The Autecology of Eudiaptomus cf drieschi (Poppe & Mrazek 1895 ...

2.4. Experimental Studies
2.4.1. Development
E. drieschi was collected from the lake (in the vicinity of Station F)
by 5 minute, horizontal plankton net (500 m mesh) tows from the RV Hermona .
Mature adults were individually selected using a modified Pasteur pipette attached to
flexible tubing and controlled by mouth. Animals were maintained in 1liter vessels with
filtered lake water (0.45 m) under controlled laboratory conditions. Prior to each
experiment, animals were incubated for at least one generation at treatment conditions
(temperature and light) and given food ad libitum. Food was a mixture
of the algae Chlamydomonas sp. and Rhodomonas sp. (0.6ml in a 1 : 1 ratio) obtained
from stock cultures maintained at the Kinneret Limnological Laboratory.
Length measurements
Body length measurements of E. drieschi were obtained by using a computer
assisted video camera system, CAPAS (Computer Assisted Plankton Assessment
System, (Hambright 1996) with an inverted microscope. The system was calibrated with
a Wild stage micrometer for 500 m (+ 0.15). Copepods were pipetted into 5 ml.
phytoplankton settling chambers (Hydro-Bios, Kiel), and copepod lengths were
measured from the top of the head to the end of the anal somite (excluding the caudal
ramus). The setae were excluded in the naplii length measurements. Although the sex
can be distinguished at developmental stage CIV, males and females were only counted
as such after they had completed the CV molt. At least 50 individuals of each life stage
were measured.