Photoperiodic and Ecdysial Control of Vitellogenesis in Lobsters (Homarus) (Decapoda, Nephropidae)

The timing of molts and of subsequent egg extrusion by female American lobsters (Homarus americanus) in the laboratory under near-ambient conditions at Bodega Bay suggested that final vitellogenesis was initiated only during the months between the vernal and autumnal equinoxes. In an experiment, the change from short-day (LD 8:16) to long-day (LD 16:8) photoperiod (long-day onset, LDO) began a 120-d period during which vitellogenesis could be initiated. Molting within this 120-d period was associated with a delay of as much as 80 d in the time of subsequent extrusion.