Spiders will live in groups if environmental conditions make it too difficult for single mothers to go it alone, new research shows.
It is rare for spiders to live in groups. The arachnids studied for this research build webs that require a lot of silk, making the rainy conditions of the lowland tropical rainforest too adverse for them to live alone. The findings dispute a long-held belief that social groups form merely so individuals can help their kin. Instead it suggests difficult environmental conditions may be the reason why some species live in cooperative social groups and others don't.
"In all species, family members are closely related, but only in some do they band together to raise each others' offspring," said Leticia Avilés, a professor of zoology. "By living in groups, the spiders can occupy spaces that they wouldn't otherwise be able to, thus helping us understand why animals evolve to be social species."
Avilés pointed to other animals to support this theory including penguins who are only able to survive extreme cold and winter storms by huddling together. She said this theory could also help explain why single-celled organisms merged together to form more complicated multicellular organisms in our evolutionary history.