Representative image. The coronavirus isn't the only plague making headlines this year -- locusts are devastating crops in several parts of the world, and now scientists are discovering why the pest forms destructive swarms. On its own, a locust is fairly harmless. But so-called solitary locusts can undergo a metamorphosis, changing colour and joining together with millions of others in catastrophic clouds that strip fields.
A study published Wednesday in the journal Nature reveals the secret lies in a pheromone. Almost like an irresistible perfume, the chemical compound is emitted by locusts when they find themselves in proximity to just a few others of their kind.
Diet: Herbivore. Group Name: Swarm. Average Life Span: Several months. Size: 0. Weight: 0. Size relative to a paper clip:. This photo was submitted to Your Shot, our photo community on Instagram. Follow us on Instagram at natgeoyourshot or visit us at natgeo.
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Meet the people trying to help. Animals Whales eat three times more than previously thought. Environment Planet Possible India bets its energy future on solar—in ways both small and big. Although their swarming behavior doesn't happen often, locusts are typically thought of as fearsome pests prone to causing natural disasters.
And although locusts don't bite people, people bite them. Locusts are edible and several cuisines around the world include locust recipes , such as peanut-stuffed locusts in Cambodia. But because modern farmers may use pesticides to protect their crops from locusts, eating locusts can be unsafe as they may be carrying residue from those pesticides.
Locusts are often confused with periodical cicadas , another type of large insect that shows up in large numbers every few years. Although cicadas may be called "locusts," they're technically not locusts, or even grasshoppers. Periodical cicadas synchronously emerge from the ground every 13 or 17 years, depending on the species, according to the National Wildlife Foundation. Related: Gaddafi's fall leads to desert locusts' rise. In this era of human-driven climate change , experts warn that the threat of locust swarms may intensify.
It's unclear exactly how climate change will affect all locust populations, but the insects are resilient, and some scientists have warned that the severity of locust plagues could worsen if conditions for locust swarming become more common.
For instance, an increase in cyclones in Eastern Africa and the Arabian Peninsula, a weather condition favorable to locusts, could lead to higher locust numbers, according to National Geographic.
The worst consequences may be borne by people who bear little responsibility for the changing climate, such as small-scale farmers and those living in rural communities. Because locusts can wreak such incredible havoc on crops, food insecurity is legitimate concern, Ngumbi said. Although people have lived with locusts for millennia, there are still many unanswered questions about how human activities may influence locust plague formation, Cease said.
The Global Locust Initiative's interdisciplinary research aims to find solutions for the international challenge of dealing with locust swarms and improve food stability worldwide. Flooding and high rainfall allow the locust to expand the area in which it can lay eggs. Adult females lay eggs in moist soil in fairly open areas. For the embryo to develop it must absorb water early in development.
Sufficient water at the time of egg laying will allow the embryos to develop and survive without drying out. In this state the embryo can survive in the eggs during the dry and cooler winter months until a rise in temperature triggers hatching.
Temperature is important for the timing of hatching. As the floods recede during the dry winter season, locusts can keep laying eggs due to the moisture in the soil. Thus the availability of suitable egg laying sites increases as well as the length of time during which the locusts successfully lay. This contributes to increasing the population density in the area.
During the winter months there is an accumulation of egg pods in the soil. As there is sufficient water, the embryos in the eggs laid by females at the beginning of winter have developed and are ready for hatching. At the onset of summer, when temperatures increase, there is synchronised hatching of eggs.
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