Background: Locust Swarms
- Locusts are a type of grasshopper that undergo “gregarisation” — transitioning from solitary to swarm behaviour under specific environmental triggers.
- Swarms can travel vast distances and cause large-scale agricultural devastation.
- The 2019–2022 outbreak severely affected East Africa, the Middle East, and India — destroying over 2 lakh hectares of crops.
Relevance : GS 3(Environment and Ecology)
Shift in Scientific Understanding
- Old model: Locusts were modeled like self-propelled particles, similar to gas molecules, aligning with nearest neighbors.
- New model: Proposes that locusts make cognitive decisions based on visual perception of motion, not just physical alignment
Key Findings of the New Study
- Conducted by researchers from Max Planck Institute and University of Konstanz.
- Field observations in Kenya revealed:
- Locusts do not align simply with neighbors.
- Vision, not touch or smell, plays the dominant role in swarm movement.
- Use of holographic virtual reality showed:
- Even in sparse swarms, motion coherence (not crowd density) drives alignment.
- Locusts are capable of integrating multiple visual inputs to decide direction.
New Model: Neural Ring Attractor Network
- Adopts a neuroscience-based model over physics-based ones.
- Locusts are seen as decision-making agents, not random particles.
- Swarm motion is an emergent phenomenon — large-scale coordination arises from individual decisions without central control.
Climate Change Link
- Unusual rainfall and cyclones in desert regions (e.g., Mekunu and Luban in 2018) enhanced breeding conditions.
- Climate variability, especially stronger monsoons, made swarms larger and more unpredictable.
- 2019–2022 outbreak was among the worst in decades, showing the urgency of updated models.
Implications and Next Steps
- Old models failed to predict swarm behavior accurately.
- Understanding initial direction selection and decision maintenance is the next frontier.
- Future research needs to be multidisciplinary — involving climate scientists and ecologists.
- Improved predictive models are essential to manage future outbreaks in a warming world.
