Aphid emits hormone

The superfamily Aphidoidea has about 4,000 species of insects of the order Hemiptera, divided into ten families. Among these species, about 250 are agricultural pests or forest, usually known as "aphid". Their size varies from one to ten millimeters long. This Aphidoidea was found on pomegranate tree.
One of the most common strategies is to produce substances repelling aphids and / or attract aphid predators (lady beetles and their larvae, syrphid fly larvae).
Thus it was recently shown (published 2010) that the orchid Epipactis veratrifolia emits a hormone that is the same as that emitted by aphids stressed or attacked. It attracts hoverflies thus sensitive to these hormones, which lay on the orchid plant and fertilize the way, spreading its pollen).