How to coexist with fire ants: The roles of behaviour and cuticular compounds

tBecause territoriality is energetically costly, territorial animals frequently respond less aggressively toneighbours than to strangers, a reaction known as the “dear enemy phenomenon” (DEP). The contrary,the “nasty neighbour effect” (NNE), occurs mainly for group-living species defending resource-basedterritories. We studied the relationships between supercolonies of the pest fire ant Solenopsis saevissimaand eight ant species able to live in the vicinity of its nests plus Eciton burchellii, an army ant predatorof other ants. The workers from all of the eight ant species behaved submissively when confrontedwith S. saevissima (dominant) individuals, whereas the contrary was never true. Yet, S. saevissima weresubmissive towards E. burchellii workers. Both DEP and NNE were observed for the eight ant species, withsubmissive behaviours less frequent in the case of DEP. To distinguish what is due to chemical cues fromwhat can be attributed to behaviour, we extracted cuticular compounds from all of the nine ant speciescompared and transferred them onto a number of S. saevissima workers that were then confronted withuntreated conspecifics. The cuticular compounds from three species, particularly E. burchellii, triggeredgreater aggressiveness by S. saevissima workers, while those from the other species did not

Projet Référentiel Plancton de la Baie de Calvi : II. Diversité de l’écosystème planctonique de la Baie de Calvi

Ce rapport présente la diversité de l’écosystème planctonique de la Baie de Calvi. Le premier chapitre rappelle les principales définitions utilisées en écologie planctonique. La suite du texte présente les grands groupes planctoniques rencontrés en Baie de Calvi, leurs principales caractéristiques morphologiques et les grandes lignes de leur écologie. Le texte est illustré de photographies originales de microphytoplancton et de zooplancton de la Baie réalisées à STARESO par les auteurs