Green male midge

2021 June 27

I had been wanting a Canon MP-E 65mm F/2.8 1-5X Macro lens for a long time now, but put off buying one because it’s a $1000+ lens. But, while my trusty old 1:1 macro lens gave excellent service for many years, I’ve mostly photographed the bugs that were big enough for it to image clearly. And, in the last year, MP-Es have started showing up used on, at a substantially lower price. So, in November 2020, I finally got one. And now, I can start photographing the tiny insects at a good resolution. Like this little green midge that I photographed on May 18, 2021:


He’s not very big, only about the size of a mosquito. That first image was taken at 1:1 magnification, which was as high as my old lens could go. We can see that the antennae are a bit fluffy, but it is hard to see much detail without going to a higher magnification.

Going to 2:1 magnification, we can more clearly see the antennae filaments and the details of the claspers at his abdomen tip.


Those filaments are extremely fine. The stalk of each antenna is smaller in diameter than an average human hair, and those filaments are pretty much invisible to the naked eye. This gives the antennae a tremendous surface area, and he uses them to sniff out pheromones from the females that he is seeking out for mating purposes.


Once he finds her, he uses his claspers to connect up with her and mate. The claspers have to match up with whatever the female has, and the need for the male and female genitalia to match up helps keep him from mating with a female of the wrong species. And so, this is one of the prime components in species identification of midges.


I’ve never been able to get such fine detail of the claspers on such a small insect before, so I might be able to get a closer identification than I would have otherwise.

I’m pretty sure this one is in the tribe Chironomini, and is most likely one of the species in the Harnischia species complex. The claspers look the most like those of the Parachironomus genus. Bugguide has no listings for individual species under that genus, but I think I actually have enough detail that it would be worthwhile to hunt down a detailed ID key at this point.

In general, the lens is working nicely. The main limitation is that the geometry is different, which has lead to some lighting difficulties. So, I have been re-working my flash concentrator to get optimal lighting for this lens. I’ll give more details once I settle on a good design.

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