Deer Fly challenge

[Tony T]

Birds have been done, so have butterflies, so have dragonflies, and moths are getting there (at least in North America and probably in western Europe). That is, there are field guides with good colour photos of just about every species in these groups.
Now it's time to move to the less-illustrated species. Deer flies (Diptera: Tabanidae: Chrysops) make great subjects with the added benefit that they come to you, no need to go chasing them. Also, they are colourful. Of the 83 spp. in NA only a handful have been well documented with images.
I am currently working on the eastern Canada species but there are a lot more species to be photographed in the rest of NA.
All that is needed are decent photographs of: dorsal body, lateral body, wing pattern, and mug shot.
This is an example for Chrysops vittatus - somewhat of a pest species here in the northeast.
Take the challenge

[beetleman]

Tony....WOW.....These are excellent. Sounds like an excellent project. I will have to remember to "not smash them so much" when they try to bite me. Are the eye patterns variable within the same species?

[Tony T]

Thanks. I was happy with my tabanid photos until I saw Charles' Horse Fly head - now I have to upgrade and start all over again .
Eye pattern is essentially consistent within a species, in fact it's reasonably consistent between species. It's the other parts of the face that can be very useful for species' identification.
There is also a need for similar photos for the Horse Flies (i.e., the genera Tabanus and Hybomitra).

[rjlittlefield]

These are excellent, Tony!

As usual, I have questions, lots of questions...

1. Technique... I am interested in lighting and any particulars of stacking. Also I notice that the backgrounds in the left and upper photos are extremely uniform neutral gray over large areas (RGB exactly = 220), except that the little chunk of background between the left wing and body is more variable and carries perhaps a little color. I'm thinking the background was masked in post-processing? And finally I'm puzzled about whether these are all the same specimen, and if not, whether you did some retouching to eliminate the black mounting pin that I'm pretty sure I see at the bottom of the "mug shot" but not in the other two photos.

2. The pattern in the eyes... What are entomologists' thoughts about the purpose of those stripes? In butterflies, the wing patterns help for species recognition and camouflage, the dark bases for basking, and so on. But I've never read anything about the striking patterns found in these flies.

3. The beasts' behavior... Is it just my misperception, or do these things actually hunt in small packs? As a kid, I spent many hours traipsing through sagebrush carrying net and collecting jar. I was often attacked by deer flies, and it seemed quite predictable that the first fly was quickly followed by another, sometimes two, but seldom more. It struck me as odd even at the time, and (much later) when I learned about statistics, it struck me as very odd. But since then I've never had occasion to observe carefully, so I don't even know if the effect was real or just some personal superstition.

--Rik

[Tony T]

Hi Rik:
I recall reading someone commenting "you don't miss much". I'll second that.
1. Technique: 105mm AF Micro Nikkor + 4T close-up lens; for dorsal shot a headless insect pin (heads these days are nylon or plastic, easily removed with a match) into ventral thorax but not all the way through (I hope Doug is not reading this -"Take nothing but pictures - leave nothing but footprints" ) pinned onto a piece of foam in front of a, theoretically, neutral grey background. So I feel justified in bringing it back to a neutral grey in Photoshop. The face shot shows the pin (sometimes I will Photoshop it out if it detracts badly).
These are meant to be 'technical' shots for identification.
For the side shot, the pin is placed horizontally into the thorax (but not through the thorax) and pinned into a vertical board.
Lighting is from a single Nikon SB800 flash, off camera above the fly. Light is diffused by a tube of regular white 8.5 x 11" office paper. The fly is pinned inside this paper tube, cheap and effective.
About 15 shots @ f16, stacked with Helicon Focus. Camera "locked down" and the fly, it's tube, and the background moved forward on a RRS focussing rail.
The fly is, of course, dead; but has to be fresh as eye colour fades quickly (about a day).
Same individual, a female. Males don't seek blood so are rarely seen.
2. Never seen any convincing explanation for eye pattern in any tabanid.
3. Hunt in packs? Yes. I did some research on arrival sequence of tabanids (mostly Horse Flies) to a tabanid trap, timing the arrival of each fly. Certainly wasn't random. Deer Flies tend to sit and wait for a host to pass near by. Likely that they select certain sites for this and thus there will be places with no flies and other places with several. But I can't rule out they are aware of each other and do actually attack as a group.

Hope to see some tabanid photos from your area next year- accept the challenge.

EDIT: set-up HERE

[Leif]

Very nice pictures. You've captured nicely the beautiful eye colours too.

I used to get huge swellings on my arms and hands whenever I walked near some lakes. The cause was Horse Flies. Beautiful insects, but a mean bite.

[Tony T]

Thanks to all for comments. I see a need for images of insect groups, such as tabanids (deer flies and horse flies), but I'm biased as an entomologist. I mean, just how many more books do we need showing full colour images of birds (I have half a dozem and don't need any more). NA is way behind Europe in well-illustrated field guides but even Europe has a way to go. I'm not up to date with the European books but "The Horse Flies of Europe" by Chvala et al. is just B&W drawings of some of the body parts of the species. Great opportunity for a series of coloured photos for this group of European insects.

[rjlittlefield]

Tony,

Thanks for the very detailed answers to my questions!

The headless insect pin is a good idea. I'm a bit embarrassed to admit that trick had not occurred to me, especially given the number of such pins that I've made by accident over the years.

"...research on arrival sequence of tabanids..." Fascinating! Never heard of such work. Do you have a report on it?

BTW, you may have already run into it, but if not I'm sure you would be interested in "Guide to the Siricid Woodwasps of North America", described in this post. The photos were done by Steve Valley, one of our forum members who has also managed to place highly in Nikon's Small World competition.

--Rik

Edit: to fix name!

[Tony T]

Thanks for the ref., didn't know of it and will try to get a copy.
The tabanid work was done about 40 years ago when I was a grad student, never did publish the results.

[augusthouse]

There is a PDF copy of the book available here:

"Guide to the Siricid Woodwasps of North America"

http://www.aphis.usda.gov/plant_health/ ... dwasps.pdf

[rjlittlefield]

Craig,

Thanks for the link to the pdf.

That file provides a good "view from 30,000 feet" of what's in the book. Alas, it doesn't come close to representing the quality of the printed photographs.

For that matter, I'm sure that the printed photographs don't come close to representing what was in the original stacked & stitched digital images. After all, an image at 9.75 x 7.25 inches (the biggest one in the book) and 305 dpi (12 dots/mm, the highest standard printing resolution) is less than 3000 x 2300 pixels --- smaller than a single frame from a modern DSLR, and much smaller than the 18,600 pixel width (300 dpi x 62 inches) described in one of Steve's posts (here). It would be really cool if they would put the full resolution images online for us diehard detail junkies!

Tony, dang, I'm always sorry to hear of interesting research not getting published. I'm also sorry to see that I got your name wrong not once, but twice(!), and only managed to fix one of them before I thought somebody would notice. Rest assured, I really do know that you're not "Tim", predilections of my fingers notwithstanding.

--Rik

[Tony T]

Rik:
My study wasn't an original idea of mine. I had read a paper by P. Trojan where he studied tabanid behaviour: "The Tabanidae move about the area in groups consisting of about 7-15 individuals...".
Seems unlikely you will be able to find the paper but, anyway the ref:
Trojan, P. 1958. The ecological niches of certain species of horse-flies (Diptera, Tabanidae) in the Kampinos Forest near Warsaw. Ekologia Polska - Seria A. Tom VI, Nr 2, pages 53-129.
Oddly enough, it's in English; (even more odd is that I would remember this paper, the last time I looked at it was in the late 60's).