I did not expect to see this this morning, and I didn't know what I had when I headed back to the car to start taking photos. I was digging around in a very small stream/spring seep at high elevation in Sugar Hollow, sifting through gravel, hoping to find another Theliopsyche (see the posting for 12/21). I picked up this case -- not even sure that it was a case -- until I saw a little brown head sticking out.
It was only when I looked through my camera that I knew what it was: the "humpless case-maker," Adicrophleps hitchcocki. This is an insect that is listed as "imperiled" in the state of Virginia (http://eol.org/data_objects/28878539), but it's the second larva that we've found in Sugar Hollow's small headwater streams. You may recall that my friend found one in December, 2013, and I posted an entry describing the find on 12/2.
1. There is only one Adicrophleps species -- hitchcocki.
2. To date, A. hitchcocki has only been found in Connecticut, Maryland, Pennsylvania, Virginia, and West Virginia. (See Nature Serve Explorer.)
3. Wiggins keys out the genus in following way: "Each half of mesonotum subdivided into three separate sclerites, posterior margin not conspicuously raised or coloured." (p. 51) (Note that the separation between sclerites 2 and 3 on each side is difficult to see, but they are distinguished by color.)
4. To this Wiggins adds, "The head of A. hitchcocki has light-coloured muscle scars and bears a pair of longitudinal ridges along the anterolateral margins of the frontoclypeal apotome." (p. 52) Both features are clear in this close-up.
Actually, those ridges on the sides of the head are visible in one of my photos.
5. On the case -- "Larval cases in Adicrophleps are four-sided, tapered, and constructed of pieces of moss arranged transversely; trailing ends frequently left attached to the moss pieces give the case a furry appearance." We can see that in all of our photos, and the transverse arrangement of the moss pieces shows up nicely in the photo that shows us the ridges.
6. I also noted in my post of 12/2/13, that in Wiggins' illustration of the larva on p. 53, it is clear that there are very long setae on the anterior edge of the pronotum. No question about it. (Also note the "divot" in the pronotum, a defining trait of the family.)
7. One final point. On the habitat -- "Larvae were collected in several cold, rapid streams from 1 to 10 m wide from aquatic moss in riffle areas at depths not exceeding 30 cm; they were exceeding difficult to find in the moss." As I mentioned, I found this little larva (case was 6 mm long) in sand and gravel, and this was the stream.
That was a treat... and what a nice way to start the new year!
Hi Bob, I'm George Devlin from DEQ's Roanoke office. I think we met 15 or so years ago when Jason Hill and I were helping Bill Van Wart from the Harrisonburg office (VRO) sample a stream in the Rivanna basin.
ReplyDeleteI am wondering if you have the elevation for the sites where you collected Adicrophleps hitchcocki? I collected one back in October 2020 in the North Branch of Simpson Creek (Rich Hole Wilderness, Alleghany Co) at an elevation of 2000'. Bill and Ted Turner from VRO have collected this taxa at other sites like Fridley Run, Mountain Run and the North River at elevations ranging from 1800' to 3000'.
I'm trying to get a bit more information on it's range and help come up with a tolerance value for it as we work on our genus-level index. The NC caddisfly guide doesn't list it as having been collected and I'm guessing that as you move north you may find it at lower elevations so to me this seems like the caddis version of a the wood turtle which if in VA they supposedly will not be found under about 3000' elevation.
Any information you can supply is greatly appreciated.
Thanks,
George