Kali Tiger Reserve, in the Uttara Kannada district of Karnataka, comprises of Dandeli Wildlife Sanctuary (475.018 km²) and Anshi National Park (339.866 km²). With its contiguous evergreen and moist deciduous forests, it is one of the richest areas for flora and fauna in the northern Western Ghats, owing to a variety of micro habitats within the reserve.
The reserve teems with insect life, so there are predators in the form of spiders. These eight-legged critters are seen in high numbers right after the monsoons, with a fall in numbers witnessed in winters and through the summer. Locally referred to as mavli in areas bordering north Karnataka and Goa, spiders are both feared and admired.
In the ghats at Anmod and Anshi, dew-covered orb webs stand out in the calmness of early mornings. Many Spiny Orb-weavers are active during the daytime along with jumping spiders and crab spiders. The leaf litter too in these evergreens reveal spiders camouflaged with the fallen leaves and twigs. Post the monsoon season, with several flowers blooming, spiders with a floral resemblance can be seen displaying their excellent predatory skills, preying on unaware bees and other insects. Crab spiders are often seen on flowers of Leea sp. which is widely found in the in the reserve.
Walking along the edges of freshwater streams and water bodies may reveal a semi-aquatic fishing spider which is known to catch aquatic insects and even small fish at times. Mimicry is an intriguing gift spiders possess, especially those which mimic the appearance of ants – a phenomenon called myrmecomorphy. A walk through the woods at Dandeli revealed an Ant-mimic Jumping Spider (Myrmaplata sp.) and an Ant-mimic Crab Spider (Amyciaea sp.) both mimicking and preying upon unsuspecting weaver ants (Oecophylla sp.).
Here are some interesting spiders from Kali Tiger Reserve, which were recorded in the evergreen forests around Anmod, Castlerock and Anshi.
Some spiders seamlessly camouflage with their surroundings. A Litter Crab Spider (Gen. Borboropactus Simon, 1884) found in the leaf litter of evergreen forest patches positions itself on the underside of a fallen twig, hiding in plain sight.
Orb-weaving spiders make orb webs which are nature’s most fascinating manifestations. One step ahead is this Leaf-curling Spider (Acusilas cf. coccineus Simon, 1895) which occurs in evergreen forests. It makes a rolled leaf retreat with a dry leaf, placed at the centre or at an end of the orb web.
Jumping spiders have extremely sharp vision and are known for their agile movements. Here is a female Green Jumping Spider (Hindumanes cf. karnatakaensis Tikader & Biswas, 1978) which was formerly assigned to Lyssomanes. It is found along streams and rivulets in evergreen forests. It has an eye pattern similar to that of Onomastus and Pandisus, but a much narrower eye field.
Mimicry comes in many forms in spiders and pictured here is a Scorpion-tailed Spider (Gen. Arachnura Vinson 1863). Completely harmless, they are known to curl up their tail when disturbed. Their bodies mimic leaf litter, dried flower petals, small twigs or even dried leaves.
A bright, yellow-coloured spider with two horn-like median spines projecting from the abdomen, the Spiny Orb-weaver (Gasteracantha cf. dalyi Pocock 1900) is seen in moist deciduous and semi-evergreen patches along the Western Ghats. These crab-like orb-weavers get their common name for the spines on the abdomen, which are thought to have an anti-predatory function.
The Bolas Spider (Ordgarius cf. hobsoni O. Pickard-Cambridge, 1877) is restricted to semi-evergreen and evergreen forests. Unlike other orb-weavers, this spider does not spin an orb web, but is known to hunt using several sticky blobs on a single line which it makes from its silk, known as bolas. The spider makes a swinging action to capture moths and other insects.
The Net-casting or Ogre-faced Spider (Gen. Asianopis Zhuanghaoyuni Lin & Li, 2020) is known for its unique way of catching prey. By positioning itself head down, it holds a rectangular capture net (made of non-sticky cribellate silk) with its front legs. Once it detects a walking prey, it pushes or casts its net to ensnare the prey. Two of its eight eyes are extremely large, which enable sharp eyesight even in low light. It is exclusively a night-time hunter, found in drier areas with patchy vegetation to evergreen forests patches.
Armoured Trapdoor Spiders (Gen. Idiops Perty, 1833) build burrow retreats with a door or lid on vertical earth banks in evergreen forests. Females are known to live in tubular burrows lined with a thick layer of white silk. The lids are closed and well camouflaged with the use of mud, moss, or lichen, which is held by a layer of silk and are difficult to locate most often.
The White-flanked Water Spider or Nursery Web Spider (Gen. Nilus O. Pickard-Cambridge, 1876) anchors one or more of its hind-legs to an object, with its remaining legs spread on the surface of water in search of semi-aquatic prey. This behaviour is also observed when they hunt in a line in forest patches, where they catch flying moths and other insects. Females are known to make a protective nursery web for the young and stand guard over that web. These medium to large sized spiders are mainly found near water bodies in moist deciduous to semi-evergreen forest patches.
Tube-dwelling Spiders (Segestriidae family) only have six eyes. They have an unusual habit of resting with the first three pairs of legs pointing forward and the last pair pointing backward (most spiders do this with two pairs forward and two pairs behind). They are nocturnal and build their tube webs on rock walls or on trees. Web lines are arranged radially around the tube with the spider near the entrance of the tube. Once the prey comes in contact with the line, it transmits vibrations through the silk to the spider’s feet which helps the spider determine the prey’s location.
Pirate Spiders (Gen. Mimetus Hentz 1832), members of the Mimetidae family, do not build their own webs. Instead, they invade the webs of other spiders, kill the occupants, and eat them. Some also wait in ambush for other passing spiders. Most species eat spiders exclusively, though some also eat insects. The anterior legs of Pirate Spiders are covered with a series of large, distinctive hairs or setae. They are seen mostly in semi-evergreen to evergreen forest patches.
The Triange Web Spider (Gen. Hyptiotes Walckenaer, 1837) creates a triangular web and sits at a vertex until it detects vibrations that signify the collision of its prey. At this moment, the spider releases a coil of silk (like a slingshot) which it holds taut in such a manner that the tension of the web causes it to entangle the prey. A study indicated that its web-slinging can reach accelerations in excess of 770 meters a second squared, or about 26 times the maximum acceleration of a space shuttle.
Indian Violets (Chilobrachys cf. fimbriatus Pocock, 1899) are large mygalomorphs, mainly ambush predators, occurring in burrows on mudbanks along forest paths. They are often smuggled from India for pet trade owing to their striking colouration and aggressive defending posture. Chilobrachys fimbriatus shares its habitat with another large ambush predator, Thrigmopoeus truculentus, and is found in semi-evergreen to evergreen forests.