Meeting Abstract

P2.140  Tuesday, Jan. 5  Effects of mangrove pneumatophore density on Uca crenulata MCDERMOTT, CG*; POPE, D; Mount Holyoke College; Mount Holyoke College mcder20c@mtholyoke.edu

An organism’s habitat plays a large role in the types of behavior they exhibit as an individual, particularly in the context of signaling to attract mates. In my study site in Sonora, Mexico, the fiddler crab Uca crenulata builds burrows within and close to areas of mangrove pneumatophores, unlike many fiddler crab species that live in more open mudflat habitat. I investigated whether the behavior of males of this species varied in areas with different levels of pneumatophore density, since the structure of pneumatophores and the visual noise they create may affect with many of their common behaviors. Over one lunar cycle I studied the behavioral patterns of U. crenulata by tracking the above-ground activity of females and males of different sizes as well as recording the behavior of focal males. I found that the ratio of males to females as well as male waving activity significantly increases at and after low tide. I also conducted an experiment to investigate whether males are attracted to pneumatophores by giving them a choice between open areas and areas with artificial pneumatophores. Nineteen out of twenty males chose pneumatophore areas, suggesting that males are strongly attracted to these structures. I determined that larger males tended to live in higher density pneumatophore areas and that these areas had a lower percentage of males waving in general. These trends in behavior are useful in explaining how males balance increased conspicuousness to predators with the necessity to attract a mate.