Crane fly face

rjlittlefield · Post by **rjlittlefield** » Mon May 19, 2008 12:24 am

It's crane fly week, I guess, and since this one turned up in a spiderweb, I figured maybe the spider could catch something else.

This beast is relatively large, but it was so fresh that stacking it was a challenge because the antennae wilted as I shot.

Actually I thought this stack was going to be a total loss, but with some aggressive cropping and careful masking, well...you decide...

--Rik

Technical: Canon 300D, Olympus 38 mm f/2.8 bellows lens at f/4, flash with tissue diffusion and aluminum foil reflector, 78 frames at 0.001" focus step stacked with HF, background masked to uniform color in Photoshop.

Harold Gough · Post by **Harold Gough** » Mon May 19, 2008 5:25 am

Very pleasing. I especially like the colour and composition of the top one.

Harold

lauriek · Post by **lauriek** » Mon May 19, 2008 5:40 am

Ahh the old saggy antennae problem, I had that with my cranefly - my first stack was of the whole head and most of the antennae but when I looked at the pictures each one had the antennae in a slightly different position, that's why I ended up zooming in on just the eye on that specimen!!

Looks good to me, like Harold I think I prefer the first... I plan to do another one of these with the specimen held upside down so hopefully gravity will hold the antennae in place!!

Harold Gough · Post by **Harold Gough** » Mon May 19, 2008 6:39 am

lauriek wrote:I plan to do another one of these with the specimen held upside down so hopefully gravity will hold the antennae in place!!

Devilish cunning!

The powers affecting shrinkage might be more than those of gravity.

Harold

beetleman · Post by **beetleman** » Mon May 19, 2008 6:46 am

Excellent work Rik. Lots of great Detail. I have probably looked at this 10 times already. Are the mouthparts basicly for lapping juices?

rjlittlefield · Post by **rjlittlefield** » Mon May 19, 2008 9:43 am

Thanks for the feedback, guys.

I see I forgot to mention that the second image is just a crop from the same stack. It shows how much detail there is hiding behind the web-sized version.

Doug, it's a good question what this thing eats, if at all. My Audubon Society Field Guide to North American Insects & Spiders has three main blocks dedicated to crane flies. They say "Adult eats little" (once) and "Adult does not eat" (twice). So I dunno.

--Rik

lauriek · Post by **lauriek** » Mon May 19, 2008 9:52 am

I know the larvae of these (leatherjackets) are a pest which eat lots of plant roots, and I know some insects don't eat at all as an adult, but what would the point be of having a mouth if the adult didn't eat at all? (Mind you I've seen a million of these things and I've never seen one eating anything!!)

Harold you could well be right about shrinkage being more powerful than gravity but it's worth a shot!!

I'll let you know how it goes!!

rjlittlefield · Post by **rjlittlefield** » Mon May 19, 2008 10:06 am

lauriek wrote:what would the point be of having a mouth if the adult didn't eat at all?

There's always the possibility that what used to be mouthparts have been co-opted or reduced to other functions, such as chemical sensing to find good spots to lay eggs.

My personal guess would be that these critters do a bit of sipping when nobody's watching, but that's based on no real information.

About the upside-down mounting strategy, I think it would have worked fine on this specimen. I thought about doing that, but I wanted the light coming apparently "from above" and I was too lazy to rework my setup so that would be physically from below.

--Rik

Harold Gough · Post by **Harold Gough** » Mon May 19, 2008 10:20 am

lauriek wrote:I know the larvae of these (leatherjackets) are a pest which eat lots of plant roots, and I know some insects don't eat at all as an adult, but what would the point be of having a mouth if the adult didn't eat at all? (Mind you I've seen a million of these things and I've never seen one eating anything!!)

The selective pressure is on the larvae having functional mouthparts. While there is no selective pressure to have such as adults there may be none to lose them either. They may be redundant but (I assume) do no harm either, making the selective pressure neutral (almost certainly not the correct term). If it ain't broke, don't fix it! (I don't think Darwin actually said that but he would have supported the spirit of it).

Harold

rjlittlefield · Post by **rjlittlefield** » Mon May 19, 2008 10:54 am

Selective pressure is a tricky thing.

Resources used to grow mouthparts are not available to grow, say, more eggs.

So unused parts always have an "opportunity cost". The critter that can get rid of them without breaking something else will be a step ahead of the competition.

--Rik

acerola · Post by **acerola** » Mon May 19, 2008 12:08 pm

I uploaded one more picture for the cranefly day. Just to add something for the discussion. I think I photographed the eating adult. http://www.photomacrography.net/forum/v ... 9522#29522

And great stack by the way. There is one specimen in my fridge for over a month. I will work wiht something else now, that first Laurie now you explored this subject.

rjlittlefield · Post by **rjlittlefield** » Mon May 19, 2008 12:32 pm

acerola wrote:I think I photographed the eating adult.

I think so too -- excellent!

--Rik

gpmatthews · Post by **gpmatthews** » Mon May 19, 2008 2:33 pm

...not sure about the legs, they do seem to use them for stabilisation in flight. They also see to lose them quite easily, so maybe they are used as a defence mechanism - hungry predator ends up with a mouthful of useless legs and cranefly escapes for another day, albeit with a limp!

Some parts of the legs are visible in an old post of mine at http://www.photomacrography.net/forum/v ... highlight= which I guess makes for interesting comparison, especially as the eyes are so different.

rjlittlefield · Post by **rjlittlefield** » Mon May 19, 2008 2:51 pm

gpmatthews wrote:...especially as the eyes are so different.

I notice in that topic, you mention that the fly had been "waiting some time for its portrait to be taken".

I wonder, did your fly have some chance to dry out before being photographed? The eyes lose their iridescence quickly when drying.

--Rik

gpmatthews · Post by **gpmatthews** » Mon May 19, 2008 2:55 pm

Rik - that's possible, although I'm pretty sure they were in fact black, but more lustrous when fresh.