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Riddle of the St. Andrew's Cross Queen of Spinners |
Riddle of the St. Andrew's CrossThe webs of the St. Andrew's Cross spiders (Argiope aetheria and pieta) are of considerable interest and seldom fail to attract attention because of the decorative saltire of fluffy white silk super-imposed upon its meshes. Argiope aetheria, the commonest species, is a striking creature with the abdomen adorned with bands of yellow and chestnut-brown, while the forepart of the body (cephalothorax) is densely clothed with long, recumbent silvery hairs. The purpose of the silken adornment of the snare is obscure, and several theories have been advanced to explain it. It is suggested that it strengthens the web—but other web-spinners construct quite efficient snares without such reinforcement. That . it provides camouflage for the spider as it rests in the centre of the snare with its legs, lying in pairs along the arms of the cross, has also been suggested. The snowy-white cross, however, seems to attract rather than to distract attention from the occupant. Since the spider usually rests behind the cross, it is possible that it may serve to divert the aim of a hungry bird which may attempt to snatch the spider from its resting place. The whole question is further complicated by the fact that the cross is not infrequently .wanting, apparently at the whim of the individual spider, without any detriment to either web or occupant. The whole question would surely reward detailed study.
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