Rotifera Life Cycle

Benefits

• Scientists enjoy studying rotifers for many reasons, including their variation, ability to withstand radiation and ability to grow easily in laboratory settings. Additionally, some rotifers can withstand arid conditions. Because of the rotifer's ability to digest organic materials, scientists see potential in the rotifer's potential to clean up sewage plants and other contaminated water sources.
  
  

About Parthenogenesis

• Some rotifers reproduce asexually; that is, they do not need to combine genetic material with other rotifers in order to reproduce. The female lays eggs, which develop genetically identical to the mother. There are no male rotifers when rotifers reproduce parthenogenetically, or asexually.
  
  

Mixed Reproduction

• The seisonid rotifers reproduce sexually, and the bdelloid rotifers reproduce asexually. Monogonont rotifers have asexual and sexual portions of the life cycle: Some species of rotifers, when there are crowding conditions, reproduce sexually; that is they combine their own genetic material with the material of other rotifers to complete a new generation.
  
  

Environmental Influences

• Sexual reproduction in rotifers may be the result of a chemical response given off by rotifers in response to crowding. Scientists are currently studying whether sexually produced eggs are more viable when food is scarce. In one rotifer study, scientists examined whether small males, called dwarves, may form as an adaptive response to stressors such as lack of food in the environment.
  
  

Fertilization and Development

• The male fertilizes the female internally, and then eggs are laid in the water, or they are laid on a crustacean host, or they stay attached to the mother. In dry conditions, some eggs develop a tough shell, and they hatch again when water is present. Rotifer eggs either develop into adult males and females, or, if they are not fertilized, they develop into males that are smaller in stature, called dwarves, and do not live as long. Male dwarves are, however, able to fertilize sexually reproducing females.
  
  

Anatomy

• When the rotifers move, they use the cilia on the head to move around, with help from its foot to propel it along. In dangerous situations, the rotifer is able to move quickly using its fins. Rotifers may feed on the bacteria or other small organic matter suspended in water. Rotifers may even eat smaller rotifers.