Immature Stages of Cleridae
Detailed information on immature stages of Cleridae is being acquired. However, Tothill et al. (1930) studied in some detail Callimerus arcufer Chapin, a natural enemy of the coconut moth in Malaya. An attempt was made to introduce this predator to Fiji for control of a related coconut moth, Levuana iridescens B.B. It is not restricted to these hosts but feeds generally on soft-bodied insects found on the trees. The eggs, measuring 1.6 X 0.4 mm., are thickest in the middle region, slightly curved, and yellow in color and are laid underneath host pupae. A maximum of 203 eggs was obtained from a single female, with the average daily rate of laying not exceeding 1, though at times up to 11 have been secured in one day. Larvae feed by preference on pupae, while adults prey extensively on larvae. There are 3 larval instars, though in some cases the 3rd is omitted. Pupation usually occurs within a cocoon. The life cycle from egg to adult takes a minimum of ca. 5 weeks, of which incubation of the egg requires 6 days and the larval feeding period ca. 19 days. The preoviposition period is 16 days or more, and several generations are produced annually.
Tarsostenus univittatus Rossi is predaceous, both as larvae and adults, on powder post beetles of genera Xylobiops and Lyctus infesting seasoned wood products. The female inserts the extended ovipositor into the gallery entrance and lays one or several eggs therein (St. George 1924). The eggs are similar to those of the host, being elongate and cylindrical and with the anterior end drawn out into a slender stalk, which are ca. 1/7th the length of the egg (Clausen 1940/62).
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Böving & Champlain (1920) have observed the behavior of several species attacking primary and secondary bark borers. The eggs are usually laid in the host entrance gallery or in cracks or crevices in the bark. The life cycle is usually correlated with that of the host, and a 2-yr. cycle is suggested in some species. Because larvae feed on the immature stages of their host, it is necessary that the cycle almost parallel that of the latter, for the stages suitable for attack are available for only a relatively short time. Species attacking a 2-brooded host are themselves apt to have 2 generations annually.
Pupation occurs in varied places, some species utilizing the host gallery or pupal cell, while others form a cell in the soil at the base of the tree. Enoclerus sphegeus F. and other Enoclerus spp. line the cell with a foam-like oral exudation. Some clerids consistently pupate without forming a cocoon or cell. Hibernation is not uniform, as larvae, prepupae, pupae and adults of a few species can be found during winter, while other species may be represented by larvae or pupae only. Adults are present in the field during midsummer and may remain for several months.
The behavior of Aulicus terrestris Linsley as a predator of the lubber grasshopper, Esselenia vanduzeei Hebard, and various larvae of Lepidoptera in California was studied by Linsley 91936). Eggs are laid singly under stones or in the soil in the immediate vicinity of the grasshopper egg masses. Larvae are very active and search in the soil for their food, which seems limited to grasshopper eggs. The life cycle coincides with that of the host, and adult beetles appear in late spring at the time the adult grasshoppers are active. However, adults do not prey on any stage of the grasshoppers but subsist instead on various naked larvae of Lepidoptera, in particular those of Noctuidae, found in or on the soil. This feeding is mostly confined to females, males regularly refusing such food (Clausen 1940/62).
Although most species are predaceous, some may develop at times as external parasitoids. Such species are principally in the genus Hydnocera. Hydnocera verticalis Say has been reared from the cocoons of Apanteles. Hydnocera pubescens Lec. seems to be parasitic on the larva of the cotton boll weevil, Anthonomus grandis Boh., in its cell in the boll, and the parasitoid finally spins its cocoon and pupates in the host cell.
An adult of Isohydnocera curtipennis Newm. was reared by Sabrosky (1934) from a goldenrod gall (produced by the larva of Gnorismoschema). An examination of the contents of the gall showed the empty shell of the lepidopterous pupa, within which the cast skin of the beetle larva was found. Development was thought to be at the expense of a single host, but whether internal, as asserted by Sabrosky (1934) or external is uncertain. Clausen (1940) cited Don Clancy's observations on Hydnocera spp. as enemies of codling moth larvae in their cocoons. It was indicated that although the larvae are generally predaceous, a true parasitic development was possible.
Species of Trichodes developing on larvae of various bees, are on the borderline between parasitism and predation (Cros 1908, 1911). Some reach maturity on a single host, others move from cell to cell, devouring several larvae, and they may also consume such of the host food material as may be present. The eggs may or may not be laid directly in the cell or nest, or they may be laid elsewhere and the host is searched for by the young larva. Adults of some species feed mainly on pollen. Several species are known to attack the larvae of honeybees in the hive, and the genus seems limited to hosts of this type. The overall habits are close to Meloidae that develop in the cells of bees.