My post a few days ago about my project on arctic flies generated an interesting question from my colleague Brian Brown. With so many possible projects, and so many unknown species, how do I prioritize? Brian and I specialize on very different families of Diptera (Phoridae and Chloropidae, respectively), but those families share many qualities – they are very species-rich and super-abundant, incredibly diverse ecologically, cosmopolitan, most of the species are undescribed or unidentifiable, and most importantly, other people who may not be specialists on these families would love to be able to identify specimens.
A challenge with chloropids is that there are thousands of undescribed species beyond the 2800 currently known, on every continent and many oceanic islands. I could spend the rest of my career describing new species. With all those projects waiting to be tackled, how do I allocate my too-limited effort? What is the best use of my time? Tropical, temperate or arctic? Canada or Costa Rica? Appalachians or Australia?
Although I’d never really thought much about it before, I suppose I go through a triage exercise when deciding where to focus my efforts. There are four questions: 1) can the genera be identified? 2) is there enough sorted material for generic revisions? 3) is there a need for species-level taxonomic resolution to enhance other projects? 4) how do we most efficiently and effectively scale up?
1) Chloropidae are fairly easy to identify to family, most of the time. Genera are the challenge. There is a good generic key in the Manual of Nearctic Diptera (MND), so that was not a major gap when I started working on the family. In Central America, on the other hand, the best we had was Oswald Duda’s 1930 key to genera which is, to put it kindly, incomplete and infuriating. So that, along with the newly launched Manual of Central American Diptera (MCAD) project, dictated my next priority – I needed to write a key to Central American chloropid genera. This meant getting to know the genera themselves, many of which I had never seen. Fortunately, I had access to a great treasure – Curtis Sabrosky’s unpublished notes on Chloropidae, amassed from the mid-1930s to the 1990s. After a lot of time and effort I was satisfied that my generic key would work, most of the time. I know it is not perfect, and there are already specimens in collections that do not key out, but that’s the nature of taxonomy. With the Central American key now finished, a complete key to Neotropical genera has become an easier objective.
My next priority in this category is Australia, where Chloropidae are one of the dominant acalyptrate fly families (so identification is definitely needed!). Other than a 1986 key to one subfamily (Chloropinae), the Australian chloropid fauna remains very difficult to sort to genus. On a visit there in 1995 I made a good start on a key to all Australian genera of Chloropidae, and I’ve been slowly updating it over the years as I study more material and discover more genera there. It’s starting to look like a more achievable goal. Hopefully sometime soon!
2) Once material in collections can be sorted to genus, revisions and species descriptions start to become more attainable. We did some of this in conjunction with the MCAD project as we discovered new things that we could not assign to known genera. Also along the way we identified a few manageable genera that were just the right size for student projects. On the other hand, some of the more diverse and difficult Central American genera (Apallates, Conioscinella, Pseudogaurax and others) will have to wait until more material accumulates and is sorted. The best indication that a group may not yet be ready for a revision is that too many species are represented only by one or two specimens.
Meanwhile in the Nearctic, we have been collecting a lot of material in a range of projects (and sorting them to genus using the MND key!), and I have spent a lot of time in Washington DC working with the extensive chloropid collection there. We are in a better position to revise some Nearctic genera than those from other regions. Some have already been revised, some are nearing completion, while others (some easy, some difficult) await our attention. How do we choose which genera to revise? All things being equal, I move on to question 3 . . .
3) Taxonomy is not just a service industry, but it does provide a critical service to other fields of biology. One way to enhance respect for taxonomy is to collaborate with ecologists and others when opportunities present themselves. Several of my students and colleagues, for example, are involved in faunal inventories or quantitative ecological projects. If one of those projects generates a lot of unidentifiable species in an unrevised genus, compared to a single common species in another genus, then it makes sense for me, and gives added value to the ecological work, to try to resolve the species in that diverse and dominant genus. My involvement with some of these projects has turned my attention to some genera I thought I would not get around to for a long time, while putting some other strange and small genera on hold for the time being. Those small genera will still be waiting for me or a keen student, and in the meantime more material will accumulate.
And after we’re done describing new species and/or revising genera and/or writing regional keys from Hudson Bay, or eastern Nearctic peatlands, or Fiji, I’ll check back on the Central American genera to see how much great new material has been collected while I’ve been busy on other things.
4) I’ve been talking primarily about one fly family in one region at a time. Of course, there are many ways to scale up our efforts. Regardless of where my focus lies at any given time, if I had the opportunity to, for example, collect Chloropidae in a standardized, repeatable way across a large spatial scale, say from the tropics to the arctic, or across a continent, I would jump at the chance. Such large scale datasets provide great data for both taxonomic projects (many of the genera are widespread) as well as ecological questions.
There is also the question of scaling up to more families. It doesn’t make much sense to train all my taxonomy students in Chloropidae when so many Diptera families remain orphans in North America. Here again, I try to find a balance. Some small chloropid projects are the perfect size for a senior undergraduate project, where I can work more closely with students on learning the characters, the range of variation and the principles of taxonomy, and some more ambitious revisions or phylogeny projects are well-suited for M.Sc. projects. At the other end of the scale, each of my PhD students in taxonomy to date has focused on a different family: Muscidae (Jade Savage); Dolichopodidae (Scott Brooks); Sarcophagidae (Marjolaine Giroux) and Mycetophilidae (Chris Borkent), and current grad student Heather Cumming works on Platypezidae. It’s very convenient being able to rely on these colleagues for identifications across such a range of families. At the same time, many of the current students in the lab working on ecological projects have become very proficient in the identification of other families. My priorities for the next five years include a few chloropid projects with former, current and future students, as well as training new specialists on some other families that I’ve had my eye on for a few years.
I’m sure other colleagues prioritize in very different ways. Perhaps that makes them more efficient and productive than I am and I must confess that my list of manuscripts “in progress” is long and terrifying. Maybe I’ll catch up when I retire and might be able to spend more time on research instead of silly meetings and useless administration (and if not, well, I’ll try to leave good notes).