Genetic variation increases during biological invasion by a Cuban lizard

Abstract

A genetic paradox exists in invasion biology: how do introduced populations, whose genetic variation has probably been depleted by population bottlenecks, persist and adapt to new conditions? Lessons from conservation genetics show that reduced genetic variation due to genetic drift and founder effects limits the ability of a population to adapt, and small population size increases the risk of extinction. Nonetheless, many introduced species experiencing these same conditions during initial introductions persist, expand their ranges, evolve rapidly and become invasive. To address this issue, we studied the brown anole, a worldwide invasive lizard. Genetic analyses indicate that at least eight introductions have occurred in Florida from across this lizard's native range, blending genetic variation from different geographic source populations and producing populations that contain substantially more, not less, genetic variation than native populations. Moreover, recently introduced brown anole populations around the world originate from Florida, and some have maintained these elevated levels of genetic variation. Here we show that one key to invasion success may be the occurrence of multiple introductions that transform among-population variation in native ranges to within-population variation in introduced areas. Furthermore, these genetically variable populations may be particularly potent sources for introductions elsewhere. The growing problem of invasive species introductions brings considerable economic and biological costs. If these costs are to be mitigated, a greater understanding of the causes, progression and consequences of biological invasions is needed.

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

“…2001; Kolbe et al. 2004). Therefore, it was somewhat unexpected that Kauai would have low levels of genetic variation.…”

Variation in founder groups promotes establishment success in the wild

“…Despite a growing interest among ecologists and conservation biologists in population-level consequences of phenotypic variation and polymorphism [3][4][5][6]10,[12][13][14], little experimental evidence is available to confirm that establishment success is higher for groups of dissimilar individuals [15,16], and the role of variation in functionally important phenotypic traits for establishment has never been examined under natural conditions in the wild. Tetrix subulata pygmy grasshoppers (Orthoptera: Tetrigidae) are well suited for such a study.…”

Ascidians as models for studying invasion success

“…Since the publication of the classic volume on "The Genetics of Colonizing Species" (Baker and Stebbins 1965), much has been learned by investigating genetic and evolutionary mechanisms underpinning biological invasions (Rius et al 2015b;Barrett 2015;Bock et al 2015). Breakthroughs (see examples highlighted in Table 2) include the knowledge that reduced genetic diversity in newly established invasive populations is not commonplace (Kolbe et al 2004;Roman and Darling 2007;Dlugosch and Parker 2008), that novel ecological contexts can drive contemporary post-establishment adaptive evolution (Lee 2002;Bossdorf et al 2005;Prentis et al 2008;Vandepitte et al 2014), and that intraand interspecific hybridization can result in the formation of particularly virulent invasive genotypes (Ellstrand and Schierenbeck 2000;Kolbe et al 2004;Rius and Darling 2014). Studies of invasive ascidians have mirrored many of these advances (Table 2) and are poised to contribute to our understanding of the genetic causes and consequences of biological invasions.…”