Biodiversity bias? The relationship between taxon diversity and research publications

15 November 2013 by Christopher Buddle, posted in Biodiversity, Publications

Yesterday I was doing some background reading on the insect order Strepsiptera (twisted-wing parasites), of which there are about 600 described species. In contrast, the order Carnivora (Mammals, bears and the like) has about half that number of described species. This resulted in a bit of discussion on twitter about whether there might be any relationship between the number of species described for an order and the number of publications on that order. Stated another way, is there a publication 'biodiversity bias'?

In an ideal world of biodiversity science (and in my opinion...), I would like to think that there should be more publications on taxon that have more described species. Hyper-diverse orders of insects or arachnids ought to have more publications than, say, the species-poor cetaceans.  To address this question, I haphazardly selected 5 orders from each of the dominant Arthropod classes (Arachnida, Crustacea, and Insecta) and 5 orders from the main chordates: Aves, Mammalia, and (Amphibia + Reptilia). Therefore, there was a total of 15 orders of arthropods and 15 orders of chordates.  Using web of science, I searched for the number of publications in which the order was found under the 'topic'.  A simple approach, I admit... but perhaps it will give some indication of whether or not a bias exists.

Here is the result:

At first glance, this looked great!  Researchers are studying animals in the proportion to their total diversity. However, I did have to use a log-log scale in that presentation, and the overall pattern is certainly affected by a few hyper-diverse arthropod Orders (in this case, Hymenoptera [wasps, bees, ants] and Araneae [spiders]). Next, I thought it would make sense to look at the total number of papers published per species.

The winner? Carnivora has about 7 publications per species.

The loser? Pseudoscorpiones has about 0.05 publications per species.

Graphically, the results are as follows:

Clearly, species with backbones (especially furry ones) see more publications.

What is even more interesting is that the bias is even stronger when common names are used instead of the scientific name of an order. "Falcons" for example, receives an order of magnitude more hits on web of science than using "Falconiformes". The same is not true of researchers publishing on arthropods - their use of the scientific name of the order is far more common. Clearly, more digging into this topic is needed.... (a future blog post perhaps).  And, interested readers should certainly look at this publication by Simon Leather. (He's done a far more careful job than I did here)

In sum, there appears to be some taxonomic bias in publication. I realize that I have my own biases, and it's not all about the diversity - there are clearly other considerations which I have largely ignored. I also recognize that "orders" are themselves are not necessarily a good taxonomic category to use for this kind of study, and many are in continual flux.  And, my methods were not overly rigorous. At first glance, however, folks working on arthropods have some catching up to do. Especially the pseudoscorpionologists.


Poor understudied pseudoscorpions... (photo by C. Buddle)

11 Responses to “Biodiversity bias? The relationship between taxon diversity and research publications”

  1. Alex Bond Reply | Permalink

    A neat analysis Chris. Some thoughts (in no particular order):
    -there are 5500 mammal species, and 10,000 bird species (roughly). And, at least from the bird perspective, we tend to view differences among species as very important. In other words, a blackburnian warbler and a black-throated blue warbler would very rarely be grouped together. Is the same true for arthropods, or is the unit of study more often at the community level?

    -what about taxon-specific journals? There are ~20 for birds, but I suspect that mammal-based papers tend to end up in "zoology" journals with greater frequency (just an anecdote with no actual data to back it up, though). But this could be a circular argument - there are enough ornithologists to support 20 journals.

    -is your "mammal" bar in the graph just for the Carnivora? Among mammals, this is probably one of the best-studied groups.

    • Christopher Buddle Reply | Permalink

      Alex - thanks for the comments! Great to have some feedback. To reply,

      First, interesting point re: difference among species and grouping them together. Certainly, for arthropods, species will often get grouped together in 'diversity' studies. It's hard to speculate on whether the 'community unit of study' is more commonly used with arthropods but I would guess it's a 'yes'.

      Second, taxon-specific journals -in the literature I know, there are dozens (hundreds perhaps) of journals devoted to Entomology, Acarology, Arachnology etc. That would be a most interesting study - ie., look at # of journals as a proxy about how much biology / natural history is know. (future blog post, perhaps!!)

      Third, the mammals included Cetacea, Chiroptera, Carnivora, and Lagomorpha

  2. Paige Brown Reply | Permalink

    This should be the subject of a future publication itself! Are we biased toward studying animals that are "more like us"?

    • Christopher Buddle Reply | Permalink

      Thanks for the comment, Paige. Based on the conversations over twitter, there seems much interest! I'll seek collaborators when the time is right and we'll see if a pub. will eventually be possible. It's a neat area of study. (note: I've also not done an exhaustive search of the literature to see whether something analogous has been published)

  3. Phil Garnock-Jones Reply | Permalink

    I suspect you'd find a relationship between journal impact factor and organism charisma for systematic papers too. You could use that as a multiplier in the analysis.

  4. D. Huber Reply | Permalink

    (Strangely, after a couple of attempts, this didn't want to post via my iPad... so I'm trying again on a desktop.)

    Congrats on landing here!

    I'd also throw into this mix the impact of the organism on, for instance:

    -human health

    These things drive a lot of invertebrate study on organisms like bark beetles, pollinators, disease vectors, parasites, and ecotourism species (e.g. monarchs).

    Another question... are there similar biases in non-zoological biological fields? That is, what do we see in botany, mycology, microbiology? A comparative study would be instructive.

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