by Matthew Cobb
Reader Michael Durham sent us these pictures of what we all think are Drosophila melanogaster flying over some blueberries in Oregon.
This first picture has one fly slurping up a lovely droplet of something, while another comes hovering in to land. All these are females:
You can just spy the halteres underneath the wing of the fly in the middle. This next photo shows a female that has just taken off (don’t forget – these are blueberries, not plums – that fly is VERY small!):
And here’s a fly that has been at the electric kool-aid. Scientists use coloured food to test for feeding preferences in the lab – you can tell which food they flies have been eating by the stain it leaves in their body. Seems like something similar has been happening here:
It’s not all fun being a fly, as this photo from Scotland by Scot Mathieson (aka @scot_nature_boy) shows:
Scot writes:
Thursday 5 September 2013: When predator feasts on predator
Visiting my mum in East Lothian today, I took the dog into her garden and was amazed to observe a wasp pounce onto a hoverfly on an Escholzia flower, disabling it by biting it behind its head. Given the aerial skills of your average hoverfly, this is no mean feat. The wasp, however, struck while the hoverfly was feeding on the flower rather than in flight. It then carried its prey off to a wooden post to immobilised it further before flying away with it. This was the best picture I could take showing both insects.
For those of you who are thinking ‘wait a minute, those hoverflies are lovely peaceful things that just drink nectar’, think again. Hoverfly maggots are vicious predators…
Scot was surprised that the wasp was getting animal protein so late in the season, given that the grubs should all have grown up by now. There are several explanations – the late spring in the UK may have delayed growth that little bit, or maybe this is an example of the plague of drunken wasps that is supposedly haunting the UK (haven’t seen any signs of it myself – fewer wasps around than in a normal year), or it could be an example of the old fable of the scorpion and the frog:
The Scorpion and the Frog
A scorpion and a frog meet on the bank of a stream and the scorpion asks the frog to carry him across on its back. The frog asks, “How do I know you won’t sting me?” The scorpion says, “Because if I do, I will die too.”
The frog is satisfied, and they set out, but in midstream, the scorpion stings the frog.
The frog feels the onset of paralysis and starts to sink, knowing they both will drown, but has just enough time to gasp “Why?”
Replies the scorpion: “Its my nature…”
I wish I could handle water like that fly in the first picture.
Great pictures.
Fill a balloon with water and you can handle it more or less like that fly handles its droplet. At that scale, the surface tension is like rubber, which is how the fly manages to keep it together.
I was rather hoping to go to ISS and play with some water while weightless. 🙂
Recently l witnessed a similar experience to Scott’s in my yard in North Carolina. We have a plant predominately growing in the side yard called a butterfly bush. It is not very pretty, but it seems to be a hit with the butterflies, especially this year. At one time or another I have seen about a dozen swallowtails visiting it at one time. This one afternoon I noticed one of them fluttering rather weirdly and my first idea was that there was mating being attempted between a couple of them. A while later I saw it next to the bush on the ground and saw what really was happening. A ‘bee’ (it resembled a bumble bee) was on the back of the swallowtail holding its ‘neck’ and stinging it repeatedly. I should have gotten my camera, but I guess I was so surprised by what I was witnessing I just looked. Even my maneuvering the butterfly didn’t deter the attacker. Later l was surprised to find the butterfly head and wings laying in a pile, the body missing. My internet investigations produced this probable attacker, a fly…….
http://bugguide.net/node/view/408221
Again, it must have attacked while the butterfly was feeding.
Those are gorgeous fly pictures!
I think you have a mix of Drosophila simulans and Drosophila melanogaster. The one with the water droplet looks like sinmulans, the one below the blue-bellied on is definitely melanogaster.
Last, I saw an exactly similar incident to the one in Scot Mathieson’s photo. The wasp straddled the hover fly pinning its wings and biting its thorax before carrying it off. I wonder if that wasp imagined it was attacking a wasp from a rival nest.
Kinda pretty for a fly, the one next to me not so much.
This is wonderful stuff. Thanks, Prof. Cobb.
Amazing, fascinating shots!
Great photos
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