Water boatmen are excellent swimmers, and you can see here how they use their oars to push themselves through the water, a motion easily imitated by the fly fisher.
Damselfly nymphs are among the most effective invertebrate predators in freshwater. You have to see one in motion to get a feel for their slow, deliberate style of stalking.
A few (not all) of the abdominal tubercles on this Ephemerella needhami nymph are circled. They are especially large in this species.
Tubercle: Various peculiar little bumps or projections on an insect. Their character is important for the identification of many kinds of insects, such as the nymphs of Ephemerellidae mayflies.).
Baetidae (Blue-Winged Olives) Mayfly NymphView 3 PicturesThis is the only Baetis nymph I found in my January 31st (read: not sane) sampling in 2004. I looked at this one under my small microscope and wrote down some useful identification features which aren't really visible in the pictures from my camera. This nymph had conspicuous gill veinlets (Veinlet: Short insect wing veins connecting the major longitudinal veins to the wing margin.), a pointed, slender 7th gill, tail bands on the middle and tip, and abdominal segments 5, 9, and 10 are definitely pale, with segment 8 in-between, debatably pale.
One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.
Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.) all have a dark-colored anterior (Anterior: Toward the front of an organism's body. The phrase "anterior to" means "in front of.") 2/3 and light-colored posterior (Posterior: Toward the back of an organism's body. The phrase "posterior to" means "in back of.") 1/3. The gill veinlets (Veinlet: Short insect wing veins connecting the major longitudinal veins to the wing margin.) are indistinct. It's probably a very early instar (Instar: Many invertebrates molt through dozens of progressively larger and better-developed stages as they grow. Each of these stages is known as an instar. Hard-bodied nymphs typically molt through more instars than soft-bodied larvae.) of some Baetis species.
A few (not all) of the abdominal tubercles on this Ephemerella needhami nymph are circled. They are especially large in this species.
Tubercle: Various peculiar little bumps or projections on an insect. Their character is important for the identification of many kinds of insects, such as the nymphs of Ephemerellidae mayflies.) on the tergites (
One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.
Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.) and the tails are uniformly covered with short black hairs. Looking at this specimen a while later, my early observations were probably not relevant because it was such as small early instar (Instar: Many invertebrates molt through dozens of progressively larger and better-developed stages as they grow. Each of these stages is known as an instar. Hard-bodied nymphs typically molt through more instars than soft-bodied larvae.) mayfly that its identifying characteristics were not fully developed.