Anomalous invasion dynamics due to dispersal polymorphism and dispersal–reproduction trade-offs

Abstract

Dispersal polymorphism and mutation play significant roles during biological invasions, potentially leading to evolution and complex behaviour such as accelerating or decelerating invasion fronts. However, life-history theory predicts that reproductive fitness—another key determinant of invasion dynamics—may be lower for more dispersive strains. Here, we use a mathematical model to show that unexpected invasion dynamics emerge from the combination of heritable dispersal polymorphism, dispersal-fitness trade-offs, and mutation between strains. We show that the invasion dynamics are determined by the trade-off relationship between dispersal and population growth rates of the constituent strains. We find that invasion dynamics can be ‘anomalous’ (i.e. faster than any of the strains in isolation), but that the ultimate invasion speed is determined by the traits of, at most, two strains. The model is simple but generic, so we expect the predictions to apply to a wide range of ecological, evolutionary, or epidemiological invasions.

Spatial heterogeneity alters the trade-off between growth and dispersal during a range expansion

“…However, we also observed some discrepan-cies in the presence of mutations, which tend to advantage the R-strategy. Additionally, as recently observed by Keenan and Cornell (2021) in a homogeneous environment, in the presence of mutations, the furthest forward phenotypes are not necessarily those associated with the largest value of the product R D (see below). Duputié and Massol (2013) argues that natural selection tends to favor dispersal to face spatio-temporal variation in local conditions.…”

“…Here, although the trade-off curve ( D, R ( D )) has positive curvature, we did not observe this phenomenon: in all of our simulations of Figures 3–5, the speed is reduced when μ > 0, compared to the speed of the fastest trait when μ = 0. The theoretical results of Keenan and Cornell (2021) require a vanishing small mutation rate, and their numerical results use a mutation coefficient 10 -6 (to be compared with μ /( δ x ) 2 = (0.1)/ (0.1) 2 = 10 in our continuous framework), which may explain these differences.…”

The speed of invasion in an advancing population

“…Systems of coupled F-KPP equations have been studied in different contexts in the literature, see e.g. [10,6,11,13,12,7,14]. There has been interest in such systems in the context of dormancy, see e.g.…”

Resource relocations in relation to dispersal in Tetranychus ludeni Zacher

“…Compared with residents, dispersers often have lower fecundity and higher mortality (Mole & Zera 1993;Bonte et al 2012;Khuhro et al 2014;Renault 2020;Nasu & Tokuda 2021), leading to slower population growth (Baguette & Schtickzelle 2006;Keenan & Cornell 2021). In addition, the cost of dispersal may increase with the distance a species moves, resulting in distance-specific resource trade-offs (Rousset & Gandon 2002;Baker & Rao 2004;Samietz & Köhler 2012;Serrano & Tella 2012), the magnitude of which can affect expansion speed.…”