Social Personality Polymorphism and the Spread of Invasive Species: A Model

Abstract

Ecological invasions are a major worldwide problem exacting tremendous economic and ecological costs. Efforts to explain variability in invasion speed and impact by searching for combinations of ecological conditions and species traits associated with invasions have met with mixed success. We use a simulation model that integrates insights from life-history theory, animal personalities, network theory, and spatial ecology to derive a new mechanism for explaining variation in animal invasion success. We show that spread occurs most rapidly when (1) a species includes a mix of life-history or personality types that differ in density-dependent performance and dispersal tendencies, (2) the differences between types are of intermediate magnitude, and (3) patch connections are intermediate in number and widely spread. Within-species polymorphism in phenotype (e.g., life-history strategies or personality), a feature not included in previous models, is important for overcoming the fact that different traits are associated with success in different stages of the invasion process. Polymorphism in sociability (a personality type) increases the speed of the invasion front, since asocial individuals colonize empty patches and facilitate the local growth of social types that, in turn, induce faster dispersal by asocials at the invasion edge. The results hold implications for the prediction of invasion impacts and the classification of traits associated with invasiveness.

Personality-dependent dispersal cancelled under predation risk

“…This could result in higher invasion success, as already shown in other species [8], and can hasten the spread of an invasion [47]. Here, we corroborated previous studies on this invasive mosquitofish in showing that dispersers tend to be more asocial than average.…”

Personality composition is more important than group size in determining collective foraging behaviour in the wild

“…invasion biology [45,46]), while others have profitably considered the eco-evolutionary consequences of both colony composition and size simultaneously [10,29]. In our system, the relative influence of group size and personality composition depended on the collective trait being considered.…”

Exploratory behaviour and stressor hyper-responsiveness facilitate range expansion of an introduced songbird

“…boldness, aggression, response to novelty) may be especially important in novel environments [5][6][7][8][9][10][11][12][13][14][15]. Different selection pressures along a range expansion could select for different levels of these traits between the site of introduction and the edge of the range.…”