Caddisfly: Snow Sedge we believe

Location: juneau alaska
November 16, 2011 10:07 am
This bug was found in juneau, Alaska yesterday. Never seen one arround here before let alone we dont see many bugs in the winter!
Signature: Gary

Snow Sedge

Hi Gary,
This is a Caddisfly in the order Trichoptera.  Caddisflies are mothlike creatures that have aquatic larvae that build cases for themselves.  According to BugGuide:  “Most species live in a mobile case constructed from plant material, algae, grains of sand, pieces of snail shells, or entirely of silk. The case is held together with strands of silk secreted by the larva. In some species the case is attached to a rock, log, or other underwater surface; a few species have no case and are free-living.  The case’s particular shape and construction material is distinctive of the family and/or genus, and can be used in identification. Example: Helicopyschidae larvae use sand grains to build spiral cases that resemble small snail shells.”  The light markings on the wings of your individual seemed distinctive, so we made an attempt at a more specific identification.  We believe your Caddisfly is in the genus
Psychoglypha, and it looks similar to this image posted to BugGuide that contains the comment from Dave Ruiter:  “The scalloped wing, color pattern and venation are characteristic of several, but not all of the species in this genus.”  Somewhere as we were clicking around, we thought we read a name Snow Sedge, so we did a web search of that term and found the TroutNut website that attributes the name to the genus and provides this information:  “These caddisflies may be important to the winter angler because they are one of the only insects around. Gary LaFontaine relays an interesting correspondence about this genus in Caddisflies:  Dr. George Roemhild explained to me how he finds these winter caddisflies in February and March: ‘They crawl up on the snowbanks, but when the sun hits their dark wings they melt down out of sight. That’s how I collect them, by walking along looking for holes in the snow.'”  To back check where we found the name Snow Sedge, we searched again, adding BugGuide as a keyword and found this posting on BugGuide.  The presence of Caddisflies is an indication of clean, unpolluted water.  Here is one final photo from the Natural History of Southeast Alaska website.  

Leave a Comment