Urban phorid flies in Los Angeles, California, USA

Last week Emily Hartop and I published a new paper on the phorid fly fauna of Los Angeles, in the journal Urban Ecosytems (get the full text here). This is the culmination of years of work by all of the BioSCAN team, in getting the project up and running, sorting and identifying 40,000+ flies (mostly Megaselia, mostly the work of Emily), and looking for patterns in the community.

Lisa Gonzalez of the BioSCAN project and Joe Hogg, one of the site hosts, in Joe's backyard.

Lisa Gonzalez of the BioSCAN project and Joe Hogg, one of the site hosts, in Joe’s backyard.

The major findings for us is that the Los Angeles urban fauna consists of about 100 species (43 of which were new to science and described by us for the first time), but individual sites (mostly backyards) had from the mid-twenties in the area just west of the museum to 83 species in Glendale, right up against the mountains.

The commonest species by far is Megaselia agarici, a fungus-feeding species possibly introduced from elsewhere. It is sometimes a pest in commercial mushroom farms, but here they are extremely common in “wild” Agaricus mushrooms that we have found in the city and brought indoors for rearing the flies. This species is so prevalent, that it was found in every one of our 30 sites (as were a few other species), and in some sites it made up over 70% of the phorids captured. Many of the other commonest species in the study were also mushroom feeders, such that at least 40% of our collected phorids have this lifestyle.

Thirty sites of the phase I BioSCAN project in Los Angeles

Thirty sites of the phase I BioSCAN project in Los Angeles

In contrast, our most diverse site had many more species that do other things, especially those that parasitize ants (including the infamous “ant-decapitating flies” I have written about elsewhere). These ant-associated species are completely absent from the downtown area, almost certainly because the introduced Argentine ants have completely eradicated the other species of ants formerly found here. It is difficult to know how much damage was caused by the introduction of “argies” here, but it was a catastrophe for phorid flies.

Many other results are in the paper, and I urge all interested fly aficionados to read it. The next step will be to associate these diversity data with variables of climate and urbanization to see if we can find some correlations that make sense. We are far from finished working on L.A. phorids! But the outstanding remaining question about this phorid community we have here is whether it is representative of other urban phorid assemblages, here in California, here in North America, and throughout the world. Are all urban sites dominated by fungivores? Do they all have a superdominant species like M. agarici (or maybe even M. agarici itself)? We just don’t have any data to know the answers yet.

Thirty of the 43 new species of phorid flies from Los Angeles

Thirty of the 43 new species of phorid flies from Los Angeles

Additionally, one of our next studies will be to look at other groups of insects (including other families of flies) to see how they are distributed in the city. I expect that there will be some major differences among groups, attributable to small-scale differences among sites. One study (Avondet et al. 2003) in Ohio, looked at, among other things, the distribution of dumpsters to help predict the diversity of Drosophlia “fruit flies” (Drosophilidae, better referred to as vinegar flies or pomace flies) in the urban landscape! Probably the diversity of plants, flowers, amount of hardscape vs yard, mulch versus grass, and so on will greatly affect the number of species at a site, but our ability to predict this is still in the infancy stage. Stay tuned for more…

Cited article:
J.L. Avondet, R.B. Blair, D.J. Berg, and M.A. Ebbert. 2003. Drosophila (Diptera: Drosophilidae) response to changes in ecological parameters across an urban gradient. Environmental Entomology 32(2): 347- 358.

The white-tailed phorid, Megaselia albicaudata

It is amazing to me that some phorid flies are found in multiple environments around the world. Less surprising are the scavengers that live mostly in human-built structures or that need scraps of our civilization to thrive. Usually, these scavengers are well-known to us, through their large numbers and occasional nuisance status. But what about the”white-tailed phorid” (I just made that name up, based on the Latin name!), an obscure but seemingly ubiquitous fly?albicaudlatsmall

There is no question that this 1.5 mm long fly is well-named: the male genitalia are a shocking white in comparison to the rest of the rather dingy brown body. It was described in 1910 from England, and is well-known from other parts of the world such as Finland, Israel, and China. It is also found in the two big fly inventories that I am part of: the Los Angeles County Natural History Museum’s urban biodiversity project called “BioSCAN” and the Costa Rican “ZADBI” project in a tropical cloud forest.

How can a species live in such disparate climates and habitats? Nobody knows, just as nobody knows what the larvae of this fly eat. I have looked at specimens from both North America and Costa Rica, and I am sure they are morphologically the same species, not two species masquerading as one doing different things in different places. It is one of thousands of Megaselia worldwide that we know nothing about, but discovering phorid lifestyles is part of our* phorid research effort. Obviously, we have a long way to go when such a widespread species remains a mystery.

*Note, when I say “our”, I mean the few people worldwide actively pursuing phorid research, including our group here at LACM, consisting of Emily Hartop, Lisa Gonzalez, and me.

Windows

No, not the operating system. I’m talking about physical windows in a building. If some doors, other windows, or even the whole side of the building are open, windows can be fantastic places to collect flies. Like most dipterists, I go right to the windows of any building I am in, to see what is there. Sometimes, people look at me as if I am crazy, but I forgive them because they just don’t realize how cool flies are yet (top to bottom, a ropalomerid, stratiomyid, and tababid).

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Wendy Porras and I just got back from La Selva Biological Station in Costa Rica, where half of the dining room is wide open, while the other half has screened windows throughout. We found a lot of extremely photogenic flies, some of which I show here. We put them in a more pleasing background than screening, wrangled them to sit still, and got the shots we wanted. A little honey on the leaves helped, as some flies were apparently hungry after several hours of banging their heads against metal cables.

The Most Beautiful Fly in the World

I know that this might be controversial; after all, people generally either don’t think flies have any redeeming qualities (never mind “beauty”), or more likely for readers of this blog, have their own ideas of what constitutes a gorgeous fly.
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silver strat zerenea
I submit, however, that this amazing silver male stratiomyid (soldier fly) from Costa Rica is the most beautiful fly in the world. It moves around on the underforest leaves like an animated drop of quicksilver, flashing in the tropical sun. It is not garish, like some of the gaudy calyptrates I have seen (see below), but has a pure beauty in its clean, sleek metallic cover. Just in case you find this boring, it also has a scutellum decorated with spines, like the crown of royalty.

The name of this creature is Artemita aurata (Macquart), and it was described in 1846, so it is not anything new, but it deserves “rediscovery” by lovers of biodiversity everywhere.

Don’t agree with me? Let’s hear your nominations!

OLYMPUS DIGITAL CAMERAA gaudy calliphorid from Australia: a runner-up to the world’s most beautiful fly

Diptera Blitz wrap-up

EOL micropezidOf course, our event was a tremendous success. Some highlights:

– bat-netting by Carl Dick got us streblid records, bird-netting by Kimball Garrett got some hippoboscids.

– Carlos de la Rosa (the Director of the La Selva Biological Station) joined the team, working on chironomid midge pupal exuviae

– Michael Turelli, professor of genetics at UC Davis and (at least on this trip) amateur drosophilid collector gave a stunning talk about using the intracellular bacterium Wohlbachia to eliminate dengue

– the final event, a barbeque, featured a short film about the week by LACM videographer Edgar Chamorro.

Some photos follow, including a group photo of nearly all participants. These photos help portray not only the enjoyment, but also the dedication of the team to document as many Zurqui flies as possible. The results of their efforts will appear soon on this website.

group
Yes, nearly all these people came to Costa Rica to study flies! (click photo for larger view)

Diptera blitz kimball
LACM ornithologist Kimball Garrett releasing a bird after checking it for hippoboscids (bird louse flies)

Manuel Art Brian
Manuel Zumbado, Brian Brown, Art Borkent: three dipterological amigos

Diptera blitz continues

Uber-collector Wayne Mathis

Uber-collector Wayne Mathis

The 30 participants in the Zurqui all Diptera biodiversity inventory in Costa Rica have been pushing back our veil of ignorance about the fly fauna of tropical cloud forests. So far, we have spent two full days at the site (Zurqui de Moravia, 20 minutes north of San Jose), and one full day at our partner institution INBio. New species and even new genera of flies are being found everywhere we look. Some examples:

Collaborators Dr. Greg Curler and Sergio Ibanez have found a strange new type of psychodid (moth fly) that holds its wings unlike any other they have ever seen. Most moth flies hold their wings either flat over the body, or roof like over the body; this one inverts its wings over the body so that they make a trough. Significance? Who knows, but it is amazing that such a fundamentally different body form has been found. Last night, Curler hoisted some light traps up into the canopy of the forest to see what other strange things he could discover. Stay tuned for what he found.

Collaborator Dr. Wayne Mathis has been collecting for several days and has pushed our family list to 69 with this collection of diastatids (sorry, no common name), therevids, and anthomyzids, as well as boosting the list of shore flies (Ephydridae) to 26 species.

Netting bats at night has been particularly productive for inventorying bat flies. Dr. Carl Dick has added several genera and species to our list that would never have been included if we had only relied on Malaise traps and other standard insect collecting methods.

In a small raid of army ants, Anna Holden I collected some bizarre short winged phorid flies running around with the ants. These flies, genus Acontistoptera, have fully winged males that transport them in-flight among army ant colonies. We know this because the flightless females turn up in our Malaise trap samples along with their more mobile mates.

acont

A tiny Acontistoptera female

Yesterday, we spent the day in the lab at our partner institution INBio, where our collaborators could interact with our Costa Rican staff and examine some of the ZADBI material in the collection. Collaborator Dr. Jeff Skevington looked at our 34 specimens of pipunculids (big headed flies) and pronounced almost every one of them a different species! Little duplication means that there are many more new things still to find.

 

This is just a taste of what has transpired over the last three days; I’ll get more reports from our scientists today. Lots of ideas have been exchanged, plans made for the future, and scientific papers outlined for publication. Two days still to go!

A monster in the garden

bumble-bee-asilidThere is a voracious predator in our nature garden at the Natural History Museum of Los Angeles County; luckily it is only about an inch long. It is a “bumble bee robber fly” of the genus Mallophora. It is hanging out on the kangaroo paws in the garden on the east side of the building. It picks off wasps and bees, injects them with venom and digestive enzymes, and sucks them dry. As I said, we can all be thankful that it is only an inch long, but it is beautiful and fun to watch!

New flies in town

asteiid drawer

asteiid drawer

The “new” collection of flies from Utah State University has arrived, and what a collection it is! The number of specimens and some of the cool species among the material surpasses my wildest dreams. Of course, we gave up a great collection to obtain this material, as documented in my previous blog (“Fly Specialization at the LACM”), but these new Diptera holdings are mesmerizing to me.

For example, in an earlier blog I wrote about finding the unusual family Asteiidae here on the Museum grounds. The supply was only our second specimens in the entire collection, yet look at the holdings from Utah State University! Half the tightly packed drawer of them-I guess they are not so rare after all.

tons of tachinids

tons of tachinids

More superlatives: seven drawers jammed with unsorted fungus gnats. Lots of tachinids (parasitic flies): about 40 unsorted drawers of them!

There was even a family new to our collection- the southeast Asian Nothybiidae. They look like a school of minnows heading upstream in the unit tray.

school of nothybiids

school of nothybiids

That’s the thing about this collection: most of it is unsorted and therefore full of potential for new species. As an example, amongst the phorids was the first-ever specimen of the genus Cyrtophorina from Central America, a new species of the previously well-known genus Anevrina from Mexico, and a few things that are just weird and unidentifiable to me at this time.

To be sure, this is a collection that only a dipterist would love (and some people I show these photos to shudder in dismay), but part of the incentive for doing this exchange was to stimulate interest in the LACM fly holdings. Hopefully, this brief report will help do so,

Giant flies with giant names

Kirks pantophthalmid

A Brazilian pantophthalmid. Yes, it is real.

Some of the largest flies in the world belong to a family called (believe it or not) Pantophthalmidae. The tongue twisting nature of this name aside, the English name “giant wood-boring flies” seems less impressive. They are found only in the Neotropical Region (South and Central America), where they are uncommonly collected, usually at light or on freshly cut wood. Although frighteningly large, these flies are utterly harmless. Their larvae, however, bore into dying or dead trees eventually growing to a large enough size to produce the iconic adults.

I have seen exactly two living adults of these flies, but recently in Costa Rica, we came across evidence of many more. We were staying at a resort oriented towards birders called “Hacienda Baru” that is situated close to sea level on the Pacific coast near Playa Dominical. It was hot and humid there, and the biting midges were fierce, but we made it through a few days before fleeing to the highlands.

Along the trails were logs cut from tree falls, and in some of them were living and freshly abandoned pupae of pantophthalmids. In the log photographed here, I counted 65 exit holes alone, and some other trees in the vicinity had hundreds of holes drilled by the larvae of these flies.

panto

empty pantophthalmid pupa

For those interested in encountering large numbers of giant wood-boring flies, Hacienda Baru should be the first place on your list!

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log full of pantophthalmid borings

(I thank Kirk Fitzhugh for the first image).

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.