Is it a Moth or a Butterfly?

You may well ask, it’s not easy to tell the difference despite a list of differences which ought to make it easy distinguish between the two.  This month is a good time for seeing butterflies and moths, or at least it ought to be if there were the usual numbers around, but in fact butterfly numbers especially seem to have dropped disastrously with some species such as small copper doing especially poorly.

We have around 56 species of butterfly in the country and maybe as many as 2,000 moths so the chances are what you see is a moth, except it isn’t that easy because moths tend to be nocturnal and butterflies fly during the day.  Even this isn’t reliable, however, because some species of moths fly during the day and I believe some butterflies are attracted to moth trappers’ lights and some species of butterflies possibly migrate during the night.  Confusing, isn’t it?  Incidentally, don’t be confused by the term moth trappers, these aren’t at all like, say, fur trappers, all moths are released unharmed and alive after trapping and trapping is normally done as a scientific exercise.  The results of such exercises can usually be found in reports produced at local, regional and even higher levels, for example Harrogate & District Naturalists’ Society produces an annual report, as does the Yorkshire Naturalists’ Union.  Now folk who research butterflies and moths are called lepidopterists and moths and butterflies come under the term lepidoptera, so they are pretty closely related but there are small differences.  Butterflies tend to have clubbed antennae whilst moths have no clubs although they might have feathered antennae, especially the males.

Any the wiser? Well maybe it’s best to just enjoy them without bothering to know whether they are butterflies or moths and maybe it’s best to be grateful that there are any around at all after the effects climate change has had on our recent summers and the effects of so much pollution in our skies from exhaust fumes, chemicals and goodness knows what else.Butterflies tend to hold their wings upright or vertical when at rest whilst moths tend to hold their wings horizontal or flat.  Another difference that you’ll probably never get near enough to see is the frenulum, which is a filament arising from the hindwing and coupling with barbs on the forewing on moths.  Many moths, especially the night flying ones, although by no means all, tend to be relatively dull coloured, although there are some spectacularly coloured night flying moths, but dull colours do serve you well if you wish to lie up during the day without being seen.

Moths and butterflies each undertake that miracle of nature metamorphism, where they change from an egg to a larva to an adult, and there are some really spectacular examples of this.  Take the cinnabar moth, which as a caterpillar is yellow and black because it feeds on ragwort and is poisonous.  After it changes into an adult it becomes a brilliant red colour, again a warning of the poison contained in its body.  Because it has these defences it seems happy to fly during the day and doesn’t have to resort to a life in the dark.  A night-flying moth which feeds on rosebay willowherb is the elephant hawkmoth.  This moth is big, but not that big, and it gets its name from the trunk-like appendage on the caterpillar.  This moth is a brilliant pink and whilst a night flyer can sometimes be seen on resting willowherb or bedstraw during the day.  The caterpillar pupates underground and when ready to do so can be seen crawling over the ground looking for a suitable piece of ground to undergo its final change.  It’s at this time that I get emails from folk saying they have seen a snake, albeit a very, very small snake, in their gardens.


Nigel Heptinstall (Outdoors2015)