Doctor Heath and Master Davis

Congratulations to Environmental Science PhD student Jeremy Heath for successfully defending his thesis this week!! Jeremy’s thesis, “Assessing the drivers of adaptive radiation in a complex of gall midges: A multitrophic perspective on ecological speciation,” took about a ream of paper to print out, and that was leaving out a lot of data and experiments that did not make the cut. Three of the chapters are already published or in press (see previous post), and I believe the two final chapters will be his biggest papers yet! Go Jeremy!

The day after Jeremy’s successful defense, Masters student Dan Davis defended his thesis research on “The phylogenetic relationships of Tachinidae (Insecta:Diptera) with a focus on subfamily structure.” This work is a big reason why our proposal to analyze the phylogeny of World Tachinidae got funded. Dan did a bang-up job with both the written and oral components. His presentation was especially well delivered (and he looked pretty damn sharp with that tie and sport jacket). Congratulations Dan!!

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Phylogeny of the Tachinidae World Tour, Part 1: South Africa

One of the major pursuits in the Stireman lab right now is to assemble and analyze a phylogeny of Tachinidae of the world. If you know what tachinid flies are (i.e., awesomely diverse parasitoid flies, again I refer you to Jim O’Hara’s great tachinid pages), then you probably know that it is a difficult group to understand and identify. The family is enormous, with nearly 10,000 described species, and there is great morphological homogeneity in some groups, incredible diversity in others, and rampant homoplasy (convergences and reversals) throughout. In short, it is a group in sore need of broad-scale phylogenetic analysis and reassessment of classification. I, along with collaborators Jim O’Hara (CNC), Kevin Moulton (U. Tenn.), Pierfilippo Cerretti (U. Roma), Isaac Winkler (WSU), are setting out to do just that with the help of the larger global tachinidology community.

Cylindromyia sp., a widespread genus of wasp-like tachinids. These were found resting on roads or in washes, acting very much like wasps.

As part of our goal of reconstructing a framework phylogeny of world Tachinidae, Jim, Isaac, Pierfilippo and I traveled to South Africa in October to try to collect key and endemic taxa from the western cape region. We met acalyptrate specialist Ashley Kirk-Spriggs (S.A. National Museum, Bloemfontein) in Capetown, rented a truck, and drove all around the western cape looking for tachinids. I say “looking for”, rather than “collecting” because it was some of the most difficult tachinid collecting I have experienced. The only person that seemed to have much luck (though I doubt it was luck) was Pierfilippo, who always caught the first and most tachinids at any site we stopped at. We were  lucky to have the privilege of Ashley’s company, not only because of the delicious Braai he cooked for us regularly, but also because of the big Malaise traps he brought that allowed us to collect many taxa we would not have otherwise gotten. Despite the difficult collecting, we did collect several hundred specimens including many important taxa, so the trip was a success. Perhaps our best find was several specimens of the odd tachinid Rondanioestrus apivorus, a parasitoid of adult honeybees!

View from Table Mountain National Park

I don’t have time (nor inclination) to go into a full travelogue right now. Suffice it to say that the Western Cape landscape is incredibly beautiful and its flora and fauna fascinating. Enjoy the associated photos.

Beautiful flowers (mostly Mesembryanthemaceae and Asteraceae) in Anysberg Nature Reserve (but we saw virtually no tachinids or much of anything aside from bees visiting them)

An example of the plentiful and diverse Mesemb flora

The view outside our cabin in the Gamkaskloof Nature reserve, also known as “Die Hel”. Probably our best site for tachinids and rhinophorids.

We were a bit late in the season for Proteas – but this was a nice one

A rocky slope in Anysberg with interesting plants. We did find some tachinids in this area (e.g., Pseudodinera) on our way to a hill top.

Rhinophorids (a family of isopod parasitoid, closely related to tachinids) were plentiful, although not very diverse. This one, photographed by Isaac, is missing legs we took for DNA.

Rhinophorids generally have a weakly developed subscutellum, unlike the well-developed subscutellum found in nearly all tachinids.

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Carnivores and carotenoids…a new paper by Jeremy Heath

PhD student Jeremy Heath had something additional to be thankful for this Thanksgiving. His manuscript entitled “Carnivores and carotenoids are associated with adaptive  behavioural divergence in a radiation of gall midges” was just officially published (online) in the journal Ecological Entomology. In this paper, Jeremy and coauthors explore adaptive phenotypic divergence in populations of the galling midge Asteromyia carbonifera that coexist on the same host plant, the goldenrod Solidago altissima. He goes beyond analyses of gall morphology (which has been explored in previous papers), to examine variation in “ovipositional phenotype” (essentially where they midges deposit their eggs) and carotenoid constituents of  salivary and accessory glands (orange-colored chemicals important in all sorts of biological processes), and how this may influence interactions with both host plants and parasitoid enemies (I won’t give it all away, read the paper!). It is a dense paper, chock full of experiments, tantalizing results, and interesting possibilities. I invite you to take a look at it, there is something in there for everybody (I am sure Jeremy ( would be happy to send you a pdf).

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Enemy mine

Bob Kula and colleagues (Oscar Dix-Luna and Scott Shaw) recently published a revision of the braconid genus Ilatha. These are relatively large, often brightly colored braconid wasps found exclusively in the New World tropics. They are certainly attractive wasps, but the most fascinating thing about them (to me) is that they are hyper-parasitoids of tachinid flies. That is, they are parasitoids of tachinid flies, which are themselves parasitoids of caterpillars. Apparently, adult female wasps locate caterpillars that already contain a developing tachinid and lay an egg with their piercing ovipositors through the caterpillar into the tachinid larva. The juvenile braconid then bides its time while the tachinid proceeds to devour the caterpillar (from the inside). Eventually, the tachinid kills the host and emerges to pupate, at which time the braconid proceeds to devour the tachinid (from the inside). It’s like those Russian dolls. Totally cool (except that they are eating my beloved tachinid flies!)

Some of the specimens that Kula et al. used in their species descriptions were reared as part of our collaborative NSF Biological Surveys and Inventories project focused on Caterpillars and Parasitoids of the Eastern Andes(on which Scott Shaw is a Principal Investigator). For attempting to identify some of the tachinid hosts of Ilatha from puparia, the authors honored me by naming one species (right) Ilatha stiremani. I am truly honored to have such an interesting and beautiful (at least in my eyes) wasp bear my name – even if it is a mortal enemy of my tachinid brethren. Thanks Guys!

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Beth Stayrook receives award

Beth Stayrook, undergraduate research assistant extraordinare in the Stireman lab, was recently awarded a $1500 scholarship award from the Women in Science Giving Circle at Wright State University. Beth is a seriously smart, dual major in Biology and Chemistry. Way to go Beth! You Rock!

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Tachinid flies and the final frontier…

Forest canopies are often referred to as one of the “final frontiers” of biodiversity exploration. We know astonishingly little about what organisms and ecological interactions occur in forest canopies, primarily due to the difficulty in sampling and studying them. In recent years there have been many initiatives to begin exploring the flora and fauna of forest canopies, particularly in the tropics. These efforts have revealed diverse communities inhabiting the upper reaches of tree canopies, often quite distinct from those occurring near ground-level in the same areas.

In a recently published study in the journal Insect Conservation and Diversity led by Pierfilippo Cerretti (Univ. Roma), we analyzed the diversity and composition of tachinid flies in the canopy and understory of a temperate forest in Italy (Bosco Fontana, right). Using 14 Malaise traps (7 suspended), we found that the canopy hosted a distinct community of tachinid flies.

Overall, more tachinids (were collected from understory traps (36) than from canopy traps (28), but the canopy traps had higher evenness and high diversity values. A number of species occurred solely or primarily in just one of the habitats and many of those that occurred in both habitats showed strong sex biases in one habitat or the other. This is one of the very few studies that have ever examined a canopy parasitoid communities, and the only rigorous quantitative study examining vertical stratification of forest tachinids. We hope to pursue more such studies of tachinid and other insect communities in this “last” frontier.

Stireman, J.O. III, Cerretti, P., Whitmore, D., Hardersen, S. and Gianelle, D. 2012. Composition and stratification of a tachinid (Diptera: Tachinidae) parasitoid community in a European temperate plain forest. Insect Conservation and Diversity 5:346-357.
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Paper on adaptive radiation in gall midges published in Journal of Evolutionary Biology

Stireman, collaborator Patrick Abbot, and Lab technician Hilary Devlin have just published a paper analyzing the extraordinary radiation of Asteromyia carbonifera gall midges on their Solidago hosts across North America. We show that this nominal species is actually comprised of a multitude of distinct evolutionary lineages that differ in host plant use and gall morphology. However, there is very little genetic structure related to geography.

These results suggest that A. carbonifera has undergone a very recent, rapid adaptive radiation, driven by ecological selective pressure from both lower trophic levels (host plant suitability and defenses) and higher ones (parasitoids, which select on gall morphology). Interestingly, divergence in gall morphology and host-plant associations appear to evolve relatively rapidly, with similar gall forms evolving multiple times, and host plants being repeatedly colonized by different lineages.

This is a fascinating example of very recent, even current, adaptive radiation in which we can still perceive the selective forces driving phenotypic divergence. However, this paper primarily focuses on patterns observed in the genetic structure of populations, and much more needs to be done confirming the processes responsible.

Please e-mail Stireman ( if you would like a pdf of this paper
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