Date

6-2012

Degree Name

BS in Biological Sciences

Department

Biological Sciences Department

Advisor(s)

Shannon J. McCauley

Abstract

Our study investigated the spatial distribution and movement behavior of predatory dragonfly larvae (Anax) and of two prey types: mosquito larvae and amphipods. Predator-prey interactions have important consequences for the population dynamics of both predator and prey groups and these interactions can shape community structure. We measured behavior of each prey type in the presence of the Anax predator and the behavior of the predator in the presence of these alternative prey types. Observations were made in five-gallon aquaria where a grid pattern allowed us to track the number of moves made by individuals. We compiled data from ten, one hour trials for each predator-prey combination (Anax + amphipods and Anax + mosquito larvae). Prey species differed in their behavior. Mosquito larvae spent more time near the water’s surface, were more likely to utilize the artificial vegetation, and were more active than amphipods. On the other hand, amphipods utilized full range of the aquarium and had a greater number of moves than mosquito larvae. Anax behavior was significantly different in the two prey treatments. Anax spent more time in the top potion of the aquarium during the mosquito treatments, utilized the artificial vegetation more in the amphipod treatments, had a greater number of moves in the amphipod treatments, and ate more amphipods than mosquito larvae. Our results indicate that Anax change their behavior based on prey type.

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