I am an amateur naturalist trying to discover what lives in garden.
As part of my mission to blog all my garden's life , I have so far covered a number of insects. So far however, all have been found during the hours of daylight. The rules of my mission are that I should identify all lifeforms however, so recently I left an outside light on after dusk and was delighted to come back an hour later to find the moth seen in photo one (click to enlarge).
From the characteristic lemon-yellow colouring and patches of brown on the costa (the leading edges of the wing), and using my copy of 'Butterflies and Moths of Britain and Europe' (Collins), I'm confident in my identifying my moth as the Brimstone Moth.
My moth's Latin name is Opisothograptis luteolata, which, by piecing together snippets of information from various sources, I believe translates as Opistho =backwards , graptis=graphics/writing , luteolata= yellowish : "the yellow-with-backward-facing-graphical-symbols moth" though I'm happy to be corrected.
In an effort to learn more about moths I have been reading the excellent and scholarly 'Moths' (Michael Majerus, The New Naturalist series). There are so many fascinating facts contained in this book that I'm sure I'll be referencing it many times in the future. Specifically on the subject of the Brimstone it mentions that it, together with a two other British moths (the Scalloped Hazel and the Peppered) was the subject of an extensive study in the 1890's showing that the caterpillars of these moths vary in colour according to the colour of the plant on which they feed, so as to afford the best camouflage protection. This site has pictures of the brown and green form of Brimstone larvae. Amongst various other shrubs, Brimstone caterpillars feed on apple, birch, rowan and hawthorn.
Those who read my blog will know I don't like to cause harm to any of the creatures in my postings. Sadly however, rather than finding my moth fluttering around my outside light, when I found it it was lying dead on the ground. I suppose it could be that the wall light itself somehow caused my moth's death (by e.g. causing my moth to collide with the wall). Equally, perhaps my moth was simply at the end of its lifespan - an old moth that used the last of its energies in a flight "towards the light!". I have read that some adult moths are doomed to a pitifully short lifespan by a lack mouth parts with which to feed (the purpose of the adult being simply to mate, lay eggs and die, feeding being unnecessary). This led me into a minor quest to try to ascertain whether adult Brimstone moths can feed and if so, on what. My moth was equipped with a proboscis and from Ian Kimbers moth site I learn that adult Brimstones can produce a number of broods across the season from early May to mid-August. Both thse facts suggest an extended lifespan. With the exception of a few vague reference to adult Brimstone moths feeding 'on plants' however, I've been unable to find any detailed description of what they eat. Can anyone comment?
Brimstone moths overwinter as pupae. Naively perhaps, of the options open to a moth - egg, larva, pupa and adult ('imago') - the rather 'dormant' pupal state seemed a natural overwintering choice to me. The Brismtone is a member of the Geometridae family of moths however, and from Michael Majerus' book I was fascinated to learn that of 288 British species of Geometridae, although 152 do indeed opt to overwinter as pupae, 41 do so as eggs, 88 as larva, and surprisingly (to me anyhow) 7 as adults. I imagine that uncovering the ecological factors that influence these choices presents a wealth of opportunities for scientific study.
And finally, partly in response to a recent comment received on this blog, and partly since I simply enjoy them: some microscope picture (click to enlarge) of the wingscales of my moth (400x magnification).