Monday, June 6, 2011

Summer Insects: The New Season Begins

(Waterfall in a small mountain stream: 4/30/10,  Albemarle County, Virginia.)

Before I return to the streams -- and I'll do that tomorrow -- I wanted to make clear that we've moved from spring into summer in terms of the insects we're starting to see in this part of Virginia.  The spiny crawler mayflies -- genus Ephemerella -- that crowded our streams in the spring are essentially gone: they've hatched, many as the "Red Quills," Sulphur Duns," "Pale Evening Duns," and "Little Dark Hendricksons" -- that are imitated by fly fishermen.  Gone too are the large Maccaffertium flatheaded mayflies, hatching as the "March Browns," "Gray Foxes," and "Light Cahills."   And "going, going, gone," are a lot of Perlodid stoneflies (the genera Clioperla, Diploperla, Helopicus, and Yugus, and Isoperla namata): Isoperla Perlodids provide fly fishermen with the much anticipated "Yellow Sally" hatch in the West in June and July.  I've also seen very few Nemourid stoneflies of late -- but then I've seen very few this spring.   I think that's because I've been exploring better streams than I have in the past (Nemourids, genus Amphinemura, are pretty tolerant of stream impairment).

What I have started to see are insects we normally see in the summer.  That includes: 1) dragonfly nymphs (a "Darner" on 5/31 and a "Clubtail" on 6/4); 2) whirligig beetles (one this weekend at Buck Mt. Creek); 3) a small squaregill mayfly (this weekend at Buck Mt. Creek); and 4) mature or maturing Perlesta common stoneflies (Perlids).  I am also seeing lots of common netspinner caddisfly larvae and lots of fingernet larvae.  Finally, I'm seeing very small mayflies and stoneflies.   These include: small minnow mayflies (Baetidae: now genus Acentrella); a new generation of Maccaffertium flatheads; quite a few common stoneflies (I've not been checking the genus); small Roach-like stoneflies, and little "Giants" (see the entry for 6/2).  "Small" is a sign that it's summer.

There are some summer insects I've not yet run across, but I should be finding them soon when I start to visit new rivers (especially the main stem of the Rivanna).  These include damselfly nymphs (both broadwinged and narrow-winged (Calopterygidae and Coenagrionidae); genus Serratella spiny crawlers;  Longhorned case-maker caddisflies (Leptoceridae); Humpless case-maker caddisflies (Brachycentridae); Northern case-maker caddisflies (Limnephilidae) -- though we've already seen some Pycnopsyche Limnephilids during the spring -- and later on in the summer, baby hellgramite nymphs.  By July, we should also find the odd-looking Macrostemum common netspinner larvae -- at least in some of our rivers.

We've turned the corner: a new season's begun.

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