Cobweb recognition system counts spider species

How would you count the number of spider species in, say, a chunk of the Panamanian rain forest? With an outsize magnifying glass, a pair of tweezers and The Observer Book Of Spiders? Forget it: an artificially intelligent cobweb recognition system is the answer, say Carlos Travieso at the University of Las Palmas de Gran Canaria in Spain and his colleagues.
Travieso reckons that the way a spider constructs its web is species-specific. "Cobwebs are made by spiders whose genetics and morphology are all different from those of other species - and so their cobwebs are different, too. It's as distinctive as handwriting biometrics in humans," he says.
To find out if that is indeed the case, the team used images supplied by William Eberhard of the Smithsonian Tropical Research Institute in Costa Rica, a spider expert who amongst much other research has photographed different types of web in Panama and Costa Rica. Travieso's team trained a variety of pattern-recognition techniques (such as principal component analysis) on Eberhard's pictures until they found a way of reliably spotting which species had spun which type of web.

They found they were able to achieve astonishing species-recognition accuracy (99.6 per cent) by extracting discriminating features from the more complex centre of the cobweb and then correlating them with the overall image of the cobweb. They tested their classifier on orb weaver spiders, the utterly bizarre Anapisona simoni, Micrathena duodecimspinosa and Zosis geniculata - you can see their webs in this Powerpoint slide.
It's an interesting notion. After all, measuring biodiversity is one key to understanding environmental change, and as spiders live in most ecosystems, they are a particularly useful bellwether. So why not automate the counting of them? The team are now aiming to spread their idea to counting other species: "We are working on different kinds of animals and insects under another research project," says Travieso - but the team have not yet said which ones.
Any guesses?

By Paul Marks

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