Clocks for sex: loss of circadian rhythms in ants after mating?

Abstract

This paper describes experiments on the locomotor activity rhythm of queens of the ant species Camponotus compressus, which were performed to investigate the consequences of mating on circadian clocks. Locomotor activity rhythm of virgin and mated queens was monitored individually under constant conditions of the laboratory. The locomotor activity rhythm of virgin queens entrained to a 24 h (12:12 h) laboratory light/dark (LD) cycle and free-ran under constant dim red light (RR) with a free-running period ( tau) of approximately 24 h. The locomotor activity of the mated queens on the other hand was arrhythmic during the period when they were laying eggs, and robust rhythmicity appeared soon after the egg-laying phase was over. The tau of the locomotor activity rhythm of mated queens was significantly greater than that of virgin queens. These results are contrary to the commonly held belief that the role of circadian clocks in ant queens ceases after mating flights, thus suggesting that circadian clocks of ant queens are adaptively plastic and display activity patterns, perhaps depending on their physiological state and tasks in the colony.

Circadian consequences of social organization in the ant species Camponotus compressus

“…Previous reports claim that, in sharp contrast to the virgin queens, the mated queens do not show any rhythmicity of activity (McCluskey 1992). In one of our previous experiments we had reported that during such arrhythmicity the mated queens laid eggs, and displayed robust circadian rhythmicity in some other phenomena such as brood care, and the circadian rhythm of locomotor activity reappeared as soon as the egg-laying phase was over (Sharma et al 2004b). It appears that the apparent loss of circadian rhythms might not be due to arrhythmic circadian clocks, but due to loss of coupling between activity and the circadian clocks (Sharma et al 2004b).…”

“…The periodicity of the locomotor activity rhythm was estimated by subjecting the primary data to Fourier spectral analysis (Sharma et al 2004b). The t of the locomotor activity rhythm in the two steady states of the media workers was subjected to mixed-model analysis of variance (ANOVA).…”

Cuticular lipid profiles of fertile and non-fertile Cardiocondyla ant queens

“…Shortly after mating, however, they become unattractive to males, shed their wings, and try to hide. Their activity cycles and phototactic behavior change substantially (Sharma et al, 2004;Lone et al, 2012). This is accompanied by immediate alterations of their cuticular profiles, which might make them unattractive to males (Oppelt and Heinze, 2009) or modify the physico-chemical properties of cuticular waxes to adjust to a life in a more humid place in the ground (Johnson and Gibbs, 2004;Hora et al, 2008).…”

Animal activity around the clock with no overt circadian rhythms: patterns, mechanisms and adaptive value

“…Egg-laying queens of ants [49,50] and honeybees [51,52] are active around the clock with no circadian rhythms. This pattern of activity may be related to the remarkable fecundity of these queens, which are typically not engaged in brood care.…”