The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note any observations you have made of the world around you. Snails, fish, insects, weather, meteorites, climate, birds and/or flowers. All are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located.
Western Washington
Pacific Northwest
Summer 2013
I was a small child when this pond was dug, in what was then rural western Washington over half a century ago, so it's old to me. And old enough to have an established community of residents and transients, some of which I enjoyed a couple of weeks ago, on a warm afternoon.
The occasion was a gathering of family and friends, and while most folks were playing a brushy game of high-grass baseball in the field beyond, some of us were poking around beside the pond.
That's a non-native weeping willow by the shore, and the field is a mass of nonnative pasture grasses and weeds, but the pond itself is an oasis of mostly native plants and animals in a part of the state that has gotten built up on all sides with subdivisions and commercial establishments. This bottomland is an unbuildable wetland...a refuge for wildlife.
The usual ducks and swallows had decamped, but invertebrates were oblivious to the human activity, busy at their own.
Several Eight-Spotted Skimmers (Libellula forensis) flew in circles around each other, occasionally alighting for a rest. Here's a male. These skippers, named for the 8 black spots on their wings, are common in muddy bottomed ponds and lakes of the western U.S. As adults they feed on soft-bodied flying insects like mosquitoes, flies, moths, butterflies and termites.
Damselflies were variously resting and mating (in the classic "wheel position").
Native cattails and rushes line about half the pond, providing food and hiding places.
More bugs and watery stuff below the algae clump.
Algae (aka "pond scum"), duckweed and cattails:
I took a look at some of the greenish brown strand-like algae under the microscope, and found it looks like this, with a lot of these crescent shaped green desmids (
Closterium) too, proliferating in the sunlight of these long summer days. There were also amphipods and flatworms and various tiny protists, along with quite a lot of detritus. Photosynthesizers, carnivores, scavengers, decomposers....lots of life.
Above the water surface, a Blue Dasher (
Pachydiplax longipennis) rested on a stem. It is another skimmer, common in still bodies of water over much of the U.S. This male may be raising his abdomen in response to the heat of the afternoon.
However, besides the tiny gnats flitting above the water, the most abundant insects at the pond were Water Striders, true bugs of the family Gerridae. These wonderfully unlikely creatures that literally walk on water are voracious predators of other insects, such as mosquito larvae, unfortunate dragonflies, butterflies or beetles that fall in the water, and even each other cannibalistically. Like many true bugs, they puncture their food source and then suck out the juices.
It is just amazing to me they are able to skate along on water. Notice the dents under their legs, stretching the water surface, which holds together due to its very high surface tension, water being a polar molecule highly attracted to other water molecules, "sticking" them together, resisting puncture. The Strider also distributes its weight carefully, and has extremely thin hairs all over which repel water. They don't get wet. In fact, if by some chance they do sink, the air trapped in the hairs makes them buoyant, and they pop back up.
Wiki says:
The tiny hairs on the legs provide both a hydrophobic surface as well as a larger surface area to spread their weight over the water. The middle legs used for rowing have particularly well developed fringe hairs on the tibia and tarsus to help increase movement through the ability to thrust. The hind pair of legs are used for steering. When the rowing stroke begins, the middle tarsi of gerrids are quickly pressed down and backwards to create a circular surface wave in which the crest can be used to propel a forward thrust. The semicircular wave created is essential to the ability of the water strider to move rapidly since it acts as a counteracting force to push against. As a result, water striders often move at 1 meter per second or faster.
Very pretty ripple patterns on the surface.
Some nonnative water-loving Curly Dock (
Rumex crispus) grows right up to the edge of the pond. This one harbors a European Banded Wood Snail (
Cepaea nemoralis).
This pond is not stagnant. Runoff water from uphill flows into it, and out the other end. Slowly, but constantly. This is the inflow, from a little bridge. The pile of cone scales was left by a Douglas Squirrel I'm fairly sure, since I saw them (and heard them) in the nearby trees.
Looking the other direction, the small stream flows quietly through emergent vegetation into the still pond. There's much more to see in here, like the fish I saw jumping for insects, the ducks, the tadpoles, and possibly even leeches. Another day.
* * * * * * * * * * * * * * * * * * * * * * * * * * * *
What's up in your backyard, or wherever you may be traveling?