Tag Archives: Diptera

Field work

For many of us, going to the field is what we like most about Dipterology (the study of flies). The chance to find new species, experience different environments and cultures, and more than anything, the opportunity to slow down; these are the rewards of the field.

I am on an airplane to Brazil to work with my colleagues Dalton Amorim and his PHD student, Danilo Ament. We have a long-term collaboration based on shared work on phorid phylogeny, thoracic morphology, and tropical inventory. Camaraderie is another pleasant aspect of field work.

This time, we are going to Rondonia, in the southern Amazon. It promises to be a trip of amazing discoveries, as very little collecting has taken place there, other than at Rancho Grande, a formerly popular collecting site that apparently doesn’t have any forest any more. We are going to stay at another area, called Monte Negro, and make excursions from there. Every day (I hope), I will post about our finds, to give the flavor of a tropical Diptera expedition.

For now, I’m just trying to endure the long flights…

A wasp-mimicing flower fly from my last field trip in Costa Rica

Weird female Phoridae – part 2

Another group of phorids with strange females are the Termitoxeniinae. In these flies, the females are found in the nests of fungus-gardening Old World termites. The males and females of at least one African species fly at the same time as their host termites’ swarming, mating and often returning to the same nest.

early stage female

The females then strip off most of their wings, and incredibly, start to grow (few adult holometabolous insects have post-imaginal growth). The head and legs lengthen, and the abdomen becomes grossly swollen, eventually mimicking a termite nymph. The abdomen also has glands that produce secretions that termite lick off. Apparently, they act as appeasement compounds that help integrate the fly into the termite society.

female termitoxeniine

These flies are found in Africa to Southeast Asia. My colleague in England, Dr. Henry Disney, has done most of the modern taxonomy of Termitoxeniinae, including recognizing that the males of the phorid subfamily Alamirinae were the previously “missing” males of the termitoxeniines. These males have little in the way of mouthparts, probably do not feed, and are likely short lived.

male termitoxeniine

What Dipterology needs: a response

Chris Raper (see his blog at http://chrisraper.org.uk/blog/) had a thoughtful reply to my post. With his permission, I’m making it available here as a guest post for flyobsession.

Costa Rican tachinid

Some good points there Brian … how about also:

– We need to work through the millions of indet. and unmounted specimens help in museums around the world. Vast quantities of material exists on our doorsteps but lacks the time and experts to work through them. I know for a fact that the NHM & OUM have a lot of material that has been collected (often in malaise traps) and just sits on the shelves waiting for someone to work on them. The initial sorting can be done by volunteers or students, pinning can be done by out-sourcing but the taxonomic work needs to be done by the very few experts around the world.

– Digitisation of types – we need to make collections more accessible and harness the power of the internet by demanding that all major museums take high-res images of their collections (or types as a minimum) and make these available online free of charge. It might be too much to think that we could see enough to completely describe something (though with deep-focus/stacked imaging this is getting easier) but one of the most basic thing we need to do is to see whether the specimen in our hands looks like reliably-detted material. Just being able to Google for images of different genera would help me immensely and would reduce much of need for loaning valuable specimens or for expensive visits to foreign museums.

– More digitisation of all journals/articles and these to be made available free online. Projects like BHL are doing great work but they are not yet as comprehensive a collection of papers as they need to be. We all still keep far too many paper journals and PDF libraries on our hard-drives – just in case.

– We need to work together – using the internet / modern comms (forums/blogs) to help each other more and to mentor young entomologists and to develop/encourage enthusiastic amateurs (‘citizen scientists’) to pick-up groups and run with them. Online forums like diptera.info and bugguide.net are great for this but I feel that they are under-used or under-appreciated by many professional entomologists who feel that giving IDs to photos or working with amateurs is beneath them or a waste of time. Since setting up the UK Tachinid Recording scheme and providing a strong online presence (as well as seminars and workshops) we have managed to take tachinids from a fringe interest here to something that more and more entomologists are keen to try. We add between 1-2 new species to the British list and most of those from amateurs who have been encouraged by our scheme.

– There needs to be more money to pay for morphological taxonomy. In Europe there are many keen citizen scientists but they have to spend most of their time doing mundane jobs to pay the bills, when their time could better be used doing important taxonomic work. They can only be freed up if they can get contracts or salaried posts, working perhaps at home but attached to major institutions. We have much of the necessary manpower but at the moment it is badly under-funded and under resourced … even simple things like equipment and travel expenses are often down to the person to fund themselves and in hard economic times like these this is getting less and less possible.

I’m sure there are more things but those will do for a start

What Dipterology Needs (in my opinion)

There is a lot of excitement about molecular phylogeny, DNA “barcoding”, whole genome sequencing, and other high-tech advances that will enable us to better understand flies (and other organisms). Doubtlessly, this is where the big money and prestigious Science articles will be concentrated. But for those of us working with whole animals, and not just their DNA, there are a different set of priorities that are no less important. Understanding the world’s Diptera biodiversity at the organism level requires (in my opinion) the following:

Brian Brown collecting in Argentina in 2003

1) More exploration, more collecting. We live in a time of great opportunity. There is easy availability to go to previously remote and inaccessible parts of the world, and to make collections there. On the other hand, other people can get there too, cut the forest, and cause the extinction of thousands of species.

 The tropics, especially, are undercollected and under threat. Huge areas of the world, even if there are well-known for vertebrates and showy butterflies, still have not had their fly faunas extensively sampled.

Collections need to grow if we are going to document life on this planet. Museums need to plan for this type of growth, and curators need to push for it.

I could go on and on about this point, but I think most of you who are reading this are already part of the choir.

2) More study of life history and larvae. The immature stages and way of life of most species of flies are unknown. Terrestrial fly larvae are all but unidentifiable past the family level, and some families do not even have any larvae described. What each fly species does during its larval stage is almost equally poorly known. What are we going to do with all of the phylogenies being generated if we don’t know life history information about our organisms to plug into the framework?

parasitic phorid (Apocephalus ritualis) approaching leaf cutter ant host

3) More study of Baltic amber fossils. Diptera are the most frequent inclusions in 40 million year old Baltic amber. Most paleontologists can only dream about seeing intact specimens of their organisms. We, on the other hand, have the window into the past. I know all groups of flies are not common in amber, but those that are found there need to be integrated with our knowledge of extant flies. There are still huge deposits Baltic amber that have been untouched, and museums have thousands of specimens waiting to be examined by experts in the modern fauna.

Those are my priorities. If you have others, feel free to comment. I have some ideas about how to push these agendas forward, if dipterists can continue to work together.

female Myriophora sp. (Phoridae) on injured millipede

Weird female Phoridae – part 1

female Aenigmatias


In a previous post “What is so great about phorids,” I showed photos of 3 strange looking phorid flies. The first of these is a female that has a body form we call limuloid, after the horseshoe crab Limulus. This is a defensive body form that allows the female fly to live within a nest of ants or termites. The rounded body form, with few large setae, makes it difficult for an ant or termite to grab them (at least, that is the theory!). They used to be all categorized in a group called the Aenigmatiinae, but our knowledge of phorid phylogeny is changing as we know more and more about the groups, so the Aenigmatiinae probably won’t be around as a name much longer.

The name bearing genus for this former group is Aenigmatias, a northern hemisphere genus that includes about a dozen species. The females have a classic limuloid shape, whereas the males are much more normal in appearance and carry the females around in copula. These flies are parasitoids of Formica ant pupae, although no modern work has been done on their natural history.

in copula pair of Aenigmatias

All of the rest of these flies live in termite nests. That makes me skeptical, in part, that they form a natural group with Aenigmatias. Here is the Southeast East Asian genus Epicnemis:

female Epicnemis

The Old World tropical genus Psyllomyia is found in both Africa and Southeast Asia:

female Psyllomyia

The Southeast Asian genus Palpiclavina is less limuloid than some of the others, as it has retained wings and large setae:

female Palpiclavina

But the most limuloid of the phorid females are those of the genus Thaumatoxena, whose abdomens are completely fused into a carapace-like shell:

female Thaumatoxena

Note that the large round things on the head are not eyes; they are antennae. The true eyes are extremely small, and on the very side of the head.

Flies as food


This morning I had to catch a fly, any fly of a decent size, to feed a jumping spider I wanted to photograph (jumping spiders are almost too easy to photograph; they have such great faces!). While I was looking for a fly, I got to thinking about a frequent question: what good are flies? Or, a variant, “what are flies good for?” Or, even more direct, “what are flies for?”

Of course, such questions are related to human values. As scientists, we usually don’t think that way; hence the common sarcastic answer “what good are humans?” What people mean by these questions, I suppose, is what “role” do they play in the environment. One of the answers that I read frequently in textbooks or the popular press is that flies and other insects are important as “food for birds and other animals.” I hate this answer. It is as if other animals, especially birds, are more important or significant than insects. In this way, the incalculable goods and services provided by flies, such as pollination and breakdown of organic materials, can be discounted, and flies dismissed as just obnoxious pests.

Humans are so oriented towards the macro organisms in the environment. There is so much more to see and admire if we look a little closer at the smaller things. There are about 10,000 species of birds in the world, but at least 150,000 described species of flies. One of the largest families of flies, the Tachinidae, has at least as many species as the birds, but doesn’t even have a common name! We scientists have to promote more fly literacy.

I caught a fly for my spider, a common blowfly, Lucilia sericata– a “greenbottle fly” to most people. I know what my spider thinks it is for.

 

What is so great about phorids?

mating pair of Psyllomyia

Let’s face it, every fly aficionado has his or her favorite group. The most popular groups of course are the large, attractive ones like flower flies (family Syrphidae) and robber flies (Asilidae). My favorite group, the one I do research on, is called the humpbacked or scuttle flies (Phoridae). I don’t really like either of these common names, however, so I just call them phorids.

Among dipterists, those who work on phorids are considered to be very brave, or, less flatteringly, crazy. There are about 4000 described species, but we think the true total is closer to 30,000 to 50,000 species.  Thus, every time we start working on groups , we end up with 10 times as many species as we started with. That’s a lot of biodiversity.

What makes it so rewarding, however, is that there are so many new things to see. I already posted about an amazing new phorid from Thailand. There are plenty more where that came from. Working on phorids is like being a naturalist in the 1800s, exploring and seeing things for the first time. You literally find new things everywhere you look, even in your backyard.  There is probably more diversity among species of phorids than there is within any other family of flies. As proof I offer three photographs showing the range of morphology within this family :

female Aenigmatistes

female termitoxeniine

female Vestigipoda

I will write in future posts what these flies are, and what they do.  For now, I hope they prove my point about phorid structural diversity.  Of course they have a huge diversity of lifestyles as well, which is more fodder for future posts.

Why have a fly blog?

There are hundreds of natural history blogs out there, and dozens of them are about insects. Isn’t that enough?

 You would think so except for one small problem: flies represent about 10% of the world’s biodiversity, yet almost nothing is written about them. Think of all the hundreds of books about birds: field guides, natural histories, stories about people chasing an elusive life list total, etc. Then realize there’s only about 10,000 species of birds, the size of a single family of flies! For flies, what do we have?

 – A fair amount of scientific publication: descriptions, taxonomy, phylogeny, and keys.

 – Some really wonderful manuals of the Nearctic, Palearctic, and Central American regions, as well as catalogs of the species from the various regions. Not bedtime reading.

 – In the public realm, for interested laypeople, there is Oldroyd’s “Natural History of Flies”, and the Amateur Entomology Society handbook on flies, the former of which is really dated (having been published in 1964). More technical but still highly readable is the recent “Diptera diversity: status, challenges and tools” by Thomas Pape, Daniel Bickel, and Rudolf Meier.

 – On the web, we have diptera.info, an excellent site for chatting about flies, and links to a few newsletters, especially the North American Dipterists Society.

 In my opinion, that’s not enough. There are so many cool things in Diptera that need to be talked about! I can go on and on about just phorids, and probably will. But I can’t do, however, is cover the whole order Diptera in a news coverage manner. Sorry, don’t have the time. What I will show you is what I see on a day-to-day basis and try to convey why I think it is so interesting. I hope you keep reading.

 

Gardening for flies 3 – adding filth

In my continued quest to attract subjects for my photography, I decided to try to attract the drone fly, Eristalis tenax, a relatively large flower fly that mimics honeybees. Their rat-tailed larvae are said to be found in extremely foul aquatic conditions, such as cesspools, and runoff from feedlots. Not wanting to deal with feces in attracting these flies, I decided to try just using plant material. I put in a few rotting peaches, some soil, and some mulch in a plastic container and filled about half full with water. I then let it sit for a month, keeping the water level up so that it didn’t dry out. A cautious sniff confirmed that I had replicated the high degree of foul stench that I was trying for. It was contained, however, in a small area, that didn’t affect the rest of the yard.

So far, no drone flies have been noted, but a different and equally interesting fly was attracted. This fly, commonly known as a “boatman fly” is a species classified in the family Platystomatidae. Its scientific name is Pogonortalis doclea, and like many denizens of the city, it is a non-native. Somehow it has arrived here from Australia and become naturalized to our city.

Its behavior is interesting: it constantly waives its wings, which are marked with distinctive patterns of black. This display is usually considered either a threat to other males, or a welcome to females. Whichever, these flies display all the time, as well as projecting their mouthparts in and out. Look at this video and you’ll see what I mean. Disgustingly, these flies feed on the foul water, and in you can see thousands of maggots writhing around it.
http://youtu.be/isH20jaD9gU

The filthy water also attracts other flies, including Megaselia scalaris, one of the most polyphagous (feeds on anything) of all the phorid flies. It is found around the world, having been successful at living wherever humans live.

I’ll keep my eye on the filth container, and see what else turns up. I still haven’t given up on the rat tailed maggots, which might show up next year when I increase the amount of filth.

Gardening for flies, part 2

Having had my garden for about three months now, I can say that there is always something interesting to see and photograph in it. Regular visitors include many flower flies, commonest of which is the little blood red flower fly, Paragus haemorrhous, followed by Allograpta obliqua, Syritta pipiens, and a Platycheirus species. During the sunny parts of the day, there are ALWAYS flower flies.

     

Another group of frequent visitors are bees. Mostly, however, they are not the common honeybee; instead, they are native bees that are much more welcome, in my opinion. Native bees do not sting people unless severely provoked, and they come in a variety of shapes and sizes from tiny little, almost gnat-sized bees to lumbering fuzzy bumblebees. They are generally faster moving than honeybees, and thus more difficult to photograph, but if you focus on a popular flower and wait, you can usually catch them eventually.

      Finally, there are the occasional visitors, that show up to feed on specific type of pollen. Among them are a couple of types of beetles, including dermestid beetles (shown below) that are occasional household pests, and the wedge-shaped tumbling flower beetles of the family Mordellidae.

all photos are copyright B. Brown, 2011. all rights retained