Which feature is characteristic of the Island Floodwater mosquito (Aedes vexans)?

The characteristic feature of the Island Floodwater mosquito (Aedes vexans) is that eggs are laid above the waterline. This behavior is crucial for the survival and development of their larvae. Aedes vexans typically lay their eggs in areas that are likely to be flooded but are dry at the time of laying. This strategy ensures that when the floods arrive, the eggs will be submerged in water, allowing for optimal hatching conditions.

While other options touch upon various aspects of mosquito behavior or biology, they do not accurately describe this species. For instance, the larvae of Aedes vexans do not mature in trees, which distinguishes them from certain other species. Similarly, although Aedes vexans can have a considerable flight range, this is not as defining a characteristic as their unique egg-laying behavior. Furthermore, while many mosquitoes may feed on both birds and mammals, Aedes vexans is not specifically noted for primarily feeding on birds, making egg-laying above the waterline the most distinctive trait of this species.