Synonyms and other taxonomic changes
taxonomy on BG follows(1)
1351 spp. in 224 genera (w/40 subgenera) in our area, of which ~80 spp. are pests of food crops and ornamental plants(2)
and over 260 spp. are adventive(3)
Overview of our fauna (* –taxa not yet in the guide):Family APHIDIDAE
Aphids may be identified by two tubelike projections on the posterior, called cornicles or siphunculi
. These appear to function as a means of chemical defense, emitting pheromones to alert other aphids about a predator nearby. They also offer mechanical protection, as the fluid emitted can gum up the mouthparts of the predators. Species may sometimes be identified by the host plant, but several aphid spp. may infest the same host. An attempt to organize aphid images by host plant is underway here
For host plant info see(4)
Aphids suck juices from plants and may be quite damaging. Some are restricted to a single plant species or group of related plants. Others may alternate between two entirely unrelated host plants as a necessary part of their life cycle (e.g. Dysaphis plantaginea
begins the year on apple, then migrates to narrow-leaved plantain for several generations before winged adults return to apple trees where they produce eggs that will overwinter).
Over-wintering eggs hatch in the spring into wingless females. These wingless females are parthenogenetic
(reproduce without fertilization) and hold eggs in their bodies to give birth to living young. Their offspring are similar to the females, but some develop wings. Near autumn male and female wingless forms are born. These mate and the females lay fertilized overwintering eggs. Males can be winged or wingless; parthenogenetic females are usually wingless. In warm climates, living young may be produced continually (adapted from U. of Georgia website).
Feeding aphids excrete a sugar-rich liquid known as honeydew, often consumed by ants who are known to tend aphid colonies and protect them from predators in exchange. Ants are herding aphids and "milk" them by stroking. Some ant species move aphids from one plant to another when the food supply is insufficient, or even take aphid eggs into their nests to help them overwinter.
Predators of aphids include (left to right, below) lacewing larvae, ladybird beetles and larvae, harvester butterfly caterpillars, and the syrphid fly larvae.
Aphids are also attacked by parasitic wasps, which lay eggs inside them. Parasitized aphids swell, become lighter in color and are eventually killed by the developing wasp inside. These are referred to as "aphid mummies."