Moths that fly in daylight

There are a number of moths that break the fly-by-night rule that we are used to and a few of them are large enough to match butterflies in size. I have described the visits of the Humming Bird Hawk moth to the valerian in our garden in a previous article, but we also have occasional visits from Tiger moths. These are spectacular insects that show their orange-red underwings while in flight, though the dark greyish brown forewings fold over them when the moth is at rest. Nevertheless, the red, white and yellow spots on the fore wings still make these moths stand out from their surroundings. This warning colouration is designed to deter predators; they have an extremely bitter taste which is an experience that a bird would be unlikely to repeat! Here in the South West we are also just within the range of the larger Jersey Tiger which has a somewhat giraffe-like pattern of white bands on the forewings rather than spots.

The Cinnabar and several species of Burnet moths are amongst a number of smaller moths that also use this red and black colour combination with patterned forewings and red underwings. A few of the day-flying moth species match our butterflies in size but many more are much smaller and could be easily ignored, although they are well worth looking at more closely as they show quite exquisite patterns on their wings. You may just want to appreciate them for what they are, but if you would like to put a name to them, one of the excellent laminated guides produced by the Field Studies Council covers all 103 species that fly routinely in the day or are disturbed while walking through vegetation. This is nearly twice the total of fifty-seven butterfly species which breed in the UK.

A brightly coloured day-flying moth may look at first glance like a butterfly, but a couple of identifying features should usually leave you in little doubt whether you are looking at a butterfly or a moth. At rest most of the former tend to fold their wings together like the pages of a book and hold them vertically above the body while the latter at rest tend to fold their forewings down to cover often colourful hind wings. All butterflies have antennae with clubs or knobs on their ends but the majority of moths have antennae which are either threadlike or feathery, though the Burnet moths do have antennae with ends somewhat similar to those of a butterfly.

About 40 of these smaller moths look like miniature tapestries; some like the aptly named Green Carpet moth can be found in gardens and nearby fields often flying in a way that closely resembles a butterfly. They belong to the Geometrid family, which also includes the well-known and larger Orange Underwing, as well as the Blood-vein that often appears on our windows in the evening, buff in colour but with a dark red streak that extends across the wingspan. Nearly as decorative but with a more typical stocky body are the Noctuid moths often seen when at rest. One common one is the Silver-y, rather dusky in colour with the eponymous marking clearly visible on the side of its folded wings.

What we think of as typical moths, the large night-flying insects that gather around our windows or buzz around the light bulb when they stray in through an open window, are the glamourous tip of the iceberg. There are hundreds of smaller ones including the micro-moths which only receive the attention of a few dedicated enthusiasts. In the last few years you may have noticed fewer sightings of larger moths but may not have realised that the same is true of the smaller species. Looking more widely at insects in general, entomologists are reporting a dramatic fall in the number of all species, matching the experience of the general public. This is probably best illustrated by the summer 'windscreen effect' when ‘any long road journey would result in a car windscreen that was insect-splattered’ as the journalist Michael McCarthy noted. However, this rarely happens now. We may only know or notice a handful of these insect species but they are a vital part of the food chain which supports the wildlife of our countryside including many of our best loved garden birds.

Pete Mayston