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Cicadas
What are Cicadas?
Cicadas are hemipteran insects (Order: Hemiptera; Family: Cicadidae) known for their loud calls produced by males using tymbal organs. India has around 250 reported species (Zoological Survey of India). They are abundant in tropical and temperate regions, often used as bioindicators of forest health.
Life Cycle
- Eggs laid in tree twigs → hatch into nymphs.
- Nymphs live underground for 2–17 years, feeding on root sap.
- Adults emerge synchronously, live only a few weeks, primarily for reproduction.
Cicadas in India
- Found across Western Ghats, Himalayas, and Northeast India.
- Silent Valley National Park (Kerala) was historically devoid of cicadas, giving the forest its English name.
- Case Study (2025): Reports suggest cicadas are making a comeback in Silent Valley—seen as either ecological recovery or a warning of climate disruption.
Ecological Role
- Soil Aeration & Nutrient Cycling: Nymph burrows improve soil structure.
- Food Web: Critical seasonal prey for hornbills, drongos, reptiles, and small mammals.
- Acoustic Indicators: Their calls are used as an acoustic index for biodiversity assessment.
Conservation Concerns
- Habitat loss due to deforestation and plantations.
- Climate change altering species distribution and phenology (Economic Survey 2023–24 highlighted biodiversity shifts in Western Ghats).
- Need for long-term monitoring of insect populations and habitat conditions.
