True Bugs, Pacific Northwest
Aphids are small green insects that suck juices from plants. They are shaped like pears and can be found on many coastal plants. There are hundreds of different species of these true bugs. Some of them are found on only one type of plant, while others can be found on many types of plants.
Most are less than 0.5 cm long and although most of them are green, they can be gray, black, brown, pink, red, yellow, or lavender. All have two tubes, called cornicles, on the hind end of their bodies. The cornicles secrete substances that help protect them from predators.
They feed in large groups on new growth. Some species such as the woolly aphids are covered with white, waxy filaments which they produce from special glands. You will usually find aphids on leaves, tops or at the base of flowers. They can do a lot of damage to plants that include foliage that is distorted, rolled, yellowed or has stunted growth. There are beneficial insects that eat them, such as ladybugs and green lacewings and it is very important to not use a broad pesticide spray as this will kill all the insects including the good ones.
Aphids create a honeydew that ants harvest. Ants often farm aphids and protect them from their natural enemies and in turn, harvest the honeydew produced by the aphids. Some types of ants take them down into their nests in winter to keep them alive until next year.
They have strange life cycles. Most aphids overwinter as fertilized eggs glued to branches of plants. The nymphs that hatch from these eggs are wingless females known as stem mothers. Stem mothers reproduce without males and keep their eggs within their bodies until they hatch. All offspring, in turn, are females that soon mature and reproduce in the same way. This pattern continues until the fall brings cooler weather. When the days get shorter and coolers, a hatch occurs which includes both males and females that mate, after mating, the females lay the fertilized eggs which overwinter and eventually hatch into stem mothers the following spring.
Throughout the summer some of the young develop wings and migrate to other plants. This allows them to move about the forest. They are an incredible bug.
Natural enemies play a very important part in controlling aphid populations. Lady beetles, lacewings, damsel bugs, parasitic wasps and birds all feed on them.