Ecology of large and small scale mosquito invasions

Livdahl, Todd

Abstract

This project will track the course of three mosquito invasions. One of these, the spread of Aedes albopictus in North America, began with the shipment of used tires to the US from Asia in the early 1980's. We are interested in its interaction with resident mosquitoes, especially competition with the treehole mosquito Aedes triseriatus. Two other invasions, by Aedes albopictus and Aedes aegypti, are early in the colonization phase in Bermuda. Tests for interspecies agonistic effects will be conducted by tracking population change in 100 US localities concurrently, with the help of an extensive network of school children and their teachers, who will send substrates from egg traps to us for species identification. Substrates from egg trap sites in Bermuda, part of a vector surveillance program, will be sent to us for species identification, using PCR methodology. Rates of change for each population will be calculated, and tests for density effects by each species will be conducted. This study, which will be among the largest concurrent census-based studies of natural populations, will attempt to link experimental work with actual changes at the population level. An independent test for competition between species will be done by sampling female adults in eight locations in the US and eight in Bermuda, selected for their relatively high and low densities of each species. Females will be measured, with the expectation that competition will result in smaller females. Tests for the influence of larvae on female habitat choice will also be conducted under field conditions in the US and Bermuda. Habitat choice can be either a mitigating or an intensifying factor for other species interactions, including competition. All species involved in this study are involved in the transmission of important human diseases, including La Crosse virus, Dengue virus, and yellow fever. All have potential to transmit West Nile virus.