Invasions of locusts: A lasting impact

School enrolment rates fell by 25 % to less than 18 %. Girls were particularly affected, leaving the classrooms at an even younger age than boys. The phenomenon is ascribed to a shortage of food following the destruction of the harvests by the locusts. This affects educational achievement, results in a fall in income of parents dependent on agriculture, which may in turn lead them to withdraw their children from schools.

These results are clearly disturbing in the current context of a new threat posed by locusts in Mali and Niger. The proliferation of insects is compounded by a political conflict that hampers anti-locust measures.

In June 2012, following a period of heavy rainfall, the Northern regions of Niger and Mali were invaded by swarms of desert locusts. In response, the United Nations Food and Agriculture Organisation (FAO) decided to introduce an action plan for the summer. As the FAO confirms, these voracious insects destroy pasture land and cereal, fruit and vegetable crops, thus constituting a threat to the food security of both countries. However, these plagues of locusts may also have lasting socio-economic effects, as has been revealed by a team of experts acting for the IRD and its partners(1). Although they occur regularly in over 60 countries in Africa, the Middle-East and South-East Asia, the effects referred to have hitherto been little studied. School enrolment has fallen by up to 25% Researchers have for the first time illustrated the serious long-term effects of such natural catastrophes.

Their studies reveal that the serious plagues of 1987-89, which hit Mali in particular, had negative consequences on the education of children in the country's affected villages(2). A considerable number of children who were born or reached school age during these terrible catastrophes had to say goodbye to any chance of attending school. The school enrolment rate fell by a quarter, dropping from 24% to 18% for the boys and from 15 to 11% for the girls. Likewise, the proportion of pupils completing primary education fell by about 15%. Girls were nevertheless particularly badly affected, since they are taken away from school at an earlier age than their male classmates. The time they spend at primary school thus fell by a year.

The reason: famine and the fall in incomes

The plagues of locusts were found to affect enrolment rates and the levels of education in the zones concerned in various different ways. First and foremost, the arrival of the insects subjects young children and pregnant mothers to localised food shortages. The deterioration in the nutritional status of the children or of their mothers during pregnancy affects their educational achievement. The children risk suffering from long-term health problems or retarded growth, which can lead to a reduction in their learning capacities. This may be the case even if the food shortages can be partly compensated by the proteins supplied by consumption of the insects themselves. Fried, boiled or roasted, the locusts are a much-appreciated delicacy in many countries in the Sahel region, and particularly in Mali. As long as they have not been sprayed with insecticides.

Secondly, farmers' children may be affected by the sudden fall in their parents' income following the destruction of their crops. They are thus taken away from school or are only sent there several years later.

The loss of harvests is also likely to result in soaring local food prices. Consequently, the poorest households are hit hard in the aftermath of locust plagues, whether farming or non-farming families.

The desert locust: the downside of the rains

These plagues of desert locusts are "the curse of the rains." The insects originate from regions in North Africa or the Middle East, referred to as remission zones, which are either uncultivated or little cultivated, and with rainfall levels of under 200 mm per year in normal conditions. When, however, rainfall exceeds this average, the locusts proliferate -- as was the case in Spring 2012.

The increase in the density of locust populations modifies their behaviour and stimulates their gregarious instinct, so that they group together in swarms of billions of insects. These huge swarms, covering areas of up to several hundred square kilometres, are capable of migrating very long distances outside their remission zones in order to find food. A swarm of locusts measuring 1 square kilometre consumes 120 tonnes of food per day, that is equivalent to the quantity of food required to feed 2,500 people for 4 months. This amounts to total devastation in the invasion zones.

In the current context in Mali and Niger of locust plagues accompanied by a political conflict that also hampers operations to identify and combat the phenomenon, such as by spraying with insecticides, the results of this study are particularly disturbing. The study underlines the long-term effects of the economic crises caused by such natural catastrophes, and makes it possible to analyse the capacity of the local populations to confront these plagues.

(1) This study was conducted in partnership with researchers from Paris Dauphine University and from the Mali Institute of Statistics.

(2)In the country on a whole, 10% of villages suffered plagues in 1987-89.