Which crustaceans can reproduce without fertilization?

While most crustaceans are dioecious (having separate sexes) and reproduce through the fusion of sperm and egg, some species are parthenogenetic, meaning they produce eggs that develop without fertilization by sperm.12

Groups of crustaceans known to include species that reproduce parthenogenetically include:

• Branchiopods: This group, which includes water fleas (cladocerans) and fairy shrimp, shows a wide variety of reproductive habits. Many branchiopods can produce eggs that develop into females without the need for males.123
• Ostracods: Also known as seed shrimp, many species within this group reproduce parthenogenetically. Some experts suggest that in certain species, this may be the only method of reproduction employed, even when functional males are present in the population.12
• Isopods: Certain members of this order are also capable of parthenogenesis.1

In some species, such as certain water fleas, this process is part of a cycle where generations produced from unfertilized eggs alternate with those produced from fertilized eggs, often in response to environmental changes like temperature or food availability.34