ClimateWatch

An initiative of Earthwatch Institute

Bug city life

Linden Ashcroft

5 September 2014

New research from the University of Sydney has found that spiders living in the city grow larger and breed better than their country relatives.

Golden orb weaving spiders (Nephila plumipes) are related to the ClimateWatch indicator species the giant golden-orb spider (Nephila pilipes), but have larger abdomens (the big bit at the back). The team monitored golden orb weavers in various places across greater Sydney during 2012, including the Royal Botanic Gardens, the CBD and even at Manly Beach.

Lizzy Lowe and a golden orb weaving spider

New research shows golden orb weaving spiders are larger in cities compared to their relatives in the bush. Image: University of Sydney lead researcher Lizzy Lowe.

They discovered that spiders in the city centre were bigger, and had larger ovaries, than those living in greener habitats. Spiders near hard surfaces, like pavements or buildings were particularly big.

The difference in spider health could be due to warmer conditions in the city, because built up areas absorb more heat and are warmer than surrounding spaces.

Urban areas also provide more food thanks to night lighting that attracts bugs. With warmer temperatures and more food, the inner city spiders could spend more energy growing larger and producing more.

Spiders in the city might sound scary, but arachnids have an important role to play in controlling bug populations and providing a food source for birds.

Monitoring insects in urban areas is crucial to understand how urbanisation is affecting our biodiversity. Look out for spiders and other critters next time you’re in the city and record your sighting for ClimateWatch. 

Read more at The Conversation.