Cyclopoids

Cyclopoids are copepods belonging to the order Cyclopoida, a diverse group of small crustaceans within the class Copepoda. They occur in a wide range of aquatic environments, including freshwater bodies such as ponds and rivers, as well as marine coastal waters and open oceans. Some species also inhabit moist sediments or semi-terrestrial habitats.

Free-living cyclopoids are an important part of aquatic food webs. They are typically omnivores or herbivores, feeding on microalgae, bacteria, and detritus, and some act as predators on small invertebrates. A number of species form parasitic or commensal relationships with hosts such as fish or invertebrates, attaching to surfaces or inhabiting bodily cavities. Because of their abundance, they are often a major source of prey for fish and other planktivores and contribute to nutrient cycling and energy transfer in aquatic ecosystems.

Life cycle and development follow the characteristic copepod pattern: development includes several naupliar and copepodite stages before reaching maturity. Eggs are usually carried by the female in a brood sac or attached egg sac until hatching. Reproduction is generally sexual, with males and females mating to produce offspring.

Morphology is generally small and compact, with a segmented body comprising a cephalothorax and abdomen, a pair of antennae, and several swimming leg pairs on the thorax. Size typically ranges from well under a millimeter to a few millimeters, varying by species.

Taxonomically, Cyclopoida is one of the principal copepod orders, alongside Calanoida and Harpacticoida, and includes a variety of free-living and, in some lineages, parasitic forms.