Preliminary data on egg production rates of Pseudocyclops xiphophorus Wells, 1967 from the brackish lake Faro (north-eastern Sicily)

Field and laboratory studies were carried out on the bentho-planktonic species P. xiphophorus Wells, 1967. This species was found in the Mediterranean Sea, in the brackish Lake Faro (north-eastern Sicily) for the first time. Specimens of P. xiphophorus were collected from November 2003 to September 2004. Immediately after sampling, all adult females were sorted and pipetted individually into 50 ml crystallizing dishes containing lake water and incubated at the same enviromental temperature, measured at the sampling time. After 24 h, the number of eggs produced by each female was counted to estimate in situ egg production rate. In the laboratory, groups of five couples of males and females were placed individually into 50 ml crystallizing dishes containing filtered sea water enriched with three phytoplankton species, Tetraselmis suecica, Pavlova lutheri, and Isochrysis galbana, given in excess concentrations. Groups of five replicates were incubated at three different temperatures, 16, 24, and 28 °C, for each replicate. Every couple was monitored daily during the entire life cycle to estimate egg production rate in relation to temperatures. In the laboratory, mean egg production rates per female per day for each group of couples exhibited a positive correlation with temperature that was recorded in in situ experiments as well.