Ghosts of the cloud forest – 11 new species of Erythromelana (Tachinidae)

Although MS student Diego Inclan successfully defended his thesis more than two years ago, the focus of his research was published this year:

Inclan, D.J. & Stireman, J. O. III. 2013. Revision of the genus Erythromelana Townsend, 1918 (Diptera: Tachinidae) with description of 11 new species and analysis of their phylogeny and diversification. Zootaxa. 3621:1-82.(Abstract here)

In this lengthy manuscript Diego describes 11 new species (as you can tell from the title) of a little known, small bodied and somewhat gracile genus of tachinids in the tribe Blondeliini that occur in the Neotropical region (Northern Argentina

to Southern Mexico). Most of the species are found in cloud forest habitats in the Andes.  Diego also examines their phylogenetic relationships using morphological and molecular approaches and examines potential modes of diversification for the genus. With only three previously described species, Diego has more than quadrupled the number of known species in the genus.

Why focus on this group of small, poorly known cloud forest tachinids?

First,  exploring, documenting and describing all of Earth’s organisms is a worthy goal in itself. Each has many fascinating biological “stories” or “lessons” to tell with its unique evolutionary history and ecological niche.  Describing these species is a first step towards elucidating these lessons, which may be far reaching (e.g., I always like to point out the vast scientific knowledge we have gleaned from studying the small and nondescript species Drosophila melanogaster).

Erythromelana cryptica Inclan, one of the new species described in this study

Erythromelana cryptica Inclan, one of the new species described in this study

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A species of the diverse geometrid genus Eois, hosts of Erythromelana

However, there is another reason that we focused on this genus. It just so happens that Erythromelana species are parasitoids of small geometrids in the genus Eois. We know this because we reared several species (first known rearings for the genus) from Eois in the cloud forests of Ecuador (see post Ecuador Expedition). Eois is a very diverse genus of geometrids that feed on plants in the hyper-diverse genus Piper (Piperaceae), and this tritrophic system of plants, herbivores, and parasitoids has been the subject of a number of studies by collaborators of our “Caterpillars and Parasitoids of the Eastern Andes” biological survey project (e.g., see Wilsonetal2011). One goal of Diego’s paper was to see if Erythromelana exhibited evidence of co-evolution and host-associated differentiation with their Eois hosts. Although the degree of specificity of Erythromelana species is difficult to evaluate due to the many undescribed and cryptic species of Eois that we know of, our rearing records suggest considerable overlap in host use among these tachinids.  Thus, it would appear that perhaps geographic isolation may play a greater role in Erythromelana diversification than host associations.

Why ‘ghosts of the cloud forest’? This somewhat dramatic title refers to the rarity of Erythromelana species. Total parasitism of Eois (from over 5000 rearings) is less than 0.5% and we only recovered a single specimen from a pan trapping effort at Yanayacu that collected over 2000 other tachinids. Several of the described species are known from just a handful of specimens. Still, these ‘ghosts’ can be observed, if one knows where to look. On a few occasions they have been seen, flitting about sunlit leaves over small streams in deep cloud forests of Costa Rica and Ecuador.

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Yard insects

Just a few recent photos from my yard (click for larger images)

BlueDashersm

The Blue Dasher (Pachydiplax longipennis: Libellulidae)

Gymnosomasp.

Gymnosoma sp. (Tachinidae)

a bee fly (Bombyliidae: Phthirinae)

a bee fly (Bombyliidae: Phthirinae)

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It’s not just what’s in the field, it’s what’s around it

I have taken a long hiatus from posting any news or other items on here (for no particularly good reason) and I thought I might try to do some catching up on news from the lab. In the next several posts I will highlight some recent publications and other events over the last half year or so.OLYMPUS DIGITAL CAMERA

First, I would like to highlight a not-so-recent publication (LetBothStire2012 – actually published in 2012) led by collaborators at UC Santa Cruz, PhD student Sara Bothwell Allen and Deborah Letourneau, her advisor. For Sara’s thesis she studied the effects of surrounding land use on parasitism levels of pests and parasitoid diversity in organic agricultural fields in California. She set out “sentinel” letourneaufigspest caterpillars, confined to their plants, for one week to examine parasitism and she set out Malaise traps for two days (twice per season) to sample parasitoid diversity. She then characterized the surrounding landscape cover using GIS. Because they got quite a few tachinids, Sara and Deborah invited me to collaborate on an analysis of how landscape variables outside the fields affected tachinid diversity and parasitism inside the fields. Interestingly we found effects of many landscape variables on the tachinid fly com

munities in the agricultural fields, but the strongest pattern was an increase in tachinid abundance and diversity with increasing coverage of semi-wild perennial vegetation in the landscape (see graphs below). These results argue for that current trends towards agricultural intensification -plowing fence line to fence line are counterproductive.  Semi-wild corridors and fragments can act as refugia for parasitoids, which may reduce the need for pest control measures in organic or conventional agriculture.

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Pivotal Pervasive Pigments: Carotenoids in insect ecology

Carotenoids are nearly ubiquitous organic compounds involved in all sorts of important

Diverse carrots colored by carotenoids

Diverse carrots colored by carotenoids

functions across all major groups of organisms. They play key roles in photosynthesis in plants, they function as antioxidants, and they provide many of the bright yellow, orange, and red coloring we see in plants, fungi, and animals. For example, the familiar orange coloration of carrots and red coloration of tomatoes is derived from carotenoids.

In a newly published paper in the journal Arthropod-Plant Interactions, Jeremy Heath (former PhD student), reviews the many varied functions of carotenoids in insects, with emphasis in how carotenoids and their derivatives influence interactions between insect and their environments (notably plants).

A stylized, schematic representation of the various known and hypothesized functions of carotenoids in insects that mediate ecological interactions.

A stylized, schematic representation of the various known and hypothesized functions of carotenoids in insects that mediate ecological interactions.

He briefly reviews the structure and biosynthesis of these molecules and then discusses their roles in cryptic and aposematic coloration in insects, their importance in vision, photoperiodism and diapause, their function as antioxidants, and their role in signaling. He also explores the possible functions of carotenoid derivatives such as strigolactones and volatile apocarotenoids in mediating interactions between insects and plants (and fungi), and between insects and their parasitoid enemies. Contact Jeremy (heath.22@wright.edu) or myself (john.stireman@wright.edu) for reprints.

Heath, J.J., D. Cipollini, and J.O. Stireman III. 2013. The role of carotenoids and their derivatives in mediating interactions between insects and their environment. Arthropod-Plant Interactions 7:1-20.

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Ecuador Expedition 2012

I (Stireman) recently returned from a trip to Ecuador. The primary reasons for the trip were 1. To collect tachinid flies for systematic and biodiversity research, and 2. To get graduate student, Karen Pedersen, set up for her studies on the multitrophic determinants of host specificity in Altinote butterflies (Nymphalidae: Acraeinae). There was also the added benefit of meeting up with some of my old grad school buddies, Harold Greeney (Tropical Ornithologist and Entomologist), Caleb Gordon (bird fanatic), Matt Kaplan (high through-put moleculoid master and lizard man), and Margy Green (Optics engineer and herp/bug photographer) and several of their biophile colleagues.

This was my favorite trip to Ecuador thus far (and I’ve been there a few times). We explored a wide diversity of habitat types and were able to travel to some magnificent areas. We started out at Yanayacu Biological Station, epicenter of my research program in

The view form Yanayacu

The view from Yanayacu

Ecuador, in montane cloud forest on the East slope of the Andes (~2000 m). This the best place to find tachinids that I have ever seen. They are everywhere, in an amazing variety of forms. They are thick as, well…flies. You hardly have to try to look for them. My pet hypothesis for their amazing abundance and diversity here is a combination of the almost infinite opportunities for habitat specialization and semi-isolation provided by the Andes, the ridiculous diversity of potential hosts, and the relative lack of ants. Perhaps I will elaborate sometime…

From Yanayacu, we travelled to the high paramo, reaching elevations as high as 4300 meters (Like 14400 ft). It is remarkable habitat of cushion plants and club mosses, but it’s awful chilly when the sun isn’t out (as it was not when we went…which explains the poor showing of tachinids).

Paramo near Papallacta

Paramo near Papallacta

From there some of us split off to visit a small reserve called Jatun Sacha. This is a lowland reserve at about 450 m with nice accommodations and some attractive old growth forest

A tree frog at Jatun Sacha (see, I like vertebrates too)

A tree frog at Jatun Sacha (see, I like vertebrates too)

(It’s also easy to get to). The group rejoined to visit another small reserve in the Andean foothills called Bigal River Biological Reserve that adjoins the huge Sumaco National Park. This reserve, operated by a French couple (Marion and Thierry, who cooked us super-delicious food) required a little bit of walking on a treacherously muddy old logging road to get to (luckily with donkeys packing in most of our gear). Though this is a fairly new reserve, the forest is old, diverse, and

Lycaenid at El Bigal

Lycaenid at El Bigal

relatively untouched. I spent most of my time walking along the road (good place for flies) and peeing on select plants to attract a diversity of flies, stingless bees, and butterflies. I cannot overstate the utility of urine as a tachinid (and other fly) attractant in the wet, salt poor lowland forest. I even saved jars of pee for this express purpose.

Finally, we traveled to the heart of the Ecuadorian Amazon to a fantastic lodge called Shiripuno, located on the Huaorani (native peoples)  Reserve and not far from the “intangible zone”, where there are people living that have no, and want no, contact with western civilization. Being in this place, it is easy to forget that there is any threat to the lowland rainforest; the forest seems endless, there are parrots and toucans everywhere,

boating down the Shiripuno

boating down the Shiripuno

there are 10 species of monkeys, and the insect diversity is amazing. The naturalist Fernando (Vaca), as well as several Huaorani guides, led us on a number of eventful outings on the river and on trails, but we were also free to explore the trails on our own. I spent a lot of time in around the edges of the main clearing of the lodge, monitoring my pee and sugar-water trapline for flies – and even this was awesome.

I should note that my good friend and scientific collaborator Harold Greeney arranged all these trips, and I am very thankful he did. I should also note that my tachinid collecting was conducted under the auspices of two major research programs the Stireman lab is involved with: A long term biotic survey and inventory of caterpillar-plant-parasitoid interactions in Ecuador (led by Lee Dyer at U. Nevada) and the World Phylogeny of Tachinidae project led by our lab (see previous post). I was able to collect quite a diversity of taxa (many of which will be deposited in the Museo Nacional del Ecuador in Quito) that will be extremely useful for our ongoing investigations of tachinid  ecology, diversity, and phylogeny. By the way, I left Karen (my student) down there at Yanayacu for four months to work on her studies of plant-butterfly-parasitoid interactions. I’m a little jealous.

Endless forest seen from the Mirador trail at Shiripuno

“Endless” forest seen from the Mirador trail at Shiripuno

One of the few tachinid shots I took (probably a blondeliine. Phyllophilopsis??)

One of the few tachinid shots I took (probably a blondeliine. Phyllophilopsis??)

Mesembrinella (Calliphoridae sensu lato) on rotting banana

Mesembrinella (Calliphoridae sensu lato) on rotting banana

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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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