blackflies at Burning Tree

Chalk up another eight hours for my naturalist work record. Last Friday Kay and I collected at Burning Tree St. and Gay St., and Monday we all (Kay, and Cheryl, Theresa, and Marilyn) spent the afternoon in the lab with Todd. 9:30 - 1:00 collecting, 12:45 - 5:15 lab time.

Friday was really chilly for collecting. It was in the forties and quite breezy out of the north. Partly sunny at Burning Tree, but by the time we got to Gay St. it was almost all clouds. Brrrrr! Spring sort of went away again. A frost was predicted for the weekend, but fortunately for my outside plants, it didn't quite happen here. But oh, the snow on the bluebonnets in Central Texas! Such pictures as are posted on Weather Underground: http://www.wunderground.com/wximage/viewsingleimage.html?mode=singleimage&orig_handle=Alfjw&orig_number=0&handle=Alfjw&number=4&album_id=0#slideanchor

Most notable at Burning Tree were hundreds of tiny snails, and many little leech-y things, which turned out not to be leeches at all but blackfly larvae. These are actually a good sign for the health of the stream, because they are filter-feeders who require a good oxygen level. I spent most of my time in the lab on them. Their heads are extremely decorative, with the antennae modified as beautiful fan-shaped, or rather miniature-leaf-rake-shaped collecting organs. Their posterior ends have a circle of neat little hooks, and they anchor in the current, hanging with their heads downstream, filtering out particles with their antennae and cleaning them off with mouth parts. It was especially interesting, because I had just been listening the evening before to the chapter in Sue Hubbell's Broadsides From the Other Orders about them. They get more research funding than many insects because of their annoyance quotient, and because in Africa they carry the parasite that causes river-blindness.

Aside from the head-fans, their morphology is most striking because they have one proleg. Not one pair of prolegs, just one centered below the head. Very strange-looking.

Kay worked on the Gay St. take. Most notable there were our huge green Aeschnid dragonfly larva, and the equally big one that she recognized as a hellgramite, that got away! We know it was in the first white pan which sat on the bank while we used the second, but when we were picking out the bugs, it wasn't there. We guess it crawled out somehow, or a mockingbird came and ate it, or something . . .