Dipteran Moments

Throughout the course of a typical year on Skye I would ordinarily encounter well over 1000 species, ranging from earth-tongues and barnacles to clubmosses and stoats, from harvestmen and sedges to wild swans and gnats in the winter. Clearly this is not in any way a typical year, here or elsewhere. 

There are several species in particular that I look forward to seeing each year. The happy level of keen anticipation as that inevitable moment of encounter draws ever closer can sometimes become quite intense. The current restrictions mean that I'm going to miss seeing some of these species this year, but there are others I can find locally. 

There are a handful of inverts on this keenly awaited shortlist, including a couple of flies. The sight of the year's first Gymnocheta viridis iridescently glinting greens and bronzes on a sunlit tree trunk is one such moment. I had a long wait this year, right up until 21st April in fact. Note the lack of leaves in the image below, winter has been reluctant to let go this year.

My first Gymnocheta of 2020. It's what could probably be called a Record Shot...

Happily I did get ever so slightly closer. What a fly!

Plant-wise, there is one very clear winner for me. I can't really explain quite why, but I have a strong love of wandering through carpets of freshly-emerged Ramsons. Maybe it's being beneath deep tree cover. Maybe it's the exquisite flowerheads or the rich smell (and sharp taste!) of garlic. Maybe all of these things combined, I just can't say. But I do love Ramsons. Happily for me, it's a common plant throughout much of the wetter areas of Uig Wood and at this time of year, just as the flowers are opening up, I make a special effort to seek and photograph a certain fly inextricably linked to this plant. One that just happens to also be on my shortlist of keenly anticipated species.

  

This is Portevinia maculata, also known as the Ramsons Hoverfly. These individuals are males with their enlarged eyes. They can typically be found sitting on sunlit Ramsons leaves, wings held partly spread revealing the silver markings on an otherwise all-black body. For a hoverfly they are pretty slow, almost clumsy seeming in fact, as they bosh and crash their way through leaf blades and flowerheads, almost always settling again within just a few seconds. Flight seems a bit of an effort for them, in fact the females usually just walk around on the underside of leaves. At least the males come out to sunbathe and offer themselves up for some pics. 

This is almost the full extent of the Ramsons bed at the site in question. There are a few bushes, and a row of young trees just out of shot to the left, but these Ramsons are essentially living outside of their usual deep woodland habitat. It's a weird plant here on Skye, I've seen it growing in shaded nooks between large boulders on hillsides with not a tree to be seen for miles around. However, this patch is clearly benefitting from the open aspect as it is flowering far sooner than are the extensive carpets in Uig Wood, most of which is still in the leaf only stage.

You can see my rucksack and fleece in the background (they were quickly shed in this sheltered suntrap!) I spent a merry hour or so walking a line back and forth between those and the spot I stood to take this photo. In fact, most of my time was spent walking a ten foot track from my rucksack into the patch and back. I estimate that I counted around a dozen different Portevinia in that small area, all males. I'll go back and see if I can find some females soon, maybe they emerge later than the males?

In case you're wondering, I passed one person as I was heading down to the woods (my housemate, as it happens) and none at all coming back. That was it. Uig is not a heavily populated spot.