Online toolkits for collaborative and inclusive global research in urban evolutionary ecology.

Urban evolutionary ecology is inherently interdisciplinary. Moreover, it is a field with global significance. However, bringing researchers and resources together across fields and countries is challenging. Therefore, an online collaborative research hub, where common methods and best practices are shared among scientists from diverse geographic, ethnic, and career backgrounds would make research focused on urban evolutionary ecology more inclusive. Here, we describe a freely available online research hub for toolkits that facilitate global research in urban evolutionary ecology. We provide rationales and descriptions of toolkits for: (1) decolonizing urban evolutionary ecology; (2) identifying and fostering international collaborative partnerships; (3) common methods and freely-available datasets for trait mapping across cities; (4) common methods and freely-available datasets for cross-city evolutionary ecology experiments; and (5) best practices and freely available resources for public outreach and communication of research findings in urban evolutionary ecology. We outline how the toolkits can be accessed, archived, and modified over time in order to sustain long-term global research that will advance our understanding of urban evolutionary ecology.

Sex-specific microhabitat use is associated with sex-biased thermal physiology in Anolis lizards.

If fitness optima for a given trait differ between males and females in a population, sexual dimorphism may evolve. Sex-biased trait variation may affect patterns of habitat use, and if the microhabitats used by each sex have dissimilar microclimates, this can drive sex-specific selection on thermal physiology. Nevertheless, tests of differences between the sexes in thermal physiology are uncommon, and studies linking these differences to microhabitat use or behavior are even rarer. We examined microhabitat use and thermal physiology in two ectothermic congeners that are ecologically similar but differ in their degree of sexual size dimorphism. Brown anoles (Anolis sagrei) exhibit male-biased sexual size dimorphism and live in thermally heterogeneous habitats, whereas slender anoles (Anolis apletophallus) are sexually monomorphic in body size and live in thermally homogeneous habitats. We hypothesized that differences in habitat use between the sexes would drive sexual divergence in thermal physiology in brown anoles, but not slender anoles, because male and female brown anoles may be exposed to divergent microclimates. We found that male and female brown anoles, but not slender anoles, used perches with different thermal characteristics and were sexually dimorphic in thermal tolerance traits. However, field-active body temperatures and behavior in a laboratory thermal arena did not differ between females and males in either species. Our results suggest that sexual dimorphism in thermal physiology can arise from phenotypic plasticity or sex-specific selection on traits that are linked to thermal tolerance, rather than from direct effects of thermal environments experienced by males and females.

Ectoparasite extinction in simplified lizard assemblages during experimental island invasion.

Introduced species can become invasive, damaging ecosystems and disrupting economies through explosive population growth. One mechanism underlying population expansion in invasive populations is 'enemy release', whereby the invader experiences relaxation of agonistic interactions with other species, including parasites. However, direct observational evidence of release from parasitism during invasion is rare. We mimicked the early stages of invasion by experimentally translocating populations of mite-parasitized slender anole lizards (Anolis apletophallus) to islands that varied in the number of native anoles. Two islands were anole-free prior to the introduction, whereas a third island had a resident population of Gaige's anole (Anolis gaigei). We then characterized changes in trombiculid mite parasitism over multiple generations post-introduction. We found that mites rapidly went extinct on one-species islands, but that lizards introduced to the two-species island retained mites. After three generations, the two-species island had the highest total density and biomass of lizards, but the lowest density of the introduced species, implying that the 'invasion' had been less successful. This field-transplant study suggests that native species can be 'enemy reservoirs' that facilitate co-colonization of ectoparasites with the invasive host. Broadly, these results indicate that the presence of intact and diverse native communities may help to curb invasiveness.