A wind’s teeth – Understanding locusts
From the ultimate biblical plagues to the modern times of natural disasters, none has stood out in resemblance like that of the locusts. The concept of climate change better explains this disaster. Cross-referencing our notes with those of the old days Egyptians, locusts fly along with the wind or as they said: “wind brought and took away the swarms”.
Understandably, locusts sense weather in advance. Hence as the wind flows from regions of high pressure (hot and dry) to those with low pressure (cold and with rains and vegetation) so do the locusts. In their devouring spree adventures, they leave behind farm waste-lands that hundreds of people depend on. On average, a single locust consumes its weight of about 1-2 grams per day. Considering there are millions of in addition to the global spread land degradation, dry weather, soil erosion, and bushfires, affected areas are drifted to an inevitable famine. Locust infestation reoccurs within a cycle of about ten to twenty years and their unmistakable pointer is their natural predator the Ibis bird.
Locusts are casually referred to as the reproducing machine. A female locust lays about seventy eggs per sitting for three times in her lifetime. As the female lays the eggs, a mounting male fertilizes them as she burrows them in the ground. The female secrets a disinfectant foam that protects the eggs from drying out in desiccated sandy soils and also hardens and seals them from predators. In about six weeks, eggs hatch into hoppers that need fat reserves to enable them to fly long distances between feeds. Locusts at the hopper stage are still destructive but are too small to fly, allowing them to buzz around without the imminent danger of swarming. Hopper stage is the best period to spray i.e. after hatching but before growing wings that allow them to fly about forty kilometers in an hour.
Locusts are of different colors and sizes, notably solitary (without wings) and swarming (with wings). Essentially, the transformation from solitary into swarming locust is partially dependent on physical closeness to each other and partly on either the scarcity or sufficiency of vegetation. Locusts, do not fly at temperatures below 190 C, hence they mostly swarm late in the morning. They have clear vision deterring them from airborne collisions with a great preference for sunshine and warmth, making their sighting in continuously cold highlands rare.
Unlike in Germany where the locust is a protected insect species, in Africa and Australia, locusts are an invasive guest. In Australia, despite the little experience by the state in handling locusts, there is extensive use of aerially applied insecticides. The spray is in a gaseous form that reduces the use of chemicals by 99%. Locust spraying calls for the use of satellites to see weather patterns and remote sensing to understand the terrain and targets allowing coordination between farmers and field officers. For efficiency, spraying should kill about 97% of the locusts, otherwise there are chances for re-infestation. Nonetheless, insecticides kill none target insects and extensively damage the ecosystem making the approach rather unstainable.
Drug use deficiencies create opportunities for alternative anti-locust research. Regrettably, developing countries that are adversely affected by locusts lack the financial resources and the scientific know-how of the industrialized nations to invest in research. Researchers in Germany are studying locust behavior: reproduction, socialization, and communication. In a worthwhile breakthrough, they have noted a scent (natural polyacrylamide) applied by male locusts on females they have mounted making them unattractive to other males. Ingeniously, scientists are hoping synthetic polyacrylamide applied on a general locust population will breakdown their reproduction hence defeat locusts without harming the environment.
By Arnold Muthanga