Diet influence on egg production of the copepod Acartia tonsa (Dana, 1896)

Abstract

Egg production in the copepod Acartia tonsa was evaluated using different densities of the microalgae Thalassiosira weissflogii, Chaetoceros muelleri and Isochrysis galbana. Male and female were kept under controlled conditions (salinity 30, 20 • C, photoperiod 12L:12D), acclimated to the experimental conditions and left over a period of 24 h to allow copulation. Algal densities tested were equivalent in biovolume and corresponded to 0, 2.5, 5, 10, 20, 40 and 60.10 3 cells.mL −1 of T. weissflogii. Ten acclimated female were separated, transferred to glass bottles and exposed for further 24 h to the corresponding experimental medium. After this period, the eggs were fixed and counted. Copepod egg production reached a threshold value when T. weissflogii, C. muelleri and I. galbana were supplied at 10.10 3 , 140.10 3 and 640.10 3 cells.mL −1 , respectively. Mean egg production corresponded to 28.0 ± 0.5, 20.1 ± 1.0 and 22.0 ± 3.5 eggs.female −1 .day −1 , respectively. Copepods fed T. weissflogii showed the highest mean egg production while those fed I. galbana reached a maximum egg production when the algae were supplied at a density two-to fourfold higher, considering the biovolume of T. weissflogii and C. muelleri. These differences are explained considering the different sizes of the microalgae used to feed the copepods.

Spatio-temporal Variations of Abundance, Biomass, and Reproductive Parameters of Pseudodiaptomus hessei (Mrazek, 1895) (Copepoda Calanoida) in a West African Coastal Lagoon (Grand-Lahou, Cte dIvoire)

“…In this study, the effects of food on P. hessei reproductive parameters were not directly studied, but positive and significant relationship between reproductive characteristics (Fw, NEF, Gf, EPR, and PF) and nutrients (nitrite and phosphate) indirectly suggest that food affects P. hessei fecundity in Grand-Lahou Lagoon. Food (quality and quantity) limitation on other copepods and congeneric species abundance and reproduction is well documented (Sullivan and Banzon, 1990; (Acartia hudsonica), (Jara, 1998) (P. cokeri), (Teixeira et al, 2010) (Acartia tonsa), Jeyaraj and Santhanam (2012) and Santhanam et al (2013) (Paracalanus parvus) and (Noyon and Freneman, 2013) (P. hessei). There have been little information about the role of nutrient on P. hessei reproduction but, according to Jordan et al (1991), exogenous nutrient inputs from rainfall runoff may have a fertilizing effect on phytoplankton and can control temporal variations in standing stocks of phytoplankton in coastal environments.…”

Progeny Production of the Copepods Pseudodiaptomus euryhalinus and Tisbe monozota in Monospecific and Mixed Cultures

“…Feeding was with 320 cells/μL of Isochrysis sp. (T‐Iso strain), which was chosen because it is considered an effective diet for egg production in copepod cultures (Støttrup and Jensen ; Teixeira et al ). The cell concentration was determined with a haemocytometer and adjusted daily.…”

The False Problem of the Maintenance of Sex (Review of the Original Approach)

“…Indeed, there is a vast literature to support the direct relationship between resources and fecundity, as expected in the lowest range of habitat quality: in copepods [83] [85], in birds (clutch size) [86]- [92], in mammals such as the arctic fox [93] and the arctic squirrel [94]. Furthermore, the saturation curve in the relation between habitat quality/fecundity has been observed in copepod crustaceans [95], in Daphnia [96] and Paracalanus parvus [97] (the latter two also crustaceans).…”