Effects of food quality and quantity on the survival, development, and egg production of Gladioferens pectinatus (Brady) (Copepoda : Calanoida)

Abstract

Effects of food quality and quantity on certain fitness traits of G. pectrnatus were examined to develop methods of culture. Five generations were successfully reared on excess Isochrysis galbana, despite intense inbreeding. The effect of food quantity was tested using outcrossed offspring fed I. Galbana at four concentrations. Generation time (from hatching to egg) decreased from 43.2 days at 1 × 10⁴ cells ml^-1 (lowest concentration) to 19.6 days at 5 × 10⁵ cells ml^-1 (highest concentration). An increase occurred in female body length (0.88 to 1.01 mm) and egg number (21.2 to 51.3) with increasing food concentration, and the total number of adults produced per brood was significantly lower at 1 × 10⁴ cells ml^-1. Results on a Dunaliella tertiolecta diet were similar to those for I. Galbana at the one food concentration tested (1 × 10⁵-2 × 10⁵ cells ml^-1); however, unlike I. galbana, D. tertiolecta did not sustain viable egg production and was therefore nutritionally inadequate for multiple generation culture. Larval mortality was high on diets of Tetraselmis chuii and Phaeodactylum tricornutum. Body lengths and egg numbers of cultured females fed I. Galbana were greater than those of the 'wild' parental females, thus indicating the suitability of the culture conditions.