Understanding the Desert-Adapted Egg-Laying Behavior of Desert Locusts

―Males act as 'parasols' to protect females during egg-Laying in high temperatures―

JIRCAS, in collaboration with the National Desert Locust Control Center of Mauritania, has elucidated the daytime egg-laying behavior of adult desert locusts (hereinafter referred to as locusts) in the harsh desert environment (extremely high temperatures).

Field surveys conducted in the Sahara Desert revealed that many adult locusts engage in mass egg-laying at night. However, some females were delayed in laying eggs and did so during the day on the surface, where temperatures approached lethal levels (over 50°C), a time when most animals avoid activity. During high temperatures, many males were found riding on the backs of egg-laying females. Using a thermographic camera to measure the body surface temperatures of the locusts, it was found that their body temperatures were lower than the ground temperature. Experimentally, fixed locusts were exposed to sunlight and their body temperatures were directly measured with sensors. It was observed that single females had higher body temperatures, whereas paired females maintained lower body temperatures. This suggests that males riding on the backs of females function as "parasols," helping to avoid high temperatures during egg-laying.

In addition to having a high physiological tolerance to heat (approximately 55°C), locusts lay eggs during times when most animals cannot be active due to high temperatures, with males functioning as "parasols."

From a pest control perspective, paired locusts during mass egg-laying remain in one place for several hours, increasing the efficiency of pesticide application. Applying this understanding of locust behavior can lead to pest control methods that minimize pesticide use and are more environmentally and health-conscious.

The findings of this research were published in the electronic edition of the journal Ecology on September 15, 2024 (Japan time).

Authors

Maeno, K.O., Ould Ely, S., Ould Mohamed, S., Jaavar,M.E.H., Benahi, A.S., and Ould Babah Ebbe, M.A.

Title

Mate-guarding male desert locusts act as parasol for ovipositing females in an extremely hot desert environment

Journal

Ecology
DOI: https://doi.org/10.1002/ecy.4416

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