All my life, I have been interested in insects. My PhD was based around insect eyes, the structure of their eyes and brains, and how they process visual information. My love of insects was almost certainly as a result of my late brother’s passion for butterflies. However, though as a teenager, I used to raise and breed some of the huge and exotic moth larvae you could get from Worldwide Butterflies, my deeper interests in moths is somewhat more recent. A few years ago, I realized that the old-fashioned mercury vapour light bulbs chosen for the high UV content of their light emissions, were going out of production. At the same time, so that I could record some of the moth species occurring in the Gresigne, I had thought to produce a ‘Skinner-style’ moth trap. These traps are a simple affair; a box with two angled glass sheets with a slot between them and a light on top. I read up on the spectral sensitivities of the eyes of the few moths that had been subject to study and designed a simple LED light that would hit the peak wavelengths of the receptors found in the moth eye. I wrote this up on my technical blog (see as 1 of 3 posts – https://tinyurl.com/y3exybyh). The LED light I described there turned out be very popular and even attracted a couple of references in the scientific literature. Quite a few moth enthusiasts built traps based around my blog posts. Of the ~100,000 (!) visitors to my technical blog since 2018, many were to the ‘moth trap pages’. Much to my shame, until last year, I only used my Skinner trap a few times. However, I recently read a book by Tim Blackburn, a scientist I knew from my time at UCL. “The Jewel Box” is about his experiences with a moth trap given to him by his wife as a birthday present. The text is a blend of the enthusiasm he developed for moths and ‘mothing’, and how moths can be used to demonstrate the principles of population biology – why do animal populations increase, decrease, turn into plagues or extinctions. It’s a great and fascinating book and I very much recommend it. After reading it, I determined to use my moth trap more regularly. I was spurred on by the fact that the French database for recording all manner of animals and plants (the local version of which is https://geonature.biodiv-occitanie.fr/#/), while it had ~30,000 observers and 3.5 million observations, my area had no-one who was systematically recording the moths that occur in the Gresigne.
Thus it was that I began to run my moth trap on a weekly basis. Why only weekly? I decided that rather than record all the species that I captured and their numbers, I would record only the new species. I simply didn’t have time to do otherwise. Also, the range of moth species flying on any particular night does not change much on a daily basis. Further, I was concerned that predation by bats drawn to the light because of the insects buzzing around it, might begin to have a significant effect on the moth population. Several surprises were in store. In the past, I have had serious difficulty identifying moths – partly because many seemed to me to be rather similar in appearance. Further, while I knew that many species were big, beautiful and colourful, I had rather dismissed many moths as drab. I was wrong. Many of the smaller species are absolutely gorgeous too – it’s another case of ‘the closer you look, the more you see’, and the more you are filled with wonder. In my earlier days of moth-trapping, I had relied on field-guides for identification. However, I have recently discovered that if one takes a good photograph, the improvements in Google Lens that have probably resulted from new AI-based algorithms, make it a pretty reliable first port of call. Indeed, it is right most of the time! Another surprise came in the form of the automated responses from the GeoNature database; almost all my observations were labeled ‘not in this location’, ‘not at this altitude’ or ‘not at this time of the year’ or all three! However, when the human curators of the database checked my observations against the pictures I supplied, they were all bar one, confirmed. I have to say that my greatest surprise was how captivated I was by the shear beauty and range of shapes, colours and sizes of moths – from the huge and beautiful Giant Peacock Moth that is bigger than your hand, to tiny plume moths that require a hand lens to really appreciate them.
Back to when I was a PhD student…my supervisor, the late Lesley Jane Goodman, brought the work of Philip Howse to my attention. She said she didn’t know if he was ‘on to something or just mad’! He wrote two books, both of which I have in my library of books on insects, “Messages from Psyche” and “Seeing Butterflies”. Both of these books are about the puzzle that the colour and patterns of butterfly and moth wings set for scientists. While the reasons for eye spots and some other features are apparent, and we understand about warning and cryptic colouration and mimicry, much is either difficult or perhaps impossible, to understand. I have to say, I think Philip Howse was spot on about most of the things he has to say about the patterns and colouration of butterflies and moths. I believe Philip while retired, is still working and if he sees this post, I’d love to get in contact.
Below are a few photos of some of my moth captures. I hope you will agree that moths are stunningly beautiful and dare I say, mysterious.
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