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Female Drunella tuberculata Mayfly Dun Pictures

 I don't know for sure that this is Drunella tuberculata, but that's my best guess for now.

It certainly has a different look and much more robust body shape from Drunella lata duns I photographed a couple weeks earlier, so I doubt it's that species. Using distribution records to eliminate other choices narrows this down to Drunella tuberculata or Drunella walkeri.

Markings described for the abdominal sternites (
One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.
One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.
Sternite: The bottom (ventral) part of a single segment on an insect's abdomen.
of the male spinner of Drunella tuberculata are suspiciously similar to those on this female dun. Also, this dun is 9.5mm long (my ruler pic isn't very good, but I'm basing this on measuring the real thing). The size range given in the old Allen & Edmunds keys for walkeri females is 7-8mm, while tuberculata is 9-11mm. For these reasons I'm sticking it in tuberculata for now.

This is the only Drunella mayfly I saw all day. I scooped it off the water as it emerged at around 7pm from a big Catskill tailwater.

This mayfly was collected from the West Branch of the Delaware River on June 1st, 2007 and added to on June 8th, 2007.

Recent Discussions of this Dun

Insect migration 7 Replies »
Posted by Mykisslayer on Jan 30, 2014
Last reply on Feb 3, 2014 by PaulRoberts
Do adult aquatic insects travel or migrate to other watersheds or bodies of water? Or do they remain close to the area where they emerged?
ReplyAnyone recognize this Drunella? 8 Replies »
Posted by Troutnut on Jun 8, 2007
Last reply on Sep 21, 2009 by GONZO
I'm a bit puzzled about this one. See the specimen description for details. I know female duns are awful for identification, but this is the only one of its species I could find. Would any of you Ephemerellid experts (Konchu!!) care to take a guess?

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