Aquatic organisms often detect predators via water-borne cues, and reduce risky behaviors accordingly. In Florida, the container dwelling invasive mosquito Aedes albopictus can commonly be found with larvae of the predatory midge Corethrella appendiculata. Previous work has established that A. albopictus will reduce movement, foraging, and time below the surface, and increase frequency of resting at the surface, in the presence of water-borne cues produced by predation. In some vertebrate predator-prey systems (fish, amphibians) the water-borne cue originates from prey tissue damage. We wanted to determine if A. albopictus responds to cues originating from prey tissue damage, predation, predator metabolic by-products, or some combination of these factors. We predicted that the cues produced both by prey tissue damage and predator by-products would produce threat sensitive behaviors in the A. albopictus. Behaviors of second instar A. albopictus were recorded in water conditioned in 1 of five ways for a duration of five days: aged DI water (control 1); A. albopictus larvae alone (control 2); A. albopictus larvae crushed (prey tissue damage), Corethrella larvae fed A. albopictus larvae (predation); and Corethrella larvae alone (predator by-product). Activity and position of larvae were recorded with a video camera and a computer for 35 minutes. Videos were scored in 30-min instantaneous scan censuses. The activities and positions were converted into proportions. To reduce the number of variables and to obtain uncorrelated descriptors of behavior, a principal component analysis was done on activities and positions. Principal component scores were analyzed using MANOVA.
Results/Conclusions
A. albopictus adopted low-risk behaviors in response to water-borne cues produced by the crushed larvae (prey tissue damage) and the predation treatment. Corethrella alone (predator by-product) also reduced movement of prey relative to control treatments. Thus A. albopictus shows a threat sensitive behavioral response to water-borne cues originating from both the prey alone, predated prey, and to a degree cues produced by predator by-product showing that the cues involved are of a diverse origin.
