Saturday, 18 October 2008

Things that aren't wasps

Though it wasn't my intention to begin with, this neatly follows on from Bug Girl's posts Things that aren’t bees (#1) and (#2).

One of my colleagues spotted both male and female Phasia hemiptera along the road at work, so the next day I brought in my camera to try to get some photographs of what is probably one of the UK's prettiest flies. I've since discovered that very few photographs of P. hemiptera do justice to the iridescent blue on the wings, so I don't feel quite so bad about failing to get any photographs over two consecutive days.

Instead I spent my time photographing the abundance of other insects, mainly on hogweed Heracleum sphondylium. Chief among these were hoverflies (Syrphidae), including the species below. Now that colder weather is setting in I'm getting around to dealing with the images.

I'm not an expert and I did not get any of the hoverflies photographed under a microscope, so don't rely on these identifications!

The most abundant hoverfly was Syrphus. I'm certain that I saw female Syrphus ribesii, so I'm assuming that this male (right) is also S. ribesii.

Also present on one day was a male Syrphus with a twisted abdomen (left). Sadly it did not pose especially well, but the shot does show the distorted abdominal tergites. I thought at the time that it might be a stylops, but they do not appear to parasitize flies at all.

Rather similar, but not as common, was Dasysyrphus albostriatus. The individual to the right is a female and shows the distinctive lines on the thorax that provide its name.


Probably the prettiest species present with regular stripes on the abdomen was Eupeodes luniger. This female (left) looked like a flying jewel in the sunshine, with a bluish sheen to the black areas on the abdomen.

Scaeva pyrastri (male, right) has more white or cream coloured stripes on the abdomen.

Another very common hoverfly in the UK, so common in fact that it has a English name, is the marmalade hoverfly Episyrphus balteatus (male left). This is possibly one of the most distinctive hoverflies in the UK, due to the overall shape and the double stripes on each abdominal tergite.

Also very distinctive is Chrysotoxum bicinctum, as it seems to be the only British species with two stripes on the abdomen as shown on the female on the right. I think that C. bicinctum is one of the few species that does a convincing job of looking like a wasp. This is on yarrow Achillea millefolium, rather than hogweed.

Finally, there was Xylota sylvarum. If I had seen this before then I obviously haven't been paying enough attention, as it is large, glossily hairy and attractive, if a little lumbering (there is also the smaller but similar X. xanthocnema). I fell in love with this female so there are two photographs (below, left and right)!

1 comment:

membracid said...

Oh, very nice! and now I have discovered another bug blog :)