Artificial lighting, lawns, urban "heat islands," and other features of city and suburban life are leading to bigger spiders with an increased ability to reproduce, a new study finds.
The study, published in the latest issue of PLoS ONE, could help to explain why some homeowners are finding particularly big spiders in their gardens. Researchers say the effect is noticeable among common orb weaving spiders. (Orb weavers are spiders that build spiral wheel-shaped webs.)
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Like an unintended Frankenstein experiment, we are facilitating spider growth with light posts.
"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 Elizabeth Lowe from the University of Sydney, Australia, and colleagues.
The researchers focused on a particular common orb weaver, Nephila plumipes, because it lives in both urban and rural settings. They measured and then compared the body size, fat reserves and ovary weight of the spiders in each habitat. Ovary weight is an indicator of reproductive ability.