Dynamic changes in death cues modulate risks and rewards of corpse management in a social insect.

In social insects, the efficiency of exploitation of resources and colony defence are mediated by chemical communication. In colonies dependent on nutritionally limited resources, corpses represent both a food resource and a risk of pathogens. Because this risk vs. reward changes with time after death, behavioural plasticity in the response to corpses would be advantageous. How social insects regulate this trade-off remains unknown., We conducted quantitative behavioural bioassay and chemical analysis to study corpse management in the eastern subterranean termite, Reticulitermes flavipes. We hypothesized that R. flavipes responds differently towards corpses with prolonged post-mortem time, and this behavioural plasticity is mediated by the dynamic change in death cues., We show that R. flavipes uses a post-mortem signalling system that depends on an early death cue that stimulates corpse retrieval and cannibalism, and late death cues that stimulate recruitment and burial. A blend of 3-octanone and 3-octanol is released immediately after death, with the alcohol (possibly in conjunction with the ketone) playing a clear role as a death cue. This cue enables the colony to recycle nutrients before decomposition occurs and before risk of pathogens increases. The accumulation of late death cues, decomposition products shared by diverse arthropods, elicits a behavioural switch from cannibalism to burial., The ability to detect and respond to the dead is vital to group-living animals. Our study reveals a behavioural shift in corpse management triggered by the interplay of an early death cue and late death cues, which balances risks and rewards associated with corpses. The post-mortem chemical communication highlights the adaptation of a social insect to its ecological niche. [ABSTRACT FROM AUTHOR]