1 Department of Bioscience - Soil Fauna Ecology and Ecotoxicology, Department of Bioscience, Science and Technology, Aarhus University2 Department of Bioscience - Plant and Insect Ecology, Department of Bioscience, Science and Technology, Aarhus University3 Department of Bioscience - Plant and Insect Ecology, Department of Bioscience, Science and Technology, Aarhus University
Weaver ants (Oecophylla spp.) are managed in tropical plantations for their biocontrol of pests and to produce ant larvae as a food source. Main management objectives are to increase ant densities and colony longevity. As weaver ant nests are susceptible to harsh weather, rain storms may decimate populations or destroy colonies. The ants, however, show adaptive nesting behavior, which may mitigate storm impact. This study tested whether Oecophylla smaragdina was willing to use plastic bottles as safe artificial nesting sites, and whether adoption of artificial nests was seasonally related to harsh weather. Bottles were used for nesting throughout the stormy rainy season in a pomelo plantation with an open canopy, whereas in a mango plantation with a denser canopy the ants, after initial colonisation, left the bottles again at the end of the rainy season, especially in the calmer part of the plantation. This suggests that exposure to harsh weather triggered the use of artificial nests. It was also found that ants preferred to nest in bottles covered with aluminum foil compared to transparent bottles. These findings document an opportunistic nesting behavior of weaver ants and suggest that provision of artificial nests may become a future tool in their management.