Can I use Dragonflies to control mosquitos or other flying pests?

Dragonflies certainly do eat large numbers of flying pest species, but using them to control these pests is not really feasible. There have been a number of studies carried out and only in very restricted and tightly controlled environments have Dragonflies, or their larvae, been shown to be able to control pest numbers. In the open, there is no reason to suppose that Dragonflies introduced to a pest rich habitat will stay there. Indeed, they certainly will not if other aspects of the environment do not suit them. It follows from this that your best chance of getting Dragonflies to prey on pests is to develop the habitat so that it is particularly suitable for Dragonflies, a worthwhile aim in itself! See the BDS publications "Dig a Pond for Dragonflies" and "Managing Habitats for Dragonflies" for more details of how to do this.  more