Recently a Mullein Moth larvae was spotted by local naturalist Shelia Norris around Manx Wildlife Trusts Billown Quarries. The picture shows a mullein moth caterpillar resting on a mullein plant, which it feeds on. The Mullein is a nocturnal moth that can be found in a range of different open habitats such as grassland, woodland and brownfield. The adult moths have a pattern of subtle streaks of brown and buff with a ragged border to the wings that range about 2.5 cm and a tuft above the head. The caterpillar is a whiteish colour with yellow patches and black dots along its body so are much more easily spotted than the adult moths.

A few years ago, this species would not have been spotted on the Isle of Man, as it is mostly found in western, southern and central Europe. This reflects patterns showing thousands of species migrating northward in response to warmer temperatures. Like other animals, insects must adapt to the changing habitats caused by climate change. There are over 2,500 species of Moth in the UK, and they are crucial for the survival of many different bats, birds and mammals. As the changing climate alters the timing of plant growth, this causes problems for many species, including moths. Moth life cycles have evolved to be synchronised with the plants they feed on, but the timing of leaf emergence is changing. The presence of Mullein Moth larvae is an indication of the effects that climate change has not just on the environment but directly on the creatures inhabiting it.

On the Isle of Man, 74 moth species are considered to have become established since 2000; this is mainly a welcome increase in insect diversity, but some species can be pests to our natural ecosystem. Most migrating insects are moving northward due to warming climates, but the globalisation of plant trade means that many different insects can be transported with these shipments. Moths are among the largest groups of newly arrived insects, with about 970 species resident on the island.

This migration of insects is expected to accelerate over the next few decades as temperatures gradually increase. This will not only add diversity but also increase the food available for our native bats, birds, frogs and lizards. The dedicated specialists and ‘Island Recorders’ enhance our ability to measure the migration of insects to the island. Declines in insects are much harder to measure because the species likely to disappear are rarer and occur in more niche, smaller habitats, making the process longer.