ABSTRACT
A survey of spiders associated with the rice agroecosystem in Ramakrishna Mission Ashrama Campus, Narendrapur, South 24, Parganas, India results a total of 17 species under 16 genera distributed over 7 spider families in kharif crop season during August 2019 – November 2019. Of these, two species Rhene decorata Tikader and Thomisus sikkimensis Tikader are recognised as endemic to India. Runcinia insecta (L. Koch) is recorded for the first time from West Bengal and Camaricus formosus Thorell, Cyclosa spirifera Simon and Neoscona theisi (Walckenaer) recorded first time from rice field of West Bengal. Total number of spiders per sample is maximum in the maturity stage of paddy when pests attain their peak. Spiders are collected from diverse habitats within the paddy field, viz. crop canopy, border weeds and in the flood water. Among spiders family Salticidae is the most dominant group. Analysis of their zoogeographical distribution reveals that the fauna apart from being Oriental also includes some Ethiopian (17.65%), Australian, Neotropical and Palaearctic (each 11.76%) and Nearctic (5.88%) elements. The dominant guild is constituted by the Ambushers (7.44%) followed by Ground Runners (6.37%) and Orb Web Weavers (3.19%). Ranking sequence of most abundant four species are [in descending order]: Oxyopes shweta (Tikader) (34.72%) > Plexippus paykullii (Audouin) (13.89%) > Camaricus formosus (Thorell) (12.50%) > Rhene decorata Tikader (9.72%). Sex ratio (♀ : ♂) is around 11 : 1. Availability of food/season and/or cannibalism may be the factors for female dominated society. This work aims to generate data-base on the diversity spectrum of spiders in the rice agroecosystem along the growth period of the rice plants and to propose definite management plan for limiting pesticidal load.
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