Warming climate making spiders bigger and more fertile

The 10-year study focused on some 5,000 carnivorous Wolf spiders in Greenland, and found that their body mass increased by an average of eight to 10 percent. The Pardosa glacialis spiders’ growth coincided with a spring season that arrived 20 to 25 days earlier on the Arctic island, the team reported.

Both male and female spiders, which normally reach up to 5 centimetres (2 inches) in length, grew faster. Males reached sexual maturity sooner and females became more fertile, the team from the University of Jena, University of Stuttgart and Danish University of Århus found.

The group’s measurements of the hairy hunting arachnids confirmed their hypothesis that “dramatic seasonal changes” in northern climates are having a significant impact on Arctic spider populations, Danish scientist Toke Thomas Høye said.

The consequences of this growth in spiders that live for several years – aside from the obvious panic for arachnaphobes – is not yet fully understood. Researchers found that cannabilism increased along with the Wolf spiders’ body mass, which could keep the population under control.