HABITAT PREFERENCE AND BURROW CHARACTERISTICS OF A TRAPDOOR SPIDER (Idiops sp.) IN THE WESTERN GHATS OF UTTARA KANNADA, KARNATAKA, INDIA Part of CEPF Project: Tarantula (Araneae: Theraphosidae) spider diversity, distribution and habitat-use in the Western Ghats of Uttara Kannada district, Karnataka: A study on Protected Area adequacy and conservation planning at a landscape level (Dr. Manju Siliwal) Ms. Neha Gupta Guru Gobind Singh Indraprastha University, Delhi (Email: [email protected]) INTRODUCTION RESULTS Abundance The family Idiopidae is one of the 8 families of primitive group of spiders (Suborder: Orthognatha) reported from India (Platnick, 2011). The members • A total of 554 burrows of Idiops sp. were found in the study area, out of which 430 of the family Idiopidae are trap door spiders and are mainly ground were active burrows (with the spider) . burrowing forms. They construct a tubular burrow with the walls covered in • This species was found in all habitats sampled during the study silk and have a cork-shape lid at the entrance to the burrow, used as a door • High abundance of Idiops sp. was found in agriculture fields, while least in the semi- (Coyle & Icenogle, 1994; Dippenaar-Schoeman, 2002. The outer surface of evergreen forest. the lid or the door is covered with soil particles and other dry vegetation • In agriculture fields, burrows were clustered and restricted to only very small area debris depending on the surroundings in order to camouflage, and very often • Though number of burrows in mixed forest were observed lesser than agriculture difficult to locate at few centimeters distance and because of this very easily but burrows were distributed uniformly and were recorded in maximum quadrates they remain unnoticed . This is one of the main reason that this group of sampled. This suggests mixed forests likely to be most preferred habitat by Idiops spider remains least studied. In India, studies on trapdoor spiders in the past sp. were very few, and were restricted to taxonomy and therefore, information on natural history, ecology and behaviour is not known (Siliwal, 2009). Therefore, the present study was carried out (January-April 2010) to understand the distribution, habitat preference and burrow characterization of the trapdoor spider (Idiops sp .) across ix different types of habitats (mixed forest, moist deciduous, semi-evergreen, teak plantations, agriculture and human settlements) in Dandeli WLS and nearby reserve forests. It is the first time this kind of information is being gathered for an Indian trapdoor spider OBJECTIVES • To understand habitats and microhabitats preference by the trapdoor spider in study area. • To understand their pattern of distribution across different habitats (semi- evergreen forest, moist deciduous forest, mixed forest, teak plantations, agriculture fields and settlement areas). Habitat preference • To study burrow characteristics & variations with the change in ecological • Idiops sp . preferred open, exposed habitats with low canopy . Habitats with high canopy parameters . cover will also lead to good amount of undergrowth throughout the year and probably these trapdoor spiders do not prefer such microhabitats. STUDY AREA • The Idiops sp. were found more in habitats with low vegetation cover, ranging from 10 to 30%, which could be due to ease of construction and later widening of burrows. With increase in vegetation cover, the network of roots in soil increases which could obstruct the construction and widening of burrows. • The maximum number of burrows were found on south facing slopes Burrow characterization • The Idiops sp. constructed simple tube-like burrows with a “D”-shaped trapdoor Uttara Kannada • Difference in thickness of the entrance door was observed, based on which, trapdoor can be categorized to two types a) Wafer like thin door b) Cork shape thick door • Three types of burrow shapes were observed in Idiops sp. viz ., straight, gently curved and C-shape. This was probably determined by the soil texture and root network of plants in the microhabitat • No significant preference to bund slope was observed • There was significant difference found in structure of female burrows (burrow diameter, depth and lid thickness) across different habitats but it was insignificant in juveniles • Variation in burrow diameter was not found significant to any habitat type but was related to body sizes of the spider • Burrow length was found more in open habitats (like human settlements and teak plantations), probably to escape excess of heat and high temperature FURTHER STUDIES • A long term study needs to be carried out across different seasons of the year to confirm the above results • Also, similar studies can be carried out for other groups of spiders to understand their natural history, ecology and behaviour MATERIALS AND METHODS REFERENCES • Five locations, viz. Kulgi, Potoli, Joida, Kumbarwada and Anshi were selected • Six different types of habitats moist deciduous forest, mixed forest, semi-evergreen forest, teak plantations, 1. Coyle, F. A. & W. R. Icenogle. (1994). Natural history of the Californian trapdoor spider genus Aliatypus human settlements and agriculture fields were identified in each selected locations. (Araneae, Antrodiaetidae) . Journal of Arachnology, 22:225-255. • Quadrats of size 5×5 sq. m were randomly laid with a minimum interval of 250 m between subsequent 2. Dippenaar-Schoeman, A.S. (2002). Baboon and Trapdoor Spiders of Southern Africa: An Identification quadrats and were thoroughly examined for the presence of burrows Manual. Plant Protection Research Institute Handbook No., 13:1–28. • In all 313 plots were sampled across different locations and habitat types. 3. Platnick, N.I. (2011). The world spider catalog, version11.5. American Museum of Natural • The number of active and empty burrows found were counted. History, http://research.amnh.org/entomology/spiders/catalog/index.html. • Ecological parameters and burrow parameters were recorded. 4. Siliwal, M. (2009). Trapped for life- The trapdoor spiders of India. Hornbill July-September. • ANALYSIS: Burrow parameters like burrow diameter, burrow depth & lid thickness were tested across different habitats using Mann-Whitney U test & Kruskal-Wallis H test (SPSS Analysis, Version 15.0). ACNOWLEDGEMENT Thanks to my supervisors (Dr. Sanjay Keshari Das, Guru Gobind Singh Indraprastha University, Delhi and Dr. Manju Siliwal, Wildlife Information Liaison Development Society, Coimbatore); the Karnataka State Forest Department for giving permissions to carry out the study; CEPF (Critical Ecosystem Partnership Fund) - ATREE (Ashoka Trust For Research In Ecology And The Environment) Western Ghats Small Grants Program for funding tarantula project, during which the present data was collected. Also, thank my field assistants and local people for their assistance and help during fieldwork..