NIW Insect of the day: Vine weevil

Posted 25 June 2014

This Insect of the Day feature has been produced as part of Harper Adams University's National Insect Week celebrations, June 23-29.

The vine weevil by Research Entomologist, Dr Tom Pope

Despite its name, the vine weevil Otiorhynchus sulcatus feeds on a very wide range of plants, although as you might expect this does include grape vines. In fact the vine weevil has been recorded feeding on more than 150 species of plant.

Unfortunately, many of these plant species, like the grape vines, are grown as crops or as garden plants. It is the immature stages, known as larvae, that cause most of the damage as they feed on the roots of plants. The adult weevil feeds on the leaves of plants and produces characteristic notches along the margins of the leaf.

Vine weevil is a species of beetle, and like other beetles, the adults have a hard shell-like covering that helps to protect them from predators and the environment. Like other weevils the head of the adult vine weevil is elongated into a snout.

Unlike the adults, the larvae living in the soil have no legs and have a soft body, although they do have a powerful set of jaws for feeding on plant roots.

Adult vine weevil are fascinating insects. The adults are active at night (nocturnal) and during the day they hide under leaves. Often the adults are found tightly grouped together in these hiding places, although we don’t know how they find each other. If you disturb an adult vine weevil it will often drop to the ground and pretend to be dead until it thinks it is safe to start moving again.

Vine weevil have benefitted greatly from human activity. Although vine weevil originate in Europe they have spread to many other parts of the world. Often this has happened when plants were sold from one area to another with some larvae living in the soil around the roots of the plant.

Vine weevil also like the way we grow many plants today, particularly when we grow plants in compost instead of soil. All this means that vine weevil has become an important pest of many crops but still remains a fascinating insect!