Friday, January 22, 2010

Scuds

I went out Wednesday night to look in the pond for breeding salamanders, but saw none. We haven’t yet had any good weather for salamander movement this winter, but I wanted to make sure I hadn’t missed their arrival. I keep a record of salamander breeding activity, so it’s just as important to know when they are not in the pond as it is to know when they are. The weather forecast is calling for some rainy nights soon and I’m sure the salamanders will come out with the first rain. Jefferson’s are usually the first to arrive and are quickly followed by the Small-mouthed. I’ve seen them in the pond as early as mid December. The sooner they get started, the better the chances of the young salamanders leaving the pond before it dries up in the summer.

I did find some activity. The pond was full of scuds. Scud is a rather unflattering name for a very interesting crustacean. You can see several of the creatures on and about the leaf. I think this species is Hyalella azteca.

Scuds are very shrimp-like in appearance. They feed on microscopic plants and animals along with any decomposing organic matter. The pond bottom is covered with plant material that grew during the dry season and is now rotting.

The scud acts like a grazing animal and displays a restless motion as it searches for food. The head is to the right in this photo. Scuds are primary prey for many larger aquatic species. In late spring, the salamander larvae will be fat from gorging on scuds.

They seem to feed by removing the outer layer of cells along with the associated plants, animals, and bacteria that are assisting in the decomposition effort. They will work over the surface of a leaf and the leaf will get continually thinner until nothing is left but the skeleton.

This is an easy species to raise in captivity and is more fun than Sea Monkeys. As a kid, I often kept a jar of pond water containing a few scuds. Later I even raised some in an aquarium and produced a couple of generations. You can learn a lot by watching animals in the wild, but you gain a new insight when you have them in front of your face every day for months at a time.

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