Most insects and other arthropods found in the yard and garden do not feed on or harm plants. Many of these are just "passing through" or have very innocuous habits. Others feed on and destroy pest species. In many cases, the activities of these beneficial species can completely prevent or greatly limit pest problems. It is important to recognize these beneficial arthropods so that they may be appreciated and conserved.
Beneficial arthropods are categorized broadly as either insect predators or parasites. During development, in both adult and immature stages, insect predators actively search out and consume several prey insects. Predators include ladybird beetles, lacewings and spiders. Insect parasites develop in or on a single host form eggs or larvae deposited by the adult parasite. Common insect parasites are tachinid flies and the brconid and ichneumonid wasps.
Insect Predators:
Ladybird beetles – Often called "ladybugs", ladybird beetles are the most familiar insect predator. Most adult ladybird beetles are round-oval in shape, brightly colored and often spotted. The immature or larvae stages, however, appear very different and often are overlooked or misidentified. Ladybird beetles larvae are elongated, usually dark colored and flecked with orange or yellow. Adult and larval ladybird beetles feed on large Numbers of small soft-bodied insects such as aphids. One group of very small black ladybird beetles (Stethorus) is also very important in controlling spider mites. Ladybird beetles can rapidly control many developing insect problems, particularly if temperatures are warm.
Green lacewings – Several green lacewing species commonly are found in gardens. The adult stage is familiar to most gardeners – a pale green insect with large, clear, highly-veined wings that are over the body when at rest. Adult green lacewings primarily feed on nectar and other fluids, but some species also consume a few small insects.
Green lacewings lay a distinctive stalked egg. Lacewing larvae emerge in four to then days. These larvae, sometimes called aphid lions, are voracious predators capable of Feeding on small caterpillars and beetles as well as aphids and other insects. In General shape and size, lacewing larvae are superficially similar to ladybird beetle larvae. However, immature lacewings usually are light brown and have a large pair of hooked jaws sticking out from the front of the head.
Syrphid flies – These flies are called by several names such as flower flies or hover flies. Most are brightly colored, yellow or orange and black, and may resemble bees or yellow jacket wasps. However, syrphid flied are harmless to humans. Usually they can be seen feeding on flowers. It is the larval stage of the syrphid fly that is an insect predator. Variously colored, the tapered "maggots" crawl over foliage and daily can feed on dozens of small, soft-bodied insects. Syrphid flies are particularly important in controlling aphid infestations early in the season when cooler temperatures may inhibit other predators.
Similar in appearance to the syphid fly larvae is a small, bright orange predatory midge (Aphidoletes). These insects often can be seen feeding within aphid colonies late in the season.
Suggested free e-books to read:
William Wynn Westcott - Historic Lecture Golden DawnIsaac Bonewits - The Enemies Of Our Enemies
Medieval Grimoires - The Secret Grimoire Of Turiel
