» Phylum Arthropoda (Arthropods)
This is page 4 of specimens of Arthropoda. Visit the main Arthropoda page for:
- The behavior and habitat of Arthropoda.
- 122 underwater pictures of Arthropoda.
- 6 streamside pictures of Arthropoda.
Pictures of 1096 Arthropod Specimens:
Hydropsyche aenigma (Spotted Sedge) Caddisfly Adult
View 18 PicturesThese big caddisflies were tempting trout as they wriggled out of their shucks (Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.), while others skated across the water at a medium pace, probably egg-laying. Female Drunella tuberculata Mayfly Dun
View 14 PicturesI 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 (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.