Big-eyed horny caterpillar sightings up

06 September 2010

Sightings of what looks like a big-eyed horny fat caterpillar have shot up at the Natural History Museum's Identification and Advisory Service (IAS) over the last month.

The adult elephant hawkmoth with its striking pink and green colours

The adult elephant hawkmoth with its striking pink and green colours

They may have alarmed some enquirers but they are just the harmless caterpillars of the elephant hawkmoth, Deilephila elpenor, a common insect found around most of the UK.

'People often call us and say they have never seen anything like it before and think that it must be a foreign species,' says the IAS insect expert Beulah Garner.

'However, it is a master of disguise as well as a great mimic. As soon as people start to describe the caterpillar we know straight away what it is.'

Some of the caterpillar descriptions people give are ‘a horn and 2 pairs of eyes’, ‘a sharp hook on its tail’, and ‘very fat at one end’!

‘Strangely enough, it is never described as looking like an elephant’s trunk, but this is where it gets its name from,’ adds Beulah.

Distinctive eye spots and 'horn'
The eye spots on an elephant hawkmoth caterpillar can be used to deter predators

The eye spots on an elephant hawkmoth caterpillar can be used to deter predators

The elephant hawkmoth larvae, or caterpillar, can grow to about 85mm in length and is brown to green in colour.

The caterpillar has distinct pink eye spots on the 4th and 5th body segments. These are an excellent deterrent to potential predators. When it feels threatened, it contracts its head segments. This inflates them, making the eye spots look larger, which helps it to resemble a much larger predatory animal.

Elephant hawkmoth caterpillars also have a 'horn' on the tip of the end body segment. All hawkmoths have 'horns’ that differ between species - the elephant hawkmoth's is black with a pale tip.

Caterpillar activity

The elephant hawkmoth caterpillar mainly feeds at night. This time of year, however, it is seen more often as it ventures out during the day, looking for a place to pupate.

Rosebay willowherb, Epilobium angustifolium, is food for the elephant hawkmoth caterpillar

Rosebay willowherb, Epilobium angustifolium, is food for the elephant hawkmoth caterpillar © Dr Brenda Harold

It feeds on rosebay willowherb, which is in the same family as fuchsias, and also plants such as bedstraw.

Gardens are an ideal habitat for elephant hawkmoths although they are not considered garden pests. 'Many of our enquirers tend to be gardeners who have found the caterpillars while weeding.' adds Beulah.

The caterpillar finds a pupation site just under the soil surface and then remains in its pupal stage for the rest of the winter.

Adult hawkmoth

In the spring, the adult elephant hawkmoth emerges. It is a striking moth with a pink and green chevron pattern on its wings and pink and green stripes on its body, which is quite fat and furry like many other hawkmoths.

The moths are seen flying from May to July when they are visiting flowers such as honeysuckle for their nectar.

Hawkmoths worldwide
Lady's bedstraw, Galium verum, is a food source for elephant hawkmoth caterpillars

Lady's bedstraw, Galium verum, is a food source for elephant hawkmoth caterpillars © Dr Brenda Harold

There are about 1,400 species of hawkmoths worldwide and they are the only moths able to hover in front of flowers to feed, like hummingbirds do.

They play a unique role in the pollination of some plants. For example, some orchids have evolved to be pollinated solely by hawkmoths. So if the moth becomes extinct, so will the plants.

Museum hawkmoth collection

The hawkmoth collection at the Museum is one of the world's largest. It is used by researchers around the world and is looked after by curators in the Museum's Darwin Centre, in the entomology collection of 28 million insect specimens.

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