Tiddi · टिड्डी
How a swarm is made
A desert locust spends most of its life alone, hiding from its own kind. Given rain, then drought, it changes colour, behaviour and even brain chemistry, and joins a swarm that can cross a continent.
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16 million km²
the desert it lives in, from West Africa to India
Alone
In quiet years the desert locust is solitarious: sandy green, camouflaged, flying at night and keeping its distance from others. You would walk past one.
Source: FAO Locust Watch
25 mm
of rain in a month is enough to breed
Rain
A good shower greens the sand within days. Moist soil lets females lay; fresh plants feed the young.
Checking this month’s rain in Rajasthan and Gujarat…
Source: FAO Desert Locust Guidelines · live: Open-Meteo
× 20
more locusts each generation, about three months
Eggs
Each female pushes her abdomen 10–15 cm into damp sand and lays a pod of up to 158 eggs. Two weeks later the hoppers dig out. Three good generations in a row is 8,000 times as many locusts.
Source: FAO Locust Watch
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hoppers per m² on the last green patches
The green shrinks
When the rain stops, plants die back to a few patches. Thousands of hoppers that were spread across the desert are forced onto the same small islands of food.
Density shown is the simulation’s, rising toward the 74 per m² threshold below.
A few hours
of jostling is enough to flip a locust
The switch
Repeated touches on the hind legs raise serotonin in the locust’s nervous system. Within hours it stops avoiding others and starts seeking them out. Its offspring hatch black and yellow. Same genes; a different animal.
Source: Anstey et al., Science 2009 · Simpson et al., PNAS 2001
74 per m²
the density where hoppers start to march together
The band
Below it, hoppers mill about. Above it, they suddenly line up and march as one, a band that can stretch for kilometres and eat everything in its path.
Alignment on screen: — (0 random, 1 all one way)
Source: Buhl et al., Science 2006
80 million
adults in one square kilometre of swarm
The swarm
Hoppers fledge, turn bright yellow, and take off by day with the wind: 5 to 130 km a day, more when the land below is dry. A square kilometre of swarm eats as much in a day as 35,000 people.
Source: FAO Locust Watch
June 2018
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The road to India
Two cyclones in 2018 filled the Empty Quarter of Arabia with rain. Locusts bred there unseen for nine months, crossed to Iran and Pakistan, bred again in spring 2019 and reached the Indian border with an early monsoon. By June 2020 they covered two continents. Keep scrolling to move through FAO’s maps, six months apart.
Source: FAO Desert Locust Information Service, infestation maps and story map, 2018–2020 · FAO in Pakistan
11 April 2020
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India, 2020
Hoppers were found in Rajasthan on 11 April, months early; swarms from Pakistan followed from 30 April. Each lit shape is a district the Ministry of Agriculture named in that day’s release. By late June one swarm had flown from Jhunjhunu past Gurugram. Keep scrolling to move through the summer.
Source: Press Information Bureau, Ministry of Agriculture releases, April–August 2020 · replay on the map
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locusts reported in the last two weeks
Today
Loading the latest surveys…
Source: FAO Locust Hub (RAMSES), including Pakistan and Iran · LWO bulletins · Open-Meteo