Observations on the swarming habits and lunar periodicity of Platynereis sp. from the Madras harbour

Abstract

Heteronereids of Platynereis sp. swarm in the Madras Harbour during the new moon in the months of March, June and September. An interval of three lunar months is observed between successive swarms. Swarming takes place in the night, between 7 and 10p.m. corresponding to the period of maximum high tide; it may occur on the new moon night as well as on one night previous or after. The Heteronereids are described; they appear to be different from the species of Platynereis already known from. India. The behaviour of the worms during swarming, swarming periods and the records of observations are given in detail. The periodicity observed in this species is compared with other known instances, and the question of lunar periodicity in reproduction is discussed.