Although there are about 4,000 species of aphids, only about 250 species are known as pests. They are sometimes guarded by ants (which eat the sweet "honeydew" aphids produce), so many predators ignore them. However, some creatures do feed on these tiny plant parasites. In addition to arachnids and birds, certain types of insects kill or eat aphids. These insects help farmers and gardeners combat aphid infestations, which can severely damage crops and orchards. They thrive in warm conditions and eat almost any type of plant. Relatively few species eat aphids; luckily for farmers, such insects prove plentiful.
A few types of beetles kill aphids, most notably the ladybug. Also known as a ladybird, it eats aphids and other very small insects. People have recognized their beneficial nature since the Middle Ages, according to the Hercules Wildlife Guide. These spotted beetles can find aphids on plants indoors and outside. Others that eat aphids include the spined soldier bug, rove beetle and big-eyed bug, according to the Canadian Wildlife Federation.
Some types of small, parasitic wasps also kill and eat aphids. Certain braconid and chalcid wasps kill aphids by implanting eggs in them, according to the Ohio State University Extension. The ichneumon wasp and a few other small varieties of wasp also kill aphids. Larger wasps typically prefer prey of greater size.
Various types of insect larvae feed on aphids, using a variety of methods. Lacewing larvae kill aphids, sometimes hiding before they attack, according to the University of Florida. People sometimes call larvae that eat aphids "aphid lions." Harvester butterfly caterpillars (another type of larvae) also kill aphids. Ladybug and hover-fly larvae eat aphids as well.
Moderately large among insects, the praying mantis kills aphids and various other bugs. People know this impressive insect for its large eyes, prominent antennae and long legs. It lives in grassy areas, gardens and shrubbery of southern Canada and the eastern United States.
The assassin bug will also eat aphids, although it is not necessarily among the insects you would want to find in your garden, due to the potential for bites. The Canadian Wildlife Federation indicates that it also devours various beetles, flies, caterpillars and hornworms.
Similar to a dragonfly but not as large, the damselfly proves just small enough to consider aphids a worthwhile food source. It often appears in swamps and areas near lakes or ponds. These long, multi-colored insects measure 1 to 2 inches long. They do not make as much noise when flying as dragonflies do.
- Friends of Hercules: Hercules Wildlife Guide
- Forest Preserve District of Cook County: Aphids
- Florida Museum of Natural History: Butterfly Q & A
- "Familiar Insects and Spiders"; Alfred A. Knopf; 1988
- Photo Credit Hemera Technologies/PhotoObjects.net/Getty Images
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