Herbivore damage to ferns caused by a chrysomelid beetle from Lower Gangetic Plains of West Bengal, India.
This paper records the occurrence of a polyphagous beetle, Schenklingia bhaumiki (Coleoptera: Chrysomelidae), feeding on ten fern species growing in the Lower Gangetic Plains of West Bengal, India viz., Christella dentata, Ampelopteris prolifera, Cyclosorus sp., Pteris vittata, Nephrolepis cordifolia, N. exaltata, Adiantum philippense, Drynaria propinqua, Pyrrosia adnascens and Phymatosorus scolopendria for the first time. The adult beetles are leaf surface scraper and skeletonize the lamina. The larvae are leaf miners and produce linear-blotch mines between the epidermal layers with continuous spiral black frass. Young leaves of all ten species of ferns are significantly less damaged than mature ones indicating that both the adults and the larvae attack leaves of all ages. Herbivore damage of the beetle infested ferns ranged from 1.94% to 25.47% and 2.68% to 54.86% for scraping feeding and mining feeding respectively. Among the host ferns, the members of Thelypteridaceae viz., Christella (Scraping feeding 25.47%; mining feeding 54.86%), Ampelopteris (Scraping feeding 24.10%; mining feeding 53.60%) and Cyclosorus (Scraping feeding 16.06%, mining feeding 27.12%) suffered maximum herbivore damage. Interspecific variation of plant size and biogeographic range of the fern species are not related to herbivore damage. Insects may perhaps attack fewer ferns than angiosperms, but there is no evidence that ferns are generally less damaged than angiosperms.