Kerala Forest Research Institute (KFRI) discovers India’s first raft spider, Dolomedes indicus, in Western Ghats streams

Key facts

• Researchers identified Dolomedes indicus in the evergreen rainforests of the Western Ghats, specifically in Lakkidi and Periya areas of Wayanad district, Kerala.
• Dolomedes indicus is an active, semi-aquatic predator that uses water surface tension to detect prey vibrations and captures insects or small fish with rapid movements.
• The species can swim and dive; one female remained submerged for nearly an hour and a half, breathing via air trapped by hydrophobic body hairs.
• Males exhibit a distinctive snow-white marking from face to back centre, while larger females display greenish-brown coloration for camouflage among mossy rocks and foliage.
• Genetic and morphological analyses confirmed Dolomedes indicus as a new species, providing the first verified record of the Dolomedes genus in India.
• Specimens have been permanently preserved and deposited in the Insect Collection of the Kerala Forest Research Institute (KFRI) for future study.
• The spider thrives only in pristine, cool forest streams, making it a potential indicator species for monitoring freshwater ecosystem health.