Nov 272015

American Thanksgiving not only marks the beginning of left-over turkey sandwich season, but has also come to represent the official start of the Holiday Season™. Traditionally rung in with the rampant purchasing of sale-priced items, the beginning of Holiday Season™ is now celebrated instead with Black Fly Day. This year, in preparation for ugly sweater parties and more family gatherings than should ever occur in such short succession, I present to you 6 fun facts about black flies that will keep your friends and family utterly enchanted!

Simulium sp from Ecuador Black fly Simuliidae

Simulium (Psilopelmia) bicoloratum from Ecuador (Simuliidae) feasting on my blood.

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Jun 242015

Oh give me a home where the buffalo roam,
Where the deer and the antelope play,
Where seldom is heard a discouraging word,
And the skies are not cloudy all day.

When it comes to evocative imagery of North American landscapes, perhaps no other song brings nature to life like Home on the Range. Sung round a campfire, your imagination can’t help but picture the Great American Plains teeming with life and big game under wide open skies as far as the eye can see. Yet, even as Dr. Brewster Higley was writing Home on the Range in 1876, the ecosystem that inspired him was already being drastically altered, and within a decade only a few hundred buffalo would roam where millions had previously.

And while buffalo, or more properly, bison, have largely been extirpated from their home on the range, they left behind an ecological footprint, if not hoofprints, that may influence the ways in which the deer and the antelope, but also the sheep, play.

When we think of animal engineers, we normally think of the beaver, reshaping waterways with dams and lodges carefully crafted with no regard for canoeists or property owners. But bison are known to wallow in their own environmental ingenuity as well, quite literally. Buffalo wallows are depressions in the plains that after decades of communal use by bison herds develop a layer of water-impermeable soil that helps trap water and mud near the surface, which in turn draws more and more wildlife to them during the hot, dry, summer months. These communal baths are even visible from space, and have stuck around for centuries even where bison no longer visit.

By rolling around and washing off all manner of biological material, from skin and hair to dust and plant matter, along with all manner of bodily fluids (bison aren’t adverse to peeing in the pool, so to speak), these wallows, when used, become highly enriched with organic matter. And where there are pools of organically-rich, wet, mud, there are undoubtedly a range of flies just waiting to make themselves at home.

Enter new research by Robert Pfannenstiel and Mark Ruder of the Arthropod-Borne Animal Diseases Research Unit of the USDA in Kansas. Pfannenstiel and Ruder wondered whether biting midge larvae (Ceratopogonidae) in the genus Culicoides were more likely to be found in wallows that haven’t been used for generations but which still collected water, or in wallows that rebounding bison have adopted and infused with fresh fertilizer.

When it comes to aquatic fly larvae associated with “Arthropod-Borne Animal Diseases”, Culicoides may not seem an obvious choice, with things like mosquitoes and black flies more often drawing our attention. But just as the megafauna of the Great Plains has changed since 1876, so too has its microfauna.

In the late 1940’s, a new disease began to emerge in the sheep and cattle of the Southwest, first in Texas, and then California. Termed “soremuzzle” by ranchers and shepherds, infected livestock, particularly sheep, would develop swelling and ulcers in and around their nose and mouth, become fevered, pull up lame, and in some extreme cases, the animal’s hooves would fall right off. Then, in 1952, immunologists finally put the pieces together and realized “soremuzzle” was actually Bluetongue Virus (BTV), a vector-borne disease only known from Africa and the Mediterranean at the time. Since then, Bluetongue Virus has spread from the American Southwest up throughout the plains and has begun creeping into the Midwest, as well as spreading to all the other sheep-inhabited continents, recently becoming a major concern for shepherds in the UK.

The wide spread of BTV was made possible in part by ranchers shipping infected sheep (which commonly don’t show signs of infection, and can remain infectious for weeks following initial exposure) around the globe, but also by the close relationships among the virus’ vectors, biting midges in the genus Culicoides. In the Mediterranean, the only vector had been Culicoides imicola, but eventually enough infected livestock spread into the neighbouring ranges of Culicoides obsoletus and C. pulicaris in Europe, who then helped spread the disease all across the continent.

Meanwhile, in North America, another pair of Culicoides species with wide ranges of their own found themselves home to BTV, Culicoides sonorensis, and Culicoides insignis, bringing us back to buffalo wallows and muddy waters.

Culicoides sonorensis - Photo copyright Adam Jewiss-Gaines, used with permission.

Culicoides sonorensis – Photo copyright Adam Jewiss-Gaines, used with permission.

Pfannenstiel and Ruder scooped mud from buffalo wallows in and around the Konza Prairie Biological Station in Kansas (where, incidentally, the state song just so happens to be Home on the Range), some of which were currently being used by bison, and some of which had not been visited by bison for years, and reared the Culicoides larvae from each sample in the lab. They found that active bison wallows were home to Culicoides sonorensis (as well as several other closely related Culicoides species), with several dozen specimens reared from mud collected throughout the summer, while relict wallows were not.

All of this leads to an extremely complex conservation conundrum. By bringing back bison, and allowing them to resume wallowing in their wallows, it seems we’re increasing habitat for a fly species that carries a disease not present the last time bison roamed the range. Bison themselves are susceptible to BTV, but like cattle, don’t normally show the extreme symptoms or mortality that sheep do. However, the bison’s range is also home to nearly half of America’s sheep, with more than 2 million heads grazing the same areas as bison once roamed. More bison may equal more Culicoides, which in turn could equal more cases of BTV among livestock, a prospect that likely won’t sit well with ranchers and shepherds in the area.

What’s more, sheep aren’t even the most susceptible plains animals to BTV. While most infected sheep may show clinical signs of BTV infection, usually less than 30% of infected animals actually succumb to the disease. Meanwhile, the deer and the antelope (pronghorn) playing alongside the wallowing bison and grazing livestock experience an 80-90% mortality rate when infected with BTV, and will likely serve to spread the disease further, faster.

Of course, being a vector-borne disease, BTV can only spread as far as its vector is found, and unfortunately, we’ve been caught a little unprepared to answer just how far that may be. Culicoides are difficult to identify, and so we don’t know where these flies may or may not be found currently, and more importantly, where they may spread to in the future as climate change broadens acceptable habitat. Luckily, researchers like Adam Jewiss-Gaines, a PhD student at Brock University, are working to not only figure out where Culicoides‘ are found, but are also developing keys and resources that will allow others to track the great migration of these tiny flies.

Conservation biology is complicated, and fraught with trade-offs, especially when we try to conserve species in landscapes on which we place a high economic value and which we have changed immutably. So while we’ve brought bison from the brink of extinction back to Home on the Range-era levels, we now find ourselves presented with a new range of conservation challenges, and there may yet be dark clouds in our future skies.


Pfannenstiel, R. S., and M. G. Ruder. 2015. Colonization of bison (Bison bison) wallows in a tallgrass prairie by Culicoides spp (Diptera: Ceratopogonidae). J. Vector Ecol. 40: 187–90.

Apr 292014

Microsoft magnate and celebrated philanthropist Bill Gates is bringing attention to mosquitoes and mosquito-born diseases in what he’s calling Mosquito Week as an homage to Discovery Channel’s yearly shark extravaganza. Modelling his outreach event after the “scary” world of sharks is pretty brilliant in my opinion, especially when you bring in the numbers of how many people are killed by sharks every year compared to how many die as a result of infected mosquito bites, which he does in this crystal clear infographic.

Infographic courtesy of GatesNotes

There are a number of interesting posts over on GatesNotes, discussing everything from Dengue Fever, to a first-hand account from someone recovering from Malaria, to a travel report from Bill & Melinda Gates on their visit to a region in Cambodia that’s infamous for breeding drug-resistant malaria strains (Ed Yong recently wrote a tremendous piece about this same area and the researchers working on the front lines of malaria control, I highly recommend you take the time to check it out as well).

The Gates Foundation has also produced a series of short, informative and visually appealing videos regarding mosquitoes and the diseases they transmit, along with a number of other visual aides that help explain the biology and impact of mosquitoes.

Now all we need is for SyFy to produce this spinoff of Sharknado and mosquitoes should be on everybody’s mind!

Me too Bill, me too. But before you start filming, please learn the difference between crane flies and mosquitoes. I am available to consult on this and any other Diptera/Entomology issues should you need it.

Bill Gates is certainly one of the most influential people on the planet, and I hope that his Mosquito Week succeeds in bringing much attention to the issue.

Aedes larva from a vernal pool outside of Guelph. Luckily for me, I have little to fear from this species aside from a few itchy bites. Unfortunately, many others across the globe are not so lucky.

Aedes larva from a vernal pool outside of Guelph. Luckily for me, I have little to fear from this species aside from a few itchy bites. Unfortunately, many others across the globe are not so lucky.

Feb 232013

When I woke up Wednesday morning, I never could have guessed that I’d stumble across the most bizarre and terrifying fly-related idea I’d ever heard later that day. But then again, the internet is a weird and wacky place, so perhaps I should have known better.

While innocently looking for scanning electron micrographs of bot fly larvae (Diptera: Oestridae), I chanced upon Insecti-cure, a website promoting, among other things, a “treatment” for fat removal involving intentional bot fly infestations. Really.

Bot fly larvae are THE safest way for fat to be removed.

the maggots are planted next to the stomach, and will eat around the organs, the treatment, is of course painless, after you have had your injection of morphine and you will only be there for 8hrs, you will be subject to 300 larvae which have antiseptic saliva, to literaly eat the fat away, before this operation you wil need to contact us 3 weeks before in order for us to get our orders ready and don’t worry after the morphine you wont be able to remember anything, even if you are squeemish!

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May 162012

I went down to an inland dune habitat in Southwestern Ontario yesterday with my lab mates to do some collecting. For the most part insects were pretty scarce to come by, except for the biting flies, which were out in abundance.

Chrysops cuclux tasting

Chrysops cuclux making sure I will taste just right

Thankfully this was the only deer fly (family Tabanidae) that I had the misfortune of waiting on. I initially went to brush it off, but when I noticed it was oriented in such a way that I could snag a photo, I bit the bullet and allowed it to continue while I contorted my camera around to document another happy customer.

Chrysops cuclux tasting

It's true; the first cut is the deepest

Unlike mosquitoes, who’s mouthparts act like a hypodermic needle to stealthily imbibe your blood, deer flies cut and slice the skin, causing bloodshed which they then lap up. Much like a skinned knee is usually more painful than the prick of a phlebotomist, a bite from a deer fly will rarely go unnoticed, and in this case, make it all the more difficult to photograph whilst squirming!



If you’re curious, here’s a shot of my arm this morning, about 18 hours after the bite occurred. There was a swollen welt about 1″ in diameter that was quite firm and which occasionally had a strange tingling sensation, yet wasn’t itchy. Things seem to be back to normal 36 hours after the bite, with only a small firm area directly below the bite.

Chrysops cuclux bite after 18hrs

Chrysops cuclux bite after 18hrs, with black fly bites for comparison


If you’ve had a run in with a deer fly before and are curious what species it might have been, check out CJAI #8 (The Chrysopinae of Canada East of the Rocky Mountains) or Tesky’s hand book to the Tabanidae of Canada.