Dragons and damsels; mosquitoes in distress

Aquatic predators can have a profound impact on the abundance of mosquito larvae. Such predators can include fish such as guppies but also aquatic insects such as backswimmers (Notonectidae) and dragonfly naiads (larvae). We conducted several experiments focusing on various aspects of the predatory behaviour of aquatic insects. One group of insects that we looked at were dragonfly and damselfly naiads (Odonata). We assessed predation rates as an effect of mosquito larvae densities, predator densities and predator size.

We found that predator density had a negative effect on the rates at which individual predators consumed mosquito larvae, but with increasing numbers of predators the total amount of mosquito consumed did increase. However, after a certain threshold of predator densities the total number of mosquitoes consumed decreased. As densities increase the naiads likely experienced a higher threat from conspecifics, because they do like to eat each other as well. While hiding for their neighboring naiads the mosquitoes larvae had a better chance of surviving.

Dragonfly and damselfly naiads appear to be effective predators of mosquito larvae. Although naiads occur in different aquatic habitats than Aedes larvae, they do often co-occur in nature with other vector mosquito species such as Anopheles (Malaria) and Culex (West Nile Virus).

You can find more about this study here.

Posted in Publications.