City living makes spiders grow larger

BY Justin Scuiletti  August 20, 2014 at 6:19 PM EDT
Photo by Wikimedia user Karora

The N. plumipes spider was found to grow larger within densely-populated cities. Photo by Wikimedia user Karora

It turns out that spiders love city life, especially rich cities.

According to a study published Wednesday by journal PLOS ONE, certain species of spiders thrive when urbanization occurs, as opposed to areas with larger vegetation. Researchers found that in densely-populated areas with hard surface cover, the golden orb weaving spider was found to not only grow to larger sizes than less-dense areas, but also possessed larger ovaries, linking to higher fertility rates.

Why does the species do so well in urban areas? Scientists attribute the prime conditions to higher temperatures and abundance of prey compared to other surroundings. Cities with more than one million people, according to the EPA, experience higher temperatures than rural areas due to the “heat island effect,” proving to be ripe grounds for spider growth. Food-wise, cities tend to have larger amounts of arthropods, while artificial lighting at night is more likely to draw more insects than usual — giving spiders a large amount of food to feast on.

The spiders were also found to grow larger in higher socioeconomic areas, because the richer areas tended to have better parks. “The increased expenditure and management of parks in wealthy suburbs could result in healthier vegetation patches,” the study writes, “which would increase prey abundance and allow spiders to grow larger and build up fat reserves.”