Larval Performance of Amphidromous and Landlocked Atyid Shrimp Species in the Genus under Different Feeding Conditions.

Freshwater shrimps in the family Atyidae exhibit two life history traits: 1) amphidromy, with many small embryos hatching into planktotrophic larvae that develop in the sea, and 2) landlocked, with few large embryos hatching into non-feeding lecithotrophic larvae, or facultative lecithotrophic larvae that develop in freshwater. The lecithotrophy of larvae is considered an adaptation to limited food conditions in the freshwater environment. Furthermore, faster development and settlement behaviours that large larvae exhibit are considered adaptations that allow the larvae to stay in or near parental habitats in fast-flowing streams.

Sexual Dimorphism and Reproductive Status of the Red Swamp Crayfish .

The red swamp crayfish is native to northeastern Mexico and the south-central USA, and it has expanded its distribution worldwide and negatively impacted the ecosystems in the invaded regions. The dynamics of the populations have been studied as the basis for the development of effective control measures against this invasive alien species. Adult males of exhibit a cyclical dimorphism between two sexual morphotypes; reproductive form I has large chelae and non-reproductive form II has small chelae.