A new type of ant-decapitation in phorid flies!

Dohrn longi plateOkay, I literally have been waiting for years to write this story! Now it is published, and you can read about our amazing (at least to me) discovery.

Most phorid flies that decapitate their hosts do so by injecting an egg into the host ant; after hatching from the egg, a larvae feeds in the head, eventually causing the head to fall off, sometimes before the rest of the body stops moving.

In species of the Dohrniphora longirostrata group, however, the female flies are attracted to injured Odontomachus ants, which they decapitate themselves, and haul off the head to feed on its contents or to lay an egg. We have seen this in several countries, and on many occasions, so there is no doubt in my mind that this is a specific behavior to these flies. They are not attracted to injured ants of other types, only Odontomachus.

Here is some video of the action!

(video by Kate Lain)

Flyobsession back online

After transferring from WordPress.com to my own site, flyobsession is back! Look forward to more stories and photos of our two-winged friends.

Pictured here is a male Adelopteromyia, a common phorid fly from the ZADBI project in Costa Rica (photo by Inna Strazhnik). The females of this genus are brachypterous (have reduced wings) and are found in army ant colonies.

fDcmpVy7ttQx4S-PXg23_8ZPUfEDci_06vOv0ttdU1U

ps. This image looks much better full size- click on it to see.

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!

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.

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

Phorid parasitoids of endangered ants also endangered

When ant-decapitating flies have endangered hosts, they become endangered, too. Today in the journal Zootaxa, I describe three new species of phorids found by my co-authors Marcos A. L. Braganca, Diego S. Gomes, Jarbas M. Queiros, & Marcos C. Teixeiras. The three flies attack Atta robusta, a species of ant found only in restinga (sandbank) vegetation in a small area in Brazil. Two of the flies are Eibesfeldtphora species, while the other is a Myrmosicarius; all are parasitoids developing in the ant’s head. We don’t have photos, but I am taking the opportunity to show a couple of fabulous photos of another Eibesfeldtphora attacking leaf cutter ants in Costa Rica by Wendy Porras.

Eibesfeldtphora curvinervis about to attack a leaf cutter ant. Photo by Wendy Porras.

The fly laying an egg into the ant’s head through the occipital foramen (neck). Fabulous photo by Wendy Porras.

Terrifying photos. If these flies were the size of crows we’d never leave our houses!

Home of the world’s smallest fly

This fly was collected at Kaeng Krachan National Park in Thailand, the country’s largest.

It is a beautiful place with hot lowlands and misty highlands where the forests are crawling with land leeches.

There are many large mammals in this park, including leopards.

We conducted a training course for the Thai parks staff who would be helping us; here is Mike Sharkey leading the group on how to properly use a Malaise trap. The fly, Euryplatea nanaknihali, was collected by one of the many traps placed in this field.