Structural specialities, curiosities and record-breaking features of crustacean reproduction

Crustaceans are a morphologically, physiologically and ecologically highly diverse animal group and correspondingly diverse are their reproductive characteristics. They have evolved structural specialities with respect to penis construction, sperm form, sperm storage, fertilization and brood care. Unique in the animal kingdom are safety lines that safeguard hatching and first molting. Further curiosities are dwarf males in parasitic and sessile taxa and bacteria-induced gigantism and infectious feminization in crustacean hosts. Record-breaking features in animals are relative penis length, clutch size, sperm size, chromosome number, viability of resting eggs, and fossil ages of penis, sperm and brooded embryos. These reproductive peculiarities are reviewed and their implication for basic and applied biology is discussed, including the early evolution and diversification of brood care in arthropods, sperm competition and assurance of paternity, posthumous paternity and sustainable male-based fishery, and ecotype changes by man-made pollution.