Desert Locust Plagues - From Pharaonic Times to the 21st Century
East Africa has had its share of locusts
The year 2020 will be referred to as the year of the locust for a long time in many parts of East Africa which includes Ethiopia, Somalia and Kenya.
The current locust plagues in parts of East Africa including Kenya, is worse than any seen in the last seventy years. The swarms started in the counties neighbouring Somalia - Turkana, Marsabit, Garissa and Wajir counties, where they had been breeding and swarming for some time. By Jan 20 the locusts had been reported in muranga and Narok Counties. They had also been seen in Narok county. Eight days later the swarms were in Embu County from where they crossed Machakos and Kitui Counties. In Feb18th the voracious insects were ravaging parts of Kisumu Countynear Lake victoria and parts of Mukurweini in Nyeri county.
The insects were so numerous that county residents often noted a blackening of the sky, something akin to an eclipse. The television was awash with images of farmers and herders frantically trying to ward off the pests by making noise, using sticks and even in one case, inviting the police to shoot in the air. Among the complaints was the voracious manner in which the pests devoured foliage, from grass, shrubs and trees to commercial and food crops of every kind. It was suddenly becoming apparent to government and citizens alike - desert locusts cause loss of food security through widespread destruction of crops.
Myths and legends about locusts
In Kenya Locusts are seen as God’s annoyance with man. God therefore sends them as a punishment. Only persistent prayers by chosen elders can the afflicted society to discover where they went wrong. This myth about God’s wrath has persisted since Pharaonic times. The kind of destruction they cause cannot be attributed to anybody else but God. In parts of India, however, locusts are not received with the same foreboding as in Africa, perhaps for being less destructive. They are actually celebrated with song and beating of pots and pans.
Taxonomy of Locusts
A Desert Locust (The desert locust - Shistocerca gregaria) is an insect with jointed legs and a hard skin called a cuticle. Insects fall in the animal kingdom of invertebrates – without a backbone.
Locusts are classified as follows:
Phylum: Arthropoda (invertebrates with jointed legs)
What is a Locust?
There is very little difference between the common grasshopper and the locust. Locusts are a number of grasshopper species in the family Acrididae that have a swarming phase when conditions are appropriate.
According to Wikipedia, there is no taxonomic distinction is made between locust and grasshopper species. The big identifier is that locusts swarm when conditions favor a migration. This happens when the locust does not face the pressures of overpopulation and scarcity of food. Locust nymphs which are green or brown will develop into adults and hop around just as grasshoppers do. More than normal rainfall, coupled with higher than usual humidity encourages a population explosion of locusts. When overcrowding occurs, followed by a scarcity of feed, the hoppers band together, change color to a yellow and black and fly over long distances in search of food. These bands can cover the breadth of several kilometers and consume tons of vegetation. Even trees are left completely bare of leaves and green stems. Swarming is a reflex response to overcrowding and food scarcity. These locust swarms could be in thousands, millions or tens of millions of locusts. Swarming takes place during the early morning before it gets too hot. The locusts then settle to eat and stay cool in mid-morning. At night when temperatures drop, they rest in trees and shrubs,
The sight of a locust swarm is such a dramatic phenomenon and the consequences so devastating that African communities have named initiates after Locusts. This naming of initiates by associating them with locust plagues during rites of passage has helped chroniclers to estimate the time in history that the invasion took place. The Kikuyu had “Ngigi,” an initiation title of the group that was initiated at the time of a locust infestation. The Name Ngigi is today a common Kikuyu name. This Swarming and aggressive feeding leads to food scarcity for other species, and especially man who relies on agriculture to feed himself.
Distinguishing male from female
The male can be identified by looking at the end tip of its abdomen which is rounded off by a sub-genital plate that covers the reproductive organs.
The female however has an ending that looks like an open bird's beak. This is the ovipositor opening. Adult male locusts are usually smaller than adult females of the same species except during the gregarious stage when they may be indistinguishable.
As locusts eat voraciously, they are also laying eggs in their paths. It is estimated that by June 2020, the swarms could grow 500 times, thereby compounding the already dire food situation.
Locust Life Cycle
Earliest Recorded Locust Infestations
Locusts are one of the 10 plagues that God sent to Egypt after the pharaoh refused to free the Israelites as mentioned in the Biblical book of Exodus,
Exodus 10:12 - And the Lord said unto Moses, Stretch out thine hand over the land of Egypt for the locusts, that they may come up upon the land of Egypt, and eat every herb of the land, [even] all that the hail hath left.
This locust plague is estimated to have taken place in Egypt around 1446 BC
In the north-western provinces around China in 311 AD, about 98% of the population died from a plague that is thought to be related to a previous locust infestation. It thought that the numerous locusts may have led to an abnormal increase in rats which carried fleas with a parasite that caused a disease that was similar to bubonic plague.
The locust that took place in Egypt is also mentioned in the holy Quran:
فَأَرْسَلْنَا عَلَيْهِمُ الطُّوفَانَ وَالْجَرَادَ وَالْقُمَّلَ وَالضَّفَادِعَ وَالدَّمَ آيَاتٍ مُفَصَّلَاتٍ
So We sent upon them the flood and locusts and lice and frogs and blood as distinct signs, but they were arrogant and were a criminal people.
In another verse, the rising of people on the day of judgement (qiyama) is likened to a locust swarm:
خُشَّعًا أَبْصَارُهُمْ يَخْرُجُونَ مِنَ الْأَجْدَاثِ كَأَنَّهُمْ جَرَادٌ مُنْتَشِرٌ
Their eyes humbled, they will emerge from the graves as if they were locusts spreading,
Between the 1724 and 1725 the Northern regions of African had serious locust infestations. An English chaplain, Thomas Shaw and doctor Jean André P. recorded what they witnessed in Rabat, Algeria in 1779. Many peasants died of starvation and some survivors were so desperate that they sold their children. Again between the years 1864 and 1875 Algeria experienced varying intensities of locust infestations. Of those plagues, the one of 1866 was by far the worst. It is highly likely that some of these plagues migrated southwards into the Sudan and finally into Kenya and Uganda in East Africa. It is this same Desert Locust that infests Kenya today. Locusts can breed in the Arabian Peninsula, notably Yemen, or the Horn of Africa in parts of Ethiopia and Somalia. Since locusts present a problem that spans several countries, no country can tackle a locust problem alone. In 2005, there was a Locust plague in a total of 26 countries, spanning Africa, The Middle East and Southern Europe.
When the primary breeding areas are inaccessible due to war or the presence of terror group, the emerging nymphs will pose a serious threat to neighboring countries. If one country establishes measures of locust control as her neighbors do nothing, the problem will recur as soon the nymphs in the non-action country mature and band together for migration.
How to Control Locusts
During an infestation, herders and farmers have been seen trying to chase them away by literally beating about the bush and making a lot of noise. In one instance on TV, policemen were seen attempting to help by firing guns in the air. But this only scares the ones closest to the humans who are disturbing them. In any case, they will fly a short distance and settle to continue eating anywa. This form of intervention will not have any effect on locusts that have covered an entire county.
Poisoning the locust’s path
Poisoning the path of locusts requires very close monitoring of the swarming in order to anticipate the direction that they are likely to take. The herbage is then sprayed with a chemical that will kill them when they arrive to feast. The disadvantage with this method is that innocent organisms, including insects that are beneficial to farmers are killed as well. There is also the possibility of poisoning humans who may inadvertently harvest vegetables in the poisoned area. This method would require very close coordination between the authorities and the local population through chiefs, headmen and clan leaders.
Spraying locusts that have settled to eat
Locusts that have settled are easy to spray. This can be done by men with backpack spraying equipment when the infestation is small. But locusts that have covered several kilometers squared are best sprayed by aircraft, In 1987 a plague that devastated large areas of Mali and Niger paused imminent threat to northern Mauritania, the Western Sahara, Morocco and Algeria. In the following year, 250 million dollars was raised by international agencies. In a period of six months, more than 3 million liters of insecticide were used. Though pesticides are inevitable in locust control, FAO encourages a preventive approach in the early stages of locust development with minimal use of pesticides.
Biological control of Locusts
Scientists discovered that fungal spores in an oil based formulation adhered well to locusts. The oil protected the spores from rapid drying in a hot climate. Between 1989 and 1992 a comprehensive list of pathogens that attack grasshoppers was prepared and their efficacy was tested in both laboratory and field conditions. Trials were done in Benin, Niger and Burkina Faso.
Locusts as human food
Several cultures in Africa, Middle East and Asia consider locusts a delicacy. There are many ways of cooking them which includes frying and smoking. While the protein content varies from species to species, this can be as high as 60 percent of dry weight. This is more than the protein in beef for the same weight. Saturated fats content are 44 percent of dry weight compared to unsaturated fats at 54 percent. A negative point is the high cholesterol content, which is far much higher than that found in chicken or beef. Locusts have traces of magnesium, calcium and selenium. They also contain the following Minerals: iron, phosphorus, thiamine, iodine, niacin, riboflavin.
Agencies that fight locusts
1. Food and Agricultural Organisation (FAO) has a committee called Emergency Centre for Locusts Operations (ECLO). FAO also has a special program to oversee this preventive approach: Emergency Prevention System for Trans-boundary Animal and Plant Pest and Diseases (EMPRESS) – Desert Locust Component
2.The Desert Locust Control Organization for Eastern Africa (DLCO-EA) is "a regional pest and vector management organization established by an International Convention signed in Addis Ababa, Ethiopia in 1962"
Fossil of a grasshopper-like insect
Earliest known fossil of a grass hopper or locust
A grasshopper fossil has been documented by the Fossil Museum. The fossil was found at the Santana – creto formation fossil site in Ceara, Brazil.
It has been classified in the Elcanidae family, a grasshopper-like family of the Late Triassic to the Late Cretaceous period. The 30 mm fossil has been dated to between 108 and 92 million years.
1. Biology Teaching Resources. The Desert Locust, Educational Material by D G Mackean: bilogy-resources.com/locust-01.html
2. International Experimentation and Control of the Locust Plague. Africa in the First Half of the 20th Century, Antonio Buj Buj: ub.edu/geocrit/locust.html
3. Biblical plagues really happened say scientists: telegraph.co.uk
4. Reconstruction of a 1,910-y-long locust series reveals consistent associations with climate fluctuations in China: pnas.org/content/108/35/14521
5. Global warming may worsen locust swarms: nature.com
8. New Strategies in Locust control, published by Birkhauser – Edited by S. Krall, R. Peveling and D. Ba Diallo 9. The Nutritional Value of Locusts, By Sirah Dubois: livestrong.com