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

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Hepialidae

Overview

There is now evidence that the Hepialidae (ghost moths, swifts) are not monophyletic. However, the family assignment of Fraus and three other genera is undetermined and they are here treated in the informal grouping 'primitive Hepialidae' and the remaining Hepialidae as the Hepialidae s. str.

Description

'Primitive Hepialidae' . Small to medium-sized; head with lamellar or piliform scales; flagellar segments bipectinate or each with one rounded lobe; mandibles small to vestigial; proboscis short or absent; maxillary palps 1-segmented; labial palps 2- or 1-segmented; epiphysis present or absent; spurs absent; hind tibia not modified; wings aculeate, with only normal-type scales, scales with larger tooth at each distal corner; fore wing with Sc simple, R 2 +R 3 and R 4 and R 5 stalked (cross-vein R-M 1 reaches R 4+5 between furcation R 2+3 /R 4+5 ), CuP present in basal half of wing; female hind wing with weak hair pencil. Pupa with one transverse row of spines on T3 to T6.

Hepialidae s . str . Medium-sized to very large; head with piliform scales; flagellar segments angular, dentate, bipectinate, tripectinate or simply cylindrical; proboscis absent; maxillary palps minute, 1- or 2-segmented; epiphysis present or absent; spurs absent in all Australian species; hind tibia with prominent hair-pencil in some species; wings aculeate, with only normal-type scales; fore wing  with Sc simple or forked; R 2 and R 3 stalked, R 4 and R 5 separate beyond cross-vein R-M in Australian species or R 4 and R 5 from stem of R 2+3 (oxycanus-type venation). Egg nearly spherical, surface without ribs, with two micropyles. Larva long, cylindrical, with 6 stemmata, 3-segmented maxillary palps, thoracic legs and abdominal prolegs present, crochets in multiserial ellipse. Pupa long, cylindrical, with rudimentary mandibles, maxillary palps absent; appendages fused to body wall, abdominal terga each with 2 transverse rows of spines and S7 with ventral transverse row of spines (often connected to anterior dorsal row on T7); segments 3-7 in males and 3-6 in females movable; cremaster absent.

Distribution

Of the Primitive Hepialidae , Fraus , endemic to Australia, and three non-Australian genera ( Afrotheora , Antihepialus and Gazoryctra ) were excluded from the Hepialidae in order to make that group monophyletic (Nielsen and Scoble 1986). Fraus (25 spp.) occurs in eastern and southern Australia. All but one of the species fly from late January to late June. F . orientalis is common along the east coast and is typical of several species with slender, longitudinally striped wings and slender body. F . simulans , a minor pest on pastures in Tas., has a wide range in southern Australia, and is typical of the heavy-bodied Fraus species without proboscis and epiphysis; its larva constructs a silk-lined vertical tunnel in the soil and feeds at night, mainly on adjacent grasses (Hardy 1973). The similar F . polyspila is locally extremely abundant in southern, mainland Australia. Flight takes place shortly after sunset; one species, F . fusca , flies during the afternoon at higher altitudes (Nielsen and Kristensen 1989).

The Hepialidae s. str . are richly represented in Australia and include many large species. Zelotypia (1 sp.) and Aenetus (16 spp.) contain beautiful species, whose larvae tunnel down vertically in the stems of living trees and shrubs. They feed on the bark regrowth around the entrance to the tunnel, where they form a vestibule covered with a webbing of silk, wood particles and faecal pellets. Pupation occurs in the tunnel, the entrance being previously closed with a silken wad. The larvae of the large, orange-brown Z . stacyi tunnel in Eucalyptus in southern Qld and eastern N.S.W. Most Aenetus species are strongly sexually dimorphic. A . ligniveren is a relatively small species from the coast and tablelands in south-eastern Australia; its larvae make a relatively short tunnel in various small trees, including Eucalyptus , Acacia and Lantana . A . eximia is larger and its larvae often make tunnels 50 cm long in the stems and roots of Acmena , Prostanthera and other trees. A . dulcis is a large species with white males and green females from south-western W.A. with larvae in Agonis . The larvae of several Aenetus species are sought by black cockatoos.
Larvae of Oncopera (12 spp.) form vertical tunnels in the soil; the larvae emerge at night to feed on the foliage of herbaceous plants growing near the entrance to the tunnel; others feed on leaf litter on the ground in rainforest. A few species are serious pasture pests in southern Australia. The larvae of Trictena (3 spp.) and Abantiades (14 spp.) live in vertical tunnels in the soil and feed externally on the roots of Eucalyptus and other trees. Their life history is well adapted to the aridity of inland Asutralia, where great flights of the moths occur after a fall of rain. Natural mortality of the early stages is very high; a single female of A . magnificus lays more than 18 000 eggs. Oxycanus (44 spp.) is the largest Australian genus and has, like Elhamma (1 sp.) and Jeana (2 spp.), oxycanus-type venation. The larvae of Oxycanus live in vertical tunnels rather similar to Oncopera . The species may be very common locally, and a few are pasture pests, while others feed on leaf litter on the soil surface or externally on Acacia roots. The flight of several Oxycanus species is, often spectacularly, correlated with rain. [Common 1966a; Hardy 1974; Tindale 1932-64.]

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