THE EFFECT OF TEMPERATURE ON THE DEVELOPMENT TIME OF EGGS OF THERMOCYCLOPS SP., A TROPICAL CYCLOPOID COPEPOD FROM LAKE GEORGE, UGANDA

Abstract

The rate of egg development in ThermocycZops sp., determined in the laboratory, increases linearly from 15-3OC. Above 32.5C development is retarded and, although eggs hatch at 356, the females die after some time at that temperature.At 4OC, mortality is 100% within 2 hr. The mean temperature of Lake George is computed to be 26.3C and, by extrapolation from the laboratory results, a mean development time of 36 hr is obtained. Both these means vary little throughout the year. From the work of others, it appears that the effect of temperature on egg development is similar in Mesocyclop~ Zeuckarti but less marked in several Calanoid copepods.

Errors in the estimation of recruitment of early stages of mesocyclops leuckarti (claus) caused by the diurnal periodicity of egg-production

“…This can be illustrated by the higher values of recruitment of eggs to the nauplii in comparison with the values of nauplii to copepodites, as recalculated from the data presented by Ravera (1954), according to the procedure utilized by Elster (1954 ;1955), Burgis (197,), found similar differences in the population of Thermocyclops hyalinus (Rehberg) in Lake George . The effect of temperature on the development time of cyclopoids was studied by Taube & Nauwerck (1967) and Burgis (1970) .…”

Seasonal variability of the embryonic development time of three planktonic crustaceans: dependence on temperature, adult size, and egg weight

“…The duration of embryonic development was determined at 2-to 4-week intervals using the method for rotifers (Edmondson, 1965) which has subsequently been successfully applied to copepods and cladocerans (Taube, 1966;Burgis, 1970;Munro, 1974;Gras & Saint-Jean, 1976;Meyers, 1984). Immediately after sampling, four series of 20 to 60 ovigerous females per species were individually transferred into culture tubes containing a food suspension (yeast cells for Daphnia, Stephanodiscus hantzschii for E. gracilis) at a concentration of 2 to 5 mg DW/I which was changed daily for Daphnia.…”

Effect of Insect Growth Regulator Dimilin® (TH 6040) on Fecundity and Egg Viability of the Marine Copepod Acartia tonsa

“…Females were allowed to lay eggs in 10 YW S for 4 h. From 65 to 335 eggs were incubated in 0.5, 1, 5, and 10 ppb Dimilin and 0.5 ppt acetone-SW solution at 25 "C. This experiment was duplicated and a total of 1615 eggs were observed 3 to 6 times each from the initiation of hatching to the time of 90 % + hatch in the controls. Time to 100 % hatch was predicted by a linear regression equation fitted to the data (Burgis, 1970).…”