November 10 2011

5:00 pm 154 BSRB

EcoEvoPub Series

Graduate Student Presentations


Dept of Ecology and Evolutionary Biology, UCLA
"Who's your neighbor? Species interactions, territoriality and habitat use in invasive Anolis lizards"

Abstract: Competitive interactions between closely related species may influence their ecology, behavior, and evolution. Biological invasions provide opportunities to observe recent secondary contact between similar species. I study two invasive lizards, Anolis sagrei and A. cristatellus, that have recently become sympatric in South Florida. Uniquely among invasive anoles in Florida, these two species are members of the same “ecomorph,” so we expect them to compete for common resources. In this talk, I will present data from two experiments. First, I tested whether sympatric and allopatric A. sagrei differed in their territorial behavior toward A. cristatellus. Behavioral differences among populations would suggest either that anoles learn species-appropriate territorial behaviors from experience, or that their aggressiveness toward heterospecific rivals has evolved in sympatry. Second, in collaboration with Dr. Jason Kolbe (U. Rhode Island), I tested whether cold tolerance in A. cristatellus has evolved following its invasion into Florida. We compared the critical minimum temperatures (CTmin) and thermal acclimation abilities of two native and two invasive populations of A. cristatellus, as well as an older invasive species (A. sagrei) and a native species (A. carolinensis).

Dept of Ecology and Evolutionary Biology, UCLA
“The Community Wide Consequences of a Naturally Occurring Toxin”


Many toxins play important roles as chemical signals in animal communication. The California newt (Taricha torosa) possesses a potent neurotoxin, tetrodotoxin (TTX), which serves as a means of chemical defense, but also elicits antipredatory behavior in conspecific larvae. TTX recently has been proposed as a “keystone molecule” with community-wide effects on species compositions and rates of material exchange. Comparable to a keystone species, a keystone molecule is a rare compound, affecting multiple trophic levels with far greater impacts on a community than would be predicted from it’s relative concentration. TTX is not ubiquitous in streams, but is introduced into pools in trace amounts by T. torosa. Community-wide effects of TTX within watersheds of the Santa Monica Mountains are being studied through behavioral assays of aquatic invertebrates in both the field and laboratory. Data from field experiments suggest that TTX could alter the behavior and community structure of invertebrates. Laboratory experiments with aquatic invertebrates exposed to varied concentrations of TTX have elucidated a consistent pattern of resistance in some invertebrates. Skin samples from T. torosa reveal mean concentrations of TTX in these newts that varies along a gradient among watersheds in the Santa Monica Mountains. These initial results with a proposed keystone molecule suggest compelling studies in future work.











































































































































































































































































































































































































































































































































































































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