is known about the ultimate causes of such feedbacks. Expanding on a previously employed model of adaptive behavioural development under uncertainty, we find that (i) behaviour-state feedbacks emerge as a direct consequence of adaptive behavioural development in particular selective environments and (ii) that the sign of these feedbacks, and thus the consequences for the development of behavioural individuality, can be directly predicted by the shape of the fitness function, with increasing fitness benefits giving rise to positive feedbacks and trait divergence and decreasing fitness benefits leading to negative feedbacks and trait convergence. Our findings provide a testable explanatory framework for the emergence of developmental feedbacks driving individuality and suggest that such feedbacks and their associated patterns of behavioural diversity are a direct consequence of adaptive behavioural development in particular selective environments.

Leveraging big data to uncover the eco-evolutionary factors shaping behavioural development

“…One major open question is how particular types of behaviour–state connections such as dynamic feedback loops (i.e. bidirectional linkages between state and behaviour) influence developmental trajectories [113–115]. So far, of the studies that have been designed to detect behaviour–state feedbacks, conclusions on the presence and consequences of these feedbacks have been mixed [116–119].…”

“…While theoretical and conceptual models employing techniques such as stochastic dynamic programming [106] have hugely facilitated the investigation of behaviour-state connections and their role in the development of adaptive behaviour [107][108][109][110][111][112] One major open question is how particular types of behaviour-state connections such as dynamic feedback loops (i.e. bidirectional linkages between state and behaviour) influence developmental trajectories [113][114][115]. So far, of the studies that have been designed to detect behaviour-state feedbacks, conclusions on the presence and consequences of these feedbacks have been mixed [116][117][118][119].…”

Reproductive individuality of clonal fish raised in near-identical environments and its link to early-life behavioral individuality

“…Such findings are important as they demonstrate that genetic and environmental differences are not the only potent source of variation between individuals, suggesting that factors like pre-birth processes (including epigenetics), development per se and/or minor experiential differences may represent other key drivers of phenotypic differences (Ehlman et al, 2022;Hiesinger & Hassan, 2018;Takagi & Benton, 2020;Vogt et al, 2008). Up to (which was not certified by peer review) is the author/funder.…”

“…Such findings are important as they demonstrate that genetic and apparent environmental differences are not the only potent source of variation among individuals, suggesting that factors like pre-birth processes (including epigenetics), development per se and/or minor environmental differences may represent other key drivers of phenotypic differences [19][20][21][22] .…”

Individual identification and photographic techniques in mammalian ecological and behavioural research—Part 2: Field studies and applications

“…As populations evolve over time, their size, composition and demographic structure may change (e.g., Holmes and York 2003;Wittemyer et al 2013) and so may the relationships between traits and fitness (e.g., Saether and Engen 2015;Wright et al 2019), which may in turn affect individual behaviour (e.g., Sapolsky and Share 2004;Ehlman et al 2022), pattern of social networks (e.g., Shizuka and Johnson 2020;Farine 2021), reproductive dynamics and survival (e.g., Cubaynes et al 2014;Reed et al 2022), thus affecting the populations' social and demographic trajectory. In other words, animal populations/communities undergo their own specific ecological and behavioural history that determines their prevalent socio-behavioural configuration and charts their socio-demographic future.…”