Copepods: Cyclops

A fresh water pond copepod, likely Cyclops spp.

Copepods are a subclass of the animal kingdom composed of tiny crustaceans. Of the Crustaceans, copepods are the largest and most diversified group with over 14,000 species identified. Although visible to the naked eye, they are often no larger than 2 mm in length, but a few species may reach 10 mm in length. Copepods can be found in ponds, marshes, streams, lakes, and coastal waters. Some species can tolerate more extreme habitats of hypersaline conditions, caves, and leaf litter.

Copepod bodies are composed of the cephalothorax and abdomen.

As the most numerous multi-cellular animal within the water community, copepods are very important ecologically. They, like many other plankton, are an important food source. Some species feed on mosquito larvae and have the potential to act as a malaria control mechanism. At the same time, some species are intermediate hosts to parasites including the guinea worm, tapeworms, and flukes.

As with other crustaceans, copepods are invertebrates with hard outer cells.

Cyclops is one genus of copepods named for the singular red or black eye. The eye is very simple, only able to detect light differentiation and not image detection. Rather than rely on the eye, the more complex antennae are the main sensory organs of plantonic copepods. They detect gravitational and inertial forces to help sense disturbances within the water generated by predators and prey. Their movements within the water are a characteristic jerking movement.