New Semi-Aquatic Spider Dolomedes indicus Discovered in Kerala

Kerala Scientists Discover Dolomedes indicus , India’s First Confirmed Fishing Spider

A team of researchers in Kerala has documented Dolomedes indicus , a newly identified semi-aquatic spider and the first confirmed representative of the Dolomedes genus recorded in India. Found in the lush rainforests of Wayanad, the discovery strengthens the Western Ghats’ reputation as a global biodiversity hotspot and brings renewed attention to the ecological importance of freshwater habitats.

Discovery in the Forest Streams of Wayanad

The species was located during field surveys in the streams of Lakkidi and Periya, two regions known for pristine hydrological systems. Unlike typical web-spinning spiders, Dolomedes indicus is an agile hunter that relies on water surface tension to detect ripples produced by insects or small aquatic organisms. The researchers observed the spider’s remarkable diving behaviour, with one female remaining submerged for nearly ninety minutes by creating an insulating air film using hydrophobic hairs.

Distinctive Traits and Scientific Validation

The species was confirmed through detailed morphological studies supported by DNA sequencing. Males are easily recognisable by a bright snow-white stripe extending from the head to the mid-dorsal area, while females show a moss-green camouflage suited to streamside vegetation. Voucher specimens have been deposited in the Kerala Forest Research Institute’s entomological collection for reference.

Ecology and Environmental Sensitivity

Dolomedes indicus thrives only in clear, fast-flowing forest streams and avoids stagnant or polluted areas, making it a valuable indicator of freshwater ecosystem health. Its hunting strategies — gliding over water, ambushing prey and long-duration diving — demonstrate advanced adaptation to semi-aquatic life.

Exam Oriented Facts

• Dolomedes indicus is India’s first validated Dolomedes species.

• Discovered in Lakkidi and Periya regions of Wayanad.

• Shows surface-hunting and semi-aquatic adaptations.

• Identification confirmed through DNA and morphology.

Conservation Importance

Researchers note that the species’ dependence on unpolluted mountain streams highlights the urgency of protecting Western Ghats watersheds from climate stress, encroachment and pollution.