PARENT SESSION
Poster Session # 19: Insect and Invertebrate Ecology.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Sarracenia purpurea pitchers: Potential oviposition sites for mosquito vectors of arboviral encephalitis?
Cochran-Stafira, Liane*,1, 2, Yakimova, Eva1, 1 Saint Xavier University, Chicago, IL2 Northern Illinois University, DeKalb, IL
ABSTRACT- Wyeomyia smithii is the only mosquito to regularly oviposit in the water-filled leaves of the carnivorous northern pitcher plant Sarracenia purpurea. Furthermore, W. smithii is restricted to the geographical range of its host plant because of its strict dependency on the plant for reproduction. The evolutionary basis for this commensalism is not fully understood, nor is the mechanism behind the exclusion of other container-breeding mosquitoes from these potential breeding sites. The increasing risk of arboviral encephalitic disease transmission by container breeding taxa calls for a better understanding of their choice of breeding habitats, especially since pitcher plants are often abundant in regions of North America where such diseases are becoming endemic. In a series of laboratory studies, we investigated whether the Asian Tiger Mosquito Aedes albopictus, a potential carrier of West Nile Virus, could or would oviposit in S. purpurea pitchers. A. albopictus females typically cling to the sides of a container habitat and attach eggs above the water line. Females presented with intact, unaltered pitchers and paper-lined plastic cups, chose the cups over 90% of the time. Drowned females, but no eggs, were often found in leaves at the end of these choice trials. Artificially enlarging pitcher openings, and providing resting places for females inside the pitchers both increased the probability of successful oviposition to nearly 100%. Our data suggest that pitcher morphology, combined with female oviposition behavior, is a major factor in deterring oviposition. We hypothesize that the small pitcher opening and the slippery, scale-covered interior of the pitcher prevent females from entering the pitcher and clinging to the walls. Our data also suggest that the type of detritus in the pitcher is not involved in oviposition decisions by A. albopictus.
Key words: wyeomyia smithii , oviposition, sarracenia purpurea , aedes albopictus