Differential Visitation of Non-Apis Bee Pollinators for Invasive over Non-Invasive Plants: A Case Study from the Kole Ramsar site, Kerala, India

Abstract

The present work investigated the pollination preferences of non-Apis bees in the Kole wetlands of Thrissur, Kerala. The twelve-month study (May 2024 to April 2025) was conducted across six different sites within the Thrissur Kole wetlands. The association between non-Apis bees and flowering plants of the Asteraceae family was specifically examined. A total of 13 non-Apis bee species belonging to eight genera and two families were recorded from seven flowering plants. Among the seven plants, three were non-invasive, and four were invasive. The bee family Halictidae was predominant, accounting for seven species under five genera, followed by Apidae, with six species under three genera. The genus Ceratina dominated the collection and was associated with a larger number of Asteraceae plants. High species abundance was recorded on Mikania micrantha between December 2024 and February 2025. Overall, significantly higher bee species richness and abundance were recorded from the invasive plants compared to the non-invasive plants. This differential visitation is due to phenology, flower colour, abundance of flowers in the invasive plants, and their rich rewards, such as abundant nectar, pollen, and long-lasting flowers that attract adapted pollinators. Increased pollinator attraction to invasive species can intensify their ecological impacts, thereby altering native plant communities, pollinator behaviors, and overall ecosystem balance of the Kole wetlands.