Mining digs deeper into trapdoor spider identification

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The Adelaide trapdoor spider Blakistonia aurea in her burrow.

Trapdoor spiders dig burrows for shelter and feeding. These spiders lie in wait for passing prey which they ambush from their burrow at a lightning pace. They are commonly found on mine sites and one particular behavioural characteristic of manytrapdoor spiders makes them very vulnerable to disturbance. Trapdoors dig their burrows as juveniles and live in the same burrow their entire life. If an adult trapdoor’s burrow is destroyed they are unable to dig a new burrow and will die. Trapdoor spider lifespans are not well studied but some individuals have been shown to live for more than 30 years.

The Museum’s Arachnology Collection is integral to a PhD project aimed at improving identification and conservation of a predominately South Australian trapdoor spider genus, Blakistonia, found on Australian mining and survey sites. Sophie Harrison, PhD student at the University of Adelaide, will use the Museum’s collection to compile a database of locations where Blakistonia spiders have been found previously. The database will be used to direct field collections of spiders for morphological and molecular analysis. During her project Sophie will work closely with Nick Birks, a long-standing Museum volunteer who holds considerable expertise in spider sampling, identification and behaviour.

Currently Blakistonia is divided into three species but researchers suspect that many spiders have been misidentified in the past. Surveys by government, university and Museum research scientists collect many trapdoor spiders which need to be identified as part of ongoing work on their biodiversity and conservation status. Female trapdoor spiders are morphologically conservative; unlike male trapdoors, females do not have distinct physical characteristics that can be used to tell them apart. In addition, juvenile trapdoors are also insufficiently developed for accurate identification. Therefore, as female and juvenile trapdoors are difficult to identify using morphology alone, DNA-based techniques are needed for conclusive identification.

Trapdoor spiders

Female (left) and male trapdoor spiders, Blakistonia aurea.

Sophie will employ next generation molecular techniques that use at least 10 genes to identify species in the genus. Where possible these will be linked to morphological characteristics that can be used to identify spiders in the field and provide accurate identification for environmental assessment companies and for ongoing work on their ecology and conservation status. New species will be formally described, named and imaged, with voucher specimens being lodged at the South Australian Museum.

Sophie’s project is part of a larger Australian Research Council (ARC) Linkage grant managed by Professor Andy Austin at the University of Adelaide, examining the evolution and biogeography of the trapdoor spider family Idiopidae.

Sophie’s project is supported through PhD scholarships from the University of Adelaide and the Australian Biological Resources Study, and research support through Professor Austin’s ARC Linkage grant with the South Australian Museum, Western Australian Museum, BHP Billiton Iron Ore Pty Ltd, Pilbara Iron Company (Services) Pty Ltd and Biota Environmental Services Pty Ltd as key funding partners.