Subject: Australian Possibly Coleoptera or Hymenoptera?
Location: Canberra, Australia
January 14, 2014 5:12 am
I usually like to entertain myself by attempting to identify insects around my house, sketch and release them. I can often identify down to the species thanks to many helpful Lucid keys such as from CSIRO. Your website is also incredibly useful in finding insects and links to info pages.
However, tonight I’m stumped as to even which Order this insect belongs to.
My mum thinks it is a beetle because it appears to have elytra and my dad thinks it is a wasp because of it’s elongated body.
It has huge compound eyes, no evident ocelli eyes, hardened forewings which do not cover the membranous hindwings stretching over just half of the body. It’s antennae are short, curved and filamented, and are tucked under the head at rest. It has long mouthparts that if anything resemble a fly’s. It also has a long “filament” which sometimes protrudes from it’s abdomen which I can only assume is genitalia.
I hope that is enough information. Sorry for phone photos!
This is quite a find, and our collective hats go off to your mother for actually correctly identifying the insect order. This really is a beetle, despite its decidedly un-beetle-like appearance. It is a Ship Timber Beetle in the family Lymexylidae and probably the genus Atractocerus, and it is represented in our archives a scant three times, prior to your submission. There is considerable information from our previous postings, but we are going to search the web for additional links with additional information. According to BioDiversity Explorer: “Adults are attracted to light at night and larvae bore into hard wood and palm stems.” According to British Insects: the families of Coleoptera, they are capable of: “Boring into living wood (causing fungal infections on which the larvae feed), or boring into dead wood.” According to Beetles in the Bush: “Nothing is known about the biology of Atractocerus, but larvae of other genera are reported to bore into hardwoods and palm stems (Picker et al. 2002). Larvae of the genera Lymexylon and Melittomma are believed to form symbiotic associations with ambrosia fungi that grow on the walls of their galleries (Young, 2002). Adult females deposit fungal spores in a sticky matrix when they lay their eggs, and the hatching larvae carry the spores into wood on their bodies. The large eyes of Atractocerus, however, suggest a predatory lifestyle. The common name of the family originates from a northern European species that has in the past been a destructive pest of ship timbers.” There is a host of information in Papéis Avulsos de Zoologia. The Atlas of Living Australia has a record of Atractocerus crassicornis Clark, 1931, from the northeast corner of West Australia, and there is a record of another species, Atractocerus tasmaniensis Lea, 1917, from Tasmania, also on the Atlas of Living Australia. Yet another species, Atractocerus victoriensis is listed, but not pictured, on the Australian Faunal Directory. According to A Guide to the Beetles of Australia (and we have to type this out because the document will not allow us to cut and paste): “Ship-timber beetles are extraordinarily slender with a distinctive shape. Members of the genus Atractocerus have very short elytra and well-developed, gauzy flying wings. When these beetles are at rest, their wings are folded fan-like but as the reduced elytra can not cover them, they are exposed. Gravid females have enormously swollen abdomens. They lay their eggs in woulds of eucalypts and possibly other hardwoods too. The cylindrical and elongate larvae have short, strong legs, and a hood-like pronotum, which partially conceals the head from above. They bore into the timber and grow to considerable size (up to 35 mm in length). Their tunnels run parallel and transversally with and to the grain. Discontinuous, irregular bands of stain marks caused by their activity discolour the timber. The larvae feed on a fungus, which grows on the walls of their tunnels in the timber. This fungus is transmitted by the beetles themselves. It is presumed that their development takes at least two years. Adults can be found in decaying timber, on tree trunks and occasioinally fly to artificial lights. Adult specimens of a Western Asutralian species of Atractocerus sometimes fly in swarms at dusk.” Thanks so much for contributing additional photos of this rarity, and our first example from Australia, to our archives.