13 September 2023

25 July 2023 – Collective Noun for Hawkmoths

Single-dotted Wave (Idaea dimidiata)

The initially inconspicuous Single-dotted Wave (Idaea dimidiata) has unexpectedly become one of my favorite moths, on account of their grace, beauty, and seemingly humble personality. I often find them perched vertically on the walls of the cottage, clinging on to the curtains, or, as in this case, blending into the pattern of my coffee cup. It seems that they are attracted to human textiles! If I could have invented their scientific name, I might have chosen Sirena mikri – ‘small siren’ – in reference to ‘The Little Mermaid’ and her sweet collection of human artifacts!

These members of the Sterrhinae subfamily are on the smaller side for macro moths, with a wingspan of only 13-18mm. They’re common throughout Britain, flying throughout July and August. Their identifying characteristic is the darker patch along the edge of their top wing which might explain their naming, (initially confusing) as they appear to have far more than just a single dot on their wings. This pattern, specifically  the darker cluster present only in the dorsal half of the moth’s forewing, is the origin of their species name dimidiata, meaning to divide in half. The genus name Idaea is a (seemingly, more random) reference to Mount Ida, the vantage point from which the Pantheon was said to have watched the Trojan War.

Poplar Hawkmoth (Laothoe populi) 

In all the traps we’ve set all summer, I don’t think we have had one without at least one Poplar Hawkmoth (Laothoe populi) turning up. However, today we had a veritable convention – nine in total! Their flight season is from May to July, which means that their appearances will be coming to an end in the near future. Unsurprising then, that signs of wear including patchy transparency and loss of scales are visible on six of the moths. Nonetheless, they have clearly decided to go out with a bang!

If you look closely, you may observe that one of the moths near the bottom left stands out from the rest. The shape of its body is more rotund than the others, and the end of its tail has a sharper tip. It’s also slightly bigger, and has wings that are shaped a little differently. Though it’s hard to tell from this back-lit photo, the coloration is also lighter and more orange than usual. This is a good example of the Poplar Hawkmoth in the rare ‘buff’ form. It’s more than likely a female, based on the fact that the buff form is far more common in female Laothoe populi than in males. It is not pregnant, as we originally conjectured when we observed it in comparison to the others. Once upon a time, I might not have been able to tell the difference between a normal Poplar hawk-moth and a buff one, but now, after a summer of mothing, I’m finding these slight variations fascinating!

Post: Autumn Cortwright [U.Penn intern]