Predation risk and abiotic habitat parameters affect personality traits in extremophile populations of a neotropical fish (Poecilia vivipara)

Abstract

Understanding whether and how ambient ecological conditions affect the distribution of personality types within and among populations lies at the heart of research on animal personality. Several studies have focussed on only one agent of divergent selection (or driver of plastic changes in behavior), considering either predation risk or a single abiotic ecological factor. Here, we investigated how an array of abiotic and biotic environmental factors simultaneously shape population differences in boldness, activity in an open‐field test, and sociability/shoaling in the livebearing fish Poecilia vivipara from six ecologically different lagoons in southeastern Brazil. We evaluated the relative contributions of variation in predation risk, water transparency/visibility, salinity (ranging from oligo‐ to hypersaline), and dissolved oxygen. We also investigated the role played by environmental factors for the emergence, strength, and direction of behavioral correlations. Water transparency explained most of the behavioral variation, whereby fish from lagoons with low water transparency were significantly shyer, less active, and shoaled less than fish living under clear water conditions. When we tested additional wild‐caught fish from the same lagoons after acclimating them to homogeneous laboratory conditions, population differences were largely absent, pointing toward behavioral plasticity as a mechanism underlying the observed behavioral differences. Furthermore, we found correlations between personality traits (behavioral syndromes) to vary substantially in strength and direction among populations, with no obvious associations with ecological factors (including predation risk). Altogether, our results suggest that various habitat parameters simultaneously shape the distribution of personality types, with abiotic factors playing a vital (as yet underestimated) role. Furthermore, while predation is often thought to lead to the emergence of behavioral syndromes, our data do not support this assumption.

Demographic Expansion and Contraction in a Neotropical Fish during the Late Pleistocene-Holocene

“…Populations of P. vivipara at either extreme of the salinity gradient differ significantly in traits such as body size and shape, fecundity, and reproductive allotment, which are likely determined genetically [38] [39]. Poecilia vivipara also varies markedly in personality traits including boldness, activity, and sociability/shoaling behaviour, which are modulated by environmental factors such as water transparency/visibility, salinity, and dissolved oxygen [40]. Variability in personality traits vanishes, however, under homogenous laboratory conditions, indicating that plasticity underlies the behavioural differences observed in nature [40].…”

“…Poecilia vivipara also varies markedly in personality traits including boldness, activity, and sociability/shoaling behaviour, which are modulated by environmental factors such as water transparency/visibility, salinity, and dissolved oxygen [40]. Variability in personality traits vanishes, however, under homogenous laboratory conditions, indicating that plasticity underlies the behavioural differences observed in nature [40]. The available data thus suggest that genetics and plasticity play fundamental roles in the distribution of ecological and behavioural traits of P. vivipara, which are potentially relevant for the colonization of heterogeneous environments subjected to climatic fluctuations.…”

Modelling the evolution of cognitive styles

“…In particular, predation pressure is regarded as a major environmental factor which may strongly influence the development of consistent inter-individual differences in behaviour (e.g. [29–31], but see [32]). Based on the above-stated findings and considerations, it seems that many different cognitive styles can emerge depending on the precise ecological circumstances in which individuals live.…”

Different preference functions act in unison: mate choice and risk-taking behaviour in the Atlantic molly (Poecilia mexicana)

“…Poecilia mexicana (including the population studied here) has repeatedly been characterized for risk-taking behaviour, and previous studies reported high behavioural repeatability, with R-values ranging between 0.53 and 0.64 ( freezing time after a simulated predator attack , R = 0.64, Sommer-Trembo et al, 2016a; repeatability across time to emerge from shelter and freezing time after a simulated predator attack , R = 0.53, Sommer-Trembo & Plath, 2018). Slightly lower, yet significant R-values were reported for the related guppy ( time to emerge from shelter , R = 0.51, Brown & Irving, 2013; time to emerge from shelter , R = 0.51 for females and R = 0.36 for males, Irving & Brown, 2013; time to emerge from shelter , R = 0.33, White, Kells & Wilson, 2016) and other poeciliid fishes (e.g., Gambusia affinis, time to emerge from shelter , R = 0.29 in Cote, Fogarty, Weinersmith, Brodin & Sih, 2010 and R = 0.39 in Gomes-Silva, Liu, Chen, Plath & Sommer-Trembo, 2017; Poecilia vivipara, time to emerge from shelter , R = 0.70, Sommer-Trembo et al 2016b). For our present study, we initially screened a large number of potential stimulus and focal individuals so as to be able to select stimulus pairs with contrasting behavioural type (see methods).…”