Social life and sanitary risks: evolutionary and current ecological conditions determine waste management in leaf-cutting ants
FARJI-BRENER, ALEJANDRO G; ELIZALDE, LUCIANA; FERNANDEZ MARIN, HERMOGENES; AMADOR VARGAS, SABRINA
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES B-CONTAINING PAPERS OF ABIOLOGICAL CHARACTER
Lugar: Londres; Año: 2016 vol. 283
Adequate waste management is vital for the success of social life, becausewaste accumulation increases sanitary risks in dense societies. We exploredwhy different leaf-cutting ants (LCA) species locate their waste in internalnest chambers or external piles, including ecological context and accountingfor phylogenetic relations. We propose that waste location depends onwhether the environmental conditions enhance or reduce the risk of infection.We obtained the geographical range, habitat and refuse location of LCA frompublished literature, and experimentally determined whether pathogens onant waste survived to the high soil temperatures typical of xeric habitats.The habitat of the LCA determined waste location after phylogenetic correction:species with external waste piles mainly occur in xeric environments,whereas those with internalwaste chambers mainly inhabit more humid habitats.The ancestral reconstruction suggests that dumping waste externally isless derived than digging waste nest chambers. Empirical results showedthat high soil surface temperatures reduce pathogen prevalence from LCAwaste.We proposed that LCA living in environments unfavourable for pathogens(i.e. xeric habitats) avoid digging costs by dumping the refuse aboveground. Conversely, in environments suitable for pathogens, LCA speciesprevent the spread of diseases by storing waste underground, presumably, abehaviour that contributed to the colonization of humid habitats. These resultshighlight the adaptation of organisms to the hygienic challenges of socialliving, and illustrate how sanitary behaviours can result from a combinationof evolutionary history and current environmental conditions.