Reduced genetic variation and the success of an invasive species

Abstract

Despite the severe ecological and economic damage caused by introduced species, factors that allow invaders to become successful often remain elusive. Of invasive taxa, ants are among the most widespread and harmful. Highly invasive ants are often unicolonial, forming supercolonies in which workers and queens mix freely among physically separate nests. By reducing costs associated with territoriality, unicolonial species can attain high worker densities, allowing them to achieve interspecific dominance. Here we examine the behavior and population genetics of the invasive Argentine ant (Linepithema humile) in its native and introduced ranges, and we provide a mechanism to explain its success as an invader. Using microsatellite markers, we show that a population bottleneck has reduced the genetic diversity of introduced populations. This loss is associated with reduced intraspecific aggression among spatially separate nests, and leads to the formation of interspecifically dominant supercolonies. In contrast, native populations are more genetically variable and exhibit pronounced intraspecific aggression. Although reductions in genetic diversity are generally considered detrimental, these findings provide an example of how a genetic bottleneck can lead to widespread ecological success. In addition, these results provide insights into the origin and evolution of unicoloniality, which is often considered a challenge to kin selection theory.

Population genetic structure of the predatory, social wasp Vespula pensylvanica in its native and invasive range

“…In contrast, the Argentine ant, Linepithema humile , the Eastern Subterranean termite, Reticulitermes flavipes , and the Buff‐tailed bumblebee, Bombus terrestris , experienced drops in allelic richness of 50% or more in their invasive ranges (Tsutsui et al. 2000; Vargo 2003; Schmid‐Hempel et al. 2007).…”

An Alpine ant’s behavioural polymorphism: monogyny with and without internest aggression inTetramorium alpestre

“…They are extensive cooperative units with many queens and very many workers integrated harmoniously over several square metres to many square kilometres (Crozier & Pamilo 1996; Giraud et al 2002; Steiner et al 2009). Supercoloniality is often considered key to the success of invasive ant species (Holway et al 2002), and supercolonies have been thoroughly studied over the last decades (Tsutsui et al 2000; Giraud et al 2002; Pedersen et al 2006; Leniaud et al 2011; Huszar et al 2014; Kennedy et al 2014). However, the factors triggering their emergence remain largely unknown (Suarez & Suhr 2012).…”

Diet-Related Modification of Cuticular Hydrocarbon Profiles of the Argentine Ant, Linepithema humile, Diminishes Intercolony Aggression

“…Introduced L. humile populations are unicolonial and frequently very large, and they often dominate native ant species (Suarez et al, 1999). Nestmate recognition in the Argentine ant is influenced by genetic (Tsutsui et al, 2000(Tsutsui et al, , 2003Suarez et al, 2002) and environmental (Chen and Nonacs, 2000;Liang and Silverman, 2000) inputs. Holway et al (1998) and Suarez et al (2002) reported that aggression persisted between L. humile colonies despite maintenance under uniform rearing conditions, whereas Chen and Nonacs (2000) observed a decrease in L. humile intercolony aggression following 2 mo of laboratory rearing.…”

“…Holway et al (1998) and Suarez et al (2002) reported that aggression persisted between L. humile colonies despite maintenance under uniform rearing conditions, whereas Chen and Nonacs (2000) observed a decrease in L. humile intercolony aggression following 2 mo of laboratory rearing. Whereas Tsutsui et al (2000) demonstrated a significant inverse relationship between L. humile genetic similarity and intercolony aggression, the colony pairs used by Holway et al (1998), Chen and Nonacs (2000), and Suarez et al (2002) were not subjected to genetic analysis. Therefore the observed changes (or lack thereof ) in aggression may have resulted from different degrees of genetic similarity, with aggression between the most dissimilar pairs unlikely to change despite similar rearing conditions.…”