Male Wolf Spiders

12 April 2011 - Male wolf spiders cannibalise older females, scientists in Uruguay have discovered. In several species, female spiders are known to eat males, but this is the first time biologists have seen the roles reversed in the wild. The male spiders were observed mating with virgins and eating older, less reproductively successful females. Researchers suggest that harsh habitats force males to prey on females for food. Their findings were published in the Biological Journal of the Linnean Society. The species in question, Allocosa brasiliensis, is a nocturnal wolf spider found in South America's sand dunes along riverbanks and the Atlantic Ocean coast. The researchers were studying the species because its status is considered an indicator of the health of coastal habitats. After observing a male spider eating a female in the wild, Dr Anita Aisenberg and her team from the Clemente Estable Institute of Biological Research, Montevideo, set out to find an explanation for the behaviour.
"In spiders in general, females are larger than males and they are the selective sex, while males are small rovers that go out and look for potential sexual partners," explained Dr Aisenberg.