Defying the Frost

[NikonUser]

No obvious difference between droplets on body and those isolated way out on the wings.

--Rik

So? Similar reason why my toes stay warm in winter; no not sun radiation but warm blood flowing into them.
Flies has a blood/circulatory system that pumps blood through the wings.
It seems possible, to me anyway, that if the body is warmed by the sun some heat can get transferred to the wings.
The plant having more mass and being pale would taker a lot longer to heat up and melt the ice.

[beetleman]

"Welcome" to the forums John. All I`m going to say is "WOW" and I agree with everyone else. Fantastic Photo. Waiting to see more.

[morfa]

Thanks again for all the comments and very much enjoying reading the discussion! I thought Rik's nucleation site theory sounded really compelling but I don't know enough to be sure.

I feel fairly certain that this fly and the others (most likely of the same species) I found nearby had spent the night sitting on these spikelets of tall, dry grass. It is perfectly possible that the fly had remained perfectly motionless until I came and disturbed it with my presence.

/John

[NikonUser]

I prefer my solar radiation idea.
Rik's idea needs a clean fly with no nucleation sites.
I have looked at several Muscids and Anthomyiids, and other flies, and they always have bits of foreign matter on them. Even after cleaning under a binocular scope, when they look completely clean, close up photos show plenty of 'dirt' (=nucleation sites).
Although your fly looks spotless I have a hard time believing that it is.

[ChrisR]

http://en.wikipedia.org/wiki/File:Snipe ... th_dew.jpg

[rjlittlefield]

As the discussion goes along, I'm actually leaning toward solar radiation too.

Some more observations might help resolve the question. For example it would be a really strong case for solar if it turns out that these flies are typically covered in frozen drops overnight, and then all the ice turns to water a few minutes after the sun hits them, while the plants stay covered with frost.

By the way, you mentioned that you had to shoot this stack several times, and that at one point (early on?) you used flash. Does the first picture you took show the same situation we see here, or does it maybe show some ice still on the fly?

--Rik

[morfa]

I clearly recall that the fly was covered in droplets rather than ice when I first found it. I remember this since it surprised me right away. Actually I thought my chances of finding any bugs out in the open this morning was pretty slim but specifically went looking for these flies since I've seen them there many times before and I thought that IF they were there, then surely they too must be covered in frost like everything else (and that would make an interesting subject).

I'm also fairly certain that the fly was in shadow when I first found it since I was in a hurry to get my tripod setup before the sun hit it directly and I thought this would make the lighting conditions more difficult (as it turned out I liked the shots with a small amount of direct sunlight combined with flash the best).

NikonUser> On the topic of fly hygiene: Were the dirty flies you're referring to alive, "untouched" specimens? I'm asking because I have spend a fair amount of time looking at living flies in their natural habitat – mostly through a viewfinder. Unless they are busy feeding or mating pretty much all they do is clean themselves! Even hoverflies and other pollen feeders that you often find covered in pollen while feeding are completely spotless as soon as you find them resting somewhere. And the first thing that strikes me when I see a dead one – even if it has just been caught and killed is how messy it looks with small grains and fibers all over.

But you could be right of course – after all, I'm not looking at them through a microscope and perhaps even living flies are dirtier than they seem on a microscopic level. I'm guessing a nucleation site can bee really tiny?

/John

[rjlittlefield]

Gee, this feels a little bit like riding a roller-coaster.

So now the picture I'm getting is that this fly is found in the shade, covered with dew but surrounded by frosty plants. Several minutes later, even after brief exposure to sun and flash, the plants are still frosty while the fly, of course, is still covered with dew. This is no longer sounding like solar to me.

Another question: do you know what the minimum overnight temperature was?

And another odd thought: was this fly active enough that it could have crawled here from someplace that was just a bit warmer, say under some leaves on the ground?

--Rik

[ChrisR]

The dung-pile if made the mistake of leaving is just out of shot..?

A thought - if the ice had melted on the body, wouldn't the water have wetted its surface insted of sitting there? The only area that appears to have happened is on its eyes, where it's been wiping. That would make it all condensation, dew.
Where water vapour condensed on ice, it would wet it, I'm sure.
The snipe fly is the same, without the overnight ice.
So I'm warming, to the idea that the fly never had ice on it.

[morfa]

It was a very clear sky that night but according to the forecast the air temperature was not supposed to sink below zero. When I got up (@6:30) it was 3-4°C.

I'm thinking about getting up early tomorrow and it's supposed to be -2°C here tonight. I'll definitely check by this location and see if I can find any additional leads!

[Planapo]

Great field photography! Welcome aboard!

And thanks for posting the shot of the equipment that was used.
I'm curious: What kind of nice wooden tripod is this? And as I'm looking for such a whatchamacallit gizmo (articulated arm?) to hold flash heads: What nice articulated arm is that which is holding your flash there?

--Betty

[morfa]

Thank you Betty!

The tripod is called "Stabil macro" and is manufactured by hand here in Sweden. More info here: http://stabil.nu/english/index.html. I'm very fond of this tripod and think it's the best I've used for macro work, but I've heard others complain about the lack of fixed leg positions so it's not for everybody. I wanted a tripod that could do really low angles and at first I thought I was limited to the ones with a center column that can be aligned horizontally (Gitzo Explorer type) or reversed (pain in the..). But with this tripod I can get the camera flat on the ground if I like – like this for instance:



The arm is a Manfrotto 819-1 hydrostatic arm. Another really neat piece of gear that I've used this season. One large rubberized knob locks/releases three independent joints which this gives great flexibility – perfect for flash alignment. Before this I used a series of small ballheads – works too, with similar flexibility but you have to manage several different adjustment knobs and it's heavier. The 819-1 is really steady and easily holds a large flash unit in any angle (mine doubles as a handle that I carry around my camera/lens/flash with when I shoot handheld).



Oops.. I guess this turned into an equipment post.

/John

[AndrewC]

The arm is a Manfrotto 819-1 hydrostatic arm.
/John

Ah hah ! I kept looking at it thinking it was a Manfrotto Articulated arm that had had surgery or had mutated

Andrew

[rjlittlefield]

\Oops.. I guess this turned into an equipment post.

Not a big problem. I thought about splitting the topic, but decided it was too much trouble to do that and then get them cross-linked properly. It would be a nice touch to make a posting in the Equipment or Technique forums sometime at your convenience, so that the information does not get buried as quickly and thoroughly as it will here in the image gallery. I cannot recall seeing this type of tripod discussed before, and I find it very interesting.

--Rik

[Planapo]

Thanks for the additional information, John.

and is manufactured by hand here in Sweden

Ah, a neighbour! Tack så mycket, then.

--Betty