Diversity of spiders (Arachnida: Araneae) in natural and altered ecosystems in Salem district, Tamil Nadu, India

A detailed investigation of the spider diversity in Salem district, Tamil Nadu was carried out across different habitats for a period of five years. A total of ۱۸۴ spider species belonging to ۹۷ genera in ۲۹ families were recorded, which represented nearly ۱۰% of Indian and ۶۵% of Tamil Nadu spider diversity. Among them ۲۵ spider species are endemic to India. From the ۲۹ families, the three most abundant families based on number of specimens sampled were Lycosidae (۲۱%), Araneidae (۱۸%), and Eresidae (۱۷%), constituting ۵۶% of the spider species. Simpson diversity indices ranged between ۰.۸۸ to ۰.۳۰ for all the studied habitats. The species richness was highest in bamboo fields (۲.۷۸), and the lowest was observed in grasslands (۰.۷۶). The highest abundance of spider species was observed in the sugarcane fields (۰.۸۳), followed by the grasslands (۰.۵۷) and paddy fields (۰.۵۳). Further, these spiders were categorised into ۹ types based on their foraging guilds. Among them, the highest species richness was observed in foliage runners. A maximum of nine spider guilds were observed in Shrub ecosystem. Natural ecosystems such as shrublands, treescapes, and grasslands had higher spider diversity than altered agricultural and domestic ecosystems. This is the first report on spider diversity in Salem District, Tamil Nadu revealing the varying spider diversity along with their guild types across different habitats.

Keywords:

Arachnida , ecosystem , guild , habitat , species diversity