Wolf Spiders

Discovered by Mark Harvey

f you’ve ever wandered in the bush at night with a head torch on you have Iprobably noticed peculiar reflections on the ground, silvery-yellow pin-pricks of light. And not just in the bush – these same lights can be seen on lawns in urban backyards. If you’re very observant you’ll see that these reflections move and if you get close enough you’ll see the culprit, a wolf spider. The eyes of these spiders reflect light and even tiny spiderlings can be detected using this method. However, the light source must be near your eyes; a torch near your waist is ineffective. Wolf spiders are among the most diverse spider families and occupy nearly all terrestrial Wolf spiders habitats in the world, from the seashore to the slopes of the highest mountain ranges. They are instantly recognisable by the arrangement Tasmanicosa gilberta, is equally widespread. Above A female Forrest’s wolf spider (Hoggicosa forresti). of their eyes, with four small eyes in a straight Of the six new species they described, two Photo – Jiri Lochman line near the front of the carapace (the ‘head’) were from WA – Tasmanicosa salmo from and four large eyes arranged in a square Salmon Gums, and T. stella from the drier regions of southern Australia. just behind them. It’s these large eyes that Wolf spiders have some fascinating reflect light. Another publication by Volker and behavioural traits. Females carry their egg sacs Despite their ubiquity, not all of the Peter Hudson from the South Australian attached to their spinnerets (situated at the Australian species are described. Indeed, Museum examined the wolf spiders of the end of the abdomen) and when the young not all of the genera are named. Dr Volker genus Tetralycosa. All members are salt emerge from the sac, they clamber onto their Framenau from Phoenix Environmental tolerant, with the widely distributed mother’s back. This provides protection for Sciences and his colleagues have been T. oraria occurring on coastal beaches across a few weeks until they are a bit larger and chipping away at a series of taxonomic southern Australia, and 12 other species able to fend for themselves. The juveniles of revisions aiming to provide descriptions of including eight new species, from salt-lakes many species are capable of dispersing by Australian wolf spiders. Recent publications in arid Australia. The spiders dig shallow ballooning, where they release a long silken include redescriptions of previously named burrows on the salt pan and roam on the thread that gets caught in a draught of wind, species – a necessary component of modern dry surface of the lake at night, where their lifting the spider into the air. It’s a game of taxonomic monographs – and descriptions pale or contracting colouration provides chance, as they can’t guarantee where they’ll of new species and genera. Many of these camouflage from predators. land. If it’s at sea, they quickly become fish new species are from Western Australia, Wolf spiders are vagrant hunters, food. But if they land in a favourable habitat it highlighting the great diversity of habitats and chase their prey at night. They prefer provides a magnificent way of locating new and the relatively unexplored nature of our to eat insects but will also devour other environments. Their ability to scatter with the biological heritage. invertebrates such as small spiders. Unlike wind has enabled wolf spiders to colonise A paper published in 2016 by Volker many other spiders, they do not use webs far-flung islands. Indeed, wolf spiders were and his colleague Dr Barbara Baehr of to capture or subdue their prey, they simply among the first colonists on Krakatau after the the Queensland Museum, studied the pounce and inject their victim with venom cataclysmic eruption of 1883 that obliterated Australian Union-Jack spiders of the genus before crunching them into a paste to suck all life on the islands. This dispersal behaviour Tasmanicosa, finding 14 species, of which six in the juices. has resulted in some species having very were new. These spiders are morphologically Many dig a shallow burrow in the broad distributions, even though others distinctive with a unique carapace colour ground and some, like the Australian have smaller ranges, presumably limited by pattern that resembles a Union-Jack flag. Hoggicosa, cover the entrance with a thin environmental factors. One species, Tasmanicosa godeffroyi, is silken flap. It’s easy to be fooled by these So, pick up a torch and head into the extremely common in south-western and spiders – closer inspection of a shining night. There are plenty of silvery points of light south-eastern Australia, where it occurs reflection can just reveal a flap with the out there to be seen – silent hunters lurking in in gardens and native bushland. Another, owner safely tucked in its burrow. the dark.

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