Search

Sex-limited polymorphism has evolved in many species including our own. Yet, we lack a detailed understanding of the underlying genetic variation and evolutionary processes at work. The brood parasitic common cuckoo (Cuculus canorus) is a prime example of female-limited color polymorphism, where adult males are monochromatic gray and females exhibit either gray or rufous plumage. This polymorphism has been hypothesized to be governed by negative frequency-dependent selection whereby the rarer female morph is protected against harassment by males or from mobbing by parasitized host species. Here, we show that female plumage dichromatism maps to the female-restricted genome. We further demonstrate that, consistent with balancing selection, ancestry of the rufous phenotype is shared with the likewise female dichromatic sister species, the oriental cuckoo (Cuculus optatus). This study shows that sex-specific polymorphism in trait variation can be resolved by genetic variation residing on a sex-limited chromosome and be maintained across species boundaries. [ABSTRACT FROM AUTHOR]

As natural habitat is progressively transformed, effective wildlife conservation relies on understanding the phenotypic traits that allow select species to persist outside of protected areas. Through behavioural flexibility such species may trade off abundant resources with risks, both real and perceived. As highly adaptable mesocarnivores, caracals (Caracal caracal) provide an opportunity to examine development of successful foraging strategies in high‐risk developed areas. Here we investigated caracal resource selection of both anthropogenic and environmental factors relative to availability at varying levels of urbanization in and around the city of Cape Town, South Africa, using GPS cluster‐located feeding events (n = 326 prey remains, n = 384 scat). We also examined spatial and temporal risk mitigation strategies by assessing behaviours at feeding clusters. We find that, within home ranges, caracals living in the urban‐dominated region (n = 14; 548 feeding events) select for the urban edge, while caracals in the wildland‐dominated region (n = 3; 162 feeding events) avoid it. Adults selected more strongly for foraging at the urban edge than juveniles and may competitively exclude them from resources. By including back‐traced scat feeding event locations, we were able to improve model resolution. We argue that caracals foraging on the edge of a large metropole mitigate risk of detection by remaining cryptic, prolonging handling time, and maintaining high feeding site fidelity where cover was available. Along with the strong functional response to the urban edge, this strategy suggests that carnivores are being drawn into, and stay longer in, areas with potentially increased prey availability despite higher risk. While behavioural plasticity clearly enables carnivore coexistence with humans in urban ecosystems, it can also be maladaptive if it reduces fitness and leads the population into an ecological trap. We provide mitigative recommendations to promote the conservation of this predator in a spatially isolated and rapidly urbanizing landscape. [ABSTRACT FROM AUTHOR]