1972] 
McCluskey & Brown — Paraponera 
34i 
ing the dark hours and continuously during the constant darkness 
(DD) that followed the days of alternating light and darkness 
(LD). Counts were not begun until the ants had been installed for 
at least a day, as well as in the appropriate LD cycle for many days. 
Ants were placed in a circle of clear plastic tubing that included 
at one point a clear plastic chamber with cotton-plugged test tubes 
of water and of sugar water inverted through its roof. The cham- 
ber, with tubes, was covered with an orange plexiglass box to simu- 
late the darkness of a natural nest (McCluskey, 1963). An adjacent 
capacitance-operated relay recorded each pass of an ant through a 
certain point (“tunnel”) in the circle of tubing. 
In these LD conditions a group of three males in one unit dis- 
played a prominent activity rhythm, the highest counts being in the 
first part of the dark period (Fig. 3 and 5A). Another counter 
assembly became available to obtain records for a single winged fe- 
male simultaneous with the last day of LD for the males (Fig. 3). 
There was almost no female activity during the middle of the light 
period, as shown more fully later (Fig. 5B). The rhythms of the 
males and of the female both appeared to persist for several days of 
DD following ( Fig, 3 ) . Then the light was turned back on once for 
12 hours but 2000-0800 instead of 0800-2000 as during the LD 
before DD. What appears to be a corresponding shift in phase of 
the ant rhythms is seen; e.g., the original “daytime” lows now be- 
came the highs. 
Nearly a month later it was possible to get a more complete LD 
record followed by another DD series for the same female (Fig. 4). 
In this case spot eye observations of the activity level were made 
also, shown by the curve under the histogram. This rhythm is seen 
to be a close match for the machine-monitored one. The highest 
activity occurred before and after dawn and dusk, with no activity 
during midday. Again there was evidence for persistence of rhythm 
Fig. 3. Persistence of rhythm in male and in female in DD. Number 
of passes per hour (4-hr ,ave) through tunnel. One group of 3 males in 
a nest, 1 winged female in another unit. Successive days shown one be- 
low the other: LD, days preceding and including Feb. 8; DD, Feb. 9-12 
and 15-18; hours of light shown by open bars Feb. 8 (0800-2000) and 
Feb. 13 (2000) -14 (0800). Dawn line (solid) and dusk line (dashed) 
are continued down through days of DD merely as a point of reference. 
The LD high of males at beginning of night seems to persist in DD, with 
a shift to morning after exposure to light through night of Feb. 13-14. 
The characteristic morning drop in LD activity of female (see also Fig. 
5B) seems to persist here in DD, with a shift to evening drops after the 
night light Feb. 13-14. 
