File: <coleopt.htm>

COLEOPTERA

Many families of Coleoptera exhibit predaceous feeding behavior, and probably includes the majority of all insect predators. Species of Adephaga families Carabidae, Dytiscidae, Cicindelidae and Gyrinidae are almost all predaceous. They feed generally on insects of suitable size that occur in the habitat, but they attack many other forms of small animal life as well. In Polyphaga, the principal predaceous groups are Silphoidea (Silphidae), Staphylinoidea (Histeridae and Staphylinidae), Cantharoidea (Cleridae, Lampyridae, Cantharidae), Mordelloidea (Meloidae), and Cucujoidea (Coccinellidae). Even though most are general feeders, certain families are very much restricted in host preference. Silphidae normally feed on larvae of Diptera present in decaying animal flesh, while most Lampyridae, in both larval and adult stages, feed mainly on snails, earthworms, etc. Most Meloidae are predaceous on eggs of Locustidae in the soil, while several species develop in the cells of bees. The large family Coccinellidae, although having some phytophagous species, attacks mainly Coccidae, Aleyrodidae and Aphididae. In crop pest control, the Carabidae and Coccinellidae are of especial importance (Clausen 1940/1962).

A parasitic life style is not so common in Coleoptera as it is in Hymenoptera and Diptera, with ca. 8 families showing this behavior. Most species of the small family Leptinidae exhibit a facultative parasitism, and in the Staphylinidae many species of the Aleocharinae (Baryodma, Coprochara and Aleochara) are parasitoids of Diptera puparia. In Cleridae, several species of Hydnocera are parasitoids, and some Trichodes seem to develop in the same way. The Ripiphoridae are entirely parasitic on hymenopterous larvae and cockroaches. Some species of Colydiidae (e.g., Deretaphrus and Bothrideres) are considered parasitic, which is true also in Catogenus of the Passandridae. A few species of Anthribidae of the genus Brachytarsus are considered parasitic inasmuch as the larval food is strictly limited to the eggs beneath a single coccid host and the stimulus for oviposition is provided by the scale host itself rather than by the eggs. A few Coccinellidae, only those which attack the larger monophlebine Coccidae, may also be thought of as parasitic because the larva may develop entirely at the expense of a single host individual (Clausen 1940/1962).

There are few internal parasitoids among Coleoptera, except in the Ripiphoridae, where it is normal for all species. Among species attacking cockroaches the entire feeding period is passed internally, while in those attacking larvae of Hymenoptera, the internal phase is restricted to the latter portion of the 1st larval instar and the following instars are external feeders. Internal parasitism by Colydiidae is suspected, especially as isolated records show larvae being collected from pupae of Chrysobothris.

Parasitic Coleoptera show a considerable uniformity in behavior and the manner of development. In the families Ripiphoridae, Staphylinidae and Meloidae, all species deposit their eggs apart from the host stages on which development is to occur, placing them in the soil, in host galleries, or on foliage or blossoms. First instar larvae of parasitic Staphylinidae search for dipterous puparia in the soil of refuse habitat; those of Ripiphoridae attacking cockroaches, and probably a few Meloidae attacking bees, gain access to the host directly. The majority of species of the latter two families that attack vespoid wasps and bees, respectively, seem to require the services of a carrier to transport them from the vicinity of hatching to the cell, and this role is usually filled by the female wasp or bee (Clausen 1940/1962). Larval development among parasitic species also reveals certain points in common that are not possessed by the predaceous forms. A notable hypermetamorphosis occurs during larval development. The planidium type of 1st instar larva is of common occurrence in the Meloidae and Ripiphoridae and in parasitic representatives of several other families. Later larval instars assume a degenerate form in which the appendages are much reduced and the powers of locomotion are very limited or entirely lacking. Nonfeeding larval stages of Meloidae have not been recognized in other parasitic groups of Coleoptera with the exception of Drilidae (Clausen 1940/1962).

A early comprehensive review of the biology and behavior of entomophagous Coleoptera were presented by Balduf (1935). Böving & Craighead (1930-1931) provided an illustrated synopsis of the larval forms of Coleoptera, dealing especially with specialized larvae of a number of predatory and parasitic species.

References: Please refer to <biology.ref.htm>, [ Additional references may be found at: MELVYL Library]