Robust cyclops
Acanthocyclops robustus
Acanthocyclops robustus is a common cyclopoid copepod found primarily in eutrophic standing waters and slow-moving streams. It is characterized by a robust body shape and the presence of two lateral egg sacs in females. This species is known for its high tolerance to varying water qualities, including low oxygen levels. It serves a vital role in aquatic food webs as a predator of smaller planktonic organisms.
Details
Identification
Robust cephalothorax, specific spination on the terminal segments of swimming legs, 5th leg two-segmented with a short distal segment.
Social behavior
Solitary, but forms dense populations when food resources are abundant.
Diet
Predatory lifestyle; feeds on rotifers, other small crustaceans, protozoa, and detritus.
Hunting strategy
Ambush predator or active seizing of prey with maxillipeds upon contact.
Spawning substrate
Eggs are carried in paired sacs on the body until the nauplius larvae hatch.
Overwintering
Overwintering as adults or late copepodid stages within the sediment.
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), larger zooplankton.
Competitor species
Other Cyclops species such as Cyclops vicinus or Mesocyclops leuckarti.
Ecosystem service
Regulation of protozoan populations and contribution to nutrient cycling.
Threats
Severe chemical pollution of water bodies, invasive predatory species.
Scientific profile
Profile
Distinguishing features
Part of the Acanthocyclops vernalis-robustus complex. Characterized by 17-segmented first antennae. The terminal segment of the P4 endopod bears a spine on the outer margin (distinguishing it from A. vernalis). Furcal rami are approximately 3 to 4 times as long as wide and lack internal hairs.
Reproduction
Sexual reproduction; after mating, females develop two egg sacs attached to the first abdominal segment.