About

These brightly coloured beetles are a common sight in many parks and gardens across the UK. As the name suggests, they feed on the leaves of herbs including rosemary, thyme, and lavender. They can often be found in large numbers on their host plants. They feed busily in spring, but become less active in the warmest months of mid summer. They start feeding again in late summer, when females lay tiny, sausage-shaped eggs on the underside of the leaves. After hatching, the grey, slug-like larvae also feed on the leaves of herbs. When they're fully grown, the larvae travel down the plant and into the soil to pupate. They emerge as adults in spring, ready to start the cycle all over again. Adults can be present all year.

Rosemary beetles have not always been found in the UK. They are native to the Mediterranean region of southern Europe, North Africa, and the Middle East. The shipping of herbs around Europe has helped them spread to new countries. The first rosemary beetle in the UK was found in Cheshire in 1963, then three more were discovered in Surrey in 1994. After that they quickly spread and became common around London. Now they are found widely across all countries of the UK.