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 Formica pratensis (Hymenoptera: Formicidae) with a behavioral assay in nature and laboratory conditions to see if the ants from neighboring colonies are more tolerant or more aggressive to each other than those from greater distances. We also tested how context (nature and laboratory conditions) affected aggression. Our results showed that the monodomous colonies were highly aggressive to all neighboring or nonneighboring conspecifics in nature irrespective of the spatial distance. The polydomous colony showed no aggression towards neighboring conspecifics but the level of aggression increased with increasing spatial distance between the colonies. The level of aggression of 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 applied to determine the genetic relatedness between the colonies. The results of the genetic analysis, in combination with results of behavioral assays, revealed that aggression behavior of the polydomous colony was affected by both the genetic relatedness and the spatial distance between the colonies while there was no clear separation of effects of genetic relatedness and spatial distance on aggression in the monodomous colonies.

Keywords: Context-dependent aggression, intraspecific aggression, social structure, dear enemy effect, nasty neighbor effect, DNA barcoding

Full Text: PDF