Arachnid Diversity Revisited: An Updated Checklist of Spiders (Araneae) from Dakshina Kannada District, Karnataka, India

Abstract

Background: Spiders play an indispensable role as natural regulators of insect populations, thereby maintaining ecological balance. Among these, spiders (order Araneae) represent one of the most diverse and ecologically significant groups, yet their study has often been marginalised due to research biases and a perceived lack of appeal. Aim: The present study aimed to document the taxonomic diversity and ecological guild structure of spiders (Araneae) across Dakshina Kannada District, Karnataka, India, highlighting their ecological roles and biogeographical distribution. Methodology: A three-year field survey employing systematic quadrat-based sampling and active search techniques was conducted to assess species richness, genus diversity, and functional guild composition. Sampling was carried out across seven taluks of Dakshina Kannada—Bantwal, Belthangady, Puttur, Mangalore, Moodabidri, Sulya, and Kadaba—including forest reserves and adjoining natural habitats, between September 2019 and September 2022. Specimens were collected using hand-picking, foliage beating, and ground-litter inspection, then preserved and identified to the adult stage using standard taxonomic keys and the World Spider Catalogue. Field photography supported morphological documentation. Data analysis focused on species richness, genus diversity, infraorder representation, and ecological guild classification (e.g., ambush hunters, web-builders, active hunters, and burrowers). Results: A total of 179 genera in 25 families of Araneomorphae, along with three families and six genera of Mygalomorphae, were recorded. Genera such as Leucauge, Neoscona, Tetragnatha, Poltys, and Thelacantha exhibited high species richness, reflecting adaptations to prey availability and habitat complexity. Ecological guild analysis revealed a broad spectrum of functional roles, from ground-dwelling burrowers and ambush predators to visually oriented jumping spiders and specialised web-builders. Distribution patterns spanned multiple biogeographical zones, indicating both local specialisation and widespread dispersal. Conclusion: Dakshina Kannada emerges as a biodiversity hotspot for spiders, with significant taxonomic richness and ecological versatility. Spiders function as key predators, contributing to ecosystem stability and natural pest regulation. The study provides a baseline for conservation planning, ecological monitoring, and future research on habitat-specialist species, emphasising the need to protect structurally complex habitats and integrate taxonomic, ecological, and behavioural perspectives for comprehensive biodiversity management.