True Bugs: What Are They? - October 12, 2011
Jeff Schalau, Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County
Many gardeners are curious and interested in bugs. We usually categorize them as good ones or bad ones depending on what we experience and learn by reading and observing. For most, the term “bug” is a casual designation we use to describe a variety of insects and sometime non-insect arthropods. Most of us know the difference between insects and spiders, but people often bring me “bugs” that have more than 6 legs. A “true bug” is an insect in the order Hemiptera. However, entomologists are still discussing whether or not aphids, leafhoppers, and cicadas are included in that group or not.
True bugs have very distinctive front wings, called hemelytra, in which the basal half is leathery and the apical half is membranous. At rest, these wings cross over one another to lie flat along the insect's back. Where the wings cross on their back, there is often a visible triangle-shaped design which can often be used to quickly distinguish true bugs from other insects. True bugs do not have a larval stage and the nymphs (juveniles) often bear little resemblance to the adults. True bugs also have piercing-sucking mouthparts which form a flexible feeding tube (proboscis) that is no more than 0.1 mm in diameter yet contains both a food channel and a salivary channel. They use this unique apparatus to feed on plants, other insects, and animals (including humans).
True bugs include a diverse assemblage of insects that have become adapted to a broad range of habitats -- terrestrial, aquatic and semi-aquatic. The aquatic and semi-aquatic true bugs include backswimmers, water striders, and giant water bugs (for which Big Bug Creek is named). All of these are predators of other insects and small vertebrates, or scavengers. Backswimmers and giant water bugs can inflict a painful bite.
Gardeners are probably aware of terrestrial true bugs because many feed on plants. Squash bugs are pests of squash and pumpkins. They feed on the stems and leaves and inject a substance which causes the plant to wilt. Squash bugs are often found in large populations, congregated in dense clusters on vines and unripe fruits. Plant bugs, seed bugs, and stink bugs are common in landscapes where they feed on foliage, fruit, and seeds. Their damage can be significant on young plants. Many of these species exude unusual odors. In my yard, stink bugs congregate at the bases of ash trees in the spring. When my weed eater hits them, it smells very distinctive (not necessarily foul, but a bit like a chemical). There are several hundred species of these bugs in North America. Box elder bugs fall into this category. The leaf-footed plant bug is another interesting species found in Yavapai County. It has leaf-like appendages on its back legs.
Some true bugs are predatory and are considered beneficial in the garden and landscape. Some of these are the minute pirate bug, assassin bug, and ambush bug. Minute pirate bugs feed on small insects and eggs of other insects like the corn earworm. Ambush bugs catch prey by sitting still on flowers. They capture prey with their mantis-like front legs. Assassin bugs kill their prey by injecting it with a toxin that dissolves the victim’s tissue. It then sucks up the liquefied tissue with its long proboscis.
Conenose bugs were the topic of the October 5, 2011 Backyard Gardener and are related to assassin bugs, but feed on blood of small mammals and occasionally humans. Conenose bugs, also known as Hualapai tigers and kissing bugs, are common in Arizona.
Bed bugs are also true bugs. These small, wingless insects also feed on blood. Close relatives of bed bugs include the bat bug which is common in attics colonized by bats, and swallow and chimney swift bugs which can be found in homes inhabited by swallows, pigeons, and other wild birds. Bat and bird bugs prefer hosts other than humans; however, they may feed on humans if other hosts are not available.
As the weather cools off in the fall, some true bugs seek shelter and warmth in the walls and crawl spaces of houses. This is common with box elder bugs and seed bugs. If this happens to you, they can be managed by collecting them with a vacuum and putting them into a tub of soapy water. Look below for photos of plant-feeding true bugs.
Follow the Backyard Gardener on Twitter – use the link on the BYG website. If you have other gardening questions, call the Master Gardener line in the Camp Verde office at 928-554-8999 Ext. 3 or e-mail us at firstname.lastname@example.org and be sure to include your name, address and phone number. Find past Backyard Gardener columns or provide feedback at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.
Drawings of stink bugs and leaf-footed bugs (from: North Carolina State University).
Leaf-footed plant bug (from: www.arizonensis.org).
Say's Plant Bug - Chlorochroa sayi (from: University of Arizona Cooperative Extension, Yavapai County).
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