Troutnut Forum > Specimen Discussion > Has anyone else seen a Hendrickson nymph like this?
The Specimen
Ephemerella subvaria (Hendrickson) Mayfly Nymph
View 4 PicturesI've never seen this strange coloration on any Ephemerella subvaria nymph in a book before, but it's similar to several other specimens I collected on the same outing, including a smaller one that I photographed. They were outnumbered by the "normal" Ephemerella subvaria nymphs in the sample.
View 4 PicturesI've never seen this strange coloration on any Ephemerella subvaria nymph in a book before, but it's similar to several other specimens I collected on the same outing, including a smaller one that I photographed. They were outnumbered by the "normal" Ephemerella subvaria nymphs in the sample.Region: Northeast
Collected Mar 29, 2005
Added Apr 7, 2006
The Discussion
| Troutnut | November 1st, 2006, 1:05 am | |
| Fairbanks, AK Posts: 1122 | I found a few of these this spring in just one small Finger Lakes tributary, mixed in with various normal-looking E. subvaria nymphs. The unusual characteristic is the pale prothorax -- the "white collar" segment just behind the head. I've never heard of that color configuration before. Has anyone else? Maybe they're mayfly clergy... | |
| Jason Neuswanger The Troutnut | ||
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| GONZO | November 1st, 2006, 1:37 pm | |
| "Bear Swamp," PA Posts: 951 | Very interesting specimen, Jason. I have no answer, but I do have an observation. Aside from the unusual translucent quality, I notice that the pronotum is also asymmetrical. The blunt forward left-hand corner would seem to indicate that the nymph sustained some sort of injury or other deformation, perhaps in an earlier instar. I hesitate to suggest this as an explanation because you indicated that you found others with the same coloration/deformity. | |
| GONZO | November 1st, 2006, 1:47 pm | |
| "Bear Swamp," PA Posts: 951 | Jason, Just took a look at the second smaller specimen. (Sorry, I'm a little slow on the uptake today.) I see no sign of injury or deformity on this one. I did notice, however, that both specimens appear to be female. (?) | |
| Taxon | November 1st, 2006, 10:28 pm | |
| Mercer Island, WA Posts: 506 | Jason- The only thing I can come up with is that, perhaps it was freshly molted, and had not yet acquired pigmentation in that area for some reason. However, I would be willing to bet that Ethan Bright has seen that condition before, and would know its cause. I owe him a response on another subject, so will also alert him to the question. | |
| Roger Rohrbeck www.FlyfishingEntomology.com | ||
| Taxon | November 2nd, 2006, 10:47 am | |
| Mercer Island, WA Posts: 506 | Jason- You know, now that I look at it more closely, particularly after lightening the photo, it appears to have mature wingpads. So, I suspect it may just be in an early stage of molt to subimago. The translucency probably results from initial separation on the pro-thoracic plate and the leading edge of the meso-thoracic plate. In any event, I'm hoping to hear for sure from Ethan Bright. | |
| Roger Rohrbeck www.FlyfishingEntomology.com | ||
| Troutnut | November 2nd, 2006, 11:15 am | |
| Fairbanks, AK Posts: 1122 | Interesting ideas. I don't think it could be molting to a subimago, because March 29th is a little early for me to be catching any like that, let alone several. I photographed 2 but I actually captured probably 4 or 5 with that color pattern. I should have mentioned that earlier. I'm fairly convinced it's a pigmentation thing. They didn't really seem "translucent" to me, just olive-colored. Of course there's a bit of inherent translucency, but it didn't seem like more than in any other olive-bodied nymph. It's interesting that the leading edge of the mesothorax has that color in these, too. | |
| Jason Neuswanger The Troutnut | ||
| Taxon | November 3rd, 2006, 1:40 am | |
| Mercer Island, WA Posts: 506 | Jason- This is the response I received from Ethan Bright this morning: Boy, he takes great photos. My thinking mirrors yours - cuticular ecdysis hasn’t completed, or the old cuticle will not come off. Based on the relative evenness of the tone, I think it rules out a fungal infection. | |
| Roger Rohrbeck www.FlyfishingEntomology.com | ||
| Konchu | November 21st, 2006, 6:46 pm | |
| Indiana Posts: 211 | I have collected many ephemerellids that show this, and more, color variation. I really don't think it is much more complicated than that. The more you look, the more you'll see. | |
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