Daily Rhythms in Social Activities of the Harvester Ant,Pogonomyrmex Badius

Daily cycles in behavior are well known throughout the animal kingdom.There is some evidence that the activities of ant colonies are temporally organized so that, at a given time of day, a certain set of tasks is done.This study explores that possibility by examining temporal patterns in the social behavior of the harvester ant, Pogonomyrmex badius.Such patterns should be distinguished from circadian rhythms to which conform endogenous, physiological events exhibited by individual animals (e.g.McCluskey 1958 and 1965).The present study is concerned with daily rhythms in social activities performed by groups of ants.Two questions are ad- dressed" 1) Are certain tasks performed at characteristic times of day? 2) How do activity rhythms vary among different colonies?There have been many studies of daily temporal patterns in the overall activity levels of ant colonies, measured as the numbers of ants entering or leaving the nest (Levieux and Diomande 1978a, Hunt 1974, Hansen 1978, Van Pelt 1966), or the numbers of ants in certain areas for specified durations (Janzen 1967, Levieux and Diomande 1978b, Levieux 1979a and 1979b, Golley and Gentry 1964).Temporal patterns of overall activity level are well docu- mented for several Pogonomyrmex species (H/511dobler 1970 and 1976a, Whitford and Ettershank 1975, Whitford et al. 1976).Some authors have described temporal patterns of selected social activities of various ant species (MiSglich and Alpert 1979, Janzen 1967, Levieux and Diomande 1978a and 1978b), including Pogonom.'rmex (Willard and Crowell 1965, Htlldobler 1976b).But, except for H tlldobler's (1976b) study of mating activity, the cited work pre- sents no systematic data on temporal patterns in behavior other than entering and leaving the nest.