PHOTOPERIODIC CONTROL OF DIAPAUSE IN THE MARINE CALANOID COPEPODLABIDOCERA AESTIVA

Abstract

The calanoid copepod L. aestiva was reared in the laboratory at 15.degree. C. Individuals which developed under a photoperiod regime of 18L[light]:16D[dark] produced subitaneous eggs; copepods exposed to a short-day regime of 8L:16D produced mostly diapause eggs. The results indicate that photoperiod is an important factor controlling the life cycle of L. aestiva. In Vineyard Sound, Massachusetts [USA], this species probably produces subitaneous eggs during the summer in response to long daylengths, and in the fall produces mostly diapause eggs in response to short daylengths.