Turning Stones
For as long as I can remember, I've been turning over stones to see what lived underneath them. As a child, hundreds of summer hours were spent snorkeling in the shallows of Lake Lida where my family owned some lakeshore. I gave most of my attention to the bigger creatures, crayfish and mudpuppies, but I was equally captivated by darter minnows and large leeches that moved like magic carpets through the water. That strangely quiet and often bizarre world took hold of my imagination and has been a source of enjoyment and mystery ever since.
Even today, decades later, curiosity still beckons and I find myself at the edge of the small creek reaching down to flip over a flat rock. A damselfly nymph clings to the underside of the rock. From the stout body shape and wide caudal fins, I'm fairly certain it is a dancer nymph (genus Argia). In the summer, at this location, Blue-fronted Dancers (Argia apicalis) outnumber the Blue-tipped and Powdered Dancers at least one hundred to one. So judging solely on odds, this nymph is likely to be a Blue-fronted Dancer as well. It would need to be reared to know for sure.
Argia is a species rich genus, especially in the tropics where well over a hundred species are known, with many more yet to be described and discovered. In Minnesota things are a little simpler; only five species have been recorded here: Argia apicalis, Argia tibialis, Argia moesta, Argia fumipennis, and Argia plana, the latter known from a single site in the southwest corner of the state.
Παρατηρήσεις
Φωτογραφίες / ήχοι
Τι
Γένος ArgiaΠαρατηρητής
scottkingΠεριγραφή
Dancer, nymph
Spring Creek
Cowling Arboretum
Northfield, Minnesota
Σχόλια
I was also captivated by large leeches when visiting our lake in Maine as a child. However I would yell out "bloodsucker" and try to catch them. When successful we dumped the leeches in a can of salt to kill the nasty bloodsuckers. Sometime in the 1970's I stopped seeing leeches in the lake. I think as the shoreline was fully developed with camps (aka cottages), moose and other mammals were no longer available for the leeches to feed on. That, plus diligent efforts by other swimmers, surely eradicated most of the leeches.
Todd, thanks for the comment. Both development and attitude toward certain animals no doubt have affected aquatic ecosystems in dramatic ways. Often very difficult to measure these changes directly as we rarely know what was there to begin with or even what lives there now. Of course comparison might be made to nearby un-impacted lakes or wetlands...if you can find one.
Probably a difficult position to argue, that swimmers might give something back by standing around in the shallows long enough to feed the leeches!
Very cool. I've been doing a lot of this lately. I need to remember to bring a little bowl to get some isolated shots of what I find.
A small white bowl, some old bottled water or filtered water (freshly opened bottles have too many bubbles, even uncarbonated drinking water) is a pretty easy setup and yields fairly decent dorsal shots as long as there is enough sunshine.
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