Come into my parlour, said the spider to the fish . .

NEW ZEALAND has spiders that catch and eat fish. Next summer, go to any open stony riverbed, turn over some large stones and you will probably turn up a water spider running for cover.

Water spiders are quite large, their legs spreading to eight centimetres but on the Chatham Islands there’s a larger species known as the Rangatira spider. When trouble looms, these spiders can dive under water, taking bubbles of air with them so can stay down for half an hour until the threat has passed. They hide away by day but emerge at night to hunt in quiet corners of streams. They don’t produce silk or make webs but hunt by resting their front legs on the surface of the water waiting for prey to arrive – usually insects but occasionally cockabullies.

The moment a buzzing insect falls on the water, or the moment a fish’s dorsal fin breaks the surface, the water vibrates and the spider quickly runs across the water to bite its prey. The bite paralyses the insect or fish with a nerve venom. The spider then fills the dead insect or fish with a digestive enzyme and sucks out the liquid innards.

American and Australian biologists have just reviewed the habits of fish-eating spiders of the world. They were surprised to find 109 kinds of spiders eat fish on all continents except Antarctica. In Australia they report spiders repeatedly catching fish, including whitebait, in suburban garden pools and streams in Sydney, Brisbane and Adelaide. An American was alarmed to find a water spider eating one of his goldfish.

Other spiders catch small frogs, toads, salamanders, lizards, snakes and bats in their webs, including a New Zealand spider that caught a silvereye in its web. The spider wrapped the silvereye in a silk tent but did not eat it.

Spiders are also in the scientific news this month as their paralysing venom shows promise as a useful insecticide.

You will know that several chemical insecticides in current use have been banned as they have been incriminated in the collapse of honey bee populations around the world. Seems that these neonicotenoid insecticides interfere with bees’ navigational skills so they become forgetful and can’t find their way home to their hives, nor can they pass information about useful nectar sources to their sister workers.

A team of English, Australian and Brazilian biologists looking for a new kind of pesticide collected venom from Australian