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Ground Beetle

Introduction

Calleida decora (Fabricius) is a small arboreal ground beetle, predaceous both as larva and adult. Common on various cultivated crops, it is apparently the only carabid to complete its larval development on Florida soybean foliage (Neal 1974). It is believed to be a major factor in suppression of several lepidopterous pests, e.g., velvetbean caterpillar, Anticarsia gemmatalis Hübner, on soybeans.

Distribution

Calleida decora is reported from the southeastern United States, extending into the Midwest, Baja California, Mexico, and Belize (Erwin et al. 1977).

Description

Adults

The adults are slender, 7 to 10 mm long, 2.5 to 3.5 mm wide. Head and elytra are green or blue-black, thorax and legs yellowish-red with tips of femora and tarsi dark. Antennae are dark with three or four basal segments lighter.

Males have a double row of papillate hairs on the undersurface of the first three protarsal segments and first two metatarsal segments (appearing white), but female tarsi are pubescent (straw-colored) (Horn 1882, McWhorter et al. 1984).

Eggs

The eggs are round, white, semi-opaque, approximately 0.75 mm in diameter, covered with sand particles, and attached by a silken thread to a leaf or other available surface such as a stem or twig.

Larvae

The larvae are active, black, campodeiform (in early stages having no abdominal appendages except cerci), with yellowish-red head capsules. Larvae are approximately 1.5 mm long at hatching and may grow to 10 mm total body length prior to pupation. Mean head capsule widths for the three larval instars are 0.60, 0.90, and 1.23 mm respectively.

Pupae

The pupae are white, exarate and approximately 5 mm long. The pupal cell is usually constructed ca. 7 to 15 mm beneath the soil surface (Hasse 1971).

Biology

Caged adult females live an average of 230 days with a mean preovipositional period of 11 days and lay an average of 800 eggs (McWhorter et al. 1984). While an egg is still held by the abdominal tip, the female covers it with sand or dust particles, and binds it with silken thread to form a purse. The “egg purse” is attached to a leaf by a silken thread. Developmental times at 22 to 28°C for eggs, larvae, and pupae are approximately four to six, 12 to 18, and four to six days, respectively (McWhorter et al. 1984; unpublished data 1973, 1982). Larvae are predaceous except while undergoing sclerotization following hatching and molting (McWhorter et al. 1984). They are highly cannibalistic and must be reared in individual containers. They feed readily on lepidopterous eggs as well as small larvae.