What Bug Is That? The guide to Australian insect families.

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Tenebrionidae

Overview

Tenebrionids are primarily scavengers, feeding on a variety of dead material of plant or fungal (rarely animal) origin, and they have been able to survive better than most beetles in arid habitats throughout the world. Many (mainly Lagriini, Adeliini, Heleini and Opatrini) occur under rocks and in leaf litter, with the larvae living in the soil or scavenging on the ground at night; among these are a number of psammophilous species ( Sphargeris physodes , Trachyscelis , Heterocheirini, Hyociini, some Opatrini) occurring on dunes or near accumulations of debris along ocean beaches or on sandy river banks. A number of tenebrionid larvae (some Adeliini, Phrenapatinae, Tanylypa , Meneristes , Asphalus , many Cyphaleini, Ulomini, some Amarygmini, Alleculinae, Gnathidiini and Coelometopinae) feed in rotten wood; adults may also feed on the wood (Ulomini, Gnathidiini), but more often they occur on surfaces at night feeding on lichens, fungi or plant material. Some larval forms may also graze on surfaces at night; these are known in Titaena , Amarygmus , and the Leiochrini. Members of the Toxicini and Bolitophagini and most Diaperini feed as both larvae and adults on fungal fruiting bodies (particularly Polyporaceae), while other tenebrionids may occur in caves ( Brises ) or animal nests. Some subterranean forms will feed on the roots of plants, including commercial crops; these false wireworms occur in several genera, including Celibe , Pterohelaeus , Isopteron and Gonocephalum . A number of species (known as mealworms and flour beetles) have become serious pests of stored products; these include Alphitobius diaperinus , A. laevigatus , Gnatocerus cornutus , Latheticus oryzae , Palorus subdepressus , Tenebrio molitor , T. obscurus , Tribolium castaneum and T. confusum . The Egyptian beetle ( Blaps polychresta ) was accidentally introduced from North Africa, and has become relatively common in S.A. around human habitations; however it is not considered a pest species.

Description

Highly variable in form, but usually black or brown and subglabrous, with concealed antennal insertions and usually stout, moniliform or incrassate antennae. Eyes usually emarginate; lateral pronotal carinae usually simple and complete; prosternal process usually moderately broad, strongly curved dorsally behind coxae, neither strongly nor abruptly expanded apically; junctions of first 3 ventrites different from those separating last 2, the basal ventrites being strongly connate and the apical ones more or less movable, often with exposed membrane. Externally open fore coxal cavities occur only in Tanylypa , internally open ones in some Tenebrioninae. Although almost all species have a 5-5-4 tarsal formula, reduction to 4-4-4 has occurred at least 7 times in Australian tenebrionids (usually in small and relatively rare species). Most members of the family are also characterised by having paired glandular reservoirs, associated with a chemical defence system, located usually at the base of the 5th ventrite. In some Adeliini, these reservoirs are completely extruded when the animal is disturbed. Most Lagriinae and Alleculinae differ from other tenebrionids in having a distinctly lobed penultimate tarsal segment, and the latter are further distinguished by their pectinate tarsal claws.

Larvae are almost always elongate (ovate in Leiochrini) and subcylindrical to slightly flattened. They may be very lightly sclerotised, moderately sclerotised and yellow in colour, with or without darker head and urogomphi, or uniformly heavily sclerotised and darkly pigmented; and the vestiture consists of scattered, fine hairs, except in Lagriini, whose larvae are densely setose. Some are called 'false wireworms' because of their resemblance to elaterid larvae, but they have a very different type of head, which is less flattened and with a distinct clypeus and labrum. A combination of frontoclypeal suture, simple and rounded mala, and no hypostomal rods will distinguish tenebrionid larvae from those of most related groups.

Distribution

All of the 7 subfamilies recognised by Doyen et al. (1989) occur in Australia. Lagriinae (37 genera) includes Adeliini, a dominant group in forested areas but not common in the dry interior, Goniaderini, Lupropini, Lagriini (formerly the Lagriidae), Cossyphini, Belopini and Chaerodini ( Sphargeris ). Phrenapatinae includes Archaeoglenes and the Penetini (4 genera); while Pimeliinae is comprised of several rare groups of doubtful affinities (e.g. Tanypypa in Zolodinini, Cnemeplatiini, Ceratanisini) plus an introduced Ocnera (Pimeliini). Tenebrioninae (90 genera) contains the bulk of the tribes, including Toxicini, Bolitophagini, Tenebrionini, Heleini, Cyphaleini, Titaenini, Alphitobiini, Triboliini, Ulomini, Heterocheirini, Opatrini, Leichenini, Amarygmini and the introduced Blaptini. Alleculinae and Diaperinae each include 25 genera, and the latter includes Crypticini, Phaleriini, Trachyscelini, Myrmechixenini, Hypophloeini, Gnathidiini, Hyociini, Ectychini, Leiochrini, Scaphidemini and Diaperini. Coelometopinae (22 genera) includes Coelometopini and Strongyliini. Adelium and Cardiothorax are the largest adeliine genera. Tanylypa morio from Tasmania is a very unusual and probably primitive species most closely related to the New Zealand Zolodinus zelandicus . The Heleini include the strongly flattened and wingless 'pie-dish beetles', which are most common in the dry interior of the continent, as well as the genus Lepispilus , larvae of which occur in rotten wood. The related Cyphaleini include many brightly coloured, metallic forms, like Prophanes mastersi , as well as the dark coloured and heavily sclerotised, xerophilous species belonging to Nyctozoilus and related genera. The large amarygmine genus Chalcopteroides includes a number of species which are metallic blue or green with an iridescent sheen. [Carter 1926; Doyen 1966, 1984, 1985; Doyen and Lawrence 1979; Doyen and Tschinkel 1982; Doyen et al. 1989; Tschinkel and Doyen 1980; Watt 1974b.]

  • Cyphaleus sp.

  • Ecnolagria tomentosa

  • Pterohelaeus sp.

  • Blaps polychresta

  • Latheticus oryzae

  • Gonocephalum sp.

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