Adela reamurella, black insects swarming around trees, day-flying moths, green long-horn moth, insect behaviour, metallic insects with long antennae, Wych Elm
Every year, from around about the end of the third week of April, I begin to watch out for the arrival and mass gatherings of insects I find particularly enchanting; the strangely beautiful day-flying Green Longhorn Moth. Their arrival and group dancing displays have become one of the highlights of the Spring for me, not just because they are entertaining to watch, which they are, but equally as this is an event that occurs at this same point in time each year. In changing times it’s reassuring to see that some elements of Nature’s complex pattern continue to repeat as and when they should, although each passing year I breathe a quiet sigh of relief when I see them for the first time, then feel the joy.
Seen individually and more closely, you could be forgiven for thinking this is some kind of a fly rather than a moth. Tiny insects; from outstretched wingtip to wingtip they might stretch to about 1½” (14-18mm).They have long black shaggy-looking hairs on their head and thorax, giving them a furry appearance and well-developed eyes. But then they brandish a pair of outlandishly and seemingly disproportionately long, white waving antennae, with those of males being longer than the females. Their beauty though is in their gorgeous iridescent wings. The basic wing colour is usually described as metallic green, hence the moth’s common name, but depending how the light catches them they can appear in a range of shades from bronze, through greens to violet.
There are several spots around Bryn Euryn where I have seen gatherings of the moths most years, that you could say are reliable. One is around Oak trees, which the insects are known to be associated with, and another is over an area at the edge of a Trail which is lined with more scrubby vegetation including blackthorn and gorse. Most noticeable in large groups dancing around the outer leaves of trees, sometimes high up, sometimes lower down, I have also found them in smaller groups in spots on woodland paths and even occasionally alone.
My own best views though take little effort on my part, as the moths gather and perform in sometimes large numbers directly in front of my kitchen window, dancing in the sunshine around the top of the Wych Elm. I took the following video, which I think gives a much better idea of how the insects look and behave in action than photographs can. My videoing is not the best, but I think anyone that has never seen this little spectacle before will get the general idea! The dancing moths are accompanied by a Blackbird singing, with a few notes thrown in by a passing Herring Gull, plus a few creaks and squeaks from my zooming camera lens which is a tad bent out of shape since I dropped it….! You may also spot the odd hoverfly and a Speckled Wood butterfly.
(you can click on the video to make it bigger to get a better view)
Timeline 2020: This year I spotted my first arrivals in one small group on April 23rd. I think it’s safe to say, all males. Numbers increased over the next few days and I’m sure there have been more than in previous years, but they’d be very difficult to count! Numbers have fluctuated over the last few days, perhaps in connection with the cooler rainy weather we had earlier this week, and yesterday, May 2nd there are only a very few to be seen, in scattered small groups. But this morning they were back in force, with a lot of activity, then by 11am I couldn’t see any at all. I wondered if like with many small insects they need to stay out of the hotter direct sunlight.
Despite some careful watching, I don’t think I saw any females, for whom all of this frenzied displaying is for of course. I definitely didn’t see any mating happening, but I’m hopeful it will have and that there will be more performances to look forward to this time next year.