Effects of genetic relatedness, spatial distance, and context on intraspecific aggression in the red wood ant Formica pratensis (Hymenoptera: Formicidae)

Abstract

In the present study, we tested the level of aggression of monodomous and polydomous colonies of the wood ant Formicapratensis (Hymenoptera: Formicidae) with a behavioral assay in nature and laboratory conditions to see if the ants from neighboringcolonies are more tolerant or more aggressive to each other than those from greater distances. We also tested how context (nature andlaboratory conditions) affected aggression. Our results showed that the monodomous colonies were highly aggressive to all neighboringor nonneighboring conspecifics in nature irrespective of the spatial distance. The polydomous colony showed no aggression towardsneighboring conspecifics but the level of aggression increased with increasing spatial distance between the colonies. The level of aggressionof tested colonies in laboratory conditions was significantly low, irrespective of whether they were monodomous or polydomous,indicating that aggression is context dependent. A DNA barcoding technique based on mitochondrial COI gene sequencing was appliedto determine the genetic relatedness between the colonies. The results of the genetic analysis, in combination with results of behavioralassays, revealed that aggression behavior of the polydomous colony was affected by both the genetic relatedness and the spatial distancebetween the colonies while there was no clear separation of effects of genetic relatedness and spatial distance on aggression in themonodomous colonies.