The story behind "Latitudinal patterns in tachinid parasitoid diversity".

Burington, Z.L., Inclán‐Luna, D.J., Pollet, M. and Stireman, J.O., III (2020), Latitudinal patterns in tachinid parasitoid diversity (Diptera: Tachinidae): a review of the evidence. Insect Conserv Divers, 13: 419-431. https://doi.org/10.1111/icad.12416 

 

When I started my doctorate working with John Stireman of Wright State University, he and I already had discussions about the chapters in my dissertation. We agreed that there should be a broad biogeographic or ecological component, a narrower phylogenetic component, and a taxonomic revision. I am happy to say that the taxonomic portion passed review in 2020 and is currently in final edits. The ecological portion was published last March in Insect Conservation and Diversity. I long ago promised that I would blog all my publications, but I've obviously dropped the ball on that here. So this is the story behind the paper. 

In 2012, I started my doctoral program at Wright State in Dayton, Ohio. At the time, Stireman had been running malaise traps out in the woods adjacent to campus and in several other locations near the University. These flight intercept traps catch all sorts of things, but his main interest was to catch tachinid flies, of which he has a sizable personal collection. One of these locations was from Huffman Metropark; most of these data were published by his former student Diego Inclan. Stireman also had a large tachinid pan-trapping data-set from his doctoral research in Arizona. And, to top it all off, he had access to specimens from a large trapping project at Yanayacu Biological Station in Ecuador. These three regions, Ohio, Arizona, and Ecuador, are spread across 40 degrees of latitude from the temperate zone to the high tropics, which allowed a rough comparison of diversity between tropical and temperate tachinid communities.

The reason this was such an interesting idea, this latitudinal comparison, is that there is this historical idea that parasitoids are less species rich in tropical zones than in temperate regions, that they have a sort of "inverse diversity gradient", inverse to the normal strong gradient of lower to higher diversity as one moves towards the tropics. Dan Janzen wrote a article about this in the mid 1980s, where he used species diversity of parasitoid wasps across North American latitudes to suggest that these wasps have a mid latitudinal peak in species diversity, at around 30-25 degrees North Latitude, and that after that the diversity declines. And furthermore he, and other authors, suggested that tachinid flies would follow this pattern similarily or even more so.

Now, this particular hypothesis was a sort of creative impulse to write this chapter of my dissertation. But at the time of publication, and even ten years ago at the time I started writing this research, the "inverse latitudinal gradient" for tachinid flies was already a rejected hypothesis. The copious amount of new species coming forth from Janzen's own rearing project in Costa Rica made that abundantly clear. So, it was not my purpose to falsify that hypothesis with this paper, but it was an interesting place to start.

Over time I added several other datasets for comparison. Sonja Scheffer and Mathew Lewis at the University of Maryland allowed us to add their dataset for comparison. Karen Petersen, a former master's student under Stireman, had surveyed in another area at Yanayacu, so I added that small dataset. And Marc Pollet had a good sized survey of tachinid flies from Podocarpus-El Condor Reserve in Ecuador that he collected while trapping for Dolichopodidae. (Marc, Stireman, and Diego all joined me as authors on the final publication.) But by far the largest later addition was all the Tachinidae collected during the Zurqui All Diptera Biotic Inventory (ZADBI) project in Costa Rica, for which Stireman and I identified a large portion of the tachinid specimens. With the addition of that Costa Rica dot I also filled a latitudinal gap, so in the paper we had a general latitudinal spread of 40--30--10--0 degrees. The result was that, every time we thought we had the paper set for publication, it grew another dataset, so what should have taken a few years instead took most of a decade.

(As an aside, I'd like to reflect briefly on the ZADBI project. Since I wasn't a forefront author for those papers, I don't feel like it's right to do a full post about it. But I do want to comment on one point, that over half the tachinid species collected there were in the tribe Blondeliini, which is my taxonomic research focus. Blondeliine diversity is absolutely insane in the Neotropics, far beyond any other group, and the ZADBI project really bore that out.)

The unsurprising result was that we saw a general increase of tachinid species richness from the temperate to the tropical zone. But as I said this had already been established by taxonomists for decades. What is far more interesting to me, is the rarity of most species in all datasets. If you look at the accumulation curves in Figure 1, you can see that none, not ONE of those datasets reaches an asymptote. Even years into collecting, species new to the longer surveys were being recorded. And this is across the board, both large and small datasets, both datasets in the temperate region and in the tropics. In all cases, 55-68% of all species were collected only once (singlets or singletons) or twice (doublets or doubletons). This to me is absolutely astounding, that even in Ohio, more than half of all tachinid species can be counted as rare. And in Costa Rica, at Zurqui, more than two thirds of all species, 68 percent (!) were collected only once or twice. What this says to me, is that any accurate measure of tachind community richness requires a long period of collecting, perhaps decades of surveying. For tachinid flies, Preston's Veil seems wide.

Overall, I'd say I'm pleased with the paper. There's still that pesky gap at 20 degrees (Mexico) and it wasn't possible to make any strong conclusions due to the low number of datasets. There are more tachind survey datasets out there, but they're survey's of caterpillars that sometimes yielded parasitoids. Since caterpillar rearing is generally not a random selection process, it's not comparable with trap surveys. So, we could say that the metrics strongly suggest higher species richness in the tropics, but there is nothing in the paper that counts as a definitive test. My question is: If someone were to repeat the same survey at Zurqui, or Yanayacu, how much would those two datasets overlap? 90% species the same? 70%? We know nothing about the turnover of richness in these communities, how many species are transients or inhabitants, or even what "rare" means for Tachinidae. Does it mean "low number of individuals"? Does it mean "widely dispersed in the landscape", and thus rarely encountered? We know that these flies often hilltop, they gather at specific points in the landscape for mating, and we know they have the flight strength to travel long distances. After all, "tachinid" comes from the Greek word "táchos", meaning "speed". Maybe how we see landscapes, with our narrow surveys, means little to a speedy fly.

The hidden trials of the taxonomic impediment.

So. I'm coming back after a long hiatus because this paper dropped not long ago and I've got feelings. Here's the press release.

A quick summary: Sarah Meierotto of the University of Kentucky and several of her colleagues collaborated with the Area de Conservacion Guanacaste project to describe 18 new species of parasitoid wasps reared in Guanacaste province, Costa Rica. The kicker is they did this entirely from sequences of Cytochrome C Oxidase subunit 1 (CO1) mitochondrial DNA sequences, sometimes known as the "barcode gene". Aside from a single habitus photograph of each species, they offer no morphological treatment of any of these species, and their only diagnostic characters are DNA nucleotides at certain positions. This has resulted in a somewhat heated conversation among taxonomists about the validity and usefulness of these new species "descriptions".

Before I go into those criticisms, I should mention that this isn't the first time a taxonomist has described species from barcodes only. Andrew Brower published
ten new species of moths from barcodes only a decade ago, but his purpose was to preemptively criticize DNA-only descriptions of new species. Quoting his abstract, "the application of names to concepts does not corroborate or endorse the biological validity of those concepts."

Meierotto and her colleagues, in contrast, say this is a "revolutionary protocol" for species description. Are these descriptions available? According to Commisioner Thomas Pape they meet all the criteria for availability. Quibbling about whether listing of base pairs are symbols or words is not really helpful.

But, are they valid? That's a much more difficult and interesting (and hair-tearing) question. How did we get to this point?

The new species are described in two different braconid genera, Zelomorpha and Hemichoma. The genus Zelomorpha has more than 50 previously described species, while Hemichoma has less than ten. Both of these genera were revised in a 2006 dissertation by University of Kentucky student Carlos Eduardo Sarmiento-Monroy. As far as I can tell, none of these manuscript names were ever published. Dissertations are not considered available under the ICZN, so Dr. Sarmiento-Monroy would have needed to publish these names in a journal, book, or other publication to become available; he never did. This year, Meierotto published a taxonomic review of Zelomorpha and Hemichoma with coauthors including Michael Sharkey, who was both the dissertation advisor for Sarmiento-Monroy and is second author on the DNA-only paper. This taxonomic review includes a large number of "new combinations", but as far as I can tell it has no new species.

What I suspected happened is that Sarmiento-Monroy completed his dissertation and never got around to publishing the species names. Maybe he disappeared, or moved on to work on some other group, or decided he hated braconid wasps so much he never wanted anything to do with them again. The names were never published. However, all the tantalizing species descriptions, photos, diagnostic information, these all still exist in dissertation form. All of that was copyright to the author, meaning, anyone couldn't come along and publish it for him. So, Michael Sharkey passed the project along to his new graduate student, Sarah Meierotto. Or maybe Sharkey continued working on the group in the intervening time. Anyway. The morphological species concepts were well known, even some genetic concepts were well known, but all the descriptions, diagnoses, and photographs would have to be redone, from scratch.

Anyone who has ever done any taxonomic work before, I can hear your groans through cyberspace.

So, they got the idea to publish some new names using the simplest description, just the barcodes. They already had some of these, but Daniel Janzen has a ton more via the ACG caterpillar rearing and barcoding project. Meierotto and Sharkey knew which species in ACG referred to new species and previously described species, because they had all of Sarmiento-Monroy's barcodes. So they took Sarmiento-Monroy's species concepts that matched with those species in ACG, eliminated everything but the barcode, gave them all new names, took habitus photographs for each species, and voila. Taxonomy published. Or so I'm guessing.



This is all my imagination. I repeat, I don't know how this happened. But it seems likely, and I don't have a problem with it. There are all sorts of reasons for the taxonomic impediment: poor 100 year old descriptions, missing type specimens, a new genus named for every new species (thank you, Townsend). These are obvious, but there are many more hidden reasons for a lack of taxonomic progress. Often times there is a taxonomic scion, the last, greatest worker in a particular family. They remember everything, all the names, the relationships, all the hypotheses. And when they pass, they take all of that knowledge with them and leave behind no heirs. Often times a group isn't difficult by way of some taxonomic mistake, but just because it is naturally so. All the distinct species groups grade together at the boundaries, all the distinct species are apparently species complexes. And sometimes, all the knowledge is there, but it's behind a copyright wall and therefore cannot be published and acknowledged.


As a taxahacker, I only really care about what is helpful, about what actually progresses our understanding. So finding some way around the dissertation impediment appeals to me. Let copyright rot if it aids our work. However, the key word is "helpful". When I plan a natural history work, I think, who is this for? Who is this helping? Most of the time I consider my fellow and future researchers. They'll probably be using a stereomicroscope, similar to what I use or with worse optics. They'll probably not have a large research laboratory with genetic tools for identification. And they'll probably be people with only incidental interest in the group. Perhaps they work in field ecology, or pest management, or evolutionary biology. They will care little for single species descriptions, and appreciate in-depth revisions the most.


In sum, the average researcher that comes to your work is not going to have access to genetic sequencing equipment. They will have eyes and a microscope. We should aim to write for this level of technology. Any species description that omits morphological characters is effectively useless. Are Meierotto et al. species valid? The above train of literature would suggest yes. At least, they aren't junior synonyms of previously described species. But they aren't helpful, not to any reasonable student of braconid wasps. From Sarmiento-Monroy's dissertation I see that color patterns are necessary but insufficient for identifying Zelomorpha species. There are other necessary components, the shape of the head, the hairing and crenulations of the cuticle, the structure of the genitalia. Many of these aren't visible in a habitus photograph. I suppose I could refer the sequences in the paper back to the dissertation to find the diagnostic characters, but what a hassle!

Natural history science isn't a filing heuristic. Our job isn't to simply give all the things names, in whatever way possible, and organize them into the prettiest tree. The authors state that we must work ever faster with the biodiversity crisis upon us. To what end? I learned very little about Zelomorpha species from this article, nothing that wasn't already available through previous works or the ACG database. I learned that there are many species and have pretty colors. Replace "species" with "postage stamps" in that sentence; "all science is physics or stamp collecting." No, taxonomy is not Pokemon. Every insect species is a hypothesis of metapopulations. Every genus is a hypothesis of species relationships. Every piece of evidence presented, morphological, genetic, behavioral, either corroborates or negates these hypotheses. As Brower said, "the application of names to concepts does not corroborate or endorse the biological validity of those concepts." The names themselves do nothing. They are often satisfying or amusing, but they don't actually increase our knowledge. They're just a filing code. The problem with the paper isn't that the names are unavailable or invalid. The problem is that the species are poorly described. If this is the answer to the biodiversity crisis, then future generations will know nothing of Zelomorpha danjohnsoni, except that it lived in Costa Rica, fed on a species of noctuid caterpillars, and had black wings and an orange body. Oh, and its mtDNA sequence had A's and T's and C's and G's at particular positions. Hardly a useful fact if the species is extinct.

Yet, I understand authors' desires. There's a deep need to put a name on things, even if naming them doesn't actually help us understand them better. It's questionable science, but it's art I guess? So I'm torn.

Using Inkscape for Biological Illustration, Version 1.1.

I'm releasing an updated version of the UIBI book today, with the following changes.

-Minor editing and changes to figure names in all chapters.
-Minor updates to several chapters, including "Detailing" and "Special Structures" (formerly Setae and Hairs).
-Major rewrite of the "Shading" chapter.

I was planning to wait a few months before publishing a new version, but my previous ideas about hatching and stippling in Inkscape were so very very wrong. I have literally wasted tens of hours of my life (or more!) trying to make regular hatch and stipple patterns in Inkscape using work around methods, when the "Pattern" fill option works very well for both of these if you understand how to adjust the density of the pattern. I only discovered this today. Ugh. Fortunately, shading isn't a major part of my line art style. And everyone else can learn from my mistakes. There is also a new curved hatching method included, using the Calligraphy Tool.

UIBI Version 1.1

Using Inkscape for Biological Illustration

Years ago, I posted a short guide to illustrating insect genitalia in Inkscape. Now in the shadow of my dissertation writing, I've managed somehow to write a more complete booklet version.

It's free, just like Inkscape! I take you through my line drawing process step by step, from importing sketches, to laying down and modifying lines, to making special structures like setae, to finishing and exporting. I also include some more experimental techniques which may be of interest to other sorts of Inkscape users. Enjoy!

Download link: Using Inkscape for Biological Illustration (PDF)

The Fly Trap (Book Review)

     The Fly Trap is a modern creative novel: one part biography, a second part history of entomology, a third scientific explanation, with rapture at flies mixed throughout. I’ve been reading Moby-Dick recently, and the similarities are striking. There’s the same tendency to switch themes between paragraphs and chapters, to weave the scientific, historical, and biographical together, and to embiggen fact when necessary. But what draws the entomologist in is Fredrik Sjöberg’s replacement of Melville’s whales with flies and the hope that the author will do the subject of our work and life passions the justice they deserve. How often is any particular family of insects besides butterflies made the subject of literature?

     Sjöberg’s centerpiece is the two-winged fly family Syrphidae, more commonly known as “hover flies” or “flower flies”, names which refer to incredible flight capabilities and the tendency to be nectar feeders. They are commonly yellow and black mimics of bees and wasps. Unlike the animals they’re mimicking they have no stingers to deter predators, so they avoid predation by looking like something dangerous. Sjöberg peppers his chapters with vignettes about individual species, including everything from taxonomic and regional history, physical and ecological diagnoses, and personal anecdotes. My favorite is the sudden “invasion” of Eristalis smilis which overtook the Swedish countryside, contrasted with Doros, of which there are only occasional sightings and elaborate rumors.

     The other subjects are “islands”, whether those be Sjöberg’s home island of Runmarö or a tree stump in a recent clear-cut. “Islands are generalizations of a kind”, he writes. “And where there are no islands, we have to invent them. If only for the fun of it.” He cites the loneliness and isolation of islands both positive and negative. Islands are perfect ground for the cataloger, sometimes disparaged as “buttonologist”, who provides a complimentary and more detailed worldview for “mapmakers”. 

“But the person who makes maps can never include everything in his picture of reality, which remains a simplification no matter what scale he chooses. Both attempt to capture something and to preserve it.” 

I particularly enjoyed his description of the Fly Tree, an enormous, 500 year old black poplar that was an island ecosystem onto itself. These species descriptions and descriptions of “islands”, are the stepping stones on which Sjöberg’s stories rest. 

     Yes, stories. There are actually two stories here, two interwoven biographies. One is of the author’s work with hover flies. The other biography is of the heroic, larger than life Rene Malaise, who sits in sharp contrast to the author. Malaise was a great explorer, eponymous trap inventor, and collector abroad, especially in eastern Russia and Southeast Asia. Sjöberg tries to avoid all collecting and exploration beyond his small island in the Baltic Sea. He says of the tropics, “Tropical nights can build into tremendous explosions of downright Cambro-Silurian cacophony when a thunderstorm starts or cicadas celebrate their orgies in the treetops. They’re magnificent, but no more than that. The indescribable sound of the Madagascar nightjar is worth the entire trip, but in the end it is merely interesting and exciting and fun to tell people about later.” Of the Congo River basin, “What an adventure! What stories I would tell! About freedom! But it didn’t happen. I never managed to say much more than that the forests were vast and the river as broad as Kalmar Sound. And that I’d been there.” Yet he idolizes Malaise and his travels, to the point where he starts a collection of Malaise-related ephemeralia. This ends ironically with an expensive purchase of a painting once belonging to Malaise. The author, so adverse to crazed collecting, has become a buttonologist. But Sjöberg stays to his island, claming glorious isolation and “slowness” allow him an illusion of control over these impulses.

     One of The Fly Trap’s most overreaching themes is what Eliezer Yudkowsky calls “The Virtue of Narrowness”. Sjöberg’s collection only contains the 202 species of hoverflies (plus one) found thus far on Runmarö island. He feels he must justify his narrowness, so he writes that it’s purely for pleasure. No, it’s because he loves the D.H. Lawrence style of isolation provided by islands. No, it’s a sort of “buttonology”, a collecting disorder, which in his case is benign. No, it’s an attempt to slow down in our fast-paced world. He doesn’t beg the reader to accept his reasons for collecting and observing his island’s hover flies as scientific. Even when he claims his study allows him to “read nature’s language”, the result is for enjoyment. Maybe he feels he can’t explain the usefulness of this small study on his small island to broader natural history, not even to a lay reader, but I don’t think he needs to. The Virtue of Narrowness is the precision and accuracy of your knowledge. It’s enough to only explain hover flies on Runmarö, and Sjöberg knows it, but he still claims “hobby” because it’s not his “real” job.

     True, he does romanticize his narrowness whenever possible. But I enjoy some romanticized narrowness. In my favorite poem by the midwestern American Tom Montag, “The Farmer’s Manifesto”, the farmer says of his father, “He had no /ideas but the things which /his hands could touch, or /those his eyes could find /at great distance—a glint /of sun off farmhouse windows. /Or close at hand, beneath /his feet. What he could /catch as breath; wind would /carry. He knew those weeds.”  Romanticized or not, that sort of narrowness holds an incredible depth of knowledge, what Montag could only name as “strange /dark madness, some amazing avalanche /of wolves, lakes, stars, tongues” and the ability to “hear corn grow in summer; /can hide your face in /the curving surface of sky; /examine a potato in light /so special you know something /flies back at you”. This is the sort of knowledge that comes from doing the same thing repeatedly over a small stretch of world and small number of subjects until they become windows. What seems like buttonology is deep expertise.

     I don’t mean to say that The Fly Trap is perfection or free from cliche. It belongs firmly within a genre of creative natural history writing first made popular in the 19th century, a Euro-centric and primarily masculine genre written by men for men and boys. Women are largely incidental to the story and are mentioned mostly as love interests or as props. His wife features prominently at the end of the first chapter, but only as the nameless “girl who sat in the audience one evening”. Of professional meetings, he says, “Normally no women take part at all. And the few who do happen to show up are usually the better halves of the biggest crackpots, wives who could easily pass as personal assistance from a psychiatric open ward. Well, maybe that’s unfair. But the fact is that unattached women could hardly find a better hunting ground than entomological societies. Unusual men, no competition. Just a suggestion.” Does that mean the only reason for women to attend meetings is to pick up men? Even the preface quote ends with the condescending line, “Me, I just concern myself with flies — a much greater theme than men, though maybe not greater than women.” The only exceptions are the short biographical sketches of the incredible, possibly lesbian Esther Blenda Nordström, a writer, explorer, and ethnologist who briefly married Malaise and traveled with him to Asia. Unfortunately, her story was abandoned when Sjöberg realized Malaise hadn’t named a species after her, and therefore Malaise’s “love” for her couldn’t be verified (unlike for Ebba Soederhall). I could have read an entire book about Nordström and her travels. Fortunately she wrote several. Unfortunately, I don't read Swedish (but maybe you do).

     The Euro-centrism is more forgivable. The Fly Trap was originally written and released in Swedish. The intended audience was Swedes, the setting was (mostly) Sweden, and Sjöberg is Swedish himself. The English translation came ten years later, so it should be read as a Swedish novelslashbiographyslashcreative-nonfiction and shouldn’t be taken as worldly. Especially since Sjöberg repeatedly admits his own non-worldliness.

      I realize I haven’t said very much about flies in this review. Fact is, if you’re still reading this and you haven’t already read The Fly Trap, you probably already have some interest in flies and will be delighted as I was of the hover fly natural history in this book. There isn’t anything to criticize about those descriptions except to say that they’re wonderful and I wish there was more of them. I recommend The Fly Trap for entomologists and non-entomologists alike.

 Sjöberg, F. 2014. The Fly Trap [English translation, Thomas Teal], Pantheon Books, NY. Amazon

Zoobank is down (the future of taxonomic publishing).

ZooBank is currently down while I'm writing this, the "official registry of Zoological Nomenclature". This is the registry that all new electronically published names and nomenclatural acts must use before publication, and that all traditionally published nomenclatural acts SHOULD use before publication (but usually don't).

I don't know if this is just temporary down time, or this has been going for a while, but it's a definite problem. Especially with the way publishing is going.

I was just talking with Morgan Jackson about social media and taxonomic publications, because I woke up with a weird thought in my head this morning: what if I took the taxonomic portion of my dissertation, registered the new names with ZooBank, and published it as a PDF on my blog? Given the standards currently in the ICZN, and assuming I'm meticulous about referencing type specimens and depositories, etc., the new names would be totally available under the code! Any person can do this now, or at least they could if ZooBank was running.

This isn't only limited to nomenclatural acts originally published as PDFs. To quote Morgan,

"The Winnower is working to publish, assign DOIs and archive blog posts and reddit threads right now. There is very little standing in the way of someone publishing a new species name in an electronic place like reddit (with the proper [ZooBank] registration and everything) and having it become valid via Winnower sucking it up...As far as I know they haven't finalized their archiving with [CLOCKSS] yet, so they haven't met all of the Code requirements for digital publication, but last I talked to them it was in the works"

The Winnower, for those who aren't familiar, is an open access publishing site that uses an open access peer review system. They specialize mostly in commentary on publications (i.e., post publication peer review), but their targets include a wide variety of non-traditional publishing platforms like blogs and web forums. CLOCKSS is an archiving platform for electronic publications, which The Winnower is using to store publications as PDFs. What Morgan is suggesting is that a taxonomic work registered with ZooBank could be originally published on a blog, adopted by The Winnower, and archived with CLOCKSS; thus it would meet all electronic publication requirements of The Code despite not being available in it's original publishing context.

It seems convoluted, but the above scenario is totally workable under the current version of The Code. I can see both positive and negative elements of this. For one, the traditional taxonomic publishing method is incredibly ponderous, even with taxonomic journals such as Zookeys and Zootaxa. Publishing is further complicated by the general feeling in biology that taxonomic works are low priority under the categories "impact" and "significance". It also opens up low or zero cost ways for taxa-hackers to publish their work, and I'm all for that. (That new species of fungus gnat I've been sitting on, for example. Hmmm...)

Conversely, I see the recent trend in taxonomy for higher quality publications and the role Zootaxa, Zookeys, and other taxonomic journals have played in this. I would hate for taxonomic publishing to slide back into Townsend-esque quality or for taxonomic vandalism in the mode of a certain Australian snake hobbyist to become more common.

Someone will try one of the above methods eventually. Or whenever Zoobank is up and running again. At the time of finishing this, the registry website is available! But it still worries me, because electronic publication is only going to become more important in the next decade. If Zoobank is unreliable, then what of the future of animal taxonomy?


Thanks to Morgan Jackson (@bioinfocus) for help in fermenting these ideas.

Adopting Orphaned Taxa (TAD2015).

(For Taxonomist Appreciation Day 2015)

I know it’s been a while since my last blog post. I’m deep into research right now and about to defend my thesis proposal. I’m also working on a publication. Which means that my writing time is going elsewhere and not here.

My thesis research overall concerns a large and varied tribe of tachinid flies called Blondeliini (Blond-el-ee-ai-nai) or the blondeliines. The core of the work is the Blondelia group of genera, called such because it includes the type genus of the tribe, Blondelia. Females of the Blondelia group have a boat-like keel on the abdomen and a sharp piercing hook for poking holes in things, usually caterpillars.

The piercer isn’t an “ovipositor” in the homologous sense, because it doesn’t contain the tube that carries the egg into the host. Instead, the egg tube (the mostly membranous segments 8-10 of the abdomen) travels down the posterior groove in the piercer and into the hole the piercer has made in the host.

A female 'sword fly' of the genus Eucelatoria with hind legs removed. (1992: Mexico, Portillo de Reon.)

In one genus (Eucelatoria), the piercer can be half the body length! I’m not sure why these species have a piercer that long, but there’s some evidence they parasitize caterpillars hidden in rolls of leaves. Some Blondelia group species have spines on the ventral keel, and others have only bristles. Some males of the Blondelia group have hairy patches on their abdomens, and other closely related species are clean shaven. Host use varies; Costa Rican species of the Eucelatoria armigera complex are particular to one or a few species of noctuid moth caterpillar, while the polyphagous species Compsilura concinnata feeds on over 200 species of Lepidoptera.

With interesting oviposition behavior, morphology, and a large number of species (>135; not including all the many undescribed Neotropical species) the Blondelia group is an enticing project for a young taxonomist. Do not fall for this trap!

Orphaned taxa are those genera or families that are without a current expert or active worker. The Blondelia group, and Blondeliini in general, are a particularly frightening example. Abandonment can be for a number of reasons. In some cases the group isn’t charismatic enough, or is of minimal economic importance. In other cases high diversity and difficult diagnosis are deterrents. A history of poor descriptions and over-splitting genera may be to blame; for this final reason orphaned taxa often have a taxonomic impediment. The longer the period between experts, the greater the impediment to future research becomes.

In the case of the Blondelia group, our good friend Dr. Townsend is mostly to blame. He is responsible for naming nearly half of all valid blondeliine genera, and most of these with one species apiece. Add to this his notorious over-splitting, his mediocre descriptions, and his terrible, no good, very bad Manual of Myiology genus key, and very few people are courageous enough to venture forth.

However, not all blame can be placed on Townsend. Disregarding the history, blondeliines are a difficult group with many examples of morphological convergence. They are small, usually dark colored, and told apart mostly by arrangements of bristles. Color patterns often fool me.

Left: Sword fly male. Right: NOT sword fly male. Really similar, but really different. Can you see the difference? (Click for embiggen)

I thank Monty Wood for his great work on Blondeliini (1981), without which I would be lost. But this is a preliminary work of broad scope. Efforts focused on a single or a few genera have revealed the scale of the mess yet to be resolved.

Diego Inclan (a graduated MS from my lab) and Dr. John Stireman (my PI and advisor) provide a vexing example of this mess in their recent Zookeys paper. In his masters thesis, Diego found that some species considered part of the Neotropical blondeliine genus Erythromelana were clearly not. This lead to a convoluted taxonomic investigation. Below is a paragraph from the Zookeys paper as illustration.

“An example of the taxonomic instability of Neotropical tachinid genera is witnessed in the species Euptilodegeeria obumbrata (Wulp). This species was first classified in the former tachinid genus Hypostena by Wulp (1890; along with many other blondeliines), based on specimens collected in Guerrero, (southwest) Mexico. […] The species was moved by Townsend (1931) to the new genus Euptilodegeeria, moved again to the genus Erythromelana Townsend by Wood (1985) and recently excluded from Erythromelana and resurrected to its previous genus (Euptilodegeeria) by Inclán and Stireman (2013). Although the taxonomy of Tachinidae, particularly of the Blondeliini, is challenging due to the scarcity of clear synapomorphies, the confusion in the generic assignment of E. obumbrata was also due to the limited number of specimens evaluated, the lack of examination of male terminalia and the use of only males for the descriptions. In the present study, we use additional information from male and female terminalia to demonstrate that these “obumbrata” specimens, previously assigned to Hypostena, Euptilodegeeria and Erythromelana, actually belong to the genus Eucelatoria Townsend (1909), in which females possess a sharp piercer for internal oviposition in the host. We also argue that the former species Machairomasicera carinata described from a single female by Townsend (1919) in the monotypic genus Machairomasicera, and later synonymized with Eucelatoria by Wood (1985), belongs to this same species group of Eucelatoria, which we here define and characterize. In the end, taxa that were assigned to four different genera in fact belong to one species group of Eucelatoria, providing an example of the taxonomic confusion that plagues many groups of Neotropical tachinids.” [Emphasis mine]

Many similar issues remain in the genus Eucelatoria. The group may not even be monophyletic. I am not revising all the species in the Blondelia group for my dissertation—or even all the species in Eucelatoria—but the challenge feels insurmountable.

There are two ways to publish natural history research. One is to be cautious, to wait until all possible evidence is covered and carefully recorded, all the museums have been visited, and every last lead has been pursued. “I only have one more type to look at, and it’s been missing for 40 years. But I can’t publish until I find it.” The other is to rush wildly into publication with any new finding, getting the information out as quickly as possible. “Never mind the types in that European museum, I have the specimens here and there’s nothing (well) written in the literature to say I’m wrong!” 

Taxonomists, myself included, fall more on the cautious side. Townsend was an exception. We want all the bits of evidence before we publish our scientific opinions, whether that be new species, synonyms, homonyms, or redescriptions. Caution is great when you start with a clean slate. But in the face of a huge mess caution is paralyzing. How do I start? I’m looking at a great wreck of a building. Do I take the debris out piece by piece and slowly repair? Or do I knock it down, bulldozer the area, and pour a new foundation?

I have sat and looked and sat and looked and wondered at my specimens guessing and second guessing myself if what I am seeing is really separate species, or if they have been previously described. This back and forth mental motion is useless. I fear too much of wreaking havoc. But plenty havoc has already been wrought.

I think there is a middle ground. Stride boldly, but document everything. Don’t worry too much about creating new species synonyms or mis-associating males and females. Those issues can easily be fixed later. Otherwise you’ll spend the rest of your life waiting for that visit to that one university in Chile (when the type was long since moved to a museum elsewhere). At the same time, document everything and carefully record your findings. If you provide photographs, written description, genitalia drawings, and adequate references to collections and literature in your publications, someone else can build upon this firm basis and correct your mistakes.

An excellent example of walking this line is Dr. Lee Herman’s 2013 revision of the New World species of Oedichirus, a genus of rove beetles (Staphylinidae). Dr. Herman, a Curator Emeritus at the American Museum of Natural History, received the “J. O. Westwood Medal and Award for Insect Taxonomy” [PDF] for this publication. Rove beetles have a taxonomic history as equally tortured as tachinid flies. As in tachinids, associating males and females of the same species is difficult. At times only male or female specimens are available, and species were described sometimes based on the male and sometime based on the female. Furthermore, the majority of specimens available (including the types) are too old for modern techinques like DNA Barcoding. Herman could have waited until new specimens were available, but instead he pushes forward. In the methods section he writes, “hypotheses of male/female association proposed herein for the other species can be corroborated or refuted by DNA barcoding techniques using newly collected specimens.”

Remember that every “opinion” of natural history is a hypothesis subject to further testing. When our hypotheses are presented as expert opinion but rest on shoddy work they are an obstacle. When we refuse to present hypotheses for fear of being wrong they are also an obstacle. But when our hypotheses are presented boldly and rest on good work, even our mistakes are outweighed by the scientific contribution. I have discovered that it does no good to worry. Any well documented progress is good progress. Anything mopped up is better than the mess we have now.