They're built up along the branches of small shrubs - mostly Sand Cherry. They're close to the ground - none more than about 8 inches high.The first thought was that they were termite tunnels, and they do resemble the connections that termites use to travel from their nests into above-ground structures. These structures, however, are made of sand, and when they were examined by a termitologist, she noted that the sand grains were fused by webbing - not a feature of termite structures. She postulates that these could be made by ants, but the puzzle is still under investigation.
Any myrmecologists out there who could confirm or clarify this? You can post your comments at her blog, or here and I'll forward the information.
Update:
The answer is in the Comment thread - this is a construction made by the larva of a moth (Prionapteryx nebulifera). The process was originally described in 1905 in the pine barrens of New Jersey.
Sort of reminds me of the ant mound Swamp posted on their blog...
ReplyDeletehttp://swampthings.blogspot.com/2010/05/put-on-happy-face.html
Snailcase Bagworm – Apterona helix?
ReplyDeleteor maybe perhaps this obscure reference would help.
ReplyDeleteOlethreutes dimidiana
On the biology of the sand areas of Illinois, Volume 7, Issue 7
Lethreutes dimidiana Sodoff? (U.S. Bur Ent., det.). H.1,2; Je. 7,8 (all immature). In these two localities many cylindrical tubes of webbed sand were found extending up the stems of Onagra Biennis, Cassia chamaecrista, and Ambrosia (?), often as much as two feet long, and following most of the stems of the plant, reaching the top, where the new growth had been fed upon. In one case a short tube was formed on the surface of the bare sand. These tubes closely resemble those figured by Daecke (’05) for Prionapteryx nebulifera, from sand areas in New Jersey. In these tubes were found small and very active tortriciform larvae. Mr. J. J. Davis of the University of Illinois, submitted an example to Mr. Daecke, who replied that it was no the same as his species. Mr. Davis was successful in securing an an adult from these larvae June 30, and the Bureau of Entomology at Washington has determined it for him as Olethreutes dimidiana, A European species, reported also from Missouri. The larva of this species, however, according to Treitschke, is quite differently marked from our specimens, feeds on birch and elder, and occurs in August instead of June, pupating in September and emergin the following May.
http://books.google.com/books?id=DgMuAAAAYAAJ&lpg=PA249&ots=KP8LMBpu91&dq=webbed%20tubes%20of%20Sand&pg=PA250#v=onepage&q=webbed%20tubes%20of%20Sand&f=false
Thank you for your help! I think I'll go back and see if I can find some larvae in the sand tubes. If I can, I'll try rearing them to see if I can get adults that can be identified. What a great puzzle!
ReplyDeleteMarcie
I actually had found one of the tunnel building moths on this prairie - it took me a while to get it identified and figure out that it had probably built the tunnels.
ReplyDeleteHere's the link to the photo I took - on bugguide: http://bugguide.net/node/view/412725
If you go to the info page for the moth, you'll see a link to the original article about Prionapteryx nebulifera, and the sand tunnels it builds, written in 1905.
Thanks for your help!