Getting lucky

Collecting flies while they are mating is a surefire way to establish conspecific identity. Many female phorids are extremely different in appearance than the males (search this site for lots of examples), and linking the two together can be almost impossible, based on morphology.
< Borgmeieriphora in copula

Borgmeieriphora in copula oblique

In this case, we have a pair of Borgmeieriphora collected in a Malaise trap by Wendy Porras in Costa Rica. The females are wingless, reduced creatures, which however have a sharpened, parasitoid type ovipositor. They lived in army ant colonies, but are rarely collected. The only large series of specimens known is a group that I caught over such ants at La Selva Biological Station many years ago. The males were flying over the ants, carrying the females, as many phorids do. Since then, males have shown up frequently in trap samples, but until now females almost never. This new capture was surely a huge stroke of luck, because most mating pairs separate before they die in the alcohol.

Something “new ” for Central America

When in Brazil a few years ago, my team of Giar-Ann Kung, Wendy Porras, and I found the spiny, brachypterous (short-winged) females of phorid genus Pheidolomyia. These flies, which live in the nests of the ant genus Pheidole, were only known from Brazil. Once back home in Costa Rica, however, Wendy quickly found them there, too. This demonstrates two important principles of dipterology: 1) Wendy is a great collector, and 2) our knowledge of the distribution of tropical flies is extremely fragmentary.

A female Pheidolomyia from Costa Rica - photo by Inna Strazhnik

A female Pheidolomyia from Costa Rica – photo by Inna Strazhnik

After I remarked on yet another interesting “South American” phorid fly showing up at La Selva Biological Station during the ALAS (Arthropods of La Selva) project, the ant ecologist Jack Longino agreed with me, only partly joking that “if you collect long enough at La Selva, you get the entire Neotropical fauna!” Now, that’s a hypothesis that would be fun to test.

Fly specialization at the LACM

We are doing something a little daring, but certainly exciting here at the Natural History Museum of Los Angeles County. We have decided to specialize on flies.

drawer-of-flies drawer of unsorted flies from the LACM collection

Why would we do this (besides because we are obsessed)? Most insect collections are comprehensive, trying to house as big a variety of all groups as possible. Basically, we want to to become one of the best Diptera collections in the country, or even the world. You can’t do that unless you are ready to give up something else. For us, it is future growth in non-target groups, like butterflies and beetles. We’ll take care of what we have, but we are not accepting any more.

An even more radical version of the specialization involves exchanging away non-Diptera parts of the collection. To do this, you need to find other like-minded institutions that wish to grow in a similar way. In our case, we found a first partner in the Utah State University, especially with Dr. James Pitts. There, Dr. Wilford Hansen has built an excellent collection of mostly Neotropical Diptera. The current staff of their entomology department, however, is more interested in Hymenoptera, and this spring we are doing a large-scale exchange of USU Diptera for LACM Hymenoptera (exclusive of ants and bees).

This exchange includes about 600 drawers of material on each side. It more than doubles our holdings of general Diptera, not including our already major collections of Phoridae, Blephariceridae, and Neotropical Psychodidae. It also makes USU a major Hymenoptera collection, a truly win-win arrangement.

Exchanges can quickly change the face of the collection, but they are expensive. Moving 600 drawers to Logan, Utah, and bringing same number back to Los Angeles will cost about $4000 and lots of staff time. Still, this is much less money than that required to build a 600 drawer collection from scratch, and we are thrilled by it.

I foresee the possibility of more such exchanges in the future for the LACM, and welcome inquiries from curators who feel that such an arrangement would benefit their collections as well.

Peacock fly

This is a message to my from my friend, biologist Lynn Faust:

Just for fun, am sending you this photo of a cool little fly that put on quite a show for me last May near (not in) the traps in the Smokies. He landed on the roof of my car and proceeding to fan his wings like a peacock and slowly turn and preen. Every time I scared him off with my camera, he circled and returned and spread his wings again. This went on for 30 minutes until I finally needed to leave. I never saw another fly (female) so it was as if he(?) was displaying for me. Of course I did not know what type of fly he was at the time, but just on a guess, googled “peacock fly” and found very similar photos in the Tephritidae family. So, I am asking nothing, just sharing this fun photo since you love flies. Sorry it is not a phorid! Lynn Faust

peacock-fly

Actually, it is a ulidiid, not a tephritid, and a very entertaining one! Thanks, Lynn.

Collecting weird lesser dung flies

I suppose I could have come up with a better title, but with all due respect to my friend and mentor Dr. Steve Marshall, the family Sphaeroceridae does not often lend itself to superlatives. You wouldn’t know this from reading his recent book, Flies: the natural history and diversity of Diptera, however, in which Steve gushes appreciatively about the hordes of dingy, drab brown flies that swarm over cow pies. He reserves special appreciation for the subfamily Homalomitrinae, a group he co-described with his colleague Jindrich Rohacek. These flies, unlike their relatively dull relatives, are bizarre looking creatures, with reduced wing venation, flattened heads, and thickened leg segments. The original specimen was a female collected with army ants in Brazil in 1930; others were found to be attracted to lights. The six known species are organized into three genera: 4 species in Homalomitra, 1 species in Sphaeromitra, and one in Podiomitra. There are fewer than 20 specimens known.

podiomitra-2

Look at the strange head, unusual “feet”, and incredibly reduced wing venation on this fly. Amazingly, we have collected at least three more already in our All Diptera Biodiversity Survey in Costa Rica, all from light traps. It will be interesting to see what other strange creatures are uncovered by our intensive survey of this tropical cloud forest. (photo by Inna Strazhnik).

Gardening for flies 4. Use Baccharis.

I recently witnessed and photographed an incredible assemblage of insects. They were on flowering female plants of Baccharis ‘Centennial’, a widely available hybrid of a plant commonly known around here as “coyote bush”. It was used extensively in what we call the 1913 Garden at the Natural History Museum of Los Angeles County, where I work.

For the last couple of weeks, the plants have been swarming with insects, including many Diptera. In fact, I was first alerted to the situation by Richard Hayden, our Head Gardener, who described a swarm of flies in the area. We went to check it out, and I had my first view of the seething mass of insects on and around the plants, apparently feeding on nectar.

The following photos are only a few of the flies on this swath of Baccharis in downtown L.A. I suggest using this plant in any insect-friendly landscape.

a female bibionid

little blood-red flower fly

thick-headed fly

Best book ever on flies

Steve Marshall’s new book “Flies: the natural history and diversity of Diptera” is the best book ever on flies. It is so stuffed with amazing photographs and interesting information that I literally cannot tear my eyes away from it.

fly-book

I showed it with my hand for scale because it is HUGE. Steve could have written a book half this size and it still would have been the best book ever on flies, but he really overshot the mark here. The number of photos of flies in this book is absolutely insane. I mean, there five pages of photos of sphaerocerids (lesser dung flies), never mind the page after page of more photogenic groups!

Steve was my MSc advisor and has remained a good friend through the years since. We’ve even traveled together and I’ve seen him clicking away with his camera while collecting at the same time, but I had no idea that he had THIS in him. Simply a remarkable book from a remarkable guy. If you are even slightly interested in Diptera, don’t stop to think, just buy this book as reflexively as you take your next breath. Its that good and I can’t imagine anyone writing one that is better.

A new fly to study

Some European colleagues were kind enough to send me specimens of a fly that I have never seen before: Opetia nigra. It is classified in its own family, Opetiidae, a group not known from the New World, but in the past has been most frequently placed in the family Platypezidae, the flat-footed flies (I kid you not; don’t blame me for these common names!).

Opetia nigra male; photo by Inna Strazhnik

I wanted to see specimens because they are a family that are probably related to my Phoridae, although the precise relationship remains elusive. Hopefully, my studying the structure of these flies will tell us something new, although they were treated in great detail by Peter Chandler in his recent book on the flat-footed flies of Europe.

Phorid flies and frogs

Phorid flies are characterized by my colleague, Henry Disney, as the most biologically diverse family of insects. With each passing year, we find more and more unusual lifestyles and larval food preferences that support this statement.

Female Agalychnis spurrelli. Photo by R. Horan III


In the New World tropics, there are a huge variety of frogs found in rain forests. Many of them live in the canopy and come down to the ground level only for mating. Often they lay their eggs on leaves over water bodies, apparently to try and limit depredation by aquatic predators. This creates an opportunity for phorid flies.

My co-author, Robert Horan III, found that eggs of the gliding leaf frog, Agalychnis spurrelli, were turning a strange white color in his study on Barro Colorado Island in Panama. Further investigation showed that maggots of a small fly were eating the eggs. He reared some adults, sent them to me, and they turned out to be a new species that we named Megaselia randi. The name was a tribute to an influential herpetologist, Stan Rand, who helped Robert in his early career.

Healthy frog eggs. Photo by R. Horan III.

Infected frog eggs. Photo by R. Horan III.

This is not the first instance of phorid flies feeding on frog eggs in Latin America. Frogs in two other genera, Phyllomedusa and Leptodactylus, are also attacked. A colleague of mine recently contacted me about a frog egg feeding species in Ecuador.

Phorid larvae in eggs. Photo by R. Horan III.

There are probably thousands of species of Megaselia in the Neotropical Region, most of which are unknown, and the lifestyles of the 350 or so known species are also relatively unstudied. It is possible that among them there are a whole range of flies attacking frog eggs. Herpetologists, keep the possibility of phorid flies in your mind!

Reference: Brown, B.V. & R.V. Horan, III. 2011. A key to Neotropical Region frog-egg-feeding species of Megaselia (Diptera: Phoridae), with a new species from Panama. Contributions in Science. 520: 1-4