|The Australian Wonder Book of Knowledge - [Home]|
The Venomous Red-Back Spider
The commonest and most widely distributed of our dangerous spiders is the red-back or jockey spider (Latrodectus hasseltii). It occurs in both coastal and inland areas almost everywhere through-out Australia, sheltering in outhouses. gas-boxes, ventilators, in house-foundations and in rubbish—empty tins, boxes, etc. It may occasionally be found within houses, in cupboards and other dark situations. In the bush, it frequents hollows in trees, stumps and logs. These were apparently its natural habitat be-fore the coming of settlement, but now it has adapted itself so readily to man-made surroundings that it is more frequently found there than elsewhere.
The female red-back spider is slender-legged, with a rounded black body about the size of a pea, and a bright red longitudinal stripe along the back. The under surface of the abdomen, too, may sometimes bear red markings. This description is of a typical example, but the coloring is variable, and the red stripe may be broken into a series of spots; the markings may be pinkish rather than red; and the ground color a dull greenish-brown instead of black. Such pale-colored examples are usually spiders which have recently moulted ' and have not yet regained their full intensity of color. The rarely seen male is very much smaller than his mate, but resembles her in color and form.
The web is extremely irregular and straggling, with long guy-lines extending far out beyond the more closely-woven snare. It is constructed of a dry-looking silk. Once identified, it is unlikely to be mistaken for that of any other spider.
As might be expected, bites by the red-back spider are extremely common, and many cases are treated by doctors in country districts each year. Compared with the frequency of bites, the death-rate accompanying them is low. This may surprise many people. Of 98 re-corded cases, six only were fatal. Unless a case is attended by unusual circumstances, it is rarely recorded, but death from a bite seldom fails to secure publicity. In one country town in western New South Wales, some twenty cases of 'red-back bite are medically treated annually, so that the number for the whole of Australia must attain a very high total. Although the death-rate is low, it cannot be considered that a bite from one of these spiders is to be treated lightly. The venom is a neurotoxin (a nerve poison), and the bite of the spider is accompanied by agonising pain together with profuse sweats alternating with fever, which may persist for some days.
|Wonder Book of Knowledge|