This has been a better year for insects in Dorset. Last year there were hardly any in the garden; this summer the long grass on the lawn is zizzing with grasshoppers. Butterflies and moths are more evident too.
In a bright flutter of tomato-red wings, the first of this year’s Jersey tiger moths appears. It settles momentarily in the lower leaves of a sycamore tree, folding away its brilliant hindwings under cream and black tiger-striped forewings. Only the furry orange tip of its abdomen hints at the vibrant colour concealed beneath, reserved as a warning to flash at predators.
Once restricted to the Channel Islands and continental Europe, hence the name, this beautiful species (Euplagia quadripunctaria) has spread gradually along the south coast from Devon and Dorset. It’s now found all through the south of England and Wales, becoming relatively common in London and up into Bedfordshire. Butterfly Conservation cites its spread as an indicator of the impact of global heating, a harbinger of how the range of moth and butterfly species in the UK is changing.
The spiky-haired caterpillars rely on a variety of plants classified as weeds, including nettle, dandelion, plantain, bramble and ground ivy. Larvae hatch in September and feed until the spring, their bristles gradually changing colour with each moult from brown to ginger. Their generalist diet means they are not reliant on one specific plant species, which is an advantage during winter when food is scarcer. The trend for warmer winters has increased the amount of greenery to be found, and this could be a significant factor in their movement north.
Jersey tigers fly by day as well as at night, which makes them more noticeable. Gardens offer an ideal habitat, with a varied mix of foliage in a relatively small area, especially when overgrown, giving the tigers a chance to lurk in the undergrowth.
A little untidiness helps them thrive at all life stages, with larvae pupating on the ground in silk cocoons among leaf litter. The two moths I have seen so far were in gardens that were nicely unkempt, their hedges twined through with honeysuckle and the magenta flowers of perennial pea.
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