Aphidoletes aphidimyza (Rondani, 1847)

Morphology

The adult measures around 2.5 mm. It has long legs and a slender body.
Males have long hairy antennae curved posteriorly whereas females have shorter, broader antennae.
The larvae are orangey to chestnut brown.

Biology and behavior

Mating and egg laying take place during the night. The female lays eggs in small groups in foci of aphids. The number of eggs depends strongly on the food consumed during its development and on the climate, but is generally over 100. The eggs are oval, orangey red and measuring 0.3 mm. After 2-3 days, the larvae hatch and begin to feed on nearby aphids, emptying them of their internal tissues. The larvae are orange yet transparent before becoming orange, red, brown or grey, according to the food they eat. A larva needs at least 5 aphids per day in order to develop, but kills more than really necessary if this prey is abundant, sometimes as many as 100 aphids per day. In order to do this it injects a paralyzing toxin into the aphid and dissolves its organs in less than 10 minutes.
After 1-2 weeks, the larva undergoes nymphosis in damp soil. It forms a brown oval cocoon, covered with grains of sand, aphid moults and excretions. 10-14 days later, the adults emerge. The development of Aphidoletes aphidimyza cannot be achieved without the presence of aphids. The female lays her eggs in quite substantial aphid foci since the larva does not go to seek its prey more than 6 cm from the place it hatched. The Aphidoletes aphidimyza adult feeds on honeydew and lives for 7-10 days. In the wild, the pupa enters diapause from the end of September until May; under glasshouse conditions the pupa comes out of diapause early in spring with the onset of higher temperatures.

Habitat

This is a common, highly widespread insect. It is used extensively for aphid control in sheltered crop production.