By TATSUYUKI KOBORI/ Staff Writer
October 30, 2021 at 07:00 JST
TSUKUBA, Ibaraki Prefecture--Scientists working to eradicate the species of desert locust that ravages crops in biblical proportions are focusing their efforts on females that generally only congregate in groups to attract mates but otherwise live separately from them.
A team headed by Kotaro Maeno, a chief researcher at the Japan International Research Center for Agricultural Sciences in Tsukuba, published its findings on desert locust traits and possible ways to rid the world of the menace that has devastating economic consequences in the Proceedings of the National Academy of Sciences of the United States of America, the official journal of the National Academy of Sciences.
There are high hopes the team's research will prove helpful by attacking breeding spots with pinpoint accuracy.
A locust swarm typically comprises billions of the winged insects that destroy vast areas of farmland in days and generally afflict countries in Africa.
Between 2012 and 2019, the researchers identified desert locusts’ groups whose members are 80 to 90 percent occupied by males or females in the Sahara Desert of Mauritania.
They found that the groups usually live in separate areas but when mating season approaches, females search out males to breed with and safely lay eggs en masse at night.
Some males exhibit relentless courtship behavior in front of females in the hope they will be selected to propagate.
According to the team, however, males and females of the grasshopper variant often are at pains to maintain a distance from each other to ensure that females are not injured during the wooing practice and are able to lay eggs healthily.
Desert locust outbreaks are typically handled through aerial spraying of huge amounts of insecticide. But this traditional method often proves to be less than effective as vast numbers of insects will always take flight to find safety.
Strong concerns have been voiced about the use of chemicals over widespread areas to combat locust swarms due to the impact it can on people’s health and ecosystems.
The locust breeding ritual lasts for several hours, during which time the insects congregate in a particular area.

Maeno and his colleagues concluded that spraying pesticides on such occasions would wipe out far more desert locusts in one go with less damage to the environment and the health of local rural communities.
Maeno is so highly regarded in Mauritania for his research on desert locusts that locals dubbed him with a middle name, “Ould,” which means posterity.
Maeno has authored theses and books under the name of Kotaro Ould Maeno to explain the significance of his research.
“Few outdoor surveys had been carried out in local regions, so the species’ breeding patterns, a crucial factor, wasn't known until now,” he said. “My team's findings allowed me to reaffirm the significance of fundamental outdoor research.”
The team's findings were published on the scientific journal’s website at (https://www.pnas.org/cgi/doi/10.1073/pnas.2104673118).
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