Monday, May 27, 2013

Jumping Spiders

For some reason, likely the cool, wet weather, a large number of jumping spiders have invaded our house this spring.  Found on all Continents except Antarctica and represented by more than 5000 species, they are the largest family of spiders on Earth.

Named for their means of pouncing on prey and escaping danger, jumping spiders are equipped with a hydraulic mechanism in their limbs that allow them to jump up to 50 times their body length.  Their hunting prowess is also aided by excellent, 360 degree vision via four eyes on their face and four smaller ones on the top of their head as well as a highly mobile anterior segment; scientific studies suggest that they also possess color vision.  Unlike many spiders, they do not use webs to catch their prey; rather, they stalk prey and then jump to attack the victim, using a single strand of silk as a safety line should they miss their target.  Primarily carnivorous, jumping spiders consume a wide variety of crawling and flying insects; some species also feed on nectar.

Small tents of silk are used for protection at night and during storms.  Females also wrap their eggs in a cocoon of silk and, in some species, she may remain with the eggs until they hatch.  Like most of their cousins, jumping spiders induce unreasonable fear in many humans but play a valuable service in the control of harmful insects.  Besides, their antics are fun to watch!