Life Cycle
The reproduction plays a fundamental role in the distribution of the population in a specific geographic area, and in the successful continuity of the organisms. Mature males and females reproduce during the breeding season; such events vary among crabs depending on suitable factors. The eggs enter an incubation period which varies depending on species and other environmental factors such as temperature. After the incubation period, the females release the planktonic larvae into the planktonic community to complete their developmental stages and dispersal through the water column.
Crabs have two different forms of planktonic larvae, the first one called zoea and the second one called megalopa. Zoea is a shrimp-like creature with dorsal, vertical, and lateral spines in the carapace. Megalopa is a more crab-like structure with an extended abdomen. Generally, crabs have several zoeal stages followed by only one megalopa stage. Then megalopa trasforms to several crab instars depending on crab species before reaching the maturity stage.
Schematic diagram of the life cycle of a brachyuran crab (Al-Wazzan, 2017).
Zoea stage of different crabs found in Kuwaiti water.
Megalopa stage of different crabs found in Kuwaiti water.
Juveniles of the rocky shore crab Leptodius exaratus