In 2020, billions of the insects descended on East African countries like Uganda and Kenya that had not seen locusts in decades, fueled by unusual weather connected to climate change. Kenya had last dealt with a plague of this scale more than 70 years ago; Ethiopia and Somalia, more than 30 years ago.
When periods of heavy rainfall follow periods of relative drought, solitary desert locusts emerge to feed on new-growth foliage and lay eggs in the newly moist soil, which prevents them from drying out.
The sight and smell of other locusts, as well as sensory stimulation from contact between locusts’ hind legs, precipitates changes in the locusts’ behaviour and morphology; the previously green, nocturnal and solitary creatures become larger, develop black-and-yellow colouring, and begin to seek out other locusts, a process known as grangerization.
These changes result in the formation of large locust swarms that gregarize nearby locusts and breed profusely, allowing them to undergo rapid, exponential growth. The swarms proceed to feed on the newly abundant vegetation, making use of improved swarm coordination, the result of larger brain sizes, as well as increased range, the result of increased metabolic activity, larger muscles, and longer wings, to travel up to 130 km a day in search of new vegetation and moist weather, often propelling them by the wind.
This particular desert locust plague traces back to May 2018, when Cyclone Mekunu passed over a vast, unpopulated desert on the southern Arabian Peninsula known as the Rub’ al Khali, filling the space between dunes with ephemeral lakes, which allowed locusts to breed undetected.
This was exacerbated in October 2018 by Cyclone Luban, which spawned in the central Arabian Sea, moved westward, and rained out over the same region near the border of Yemen and Oman. According to the research, the Indian Ocean Dipole, an irregular oscillation in sea surface temperatures between the western and eastern parts of the Indian Ocean, has increased in magnitude due to the effects of climate change.
This shift has resulted in increased cyclone activity over the last decade in the Persian Gulf, previously home to very few cyclones, and is associated with flooding in countries along the western Indian Ocean, dry weather in the east, and bushfires in Australia.
The two cyclones created conditions conducive to mass locust reproduction, enabling three generations of locusts to breed over a nine-month period, which increased their number in the Arabian Desert roughly 8,000-fold.
The first swarm of locusts entered the Karamoja – already the most food-insecure sub region in the country – on 9 February 2020. By September 2020, desert locusts had been sighted in over 20 districts in the Acholi, Elgon, Karamoja, Lango, and Teso subregions.
In Kenya, immature swarms have been reported in 17 counties, some of which share a border with Uganda, such as Turkana. Uganda is now on a high alert and increasing its readiness to respond to and control the destructive migratory pest. The locusts headed toward Uganda and fragile South Sudan, where almost half the country faces hunger as it emerges from civil war. Uganda has not had such an outbreak since the 1960s and was already on alert. Uganda had not deal with a locust infestation since the ’60s so there was concern about the ability for experts on the ground to be able to deal with it without external support.
Uganda is expected to be heightening the preparedness as the possible locust invasion is expected in March or April 2024.The last locust invasion, Uganda nearly spent shs 200 billion in fighting locusts of shs 181 billion was obtained from World Bank as a loan.
written by Karukiko Denis
