Mating pair with cryptic female, 1 observation or 2?

A quick attempt to find a reference to this in the archives came up empty.

I have a series of photos of mating dragonflies that I’ve IDed as Sympetrum obtrusum based on the male’s colouration. On its own, the female would be identifiable only as Sympetrum sp. but is presumably safely IDed as S. obtrusum given its choice of mate. Yes?

Is this one observation with a note or 2 observations?


It would be a clue, but not an absolute. They might hybridize. See p. 23…
The Meadowhawks (Sympetrum): America’s Oldest Problem Odes; or, the Romance of Hybridization


Yeah. That’s the issue.

I’m not a specialist but I had thought that obtrusum was generally accepted to be a good species without the hybridization issues of some of its congeners. The article doesn’t discuss obtrusum.

This is the issue under discussion in .


Being a valid species does not preclude it from being able to hybridize with other species - that would be an interspecific hybrid.

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To clarify, there are two connected questions and it may make more sense if I change the order.

  1. Is this: properly 1 observation or 2? The annotations only permit a record for one sex, age, etc. and I have opted to mention the female in a note for the stated reasons.

  2. If there are 2 observations here is it acceptable to identify the female as Sympetrum obtrusum based on the pairing, given the issues with hybridization described by the article linked to by @pfau_tarleton .

Yes, with qualifications. There is no precise definition (or perhaps it would be more accurate to say that there are many definitions) of where the ability to hybridize ceases to be interspecific and starts being evidence that there is only a single species.

Regardless, my thought was that obtrusum is a good species “without the hybridization issues of some of its congeners”. I’m definitely not an expert, however, either on Odonates or on iNaturalist best practice in these sorts of matters. Thoughts on this gratefully accepted.

It’s up to you to decide if you want 1 or 2 obs. If you photograph a flock of 500 birds, it would be superfluous to add 500 observations. Generally, I would post closely associated individuals of the same species (copulation, flock, aggregation, etc) in a single observation. I might post certain individuals in a separate observation if they stand out in some way - parasitized, abnormal, etc.

You can add observation fields like “Number of individuals” = 2, “Copulating” = Yes to better describe what’s happening in a structured way.

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There’s no definition of species that precludes hybridization between species. What makes them separate species - according to the traditional definition - is that those hybrids of separate species (if possible at all) cannot produce an offspring themselves.

And since there exist (in general) hybrids between dragonfly species, we cannot exclude the possibility that those are different species in copulation. Besides that, their copulation might not even lead to a viable offspring. Some species will (try to) copulate with very unrelated species without producing offspring.

OK. Of course that includes an assumption that the species of the female and male are the same without the ability to verify the assumption.

Identifying some species of Sympetrum beyond genus is challenging. In most instances it is impossible for females. In the case of obtrusum the males are mostly identifiable to species but the females are as iffy as other of this genus.

This is getting off topic but it’s an interesting subject so what the heck. I linked to a conversation that is more relevant in an earlier post:

Mostly agreed.

That’s one definition, although it’s usually about producing fertile or viable offspring and it’s pretty much only applied with anything approaching consistency to large animals. Even then there are examples (e.g. ring species) in which the definition breaks down. Ultimately the species concept is at least as much about how the human mind sees the world as it is about how the world actually is.

To bring this back to the original post, the genus Sympetrum includes species which appear to hybridize and to produce viable, fertile offspring in some circumstances. With that in mind, is it reasonable to assume that the observation to which I linked upthread involves a male and female of the same species? If not, should the female be a separate observation?

There’s no right or wrong way to do it. But what I’d do is have just one observation, base the identification off the male, and then add some of the ideas developed here in this thread in the description. I’m not seeing much value in having separate posts for the male and female unless, one day, it becomes possible to ID females based on some yet-unknown feature visible in the pic (not likely).

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Under the strict definition of an observation used by the site, an observation consists of an encounter with a single organism. Therefore, by definition, regardless of how many individuals are in the photo, the record only actually documents one of them.

If you wish to submit the photo as 2 separate records, one for the male, one for the female that is fine. Just indicate as such or you risk the duplicate police flagging you.

As noted, you can use observation fields to document abundance.

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