Leaf-Footed Bugs

Nearly 90 species in North America north of Mexico

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Leaf-footed bug on a leaf
The western leaf-footed bug (Leptoglossus clypealis) is not limited to the western United States — indeed, it is one of many species of leaf-footed bugs that occur in Missouri. Apparently it has gradually expanded its range eastward since the early 20th century.
Donna Brunet
Other Common Name
Coreids; Squash Bugs
Family

Coreidae (leaf-footed bugs) in order Hemiptera (true bugs)

Description

Leaf-footed bugs are a family of plant-eating true bugs that are named for the flattened, leaflike extensions that many have on their hind legs. Good flyers, they usually make a noisy buzzing as they fly. When disturbed, many species give off a bad odor in defense. They are usually dark colored, though some are tan, orange, or yellowish, and may have contrasting colors.

In North America north of Mexico, there are 11 tribes in 3 subfamilies in this family of true bugs. The common names of several species name the food plants they are associated with, such as the passion vine bug, the milkweed bug, sweet potato bug, and — most famous of the bunch — squash bug.

Similar species: Several other groups of true bugs look similar. See Key Identifiers, below, for special ID characters for leaf-footed bugs that will help distinguish them from similar bugs.

  • Seed bugs (family Lygaeidae) have only 4 or 5 veins on the forewing membrane (visible, at rest, on the diamond-shaped, posterior portion, covering the end of the abdomen).
  • Stink bugs (family Pentatomidae) have a rounder or squarer, shieldlike body; large, triangular scutellum at the middle of the back; and 5-segmented antennae.
  • Assassin and ambush bugs (family Reduviidae) are predatory, with a short, 3-segmented beak that fits into a groove under the head, and their forelegs (not hindlegs) are typically thickened and muscular looking. There is usually a narrower, necklike constriction at the base of the head.
Key Identifiers

 

  • Many parallel veins on the front wing membrane (visible, at rest, on the diamond-shaped, posterior portion that covers the end of the abdomen)
  • Usually more than ½ long
  • Usually dark colored
  • Usually oval
  • Head narrower than pronotum (shoulderlike plate behind the head); head usually shorter than pronotum, too
  • Hind leg tibiae (shinlike leg segment) often flattened or leaflike
  • Outside edges of abdomen often raised, with folded wings fitting in a bowl-like depression
  • Antennae with 4 segments
  • Fairly long beak, with 4 segments
Size

Length: most are ½ to ¾ inch, though some Missouri species may reach 1¼ inches.

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Leaf-footed bug, viewed from below as it rests on a window
Leaf-Footed Bug Ventral View
This leaf-footed bug rested on a window, so we can see it from below. Note the flat extensions on the hindlegs and the relatively long, 4-segmented beak.

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Squash bug on sand
Squash Bug
Squash bugs feed on the foliage of squash, pumpkins, and other plants in the squash family. Adults of our most common species (Anasa tristis) are shiny, brownish, speckled in the front parts of the body, and rather oval. The head is narrow.

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Squash bug nymphs clustered on a leaf
Squash Bug Nymphs
Squash bug nymphs go through several stages, the youngest light green and aphid- or spiderlike, the older ones grayish, all with dark legs. It is only when they become adults that they have wings and can fly.

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Squash bug egg cluster on leaf between midvein and another vein
Squash Bug Eggs
Adult squash bugs mate in spring and lay small masses of shiny, oval, copper-colored eggs beneath leaves on squash plants. Hatchlings are pale green. Older nymphs are gray with dark wing buds. Often a mixture of stages congregate together on the same plant.
Habitat and conservation

Leaf-footed bugs occur where their food plants are present. Some species are attracted to lights at night. Sometimes, people find these insects floating in swimming pools or birdbaths.

Foods

Most species eat plants, feeding on them in true-bug fashion: the mouthparts are modified into piercing-sucking tubes, which they insert into foliage, fruits, seeds, or other plant parts and then use to suck out sap and other nutrients. Some species are serious agricultural pests (the squash bug is a prime example).

Distribution in Missouri

Statewide. Distribution of these bugs mirrors the distribution of their various food plants. Different species have different food plants, and some species have a wider range of food plants than others.

Life cycle

Female leaf-footed bugs typically glue their eggs in masses on the undersides of leaves of suitable host plants. The nymphs hatch and begin feeding. Like other true bugs, metamorphosis is simple (there is no drastically different caterpillar or grub stage or pupation). The various nymphal stages look more or less like smaller, wingless forms of the adults. Depending on the species, there may be only one, or there may be up to several generations each year. The mothers of some species of leaf-footed bugs carry eggs on their backs, which reduces the chance of them being parasitized or eaten. Apparently, most species overwinter as adults.

Human connections

Several types of leaf-footed bugs eat garden or crop plants, and some are serious pests. People have created an array of pesticides and other strategies for battling these insects. Many home gardeners, however, have decided that the best way to manage squash bugs is to simply pick them off the plants and kill them.

Although we humans habitually think of any insect that eats plants as a competitor, we should remember that herbivorous insects are nature’s drivers. They have important roles in balanced ecosystems, and nature would collapse without them.

Ecosystem connections

Leaf-footed bugs — and the legions of other insects that feed on plants from early spring until freezes stop them in late fall — play an immense role in converting plant nutrients into a form that can be eaten by other animals. These insects’ protein-rich bodies feed birds, amphibians, reptiles, mammals, and fish. Simply put, they are wildlife food.

A variety of parasitic insects help control leaf-footed bugs naturally. One example is tachinids (flies in the family Tachinidae). They commonly parasitize leaf-footed bugs, laying their eggs directly on their bodies. Look closely at leaf-footed bugs for the (usually white) eggs of these flies. The eggs hatch into tiny grubs that burrow into their host and feed on them from the inside, usually killing the host. For this reason, tachinid flies are often used as biological control agents on a variety of pest insects.