If ornament quality advertises heritable resistance to a directly transmitted parasite, female preference for males with higher quality ornaments could reduce parasite prevalence via two pathways. Preference for, and thus more contact with, resistant males should: 1) change parasite transmission opportunities; and 2) increase offspring parasite resistance. Here, we used data and parameterized a SIR model to test the hypothesis that, across populations of guppies (Poecilia reticulata), the strength of female preference negatively correlates with prevalence of directly transmitted gyrodactylids. Female guppies exhibit between-population variation in preference for males with larger orange ornaments that are heritable and forecast resistance. Using 89 prevalence estimates from 10 populations, and controlling for ecological covariates, we found that populations with significant female preference had lower prevalence than those without. Our theoretical model inferred that preference affects prevalence largely by affecting offspring parasite resistance. Female preference can thus drive the dynamics of ordinary infectious diseases. 

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.

Although the field of urban evolutionary ecology is in its infancy, much progress has been made in identifying adaptations that arise as a result of selective pressures within these unique environments. However, as studies within urban environments have rapidly increased, researchers have recognized there are challenges and opportunities in characterizing urban adaptation. Some of these challenges are novel as a consequence of increased direct and indirect human influence, which compounds long-recognized issues with research on adaptive evolution more generally. In this perspective, we discuss several common research challenges to urban adaptation related to: (1) methodological approaches, (2) trait-environment relationships and the natural history of organisms, (3) agents and targets of selection, and (4) habitat heterogeneity. Ignoring these challenges may lead to misconceptions and further impede our ability to draw conclusions regarding evolutionary and ecological processes in urban environments. Our goal is to first shed light on the conceptual challenges of conducting urban adaptation research to help avoid propagation of these misconceptions. We further summarize potential strategies to move forward productively to construct a more comprehensive picture of urban adaptation, and discuss how urban environments also offer unique opportunities and applications for adaptation research.