Collotheca (genus)
Y. Tsukii
Rotifers are a group of
microscopic animals that live just about anywhere there is
fresh water, including lakes, ponds, streams, puddles,
ditches, wet shorelines (especially sand), and even on wet
mosses. On this page, we will focus on the Collotheca
genus of rotifers. Rotifers have a
cylinder-shaped body made of three sections: head, trunk,
and foot. The "foot" usually has two "toes" at the bottom.
The head of a rotifer has a large, cup-shaped mouth,
surrounded by cilia. Cilia are tiny hair-like things which
wave back and forth. The rotifer's cilia are used to trap
food and to move around through the water. Some rotifer species
spend most of their lives swimming around, but most
Collotheca rotifers are sessile. "Sessile" means it
attaches to one place and stays there for the rest of its
life. The one time Collotheca swims is when it is
young and hasn't found its place to attach yet. When the
young rotifer is ready, it uses a sticky substance from its
foot to attach itself to an aquatic plant. Greater
Bladderwort is a favorite plant for Collotheca to
attach to. Micrographia
Microscopy-UK.org
UK Collotheca are
large compared to most rotifers. Each rotifer has a clear
tube it can pull itself into, like a turtle. The entire
animal is transparent, so you can see its food
inside. To eat, Collotheca
extends its body fully from its tube and waits for small
swimming organisms to get close. Once an organism touches
the rotifer's cilia, it gets sucked into its mouth. Common
foods of rotifers include: algae, protozoa (such as amoeba
and paramecium), small crustaceans (such as water fleas and
copepods), and small bits of plant or animal matter floating
in the current. They'll pretty much eat anything that fits
into their mouths.
Nikon Microscopy U
