So ants are a mixed blessing, depending on the type of plants and pests present. Red imported fire ant, a common predatory ant species. Parasitic Wasps Most parasitic wasps are small and inconspicuous, but wasps that parasitize insect eggs are even smaller, almost microscopic in size. Growers and gardeners are therefore often unaware that parasitoids are helping control their insect pests. The most common evidence of parasitism is often a sickly caterpillar from which parasitoid larvae are emerging, or a dead caterpillar on which a cocoon is hanging.
Parasitic wasps are important natural enemies of caterpillars, grubs, whiteflies and aphids.
A parasitic wasp depositing its egg within an aphid. A Trichogramma wasp depositing its egg within a moth egg. Clusters of parasitic wasp larvae developing externally on a caterpillar. Others deposit their larvae into host, with the same result. However, flies lack the long egg-depositing structure found in most wasps.