Wednesday, April 6, 2016

Isoperla roguensis?: Let's take a step back

In the entry I put up yesterday, I made the case for identifying this nymph as Isoperla roguensis.  Since then, I've been in touch with John Sandberg who has reminded me of how difficult species identification can be.   To wit, in this case, species identification depends on exacting examination of the lacinia using a compound microscope -- something I just cannot do.  It is not enough to go by pigmentation and pattern.  Moreover, provenance of this nymph has not been established in the state of Montana.  To date, it has only been found for sure in California and Oregon.

So, the nymph in the photo at the top of the page may or may not be I. roguensis.  It looks a lot like the nymph that Sandberg has identified in that way, but the jury is out.  If I have further word on this matter, I'll let you know.

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