The Shield-Back Trapdoor Spider is native to the area around SMC’s Weld Range DSO Project, located 65km south-west of Meekatharra and 50km north-west of Cue in Western Australia. Due to its classification as a protected species the Company has made a significant investment into researching the species.
The Shield-Back Trapdoor Spider (scientific name Idiosoma Nigrum) gets its name from its thickened, deeply grooved abdomen that acts as a defence against predators and reduces water loss. Shield-Back Spiders live in burrows below the ground with a neatly-fitting trapdoor which ensures the air inside is humid and moist. Leaves and twigs are carefully positioned to radiate outwards from the trapdoor burrow entrance. These serve as trip-lines, which alert the spider of nearby prey.
When threatened by a predator, the spider drops head-down into the narrowed section of its burrow, plugging the hole with the shield-like end of the abdomen. This impenetrable blockage deters predators like scorpions, centipedes, hunting wasps and sometimes even birds. The Shield-back Spider has a long life cycle and does not move far or often from their burrows, with females sometimes living for more than 20 years in the same burrow – although males die shortly after mating.
Since early 2009, SMC’s environmental team has been conducting a comprehensive research program to survey the habitat of the Shield-Back Spider in the area around Weld Range. In addition, SMC’s exploration team has worked hard to plan around this activity and avoid any impact on the spider.
SMC has worked in close collaboration with Crosslands Resources, whose Jack Hills project is near Weld Range, and the Department of Environment and Conservation (DEC), undertaking significant surveys which have resulted in a better understanding of the distribution and numbers of the spider locally at Weld range and regionally across the Mid West.