Phenotypic response to a major hurricane in Anolis lizards in urban and forest habitats

Abstract

Little is known about the synergistic impacts of urbanization and hurricanes on synanthropes. We compared morphological traits of the lizard Anolis cristatellus on Puerto Rico sampled before the 2017 category 5 Hurricane Maria and 4 and 11 months after the hurricane. We measured limb lengths, toepad size and the number of subdigital scales, termed lamellae, that facilitate adhesion. We hypothesized that the hurricane should have selected for longer limbs and larger toepads with more lamellae, which are traits that other research has suggested to increase clinging performance. Given prior work demonstrating that urban lizards of this species tend to share this phenotype, we also predicted increased phenotypic overlap between post-hurricane urban–forest pairs. Instead, we found that forest and urban populations alike had smaller body sizes, along with a small size-adjusted decrease in most traits, at 4 months after the hurricane event. Many traits returned to prehurricane values by 11 months post-hurricane. Toe morphology differed in the response to the hurricane between urban and forest populations, with significantly decreased trait values in forest but not in urban populations. This difference could be attributable to the different biomechanical demands of adhesion to anthropogenic substrates compared with natural substrates during intense winds. Overall, more research will be required to understand the impacts of hurricanes on urban species and whether differential natural selection can result.

No evidence of predicted phenotypic changes after hurricane disturbance in a shade-specialist Caribbean anole

“…Therefore, the potential for toepad size to follow the predictions of the hypothesis remains to be tested. Nevertheless, toepad size in A. cristatelus in forest habitats in Puerto Rico decreased four months after the hurricane, a pattern contrary to that predicted by the hypothesis [17].…”

“…Our analyses in a shade-specialist in Puerto Rico do not support this hypothesis. Similarly, a study quantifying traits of A. cristatellus —an open/disturbed area specialist — before and after hurricane disturbance also found no support for phenotypic changes that favour clinging ability [17]. What can explain this contrasting result on studies following the same hurricane disturbances in different islands?…”

“…The clinging ability hypothesis has been key to interpret the higher prevalence of larger toepads in hurricane-prone regions [16]. Still, this pattern is not necessarily unequivocal with studies finding lack of evidence for this pattern in other systems [17]. Moreover, even in cases when longer limbs are selected after the hurricane, some challenge the generalizability of the clinging mechanism as an ultimate explanation where locomotor performance, availability of retreat areas and changes in vegetation structure may ultimately lead to similar phenotypic patterns [18].…”

Blowing in the wind: Experimental assessment of clinging performance and behaviour in Anolis lizards during hurricane‐force winds

“…Results from recent studies of hurricane‐induced selection (Donihue et al, 2018) and phenotypic shifts (Aviles‐Rodriguez et al, 2021; Dufour et al, 2019; Fokidis & Brock, 2020; Rabe et al, 2020) provided the impetus for our experiments, which were designed to investigate the ecological and functional relationships that influence clinging performance as well as how behaviour might affect the ability of lizards to survive hurricanes. Our experiments showed that clinging force based on the physical ability of lizards did not predict clinging ability when experiencing the more realistic conditions of hurricane‐force winds.…”

“…Other studies show selective mortality based on morphological trait variation; for example, using comparisons of preand post-hurricane populations, Donihue et al (2018) found that natural selection favoured lizards with larger toepads and longer forelimbs, trait values that enhance clinging ability in anoles (Elstrott & Irschick, 2004;Kolbe, 2015), as well as shorter hindlimbs that reduce aerodynamic drag and improve the clinging ability of lizards (Debaere et al, 2021). Several other studies have reported changes in performance, behaviour and morphology of anole populations after hurricanes (Aviles-Rodriguez et al, 2021;Dufour et al, 2019;Fokidis & Brock, 2020;Rabe et al, 2020). The limb and toepad morphology of lizards surviving hurricanes is mostly consistent with survivors having greater clinging performance (Debaere et al, 2021;Elstrott & Irschick, 2004, but see Aviles-Rodriguez et al, 2021), pointing to the likely functional relationship underlying the observed selection.…”