Summer cyclops
Thermocyclops crassus
The summer cyclops is a planktonic copepod that primarily occurs in standing waters during the warm summer months. It is characterized by a pear-shaped body and its typical hopping movement. The species is an essential component of limnic zooplankton and serves as an important food source for juvenile fish.
Details
Identification
Short first antennae not extending beyond the first thoracic segment; specific structure of the furcal rami.
Social behavior
Mostly solitary in the pelagic zone, but can reach high individual densities during algal blooms.
Diet
Omnivorous diet consisting of phytoplankton, protozoa, bacteria, and organic detritus.
Hunting strategy
Filtering and raptorial feeding from the open water.
Spawning substrate
No substrate; eggs are carried in sacs attached to the body.
Overwintering
Overwintering in the sediment as a diapause stage (Copepodid IV or V).
Ecology
Ecological role
Important primary consumer and transfer of energy to higher trophic levels.
Natural predators
Planktivorous fish, phantom midge larvae (Chaoborus), and predatory water fleas.
Competitor species
Other cyclopoids and Daphnia species.
Ecosystem service
Contributes to the self-purification of water bodies by consuming algae and bacteria.
Threats
Excessive eutrophication, pesticide pollution, and climate change (extreme heat).
Scientific profile
Profile
Distinguishing features
Characterized by short caudal rami (length-to-width ratio approx. 2.0-2.5). The terminal segment of the endopod of the 4th swimming leg (P4) bears two apical spines, with the inner one being significantly longer than the outer one. The seminal receptacle of the female has a typical T-shape with wide lateral expansions. The ornamentation of the connecting plates of the swimming legs is species-specific.
Reproduction
Exclusively sexual reproduction. Females carry two symmetrical egg sacs laterally on the urosome. Development proceeds through six naupliar and five copepodid stages.
Role in food web
Important link in the pelagic food web; transfers energy from primary production and the microbial loop to higher trophic levels (secondary consumers).
Protection & threats
Status not on standard scale
Main threats
No known threats at present; the species tends to benefit from anthropogenic eutrophication and global warming.