An experimental evaluation of foraging decisions in urban and natural forest populations of <Emphasis Type="Italic">Anolis</Emphasis> lizards

Foraging decisions reflect a trade-off between the benefits of acquiring food and the costs of movement. Changes in the biotic and abiotic environment associated with urbanization can alter this trade-off and modify foraging decisions. We experimentally manipulated foraging opportunities for two Anolis lizard species – the brown anole (A. sagrei) in Florida and the crested anole (A. cristatellus) in Puerto Rico – to assess whether foraging behavior differs between habitats varying in their degree of urbanization. In both urban and natural forest habitats, we measured the latency of perched anoles to feed from an experimental feeding tray. We manipulated perch availability and predator presence, while also taking into account population (e.g., conspecific density) and individual-level factors (e.g., body temperature) to evaluate whether and how these contribute to between-habitat differences in foraging behavior. In both species, urban anoles had longer latencies to feed and lower overall response rates compared to lizards from forests. Urban anoles were also larger (i.e., snout-vent length and mass) in both species and urban A. sagrei were in better body condition than the natural forest population. We postulate that the observed patterns in foraging behavior are driven by differences in perceived predation risk, foraging motivation, or neophobia. Although we are unable to identify the mechanism(s) driving these differences, the substantial differences in urban versus forest anole foraging behavior emphasizes the importance of understanding how urbanization influences animal populations and their persistence in anthropogenically-modified environments.     

Latinos,Blacks, and the Competition for Low-Skill Jobs: Examining Regional Variations in the Effect of Immigration on Homicide in the U.S.

Past research has shown that a lack of low-skill jobs increases both unemployment and homicide for blacks. Therefore, it is important for scholars to understand the potentially negative effects brought about by increased competition for these jobs. Given the recent dramatic rise in the number of low-skilled Latinos in the United States, this paper examines how increased Latino competition for low-skill jobs affects black homicide victimization. Using negative binomial regression, I examine black homicide victimization data obtained from coroner's reports. Results indicate that Latino competition for jobs only affects blacks in urban areas that have recently experienced a large increase in its Latino population; however, the effects vary by industry.