Saturday 21 April 2018

Peak time for hawk-moth caterpillars

Elephant Hawk-moth caterpillar in snake pose
Elephant Hawk-moth caterpillar in snake pose

Caterpillars can be either very difficult to identify or very easy to identify. The easy ones are made easy in that they are impressively big, have amazing shapes and have either beautiful colours or markings. The difficult ones are small, do not have a distinctive shape, have drab green or brown colours without any markings and are completely devoid of any distinctive features.

The Elephant Hawk-moth caterpillar is one of the easy ones to identify and is reasonably, though locally, common at present. The adult moths are large, handsome creatures with a bright pink and greenish-tan markings that make them unmistakable. They were on the wing in May and early summer and they bred before their brief lives came to an end in July.

The species now survives in the caterpillar stage only. These are very effective eating machines and are munching their way through garden and hedgerow plants. In gardens the species is most often found on Fuchsia hedges. In hedgerows, Rosebay Willowherb and bedstraws are said to be the main food plants.

Hawk-moths get their name for their rapid, hawk-like flight. They all have narrow wings and are distinguished among all other moths by their rapid flying ability.

The Hummingbird Hawk-moth is a superb flier. It can even hover in front of a flower as it sips nectar with its long tongue. If threatened by a predator it has perfected an aerial manoeuvre called 'side slipping': the ability to suddenly slip out of the way by apparently flying sideways.

So, while it is too late now to see an adult Elephant Hawk-moths on the wing it is peak time for seeing their caterpillars. The caterpillars come in two colour forms: bright green and olive brown. Irrespective of ground colour the head end is distinguished by two pairs of large, black, eye-like markings and the rear end bears a single, horn-like, backward-curved spike.

The species gets its name from the trunk-like snout at the caterpillar's head end. The snout resembles an Elephant's trunk and can be withdrawn into the animal's body when it is frightened. The withdrawal of the snout causes the head to expand greatly and the scary, snake-like eyes to become alarmingly prominent.

By September the caterpillars will be fully grown. They will then descend to the ground, bury themselves in protecting surface leaf litter, turn into chrysalises and survive the winter in that form before the new generation of adults emerges during May of next year.

New Ross Standard