The moult cycle of Jasus lalandii (H. Milne Edwards, 1837) (Decapoda, Palinuridae), a cold water spiny lobster species: changes in ecdysteroid titre and setogenesis

Abstract

The moult cycle of the South African spiny lobster Jasus lalandii (H. Milne Edwards, 1837) was investigated with respect to ecdysteroid concentration in the haemolymph and morphological changes evident in pleopods of individual adult specimens. The morphological changes (observed by light microscopy) in pleopods from the adult specimens are clearly different to those previously published for juvenile J. lalandii, and thereby, alters the interpretation of moult stages. The repeated simultaneous sampling of haemolymph (for measuring 20-hydroxyecdysone via an enzyme-immunoassay) and a pleopod from captive specimens, allow for determining the underlying endocrine activity at each moult stage and a conservative estimate of the duration of some of the moult stages. The resulting pattern suggests that adult J. lalandii may spend more time in premoult than in intermoult, thus hinting that these cold water spiny lobsters may not have a terminal moult. Finally, not all hormonal changes are reflected by morphological changes.