Monday 11 June 2012: Small elephant hawk-moth
Chris and I were supposed to be out at Portholme today, finishing off the quadrats, but once again we've had more or less continuous heavy rain. I'm getting a little worried that the site will be under water when we return, as it's a flood meadow, and I'm sure the river levels will be rising again. Instead I had a day of catching up after the busy weekend. I'm finally up to date with my blips, after a few days away. I've back-blipped a blue-tailed damselfy for Saturday and a common blue butterfly for Sunday.
When I looked out of the window this morning I wondered what on earth I would blip today. Fortunately Pete had the moth trap on last night, and although the catch was sparse it included this very beautiful small elephant hawk-moth. This is the first hawk moth we've seen this year - usually we've had several species visit by the middle of June!
The small elephant hawk-moth is one of the least common hawk moths to visit our garden. Slightly smaller but even more brightly-coloured than its cousin, the elephant hawk-moth , it's more locally distributed, but still occurs widely in Britain. It prefers chalky districts and dry grassy localities, but is found in a range of habitats. The larvae, which are similar to those of the elephant hawk-moth, feed mostly on bedstraw.
The elephant hawk-moth possesses good night vision. Its eye includes two different kinds of ommatidium; each contains nine light sensitive cells, of which seven contain a pigment whose absorption spectrum peaks in the green part of the spectrum, but in one type the remaining two receptors have peak absorption in the blue and in the other type they have peak reception in the ultra violet. The moth therefore has the cellular prerequisites for trichromatic colour vision. Adults have been shown to be capable of making colour discriminations at night-time levels of illumination, and they sustain these discriminations despite changes in the spectral content of the incident light. The eyess of the small elephant hawk-moth appear very similar, and I suspect that they work in the same way.