Glow Worm

Though this blip was taken today it feels more like a second blip for yesterday.

Our local church yard has a colony of the common glow worm (Lampyris noctiluca). Last year we performed a detailed survey, mapping them every other night on a high resolution map we had made. Though it's called "common" it is actually quite rare in the UK, probably the result of habitat change, hence our interest in surveying them.

This year we decided to try to look for males. Only the adult females glow in a highly visible manner, the males and juveniles don't really glow much and so are harder to find. In theory you can find a male as they fly to the flightless glowing females, but we've never found any by waiting next to a female. This year we decided to try our own super females.

We found a paper where someone had used a green LED to attract British males. Using a bright green LED of the same wavelength (565 nm), a resistor and a 9v battery we made our own super bright glow-worm. We already knew that the females were glowing this year so after the Saturday night BBC Four detective show we went down to the church yard armed with our lure and camera stuff.

The lures glowed but no males came visiting, it may be a bit early for the males. The females start to glow a few days earlier than the males emerge, and initially the males are so heavy that they can't fly so they only walk...

This blip was taken just after midnight*, I took my camera, a small bendy tripod and a tarpaulin so I could lay down without getting drenched. I used spot metering on the glowing bit and stopped the ISO setting from going to high (to reduce noise) and because they don't move, set a small aperture for maximum DOF. The first few pictures were just green glows, so for this picture I swept the scene with my torch and hoped that the camera could cope (which it did).

I loaded the RAW image into GIMP via ufraw and cropped it a bit and tinkered with the balance but it's pretty much as is. If it's not cold and pouring with rain I'll try again tonight for another shot.

Because they don't move much, I'm tempted to have a go at HDR, one exposure for the green glowing bit, virtually everything else shows up as black, and then one illuminated exposure where the glowing bit is overexposed. Any tips?

* Which because I'd not gone to bed yet to my mind still feels like yesterday....