Context:

Recently, Cicadas have made a surprising return to Kerala's Silent Valley National Park, a region that had previously been characterized by their absence. Experts from the Botanical Survey of India suggest this resurgence could be linked to ecological upheaval, potentially triggered by environmental changes.

About Cicadas:

Cicadas are hemipteran insects best known for their loud, complex, and species-specific songs, which they produce by vibrating membranes on their abdomens. These insects undergo a remarkable life cycle, spending most of their lives underground as nymphs.

·        Cicadas are typically canopy dwellers, found in natural forests with tall, mature trees that offer suitable environments for their growth.

·        Most cicadas prefer warm, humid conditions and are primarily found in tropical and temperate forests around the world.

·        The insects are highly adapted to this habitat, where they have developed unique behaviors to survive.

Types of Cicadas:

Cicadas are divided into two broad categories based on their emergence patterns: annual and periodical cicadas.

·         Annual Cicadas: These cicadas emerge from the ground at varying times during the summer. They are typically dark in color with greenish markings. To avoid predation, annual cicadas camouflage in the trees and use their ability to fly to escape predators like birds and moles.

·         Periodical Cicadas: A rarer group, periodical cicadas are unique for their synchronized mass emergence, occurring every 13 or 17 years. Only seven species fall under this category.

Ecological Importance:

• Cicadas play an essential role in maintaining the health of forest ecosystems. As they emerge, they help prune mature trees, allowing sunlight to reach younger plants. Their burrowing activity aerates the soil, improving its structure and promoting better water and nutrient absorption for plant roots.
• When cicadas die, their bodies decompose and add nitrogen to the soil, enriching the ecosystem and benefiting the growth of surrounding trees and plants. This nutrient cycling ensures the continual health of the forest.

About Silent Valley National Park:

·         Location: Silent Valley National Park, located in the Nilgiri Hills, Kerala, spans 89.52 km² (core area) and is part of the Nilgiri Biosphere Reserve.

·         History: Declared a Reserved Forest in 1914, became a national park in 1984 and in 1986designated core area of Nilgiri Biosphere Reserve.

·         Flora & Fauna: Home to 41 mammals, including the Lion-tailed macaque, 211 bird species, 49 reptiles, and 47 amphibians.

·         Rivers: Origin of Bhavani, Kunthipuzha, and Kadalundi rivers.

·         Indigenous Tribes: Inhabited by Irulas, Kurumbas, Mudugas, and Kattunaikkars.

·         Surrounding Protected Areas: Includes Karimpuzha Sanctuary and Mukurthi NP.