The Relationship between Vulnerability to Predation and Behavior of Larval Treehole Mosquitoes: Geographic and Ontogenetic Differences

Abstract

Tested predictions of the hypothesis that behavioral differences are the proximate cause of interpopulation differences in vulnerability of predation in Aedes triseriatus: 1) A. triseriatus from sites where the predator Toxorhynchites rutilus is abundant vs rare differ in types of activities and positions occupied, or the degree to which they change behavior in the presence of T. rutilus; 2) some activities or positions entail greater risks of predation than others; 3) high-risk behaviors are more common among larvae from sites where T. rutilus is rare. Populations from Normal, IL (T. rutilus very rare) and Vero Beach, FL (T. rutilus common) differ in patterns of activity and position occupied, confirming prediction: 1. Changes in behavior in the presence of T. rutilus did not differ between populations. Thrashing was the most- and resting the least-risky activity; the bottom was the most- and the surface the least-risky position, confirming prediction 2. Larvae from Normal spent more time thrashing and at the bottom than did larvae from Vero Beach (high-predation population), confirming prediction 3. For both populations, earlier instars spend more time thrashing and less time at the surface than did later instars. Larvae at the surface rarely thrashed and frequently filtered. -from Authors