Marbled Pug

On 11th May I wrote a post (here) with some moths for confirmation that I had caught on the night of 9th May. These included a pug which I incorrectly identified as a possible Oak-tree. I had reached this tentative conclusion after eliminating a number of other possibilities. I didn't mention these at the time - except as a response to a comment, but one of the species that I had eliminated was Marbled Pug because of its scarcity in Bucks. As a beginner, I operate on the basis that any time I come up with an identification that is not found here or extremely scarce or which has a different flight season, it's time to go back to the books and have a closer look as the moth is going to be something much more normal.

Marbled Pug, Newton Longville 9th May

The comments on my post were mostly suggestions in the direction of Marbled Pug, so I sent it to Peter Hall for dissection. Peter has kindly confirmed it as a male Marbled Pug. Dave Wilton tells me that it is only the sixth record for VC24: the most recent previous record was in May 1992 in Salcey Forest (Rose Copse, which is just on the VC24 side of the boundary with VC32). It hasn't been seen in Finemere Wood since 1988 or in Bernwood since 1984.

Genitalia, courtesy Peter Hall

I'm quite excited that it has turned up in my garden in Newton Longville. Where it came from, I don't know: the moth is quite worn and looking at the latest Atlas, it would have needed to have wandered about 100km from anywhere with a post-2000 record.

It's also a virtual notch on the side of my LED-based light. I've been experimenting with my own designs of this since last summer and in 2020 I'm running two traps in parallel (the other with an actinic light), twice a week and alternating the lights between the two locations in the garden in order to compare their ability to attract moths. The light uses several LEDs of various wavelengths and I recently realised that the ultraviolet LEDs were very inefficient: the UV output was only about 2% of the electrical power input to them, which turns out to be a widespread and little-publicised problem specific to LEDs in the ultraviolet spectrum. I found a different component manufacturer who makes UV LEDs that are more than ten times as efficient and I ordered some from China. The 9th May was only the second outing of the LED light with these new components, so catching the Marbled Pug was either a good omen or an incredible piece of luck: I suspect that it was mainly the latter.

Tim Arnold
Newton Longville, Bucks