I am an insect taxonomist, studying a group of small flies, describing them and working on their evolutionary relationships (phylogeny). I prefer the word systematist and better yet, biosystematist to describe what I do because that catches my perspective and goals – to describe biodiversity and to interpret the various species’ biology, behaviour, ecology and so much more by studying their phylogeny. It is through that lens that so much of our world makes sense: as Theodosius Dobzhansky, a famous evolutionary biologist who in large measure, through his study of fruit flies, kick started almost everything we know about genes, famously said “Nothing in Biology Makes Sense Except in the Light of Evolution”. It is as true for the biological world as it is within the human family – history and relationships influence and make sense of much of who we are and what we do.
My expertise is on a particular group of flies called the Culicomorpha, which includes 8 families, some of which are mosquitoes, blackflies, and my favourite, no-see-ums or also ‘biting midges’. I have published on each of the 8 families in this group but particularly on just a few, including the Ceratopogonidae (no-see-ums, biting midges). See the list of my publications. Standing on the shoulders of many others, there are now over 6,300 named species and an understanding that there are thousands more needing names. Sorting out their phylogenetic relationships is like working on a huge puzzle, with pieces coming together slowly but surely as we learn more about their anatomy (including some molecules), The group is particularly well suited to understanding their phylogeny because of four very important factors. First, there are a lot of them, so we can often see the evolutionary steps resulting in very diverse morphologies. Second, each life stage is morphologically diverse, so we can look at larvae, pupae and then adults to see which characters are most informative to indicate relationships. Even the eggs tell about some of the relationships. Third, we know the relatives of Ceratopogonidae, the families that they are closest to and so we can better understand what are primitive or advanced characters. Just like we know that the egg-laying habit of the platypus is primitive among mammals because we know that other vertebrates lay eggs, so too we can understand, for example, that blood feeding on vertebrates by only some biting midges is primitive. Fourth, the Ceratopogonidae have the best fossil record of any group of insects, with the possible exception of ants; they are diverse and abundant in the various ambers around the world, of which there are many and of very different ages, from 15 to 128 million years old and we are fortunate to have a single wing from a compression fossil dated at 142 million years old. If we are the right track about the relationships of the living species, the fossil record should reflect that, with the oldest fossils, for example, representing the earliest lineages within the family.
I’ve also extensively studied two other families of Culicomorpha. Corethrellidae are a particularly unusual family because for many years they were exceptionally rare in collections with, for example, nearly all of the 64 previously described species were known from 1-5 specimens and most museums with less than 20 specimens in their collections. Then in 1979 a scientist in Georgia, Sturgis McKeever, made a great discovery. While watching calling frogs he spotted a small midge come in and feed on the frog. He collected it and put two and two together. Shortly after he went back one evening with a tape recording of the frog call and a trap made up of a fan and a bag and he collected over 500 in 30 minutes in one evening! He had discovered that the Corethrellidae, now known as the Frog-Biting Midges, were attracted by the call of the frogs, unlike other blood-feeding midges which are attracted (at least initially) by carbon dioxide emanating from their hosts. Using this technique, I collected Corethrellidae in Costa Rica for 9 months while living there and found many more undescribed species and this led to a worldwide revision of the group and a monograph in 2008 of some 456 pages. This work was honoured in 2010 with the J.O. Westwood Award by the Royal Entomological Society for the best taxonomic work on a group of insects, worldwide (presented biennially at that time). Other publications describe the first instar and a catalog of all species.
Earlier work focused on the Chaoboridae, close relatives of mosquitoes and commonly known as phantom midges. The most abundant and diverse genus are the those with transparent larvae that are predators in standing waters and which have the capacity to move up and down in the water column, similar to submarines. One publication details the minute differences between the species in one subgenus. Others discuss their distribution, coexistence and a catalog of all species known.
Other major work includes various generic revisions, the first broad homologies of pupae and a new family tree of the families of Culicomorpha (2012), the first comprehensive comparisons of the pupae of genera of Ceratopogonidae (2014), a book on the Ceratopogonidae in Canadian amber (2005); 78 million years old; including 2 species that likely fed on dinosaurs), a study of the midges (2000) in Lebanese amber (128 million years old) and an interpretation and synthesis of the fossil genera of Ceratopogonidae (2019).
A very informative study was the 2018 analysis of all the Diptera (flies) species found in a four hectare (150 X 266 meter area) cloudforest in Costa Rica that yielded 4,332 species – an international effort of 59 experts and spearheaded by Brian Brown (Los Angeles County Museum) and myself– that provided the first detailed insight into tropical diversity of a major group of insects. Scientists are very short on comparative information on the biodiversity of tropical regions and this was the first complete survey of a major group of insects in the tropics.
My interest in how phylogenetic trees are determined, an area of strong debate in the past, led to another paper in 2018 providing a critical interpretation of how phylogenetic trees are currently produced by the majority of evolutionary biologists, with suggestions on what might be improved.
Concern for the environment is central to the lives of taxonomists collecting and studying biodiversity. Insects are in decline in numerous areas of our planet and, especially in the tropics, it is certain that extinction rates are high for insects (and likely other small organisms). This was partially addressed in a 2020 paper. It is certainly an area that is ignored by many environmental groups, which accent mammals and species of economic concern (like fish). Sometimes butterflies or dragonflies are included but the biggest diversity, by far, many with much more limited distributions are small insects of flies, beetles, wasps (in their scientific broad sense), and moths within the Lepidoptera. That is certainly where most of the extinction is happening in our world today as tropical habitats disappear as a continuing and alarming rate.