Here is an even more beautiful reconstruction of Euryplatea nanaknihali by Inna-Marie Strazhnik.
Tag Archives: biodiversity
Worlds smallest fly discovered
In a paper appearing today, Monday, July 2, 2012, I describe the world’s smallest known fly. It was collected during the TIGER (Thailand Inventory Group for Entomological Resources) project, funded by the National Science Foundation with the grant to Dr. Michael Sharkey of the University of Kentucky and me (as co-PI).
Many stories about small things, especially parasites, quote Jonathan Swift:
“So, naturalists observe, a flea
Hath smaller fleas that on him prey;
And these have smaller still to bite ’em;
And so proceed ad infinitum.”
In this case, the quote is especially apt, because the newly discovered worlds smallest flies are parasites!
The smallest fly in the world is a member of the family Phoridae, and is one of the “ant decapitating flies”. Adult females lay an egg in the body of an ant, and the resulting larva feeds in the ants head, eventually causing the decapitation of its host. Some of these flies are being used to attempt biological control on imported fire ants, and were even featured on an episode of the popular television show “King of the Hill”.
Because these flies usually develop in the head of their host ant, they are smaller than their hosts. One would think that the smallest ants would be therefore immune to these nasty parasites, as their heads are vanishingly small. But the world’s smallest fly is one of these ant killers, and at the astoundingly small body length of 0.4 mm, these flies can probably decapitate ants with heads as small as 0.5 mm. That is pretty close to the smallest size that ants can get!
When we think of animals that are small, usually a fly or a flea come to mind. Let’s forget about fleas; they are comparative monsters at around 1-2 mm in length. But what about flies?
The common house fly is something that we think of as being small. In the world of tiny insects, however, they are virtual Godzillas at a whopping 6 mm.
Many flies are much smaller than this. Fruit flies that you see hovering over overripe bananas, for instance, are about 2 mm long, one third of the size of the “giant” house fly.
Some of the biting flies are much smaller than this. One aptly named family of flies has the common name “no see ‘um”, because of their almost invisibility when they are biting you. These flies are getting really small, usually around 1 mm in length.
The world’s smallest fly is 0.4 mm in length. Here is a microscope slide, 1″ x 3″ size, with the holotype specimen of the fly mounted on it. It’s unimaginably small, smaller than a flake of pepper you shake out of the pepper shaker.
holotype specimen of Euryplatea nanaknihali Brown
Do you see it, within the small circle, to the right and slightly above center?
The world smallest fly doesn’t really look like a fly. It’s one of those weird phorids whose body form we call “limuloid”, after Limulus, the horseshoe crab. It is a defensive body form that allows the flies to live in the ant nest which, based on this body structure, is probably part of the fly’s life. It has short wings, but they are functional sized, so this fly could easily fly from ant nest to ant nest. It also has a sharply pointed tip of the abdomen, indicating that it is a parasitic species.
My research is funded by the National Science Foundation, currently grant No. DEB-1025922.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.
Massive tropical fly inventory funded by the United States National Science Foundation
A tachinid fly photographed by Wendy Porras at Zurqui
This project is a collaboration of more than 40 experts worldwide, as well as Costa Rica’s Instituto Nacional de Biodiversidad (INBio). Together, we will collect extensively and identify all groups, even the “impossible” ones like ceratopogonids, cecidomyiids, and phorids. We expect to find a number of species that will surprise even us!
This will be the first time that such an intense effort will be made for any mega-diverse group of insects in the tropics. We were inspired by Terry Erwin’s fogging samples in Peru (and elsewhere), but wanted to go a different route in understanding tropical biodiversity. The “All Taxon Biodiversity Inventory” (ATBI) model appealed to us, but we knew we had to restrict our collecting to prevent the project from getting out of hand. We therefore decided to collect in just two small ravines in an area 100 m x 200 m in size.
We are calling the project the “Zurqui All Diptera Biodiversity Inventory”, or ZADBI. Collecting will start in September; meanwhile we are getting organized for the massive job of collecting, preparing, and identifying the tens (or hundreds) of thousands of specimens we will collect. Of course, we will be broadcasting our discoveries and experiences both here on flyobsession and on the project’s website (TBD). Get ready for some more cool flies!
More microfraction miracles
I call these “miracles” not in the religious sense, but in the unlikelihood that I would notice them in a “normal” sample with all the macro-garbage obscuring them.
The first is a male, perhaps of the genus Metopina, with the thick costal vein almost as long as the wing.
Metopina group male
Next is a bizarre female termitoxeniine that has not yet shed its wings.
female termitoxeniine
A relatively “normal” wingless female Chonocephalus.
female Chonocephalus
Finally, a flattened male of a new phorine genus with a short costa.
new phorine genus
And I still have many more vials to look through! Life is good.
All photos were made by Inna-Marie Strazhnik, who is a superb artist.
Microfractions rule!
I am sorting through a bunch of Malaise trap samples from Thailand from which all the insects larger than about 2 mm have been removed. The absence of larger insects makes all the tiny ones stand out, so these samples, the “microfraction” are golden. They are full of treasures: usually overlooked tiny things like Chonocephalus, termitoxeniines, and weird Metopina group males. I’ll publish more photos soon, but here are a couple I photographed previously.
a Metopina group female
new phorine genus
Note the shieldlike crest on the back of the head in the second photo. Totally bizarre.
Microfractions represent yet another largely unexplored frontier of tropical phorid diversity. After nearly 30 years of doing this, I can still be amazed and awed by “my” flies.
Problems photographing flies. 3. You need light.
Okay, based on parts 1 and 2 of this series, you want to use high apertures (lens f-stop settings) to get lots in focus, but you need to use intermediate apertures to avoid diffraction blurriness. Either you have to focus stack (often impractical in the field) or accept a compromise f-stop like f11. So how does f11 work for you?
In all but the brightest light, f11 (or f8) will require long exposure times, giving ample opportunity for you or the fly to move, blurring the exposure. We’re back to either needing a motionless fly (unlikely) or, this time, more light.
Wait, can’t you just dial up the ISO (sensor sensitivity) on your new digital camera so you can use a faster shutter speed? Yes, but you increase the digital graininess (“noise”) in the photo, such that resolution at high magnifications is destroyed.
Here are a series of closeups of bristles on a tachinid fly showing this effect:
ISO 100
ISO 200
ISO 400
ISO 800
ISO 1000
ISO 1600
ISO 6400
This series of shots tells me that, for my camera, ISO 200 is about the same as 100. For ISO 400-800 I get some degradation, but it is still pretty good. Above ISO 800, thing get pretty mushy. You need to check this in your camera, too.
The result is that changing ISO only helps me a little. If I want the highest quality images, I need more light. How to get this light is my next topic.
Why so spiny?
I got a lot of questions about why yesterday’s fly would be so spiny. I can think of two plausible answers, both of which might be right.
Firstly, such spiny flies are almost invariably found in species associated with ants, especially army ants. As evidence for this, here are 3 flies from the New World tropics found with Labidus army ants: Acontistoptera, in which the long setae (bristles) are found almost only on the wing rudiments, Adelopteromyia, which are spiny on the wing and on the body (especially the head), and Xanionotum, which has multiple rows transversely across the abdomen.
The large setae could be used to fend off attacking ants, like a porcupine, or for sensory purposes in the darkness of underground ant colonies. Or both. One thing to keep in mind is that the flies probably can move the setae, erecting them or laying them down. They are much more flexible, mobile, and speedy than you might think, as they literally runs circles around the host ants.
A brief respite from photography posts: another bizarre phorid
My friend in New Zealand, Hugh Oliver, saw the picture of the wingless female phorid in my last blog post, and asked for more photos of weird phorids. I didn’t even know he was looking at my blog, but just for him I am posting this photo of an extremely bizarre specimen we found just this week in material from Thailand. I think it is a female of the genus Rhynchomicropteron, but if so, it is an extremely unusual one! Thanks to Lisa Gonzalez for pointing it out to me, and Inna-Marie Strazhnik for photographing it. Maybe it can be number 16 in Terry Wheeler’s posts about why flies are great.
Problems photographing flies. 2. To stack or not to stack?
female Aenigmatias
As I showed in the last post, at high magnifications you can only have a small amount of your subject in the sharpest focus because diffraction limits useable depth of field. Now you have two choices: stacking or settling for some different compromise.
The image above is a blended stack of 25 images, all of which only have a bit of the fly in focus. I used a program called Zerene Stacker to do this, but there are other options. You can make some phenomenal images this way (just look at the forums at www.photomacrography.net), especially using tens to hundreds of source images, but there is a catch – your subjects have to be motionless, preferably dead. Some field photographers can get short stacks of a few images of resting flies, but generally flies are 2. active. For me, it is better to pick a compromise lens setting like f 8-11, as discussed last time, to get good shots of lively, moving flies. If you want more information on stacking, though, see the free resources at www.macrostop.com.
Next: how do you get enough light to use f 11?
Problems photographing flies. 1. Of what is your camera capable?
A tachinid fly - looks good, right?
Flies are fantastic subjects for photography, but they present many challenges because they are
1. small,
2.active,
3. often metallic and bristly.
All of these are factors that cause problems that I’ll discuss in the next few postings.
[The reason I’m writing about this is that there is so little good macrophotography information about insects like flies. I assume interested readers know the basics of 35 mm digital photography. If this subject doesn’t grab you, go back and re-read the last post by Lisa Gonzalez, which was a real crowd-pleaser]
When you photograph small things at high magnification, your depth of field is frighteningly shallow. Take a shot at f 1.4 and you’ll get maybe one tarsomere and a wingtip in focus. The rest will be a blur. Therefore, you need to close down to f 22 or f 32 to get everything in focus- correct? Unfortunately, when you do this, you start to distort the image through diffraction. It’s not really a problem when photographing big things (like landscapes), but flies are 1. small.
Above is a good-sized tachinid fly. I photographed it with my camera (Nikon D-7000) on a tripod, using a 125 mm macro lens set at f 22. At this magnification it looks pretty sharp, but look closer (below). You’ll softness from diffraction that no fly obsessed photographer (and I hope you are one) would tolerate. And since most flies are smaller than this tachinid, what we see in this magnified view is ALL we’ll get.
f 22 -blech!
At the next setting, f 16, sharpness is definitely better. Scroll down to see other settings.
f 16, a little better
f 11, better yet
f8 - sharp
f 5.6 - who knew?
The problem, of course, is that by f 5.6 the legs are all out of focus. You have to pick a compromise (f 11 works for me) or do something else, photostacking, which only works well with stationary objects (and remember, flies are 2. active). More compromises are ahead.
To get the best results, you first need to know what your camera can do. Everyone needs to test their camera and lenses this way to see what is possible. Then you can move on too what is practical.
Next- how do you get to use that f 11 setting?