Byers, J.A. 1987b. Novel fraction collector for studying the
oviposition rhythm in the turnip moth. Chronobiology
Turnip moths, Agrotis segetum (Schiff.) (Lepidoptera: Noctuidae), were
held in a transparent plastic box with a window opening to a rotating
paper drum upon which the females could lay eggs. A novel fraction
collector, consisting of a standard 24-hr wall timer and simple
electronic circuit, served to rotate the paper in hourly increments.
The entire apparatus was housed in an environmental chamber on a 16
hr light : 8 hr dark photoperiod at constant 23.7 degrees C and 55%
r.h. Under these conditions a circadian rhythm of egg laying was
indicated with a mean activity time 0.2 hr before dark and standard
deviation of 2.1 hr. The relative egg productions during the second
to seventh day of oviposition peaked on the third day. Differences in
the circadian rhythms of mating and oviposition are considered in
terms of ecological fitness.
Figure 1. Schematic circuit of the fraction collector timer (with the 24-hr wall timer),
test-tube position sensor and motor turn-on interval control. Integrated circuits (IC)
1 and 2 have +12 V (DC) applied to pins 14 and 16, respectively, and ground at pins 7 and 8,
respectively. All resistors are 0.25 W. CMOS integrated circuits should not be inserted into their
sockets until all connections have been made.