Friday, Dec. 21, 2001
* Japanese name: Ari-gumo
* Scientific name: Myrmarachne japonica
* Description: This spider looks like an ant, but it is an arachnid, not an insect. You can tell because it has eight legs. The ant spider mimics ants, and sometimes flutters its forelegs like the antennae of ants, because it has no antennae of its own. The distinguishing feature of the ant spider, however, are its huge front eyes. Ant spiders have eight eyes, but the front two are like car headlights. They can see 360 degrees, without any head movement. They also have a powerful pair of jaws, which they use to inject venom into prey, to kill or stun it before sucking it dry. Males are about 7 mm in length, females 8 mm.
* Where to find them: In woods and meadows, on foliage, in spring and summer. Also in houses, all year round. Ant spiders are active during the day.
* Food: Insects. If you have ant spiders in your house, you should be happy, because they will attack pests such as flies and moths. They are not dangerous to humans.
* Special features: Ant spider vision is far superior to that of normal spiders, who sit in webs all day. The ant spider belongs to a group of spiders called jumping spiders. Unlike other types of spiders, jumping spiders don't spin a web to catch prey; they actively hunt it. Some species can jump 40 times their body length. Before leaping, the spider fixes a silk safety line, so that if it misses its landing spot, it can hang, like on a bungee cord. The scientific name for the family is Salticidae, from the Latin salto, to dance. This refers to the elaborate courtship dance that the male performs before copulation. Females decide whether to mate with a male on the basis of his dancing ability: Some males are better than others. Males will jump quickly away from a female if she approaches too quickly, no doubt because females are known to kill and eat males.