Green Cyclops
Megacyclops viridis
The Green Cyclops is one of the largest and most common representatives of cyclopoid copepods in Central Europe. It inhabits almost all types of standing waters, from small puddles to the littoral zones of large lakes. The species is known for its characteristic jerky swimming style and its predatory diet. Megacyclops viridis shows a high tolerance to various environmental conditions and is often found year-round.
Details
Identification
Robust, pear-shaped body; first antennae short (barely reaching the end of the first body segment); females with two laterally protruding egg sacs; often greenish or brownish coloration.
Social behavior
Predominantly solitary, but can occur in high densities when food supply is abundant.
Diet
Predatory lifestyle; feeds on rotifers, small crustaceans, protozoa, and occasionally fish larvae or algae.
Hunting strategy
Active ambush predator that seizes prey with its mouthparts as soon as it swims within reach.
Spawning substrate
Eggs are carried in egg sacs directly on the female's body.
Overwintering
Overwintering as adults or in late copepodid stages, often in the sediment or deeper water layers.
Ecology
Ecological role
Important link between microzooplankton and higher trophic levels such as fish.
Natural predators
Juvenile fish, predatory insect larvae (e.g., dragonfly larvae), water mites, and other larger zooplankton.
Competitor species
Other large cyclopoid species such as Macrocyclops albidus.
Ecosystem service
Regulation of smaller zooplankton populations and contribution to the nutrient cycle.
Threats
Input of insecticides into water bodies, extreme acidification, and habitat loss through drainage.
Scientific profile
Profile
Distinguishing features
Largest native species of the Cyclopidae family. The 5th leg is two-segmented, with the distal segment bearing two strong spines of approximately equal length. The caudal rami are usually 3 to 4 times as long as wide and feature fine hairs on the inner margins. The first antenna consists of 17 segments.
Reproduction
Exclusively sexual reproduction. Females carry two laterally arranged egg sacs. Development proceeds through 6 naupliar and 5 copepodid stages to the adult.
Role in food web
Important secondary consumer and predator in the littoral food web; regulates microcrustacean populations and serves as an energy-rich food source for higher trophic levels.
Protection & threats
Status not on standard scale
Main threats
Loss of small water bodies through drainage, destruction of littoral vegetation (weed removal), and excessive input of insecticides from agriculture.