Spider research shows that invertebrate decline is a tangled web

A study on a common European garden spider species in Switzerland reveals a startling drop in abundance since the 1970s and '80s.

Garden cross spider. © Klaus Vartzbed/Getty

The well-publicised decline in insect populations is having knock-on effects up the food chain, according to new research showing a startling drop in one of Europe’s most widespread and familiar spiders over the last four decades.

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The research, conducted in Switzerland, found that the garden cross spider – the classic orb web spinner – was about 140 times more abundant in the 1970s and ’80s than it is now.

The most extensive and up-to-date estimate for the decline in terrestrial insects worldwide suggests that they are disappearing at a rate of nearly one per cent per year, or 24% over the last 30 years.

“This must have consequences for spiders, birds, bats, et cetera, since flying insects are the major diet for many of these creatures,” says Martin Nyffeler of the University of Basel, who led the spider work.

“Due to the fact that the number of insects found in spider webs is much lower nowadays compared with 40 years ago, I am very confident that insect decline is the problem.”

Nyffeler says that similar surveys are now needed in other parts of Europe, including the UK, and on other species of spider, to test whether this is more than a local effect.

Read the full paper in Insects.


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Main image: Garden cross spider. © Klaus Vartzbed/Getty