ABSTRACT
The mating systems of decapod crustaceans are reviewed and classified according to general patterns of lifestyles and male-female relations. The scheme employs criteria that focus on ecological, life history, and social determinants of both male and female behavior, and by these criteria nine types of mating systems are distinguished: (1) Short courtship: Both males and females are free-living (= not symbiotic with other organisms), and copulation occurs after brief behavioral interactions between a male and a female. (2) Precopulatory guarding: A male guards a mature female one to several days before copulation; both males and females are generally free-living. (3) Podding: In some largesize decapods, aggregations consisting of an extremely large number of individuals are formed, and mating occurs inside those aggregations. (4) Pair-bonding: In many symbiotic and some free-living species, males and females are found in a heterosexual pair and are regarded as having a monogamous mating system. They may live on or inside other organisms such as sponges, corals, molluscs, polychaetes, sea urchins, ascidians, and algal tubes. (5) Eusocial: In some sponge-dwelling snapping shrimps, a colony of shrimps contains a single reproductive female and many small individuals that apparently never breed. (6) Waving display: In many intertidal and semi-terrestrial crabs inhabiting mudflats or sandy beaches, males conduct visual displays that include species-specific dances to attract females. (7) Visiting: In some hapalocarcinid crabs, females are sealed inside a coral gall, and the male crab normally residing outside the gall is assumed to visit the gall for mating. (8) Reproductive swarm: In some pinnotherid crabs, mating occurs when a female is a free-swimming instar before she enters her definitive host. (9) Dwarf male mating: In some anomuran sand crabs, an extremely small male attaches near the gonopore of a free-living female.
