Sunday, May 15, 2016
Perlesta stoneflies -- still have to leave them at the level of genus
A little surprised by this one this morning -- not that we shouldn't be finding Perlestas (common stonefly, Perlidae) at this time of year -- this is when we normally see them (May, June, July), but I was in a small mountain stream. Don't see many Perlids in this type of stream other than Eccoptura xanthenses. That means that there are Perlestas in most (all?) of the streams that I visit, from these small, first order streams, to medium streams like the Doyles and Buck Mt. Creek, to our large river, the Rivanna.
While most Perlids are multivoltine (life cycle of 2-3 years), Perlesta is not. It matures, hatches, and mates within the space of a year (univoltine). And, unfortunately, we're still in the dark on the question of species ID. As I've mentioned before, Steve Beaty published online a revised version (4.1) of "The Plecoptera of North Carolina" just last year in December. But his advise on Perlesta remains the same: "LEAVE AT GENUS". (p.48) He lists the names of 13 different species but notes that "most of [these] are currently undescribed in the immature stage." (p. 49) So we wait. I have no doubt that the species that I found today is not the same as those that I find in the Rivanna.
I had high hopes of finding some new Isoperlas today, but all that I saw was I. holochlora. Maybe tomorrow at Entry Run up in Greene County.
Just two other pics from today. A fairly mature Ameletid: Ameletus cryptostimulus. (There were a lot of them.)
And a small Leucrocuta flatheaded mayfly, the one that I think is Leucrocuta juno (see the entry of 5/27/15). Regret that the tails aren't fully intact.
This too, is a species I only see in first order streams.