The reason insect populations seem higher during this season is a complex interaction of rainfall, food sources and increasing temperatures.
Because insects are ectothermic their body temperature depends on the external environment, in summer the increase in temperature correlates with an increase in insect activity.
Despite the higher insect turnout, these critters benefit your garden and the community. Many Australian plants thrive on pollination from ants, butterflies, moths, beetles, wasps, flies, and bees. Blowflies have the most pollination potential while soldier flies transform organic waste into fertiliser.
Read more at http://theconversation.com/from-warm-to-swarm-why-insect-activity-increases-in-summer-69637