Brachionus (Rotifera) Videos

These rotifers have a transparent turtle-like shell called a lorica and are found in a variety of habitats, freshwater and marine. Several species are cultured to provide food for fish larvae in aquaculture. Like most rotifers, Brachionus rotifers have pedal glands and extrude a small amount of sticky cement to anchor themselves temporarily on substrate. They also anchor, then spin out a length of filament at the end of which they stay with corona extended to feed.

Rotifers are extremely common and can be found in many freshwater environments and in moist soil, where they inhabit the thin films of water surrounding soil particles. Their habitats may include still water environments, such as lake bottoms, as well as rivers or streams. They are also commonly found on mosses and lichens, in rain gutters and puddles, in soil or leaf litter, on mushrooms growing near dead trees, in tanks of sewage treatment plants, and even on freshwater crustaceans and aquatic insect larvae.

Nearly all rotifers have chitinous jaws called trophi that grind and shred food. The trophi are the only part of a rotifer that can be fossilized and have been found in amber dating back to the Eocene epoch (38-55 million years ago).

Many rotifer species have no males, females producing only females (parthenogenesis). In some rotifer species, stress can cause females to produce eggs that hatch as males. They have no mouth or digestive tract and die within hours or days. The appearance of males is followed by sexual reproduction. The females then produce resting eggs, which settle to the bottom to hatch when conditions permit. The tiny eggs can withstand desiccation for considerable periods of time and can be carried by wind or birds to any place that holds water (even bird baths and gutters) where they will hatch.