RHYTHMS AND OTHER BIOLOGY OF 
THE GIANT TROPICAL ANT PARAPONERA 1 
By Elwood S. McCluskey 2 and William L. Brown, Jr. 3 
Introduction and Field Rhythm 
In January, i960, the authors were associated in a survey of the 
ants of Barro Colorado Island, Canal Zone. A nest of Paraponera 
clavata (Formicidae: Ponerinae: Ectatommini) was located at the 
base of a i-dm tree by a flashlight search of trees after dark. One 
of us (ESM) studied the rhythmic activity of ants from this nest in 
the field, then later in the laboratory. There have not been many 
laboratory studies of rhythms in social insects. This makes it impor- 
tant to present the results here, even though only a limited number 
of ants could be observed. 
Near dusk, workers were seen in the entrance of the nest. They 
soon began emerging, so that by the time it became almost too dark 
to see, a good column extended a meter up the trunk and from there 
along a vine to adjacent saplings. Night counts were made by dim 
red flashlight. Figure 1 shows the number out on the trunk and vine 
within 2 m of the nest, as well as the number per minute passing a 
given point on the vine. Foraging apparently continued through the 
night, though no observations were made from 0100 through 0500. 
By an hour or so after dawn the number of workers out had dropped 
to zero, and only rarely was one seen until the next dusk. 
One male appeared in the entry one evening at 1830 just before it 
became too dark to see in without a light. Winged females were seen 
elsewhere at a light at night. Bequaert (1926) says “the males ap- 
pear to be nocturnal and are frequently attracted by artificial light.” 
We knew the reputation of this ant as a fierce stinger (see Her- 
mann and Blum, 1966, for review). Nevertheless, one of us (ESM) 
got stung one evening while kneeling beside the nest making counts. 
The sting entered the leg below the knee through the stretched cloth 
of field trousers, and for the next two hours the leg felt as though 
it had been struck by a heavy club. 
Culture and Other Observations 
Later we dug out the nest under the base of the tree to a. depth of 
An abstract of a part of this work was given by McCluskey (1964). 
departments of Physiology and of Biology, Loma Linda University, 
Loma Linda, CA 92354 
department of Entomology, Cornell University, Ithaca, N.Y. 14850 
Manuscript received by the editor November IS, 1972 
335 
