July Bug of the Month

A Scarlet Tiger Moth at Hidcote

This month I thought I would leave our more troublesome bugs and look at one of our garden moths that can be seen flying in the late afternoon sunshine down by the stream.

Moths may be regarded as boring brown jumper munching pests but in reality they are just as colourful as butterflies and play an important role in nature. They pollinate plants and are a vital food source for many other creatures including bats and birds. Almost all our garden birds feed on moth caterpillars and other insects.

The scarlet tiger Moth is a very pretty day flying moth, though it also fly’s at night. It is one of the few moths we have that has developed mouth parts which allows it to feed on nectar. Its range and distribution are relatively restricted, most common in South West England and South Wales with a couple of populations in the North West. It prefers marshy or riverine habitat which is why we may be seeing it down by the stream.

A Scarlet Tiger Moth in the garden at Hidcote
A Scarlet Tiger Moth in the garden at Hidcote
A Scarlet Tiger Moth in the garden at Hidcote

June and July are the months to see this moth with its vivid red hindwings and metallic green sheen, almost black, forewings. The female moths lay eggs on a variety of food plants but favour Comfrey and Nettles. The eggs hatch in about 7 days with caterpillars overwintering when about 15mm long.

From March till May the caterpillars can be seen in the daytime feeding or resting in the sun on the food plant, such as Comfrey, Hemp agrimony and Hounds-tongue. As they become larger some may disperse and be found feeding on other nearby plants, we were seeing them on the Brunnera and Anchusa. By the end of June they are about 45mm and fully grown when pupation takes place a cocoon is spun amongst the plants or leaf litter and the moth emerges in about a month, depending on temperature.

A Scarlet Tiger Moth Caterpillar in the garden at Hidcote
A Scarlet Tiger Moth Caterpillar in the garden at Hidcote
A Scarlet Tiger Moth Caterpillar in the garden at Hidcote

We have seen much larger numbers of the caterpillar this year, maybe due to the mild winter and although the plants suffered from early damage by the caterpillars the Symphytum has grown through and flowered well.