Presence of an invasive species reverses latitudinal clines of multiple traits in a native species

Abstract

Understanding the processes driving formation and maintenance of latitudinal clines has become increasingly important in light of accelerating global change. Many studies have focused on the role of abiotic factors, especially temperature, in generating clines, but biotic factors, including the introduction of non‐native species, may also drive clinal variation. We assessed the impact of invasion by predatory fire ants on latitudinal clines in multiple fitness‐relevant traits—morphology, physiological stress responsiveness, and antipredator behavior—in a native fence lizard. In areas invaded by fire ants, a latitudinal cline in morphology is opposite both the cline found in museum specimens from historical populations across the species’ full latitudinal range and that found in current populations uninvaded by fire ants. Similarly, clines in stress‐relevant hormone response to a stressor and in antipredator behavior differ significantly between the portions of the fence lizard range invaded and uninvaded by fire ants. Changes in these traits within fire ant‐invaded areas are adaptive and together support increased and more effective antipredator behavior that allows escape from attacks by this invasive predator. However, these changes may mismatch lizards to the environments under which they historically evolved. This research shows that novel biotic pressures can alter latitudinal clines in multiple traits within a single species on ecological timescales. As global change intensifies, a greater understanding of novel abiotic and biotic pressures and how affected organisms adapt to them across space and time will be central to predicting and managing our changing environment.

Rapid adaptation to invasive predators overwhelms natural gradients of intraspecific variation

“…The new selective forces exerted by invasive species are expected to interfere with the pressures imposed by the extant environmental context 13 , thus the effectiveness and long-term consequences of evolutionary responses to invasive species remain difficult to predict 14 . Despite the growing literature on the evolutionary consequences of biological invasions, few studies have considered how selective pressures imposed by invasive species interfere with pre-existing patterns of local adaptations and environmental heterogeneity of native populations 15 , 16 . This is likely a result of the complexity of disentangling multiple selective forces.…”

The evolution of thermal performance in native and invasive populations of Mimulus guttatus

“…Finally, we focused only on temperature, one axis of the species’ climatic niche, but evolution along other niche axes such as precipitation and edaphic properties could also contribute to invasion success (Hall & Willis, 2006; van Kleunen & Fischer, 2008). Further, the biotic environment, including competitors, enemies, and pollinators may also differ in the introduced range (Holeski, Keefover-Ring, Deane Bowers, Harnenz, & Lindroth, 2013; Thawley et al, 2018), implying that many factors beyond abiotic conditions can play a part in adaptation to novel conditions during invasions.…”

“…Failure to account for the presence of latitudinal or environmental clines can mask inferences of trait evolution between native and invasive ranges (Colautti, Maron, & Barrett, 2009). Adaptive phenotypic clines across geographic, latitudinal, or climatic gradients are commonly detected in both native and invasive ranges (Li et al, 2016; Thawley, Goldy-Brown, McCormick, Graham, & Langkilde, 2018; Hernández et al, 2019; van Boheemen et al, 2019; Fig. 1E-G).…”

Raised by aliens: constant exposure to an invasive predator triggers morphological but not behavioural plasticity in a threatened species tadpoles

“…This requires novel predator recognition from native naïve prey, which can occur through several mechanisms (e.g., predator phylogenetic relatedness (Ferrari et al 2007;Davis et al 2012); generic predator cue recognition (Mathis and Vincent 2000;Cox and Lima 2006;Carthey and Blumstein 2018); neophobia (Brown and Chivers 2005;Rehage et al 2009)). Third, selection can act on existing genetic variation, favouring rapid adaptations that can help withstanding the novel predator (Moore et al 2004;Langkilde 2009; Bytheway and Banks 2019; Thawley et al 2019;Melotto et al 2020). Interactions between genotypic variation and environmental conditions are also possible, and interplays between plasticity and standing genetic variation may further complicate the responses of native species (Levis and Pfennig 2019;Noble et al 2019).…”

“…Even though there is growing evidence that exposure to strong selective forces during biological invasions can determine rapid adaptive shifts (Phillips and Shine 2006;Langkilde 2009;Nunes et al 2014b;Cattau et al 2018;Thawley et al 2019), knowledge of the mechanisms and dynamics leading these processes is far from exhaustive.…”