Explaining Leptokurtic Movement Distributions: Intrapopulation Variation in Boldness and Exploration

Abstract

Leptokurtic distributions of movement distances observed in field-release studies, in which some individuals move long distances while most remain at or near their release point, are a common feature of mobile animals. However, because leptokurtosis is predicted to be transient in homogeneous populations, persistent leptokurtosis suggests a population heterogeneity. We found evidence for a heterogeneity that may generate persistent leptokurtosis. We tested individuals of the Trinidad killifish Rivulus hartii for boldness in a tank test and released them back into their native stream. Boldness in the tank test predicted distance moved in the field releases, even after effects of size and sex were removed. Further, data from a 19-mo mark-recapture study showed that individual growth correlated positively with movement in a predator-threatened river zone where the Rivulus population is spatially fragmented and dispersal is likely to be a hazardous activity. In contrast, no such correlation existed in a predator-absent zone where the population is unfragmented. These results show that a behavioral trait, not discernible from body size or sex, contributes to dispersal and that a component of fitness of surviving "dispersers" is elevated above that of "stayers," a fundamental assumption or prediction of many models of the evolution of dispersal through hazardous habitat.

Phylogeographic inferences from the mtDNA variation of the three‐toed skink, Chalcides chalcides (Reptilia: Scincidae)

“…This process would be repeated many times over a colonizing route, and these founding events would lead to the loss of alleles and to homozygosity (see Hewitt, '96, 2000). Ibrahim et al ('96) showed, by computer simulations, that such large areas of homozygosity are indeed produced by leptokurtic dispersal rather than dispersal achieved by normal or stepping-stone modes (see also Fraser et al, 2001). A recent sudden expansion for the threetoed skink populations of the Italian peninsula seems to be corroborated by the result of the mismatch analysis distribution that revealed demographic characteristics typical of expanding populations (P SSD 5 0.14).…”

Ecological effects of pharmaceuticals in aquatic systems—impacts through behavioural alterations

“…The ability of potential prey to correctly assess predation risk is therefore crucial for fitness. Dispersal and migration are also examples of behaviours that have direct importance for population persistence, especially in the face of rapid environmental change [11], as individuals that express more active, bold and/or asocial behaviours tend to be more prone to disperse or migrate [12][13][14][15]. Lastly, among fish, schooling-a behaviour tightly linked to sociality-is directly important [16], as it confuses the predator and thereby increases each schooling individual's chance of survival [17].…”

Comparative brain transcriptomic analyses of scouting across distinct behavioural and ecological contexts in honeybees

“…Many such differences are heritable, relatively stable over the lifetime of an animal, and consistent across distinct behavioural and ecological contexts, in both humans [1,2] and non-human animals [3][4][5]. This phenomenon exists in a wide range of species, from insects to primates [5][6][7], and also involves many different types of behaviour, including aggressiveness [8,9], fearfulness [10], risk-taking [11][12][13] and exploratory or novelty-seeking behaviour [14,15]. Relatively little is known about the molecular basis of consistent tendencies that are manifest across different behavioural and ecological contexts.…”