Moths to look out for in September


Large Yellow Underwing

More experienced ‘moth-ers’ will wonder why I have put in this most abundant and ubiquitous moth. But I find it’s one of the most frequently asked questions about wild-life. Such as “I got quite a jump. I was weeding and this big brown thing scuttled off like a mouse. I could have sworn I saw a flash of yellowy-orange…”

Yes! This was a Large Yellow Underwing (known as a short-cut as ‘pronuba’ by moth-ers, as that is its specific name, Noctua pronuba).

As the pictures show, its upper wings are very variable and the lower wing is rarely seen except briefly in flight.

It has a long season, from June till October, peaking in late August so it may completely dominate the catch in a light trap at that time. It can also be seen nectaring at dusk of a variety of nectar-rich flowers like Buddleia, as well as being disturbed by day.

Its caterpillar, a bulky rather grub-like greenish brown, feeds on a wide variety of plants.

Just two variations of Large Yellow Underwing

Treble Bar

This is a distinctive moth, more often disturbed by day although it will occasionally come to light. Described in the books as ‘common’ I would interpret that as ‘widespread’. I scarcely ever see it but it can be seen in open heathy grassland  in June, but here in the south it has a second, September generation.

Its caterpillar feeds on St Johns-wort.

Frosted Orange

A real sign of impending autumn, this moth will come to light or will settle on the vegetation nearby. Like a dollop of marmalade, it is another of the golden autumn-leaf coloured moths that we see as the leaves start to change colour.

It can be seen in a wide variety of habitats in the countryside.

The caterpillar is hardly ever to be seen as it feeds and pupates inside the  lower stem of robust plants such as thistle, foxglove, hemp agrimony.


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