Giant caterpillars munching their way through gardens in Sussex have sparked fear among residents who think they are an exotic species.

People have been plucking the black caterpillars off plants and popping them into jars and taking them to nature experts believing they have found a rare or poisonous species.

But the bugs, which are dark in colour and can grow to 9cm, are native to Britain and are completely harmless to humans.

They are the caterpillars of the Elephant Hawk Moth.

The bugs have earned themselves the name because the caterpillars resemble an elephant's trunk.

Simon Woodard, education officer at Tilgate Nature Reserve, Tilgate Park, in Crawley, said people were bringing in two or three of the giant caterpillars a week to ask what they were.

Mr Woodard, who has worked at the reserve run by Crawley Borough Council for six years, said: "You can almost guess what it's going to be before you open the jar. They're common for this time of year."

The caterpillars feed on rosebay willow-herb and pop up in Britain's gardens from late June to September.

Once the caterpillar has eaten enough it will go into the soil until May when it hatches into a pink and brown adult moth which has a wingspan of up to about 72mm. Mr Woodard said: "They're perfectly harmless.

"It's just people aren't used to seeing caterpillars this big.

"People think they're something quite exotic.

"When they're moths they are quite nice, brown with subtle pink on them."

The caterpillars which have been handed to staff at Tilgate have been released in the grounds to complete their life cycle and Mr Woodard recommends Sussex residents leave them to do the same if they find them in their gardens.