Sunday, 7 March 2021

 An agg.ravating issue? 

I have been meaning to get around to throwing this potential "spanner in the works" for a while now.

Below is the link to an article in The Guardian dated Friday 25th December2020 by Patrick Greenfield. Some of you may have read it already:

It discusses the increasing use of DNA barcoding technique for identifying flora and fauna species and presents surprising results with potential far reaching consequences.

Put briefly, this currently laboratory based technique, is discovering many actual genetic divergences in species where it was formerly assumed to be natural variation. Included as an example, is the caterpillar of the Two-barred Flasher butterfly and the wide variation in body stripes this species displays.

It may sound a rather dry and remote science but having read it I can not help but now wonder about the moth species we record and what this discovery may imply for our field recording in the future? 

Will a time come where DNA barcoding is the only acceptable true identification of a species? How will this shape the confidence in current field species identification records/techniques? How important, in terms of identification ethics, is this new technique? Would agg. be the new normal for general field species monitoring without DNA analysis? Could bar coding be a possible field technique for the future (Don't even begin to think about the fund raising for that)?

As usual with scientific discovery, more questions than answers!

It does cause me to wonder if even common moths we identify with "certainty" and do not attach agg. to, may no longer be the case and that they could all be agg. without establishing their individual genetic codes? I hope I am wrong!

No two moths even within current sub-species groups are identical. This could now be due to new sub-species groups, only determinable by DNA bar coding until we have a fully illustrated 5000 page field guide!?

This may all seem a bit sci-fi at the moment but I imagine there must be at least a beginning in discussion about potential effects this new arm of species identification will have on current field recording techniques and results classification?

Mercifully all theoretical for us field recorders at the moment!

Phil McGregor.


  1. Hi Phil,

    I think this is probably an issue that is more relevant for areas with less intensively studied fauna. I would venture that the current unknown cryptic diversity amongst UK moths is probably low (phew!). There are a few possible examples I can think of: the White-line Dart group, Cryptic Burnished Brass, and a few leaf miner groups. There are likely to be more but I don't think that many. Virtually all European moths have been barcoded now. Of course, this may not be enough to uncover all cryptic species yet (i.e. if a cryptic species exists in one small area).

    We wouldn't expect cryptic species to exist without any consistent differences in morphology (e.g. genitalia in Lesser Common Rustic) or ecology (e.g. habitat of Fen Square-spot) - as they shouldn't have evolved with sufficient isolation to be separate species otherwise. But for species where the natural history of the early stages is not well known, these could easily slip through the gap...

    I'm currently collecting moths near Oxford for the Darwin Tree of Life project, which is sequencing the WHOLE genomes of all species (i.e. every single gene: over 1 billion base pairs; whereas barcoding is just a short, few hundred base pair fragment of one gene). We've already done a couple of hundred moths and no real surprises yet in terms of species diversity. Nice to be able to have my ID error checked by barcoding! Will be interesting to see if any surprises emerge (i.e. new cryptic species) but suspect that the European moth fauna is fairly well known.


  2. Hi Doug,

    Very interesting additional information. Sounds like you are doing some great research.

    Puts my "thoughts" at rest! So business as usual when the moth group resumes!