Darwin’s Bark Spider

Prelims: Current events of national and international importance | Species

Why in News?

Darwin’s bark spider has drawn scientific attention as studies explain why only adult females produce the toughest spider silk ever recorded.

Darwin’s Bark Spider is a large orb-weaving spider.
Scientific name – Caerostris darwini.
Family – Araneidae (orb-weaver spiders).
Related species – Caerostris kuntneri.
Habitat – Forests and wetlands in Madagascar.
They build orb webs directly above rivers or lakes, a habitat other spiders can’t access.
Distribution – Endemic to Madagascar.
Characteristics – Females are largely black in colour, with white hairs, and Males are redder and lighter brown in colour.
Adult females are significantly larger than males.
Behaviour – Largest orb webs ever recorded, reaching up to 25 metres in width.
Only large adult females produce exceptionally tough silk, that outperforms steel and most human-made fibres in both strength and toughness.
Used as safety lines, anchor threads, and escape ropes by the spider.
Threats – Habitat disturbance from river/wetland degradation and infrastructure projects (e.g., hydroelectric dams).
Water pollution reduces prey availability and impacts silk quality.
Ecological Significance – Large river-spanning webs help control insect populations, especially flying insects.

References