Cities are causing spiders to grow bigger and breed faster

Cities are causing spiders to grow bigger and breed faster

Spiders are starting to become bigger and reproduce faster thanks to the numerous amenities that are provided for them by cities. Things such as artificial lighting, lawns, urban heat islands, and many other features that are present in all cities have combined to create a new generation of super spiders, according to a new study.

The findings in the study, which was published in the last issue of PLoS ONE, could help explain why many homeowners are finding exceptionally large spiders in their homes, lawns, and gardens. Researchers say that the effect is noticeable among common orb weaving spiders, which are the ones that build the usual wheel-shaped webs.

“Artificial night lighting has many implications for spider fitness as it leads to local increases in insect abundance, and increased prey capture for spiders in lit habitats,” wrote lead author of the study, Elizabeth Lowe from the University of Sydney. Most wildlife struggle to survive in urban environments, but some “urban exploiters”, such as pigeons and raccoons, readily adapt to, and even thrive in, the new environment.

Lowe believes two things about cities are influencing these critters’ bulk: temperature and an abundance of insects to eat. “Hard surfaces and lack of vegetation lead to the well-known ‘urban-heat island’ effect, with more heat retained than in areas with continuous vegetation,” she says. “Higher temperature is associated with increased growth and size in invertebrates.”

“The increased expenditure and management of parks in wealthy suburbs could result in healthier vegetation patches,” the researchers wrote, “which would increase prey abundance and allow spiders to grow larger and build up fat reserves.”

Read more about the story at Wired.

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