How do brine shrimps mate?

Brine shrimps engage in a unique form of reproduction called cyclic parthenogenesis, alternating between asexual and sexual modes of reproduction depending on environmental conditions. Let's explore how they mate during the sexual phase:

1. Environmental Trigger:

- Environmental factors such as changes in salinity or temperature can induce male and female brine shrimps to develop and prepare for mating.

2. Male and Female Development:

- During the sexual phase, male and female brine shrimps emerge. The males are typically smaller than the females and have modified antennae for grasping.

3. Mating Pairs:

- Male brine shrimps actively search for females. When males encounter females, they attempt to grasp the female's body using their antennae.

4. Copulation:

- Once the male successfully grasps the female, the pair engages in copulation. The male transfers his sperm to the female's oviduct.

5. Internal Fertilization:

- Fertilization occurs internally within the female's body. The fertilized eggs, known as cysts or dormant embryos, develop inside the female's brood pouch.

6. Release of Cysts:

- The female carries the fertilized cysts until the environmental conditions become unfavorable. She then releases the cysts into the water.

7. Cyst Development:

- The released cysts can survive harsh environmental conditions, such as extreme temperatures, salinity fluctuations, and desiccation.

8. Hatching:

- When favorable conditions return, the cysts hatch, releasing nauplii, the first larval stage of brine shrimps.

9. Life Cycle:

- The nauplii grow through several molting stages until they reach maturity. If conditions remain suitable, they continue their asexual reproductive cycle, producing offspring genetically identical to the parent.

10. Return to Asexual Reproduction:

- When environmental conditions deteriorate again, brine shrimps may revert to asexual reproduction (parthenogenesis).

It's worth noting that brine shrimps can reproduce asexually for several generations before transitioning to the sexual phase when environmental cues dictate the need for genetic diversity and resilience. This versatile reproductive strategy allows brine shrimps to survive and thrive in varying habitats, contributing to their success and widespread distribution in saline waters.