National Geographic : 1961 Jun
Murder in a garden THIS COMMONPLACE CRIME often escapes the naked eye, so tiny are the antagonists (inset, life-size). Magnification of a life-and-death struggle between flower-fly larva and aphid shows the larva holding aloft its hapless victim and draining its life juices (right). Though it lacks eyes and legs, the wormlike flower-fly larva ravages aphid colonies. Maturing into a winged adult, it feeds on nectar and aphid honeydew. Because of its springtime habit of hanging suspended, wings vibrating, above aphid-infested plants, the predator is also called the hover fly. The female lays her eggs among the aphids. Flower-fly larva, having killed an aphid twice its size, drags the corpse down a rose stem. Young of many flower-fly species, varying in size and color, prey on aphids. Winged adult and half-grown aphids feed among black eggs and the bleached skins of insects that have recently molted. Eggs will ensure another year of survival for this colony, despite the slaughter among 858 its ranks throughout the summer.