Lemon rotifer
Rotaria citrina
The lemon rotifer is a widespread inhabitant of freshwater bodies and damp mosses. It is characterized by its eponymous yellow to lemon-yellow coloration and a spindle-shaped, telescopically retractable body. The species belongs to the Bdelloidea group, which reproduces exclusively asexually via parthenogenesis and can survive extreme periods of drought through anhydrobiosis.
Details
Identification
Lemon-yellow body color, two red eyespots on the proboscis, two rotating wheel organs on the head, telescopic body with two toes on the foot.
Social behavior
Usually lives solitarily, but can occur in high individual densities in moss cushions or plankton under favorable conditions.
Diet
Feeds by swirling bacteria, unicellular algae, and fine organic detritus from the water column using its corona.
Hunting strategy
Passive filter feeder; creates a water current for food intake using the cilia of the wheel organs.
Spawning substrate
Substrate-bound or free-swimming; eggs are often deposited individually on aquatic plants or detritus.
Overwintering
Survival of extreme conditions (frost, drought) by forming a tun stage (anabiosis).
Ecology
Ecological role
Important component of the microbial loop; converts bacterial biomass for higher trophic levels.
Natural predators
Predatory rotifers (e.g., Asplanchna), small crustaceans (Cyclops), and fish larvae.
Competitor species
Other filter-feeding rotifers of the genera Philodina or Brachionus.
Ecosystem service
Contributes to the self-purification of water bodies by breaking down bacteria and organic suspended solids.
Threats
Severe chemical pollution of water bodies and complete destruction of small water bodies through drainage.
Scientific profile
Profile
Distinguishing features
Conspicuous yellow to lemon-yellow coloration of the entire body or internal organs. Possesses two red eyespots on the proboscis. The corona is well-developed with two trochal discs. The species is viviparous (gives birth to live young).
Reproduction
Exclusively obligate parthenogenesis; males do not exist within the Bdelloidea group. Embryos develop inside the mother (viviparity).
Role in food web
Primary consumer and important decomposer in the microbenthos; links bacterial production to higher trophic levels.
Protection & threats
Status not on standard scale
Main threats
Loss of small water bodies through drainage, intensive agricultural use of riparian zones, and severe chemical pollution (pesticides).