Overview
Elaterid larvae may be saprophagous, feeding in rotten wood; phytophagous, feeding mainly on roots of plants; or predacious. In all cases, however, they are liquid feeding and practise extraoral digestion. Phytophagous larvae known as wireworms are pests of cereals, grasses and root crops.
Description
Beetles of characteristic elongate form, with acute hind angles on prothorax and a 'clicking' mechanism enabling them to jump by forcing the long prosternal process suddenly into a cavity on the mesosternum causing a sudden movement of the prothorax relative to the hind body (Evans 1972, 1973). Labrum always visible; frontal area usually with sharp transverse ridge between eyes; antennae almost always serrate; tarsi simple or provided with setal brushes or membranous appendages; 5th ventrite more or less free, so that membrane usually visible between it and ventrite 4.
Larvae elongate and cylindrical to slightly flattened, and either uniformly sclerotised and yellow to brown in colour, or more lightly sclerotised, except for head capsule, protergum and T9. Labrum and clypeus solidly fused to remainder of head capsule forming nasale, which is variously lobed or toothed; stemmata often reduced or absent; ventral mouth-parts consolidated to form maxillolabial complex; 10th segment reduced and ventrally situated; T9 terminal, with characteristic modifications (cylindrical, acute, forming concave plate or with simple or bifurcate urogomphi) in different genera.
Distribution
Species of
Pseudotetralobus
include the largest of Australian elaterids, and their larvae, which live in termite nests, are grub-like and densely clothed with long hairs. Agrypninae include the common genera
Agrypnus
and
Conoderus
, which have soil-inhabiting larvae, as well as
Paracalais
, which are predators of wood-boring beetles;
Agrypnus variabilis
is a major pest of sugar cane in Qld. Among Australian Denticollinae are
Hapatesus
,
Elatichrosus
and
Glypheus
, as well as the large Bassian genus
Crepidomenus
and its allies (Calder 1986). Common genera of Elaterinae include
Anilicus
,
Glyphochilus
,
Dicteniophorus
and
Melanoxanthus
.
Paracardiophorus
(Cardiophorinae) are abundant, and their unusual, slender larvae are predators in soil. Two groups often included in the family Throscidae but indistinguishable from elaterids on the basis of larval features are the Thylacosterninae and Lissominae. The former are represented in North Qld by
Cussolenis mutabilus
, a cylindrical, eucnemid-like beetle with flabellate antennae, and the latter include
Drapetes
and
Lissomus
, which are throscid-like in form, with long membranous lobes on the tarsi and antennae enclosed in deep cavities beneath the prothoracic hypomera. [Burakowski 1973; Crowson 1961b; Eidt 1959; Gur'yeva 1969; Lawrence 1988b; McDougall 1934; Neboiss 1956, 1961, 1967; Stibick 1979.]