Ecology of the Nilgiri Large Burrowing Spider Haploclastus Nilgirinus Pocock, 1899 (Araneae, Theraphosidae) of Nilgiris, India

Abstract

The Nilgiri large burrowing spider, Haploclastus nilgirinus Pocock, 1899, an endemic tarantula in the Nilgiris Region of India, is critical for conservation yet poorly understood in terms of its ecology and habitat. This study addresses this gap by examining the nesting habits, tree-hole dynamics, and prey diversity of the species in Coonoor, The Nilgiris, specifically within tea plantations and fruit orchards. Observations focused on seven pear trees serving as nesting sites, with detailed measurements of nesting holes, including outer and inner circumference, depth, trunk base, ground-based height (gbh), and height from the ground. Data were collected over four consecutive months, both morning and evening. Insect diversity in the orchard was also assessed through counts and diversity indices, revealing variability among trees. The seventh tree had the highest spider population, with 13 spiders in 10 nests. Insect orders such as Blattodea, Orthoptera, Diptera, Hemiptera, and Lepidoptera were most prevalent around the seventh tree’s nests. Across all trees, a total of 25 spiders in 21 nests were documented, with variations in hole size and other tree measurements. This research provides crucial insights into the nesting habits, tree-hole dynamics, and prey diversity of this species, informing conservation efforts for this vulnerable species. As H. nilgirinus faces threats from habitat destruction, climate change, and illegal trade, understanding its ecological needs is vital for developing effective conservation strategies and sustaining ecosystem health.