X. Irigoien et al., The effect of food on the determination of sex ratio in Calanus spp.: evidence from experimental studies and field data, ICES J MAR, 57(6), 2000, pp. 1752-1763
The effect of food concentration on the sex ratio in Calanus spp, has been
investigated in laboratory and mesocosm experiments. The results of the exp
eriments are compared with time series in the field and with physiological
rates. The food concentration and quality had an effect on the sex ratio of
adult Calanus, with higher percentages of males obtained with increased fo
od concentration. Laboratory experiments and field time series suggest that
sex can still change at stage CIII-CIV, but is determined at stage CV. The
energy budget of males was very unbalanced, suggesting that the shorter li
fespan often reported could be due to exhaustion of lipid stores.