The role of algae in the ecology of the invasive mosquito species Aedes japonicus

The mosquito Aedes japonicus is native to Asia and invasive in North America and Europe. This species breeds in both natural and artificial water-filled containers that vary considerably in size, composition and content. In some localities this species may be responsible for the decline in abundance of native mosquito species. Due to the status of A. japonicus as a potential disease vector, it is important to determine key ecological factors leading to its success. Algae are a valuable food source for invertebrates in many aquatic ecosystems, and may provide mosquito larvae in sunlit and partially shaded containers with an additional resource. Larvae of A. japonicus are known to colonize containers with visible algal growth in both their native and invasive ranges, and thus may benefit from the utilization of algae as a food source. The objectives of this study were to determine the effects of algae on the colonization, growth, and competitive success of larval A. japonicus. In a field experiment, we utilized artificial containers with canopies of varying shade levels to manipulate algal densities and examined oviposition preferences. In laboratory experiments, we compared the production rates of A. japonicus with local species in microcosms containing varying levels of algal growth. Results from these studies help clarify the role of algae in container habitats, and also provide information that can be applied to the management of an invasive mosquito species.