The biting midges are an extremely diverse group, with 6346 species presently named worldwide. As for so many insect families, the number of described species is only a fraction of what is actually present in nature. Although it is a frequently asked question, it is difficult to know how many more species remain to be named. In a previous webpage I estimated that there are likely more than 12,000 species worldwide but this is only a “guesstimate”. In a 2017 chapter on the Afrotropical fauna (see publication #119) I suggested that there may be 9,000 species yet to be named. However, most recently, a paper published in 2024, for the first time, looks at detailed information from Costa Rica where it appears that there may be at least 5,000 species, with only 430 of them named! Based on further comparisons, we estimate that there are nearly 73,000 species of Ceratopogonidae on our planet. Obviously, the vast majority need to be examined and named. And that is just naming them – we don’t know the larvae or pupae of most of the named species and that means we don’t know where they live, nor their ecological roles, nor their behaviours, among other missing info. Considering that each species has its own story, it is clear that we are a long, long, long way from understanding this interesting group of flies.
As such, there remains a great need to make more comparisons and complete further detailed studied. There were several further reasons why more study is needed, as follows:
– There are many species already in collections which remain unnamed but there are just too few taxonomists working on this group to study all of these. Therefore we are even unsure how many unnamed species are in our collections already. One thing that is certain is that many hundreds (thousands??) of unnamed species are present in established museums, waiting for a researcher to study them.
– Many areas, especially in the tropics, are poorly known (or haven’t been collected from at all!). Every major collecting expedition is virtually guaranteed to reveal new species. In many areas of the tropics and especially at mid or high elevations that have not been sampled before, often a majority of the species taken over an extended period of time are new (i.e. hundreds of new species). In fact, our understanding of biting midges is still so poor that even collecting in the high arctic, where diversity is much reduced, produces species which are unnamed.
– Some groups of biting midges, like the genera Dasyhelea, Forcipomyia and Atrichopogon have many named species. However, the descriptions by previous taxonomists (some of these in the 1800’s and early 1900’s) were so poor that we have little or no idea of which of these are actually valid species. This is why museums are so important as a repository for material of species after they are named; we often have to check later to see what a particular author was talking about, now that we have new material of perhaps the same or a new species.
– At the present time, taxonomists working on biting midges are mostly working at a morphological level (this means that we study the structures that we can see with regular microscopes). Consistent structural differences between groups of biting midges is taken as evidence of them belonging to different species (i.e. what looks consistently different is probably a different species). However, we know from DNA barcoding and detailed studies in non-biting midges, blackflies, mosquitoes and other better known groups of insects that often groups of individuals that look for all intents and purposes as identical are actually made up of 5, 10 or sometimes even more than 20 different species which can only be distinguished through the study of their genes (like barcoding). It is almost certain that many recognized species of biting midges that are identified on the basis of their larger structures are actually made up of a number of species (but how many no one knows!).