Scoping Out the Scorpion Spider
Scorpion-tailed spiders, also known as drag-tailed spiders or simply scorpion spiders, are spiders in the genus Arachnura. Its members are distributed throughout Australia and the other Oceania islands and southeast Asia; one species, Arachnura scorpionoides, is located in Africa. These spiders are typically found in forests, including both tropical rainforests and tropical dry forests. Some species have also expanded into urban environments.
Scorption-tailed spiders are fairly small in size; the largest femails only reach 1 to 3 centimetres (0.39 to 1.18 in) in length, while males rarely exceed 2 millimetres (0.079 in). The genus is named for their unique 'tail', which only the females posses. Like true scorpions, the tail grows in length with each moult. In most species, the abdomen is somewhat elongated, and coloration can vary from yellow to brown to red.
Like most spiders, Arachnura spiders feed primarily on insects, which they catch with a spun web. Some of the larger species may also feed on small lizards and rodents. Scorpion spiders are members of the orb-weaver family, so despite their small size their webs can be quite impressive, up to 20 cm (7.87 in) in diameter. Predators of drag-tailed spiders often include birds and larger reptiles. To avoid predators, male scorpion-tailed spiders rely on their small size and duller coloring; meanwhile, female spiders will actively mimic scorpions by curling their tail over their back. However, neither males nor females posses any kind of venom that would be effective against larger animals.
Male scorpion spiders typically don't retain territories or permanent webs. During the mating season, which stretches from June to December, they seek out the nearest female and wait at the edge of her web. To entice her, the vibrate various strands of the web, and only approach if she is receptive. After mating, the female may consume her partner. Shortly afterwards, she produces a string of elongated egg sacs, each of which contains up to 50 eggs. She then guards them until they hatch. Once the young emerge, they disperse to establish their own webs and territories.
Conservation status: None of the Arachnura species have been evaluated by the IUCN. Little is known about the population status and habits of most species.
Photos
Peter Woodward
Reiner Richter
Michael Doe
Tony Eales
