Flora and Fauna


Manjunath Nayak

The sighting of one of the world’s deadliest spiders – the Black Widow Spider is a cause for excitement for any researcher. A few days back, this species was documented in Karnataka, India.

So far, 31 species of Lactrodectus spiders have been identified in the world. However, in India, four different species of the same genus have been recorded.

With almost 48,200 species of spiders spinning their web for millions of years, scientists have been curious and studying arachnids that are spread across the world except the Antarctic. In the world of spiders, there exist many spider species that are venomous too.

On a trail on June 10, seeing some locked rooms, I opened a toilet door which was tangled with spider webs particularly on the surface of a door. Suddenly to my surprise, a black spider with red bands on its back attracted my attention. It was a female black widow spider guarding its egg sacs. Later, I managed to get good quality images for record of observation of this rare species.

Red black or Black Widow (Latrodectus – Theridiidae family) is a native of Australia. There are records of this spider’s appearance in most parts of Southeast Asia. In India, Black Widows are recorded in Gujarat state to a maximum extent with a good population. In fact, it is less documented in South India.

For the first time in Karnataka, this Female Black widow with egg sacs has been recorded in Jnana Mudra Public School, Naragund, Gadag district. It’s a nocturnal spider which prefers dark spaces like storerooms, godowns and unused toilets to build their tangled web.

Now why is it called a Black Widow?

After mating, the female spider feeds on male (Sexual cannibalism) hence, the name black widow spider. The size of the spider is just 10mm. The female lays multiple batches of eggs with each batch containing 10 egg sacs. Each sac has 200-250 eggs.

Black Widow females are venomous, and it uses venom to inject its prey to paralyze and kill while enzymes help in liquefying the corpse. The spider then sucks up the fluid. Black widow species are insectivores that prey on small insects caught within their webs such as ants, flies, mosquitoes, grasshoppers, beetles, crickets, caterpillars including other spiders.

Sometimes Black Widows are known to feed on vertebrates such as wall lizards stuck in their web. The life span of these female spiders is 2-3 years. Males spiders live about 6-7 months since their life span is limited by sexual cannibalism.

Their venom is rarely fatal to humans, but its bite may cause complications depending on the immunity potential of an individual. Spiders intentionally never bite but if we disturb them accidentally, they are likely to bite. There have been instances when children have deliberately invited Black Widow spiders to bite them in the hope of turning into a spiderman.

These deadly spiders are distributed across temperate and tropical zones – in urban and suburban areas. Spiders are farmers’ friends since they feed on agricultural pests and garden pests keeping a check on crop damaging pests naturally.