The University of Sydney's Elizabeth Lowe said while research showed invertebrates were sensitive to urbanisation, not all species were negatively affected by living in cities.
In fact, golden orb-weaving spiders, which are common in both urban and natural environments in Sydney and its surrounds, were getting fattest in those built-up areas with the most concrete, roads and buildings.
"We found that they were bigger in the city and particularly in areas with lots of hard surfaces and less vegetation," Lowe told AFP on Saturday.
Lowe, a PhD candidate in the university's school of biological sciences, puts the finding down to the idea that concrete holds heat, meaning city spiders' days and nights were warmer than those of their bush cousins.
Meanwhile urban parks were a good source of food for spiders because lighting in these areas attracted insect prey.
Lowe said the researchers did not know why they also found the golden orb-weaving spiders, or Nephila plumipes, were larger in the wealthier pockets of Sydney.
"We think that it could be that in the wealthier areas people put more money into land management," she said, meaning more parks and greater biodiversity in these areas.
Lowe said the fact that any species could thrive in an urban area was a positive.
"We think it's a good thing that anything can live in cities," she said.
