Black-winged damselflies and tiny forget-me-not flowers together are summer beauties along stony-bottomed brooks in Lancaster County, Pennsylvania's farmland. Male damselflies have black wings and iridescent-green bodies that are particularly beautiful in rays of sunlight as those predatory insects flutter butterfly-like over shaded, clear-water brooks. Adult damselflies prey on flying insects they catch over and near small waterways.
Female damselflies of this species spawn in those little waterways where their larvae grow up by eating tiny invertebrates under submerged stones.
Forget-me-not flower petals are pale blue and surround yellow stamens, which makes lovely bouquets of blossoms along water lines. And they are especially beautiful when male damselflies rest on them.
Though they are small and appear barren, deeper "holes" or pools in shallow, narrow brooks of flowing fresh, clear water in this county's cropland, as elsewhere, have slower currents, allowing fish and other creatures to have homes without fighting swift flows of water. Each hole has its own community of interesting water critters, all of which are enjoyable to see in the clear, sparkling water.
Each deeper pool is gouged out by its small waterway's swift current. Mud and stones are washed out by the water's flow and carried downstream, creating a deeper bed.
Water in Lancaster County brooks are usually clear, allowing a person to see to the bottom of each pool. And that crystalline water and its inhabitants are intriguing to experience.
Water striders inhabit the surfaces of many holes in brooks, where they capture and suck the juices out of helpless land invertebrates fallen on the water's surfaces. Striders are dark-gray on top, which camouflages them against the waterway bed. And, like all insects, striders have three pairs of legs. The back pair they use as skis on water, without breaking through, the middle pair function as skis and poles to thrust these insects forward over the water and the front pair serve to capture prey and to ski on the water.
I've also seen lovely bluet and violet-tail damselflies hovering over these deeper pools in shallow brooks. These small, thin damselfly species have much the same life cycles as black-winged damselflies.
Mayfly and stonefly larvae need good water quality to survive. They live under stones on the bottoms of waterways and feed on detritus, and algae on rocks. And, many of them, in turn, are eaten by crayfish, small fish and damselfly larvae. Many adult mayflies and stoneflies on the wing are consumed by bats, swallows and other creatures.
Black-nosed dace are small, attractive fish living in many brooks. This species needs good quality water to survive. Dace are about two inches long, dark on top, which camouflages them, and have a black line on each flank from nose to tail, which breaks up their form. They are stream-lined to easily swim into the current. In June, males have beautiful orange fins and flanks, which shows their readiness to spawn. Dace constantly face into the water flow to watch for invertibrates and other edibles coming toward them.
Blunt-nosed minnows, banded killifish and Johnny darters are small fish that have life histories similar to that of dace because they all share the same habitats. The minnows look like dace, but are bigger. Darters live among rocks on he bottoms of brooks because they have no air bladders to keep them buoyant in mid-water. Herons, kingfishers and northern water snakes feed on these small fish.
Crayfish live in many holes in brooks. They are crustaceans that look like their bigger cousins- the lobsters. Crayfish are scavengers, feeding on algae and decaying plants and animals on the floors of pools. They are camouflaged and difficult to see until they crawl forward or jet backward with a flip of their tails. Some are eaten by raccoons and herons.
Handsome fishing spiders sit in ambush on plants that extend into the water, the only spider to do that. These large,brown spiders pounce on invertebrates, tadpoles and tiny fish that venture near. Some of these spiders, in turn, are eaten by birds, green frogs and larger fish.
A few each of attractive green frogs and pretty painted turtles can be spotted in some clear pools in brooks. The frogs feed on insects and spiders, while the turtles ingest snails, scuds, which are a small crustacean, other kinds of invertebrates and water plants.
Little, deeper holes in brooks are not devoid of life. Many kinds of water creatures call them home, and we can enjoy seeing those animals in summer.
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