Ecological Associations of Oecophylla smaragdina with Tree and Climber Species and their Seasonal Dynamics in Mayiladuthurai and Cuddalore Districts, Tamil Nadu, India

The Asian weaver ant Oecophylla smaragdina is an ecologically important arboreal species known for its complex nest building behaviour and role in natural pest regulation. The present study investigates the ecological associations, seasonal dynamics, and host plant preferences of O. smaragdina across Mayiladuthurai and Cuddalore districts of Tamil Nadu, India, over two consecutive years twice a monthly. Systematic monthly surveys were conducted to record nest presence on tree, shrub, climber, and parasitic plant species, and seasonal and inter-annual variations were analysed. A total of 41 plant species belonging to 24 families were documented as nesting substrates, with Mayiladuthurai exhibiting higher host plant diversity, while Cuddalore consistently recorded greater nest abundance, indicating higher habitat suitability. Nest presence showed marked seasonal variation, with peak occurrence during summer months (March–May) and a decline during post-monsoon and winter periods. Inter-annual comparison revealed increased nesting activity in 2024, suggesting colony stabilization under may be favourable environmental conditions. Weaver ants showed a strong preference for evergreen and broad-leaved host plants, particularly members of Anacardiaceae, Moraceae, and Menispermaceae. The findings highlight the importance of vegetation structure, seasonal climate, and floristic composition in shaping weaver ant nesting dynamics and underscore the potential of O. smaragdina as a natural biological control agent in tropical agroecosystems.