Latest news with #Schistocerca
Newsweek
28-05-2025
- Science
- Newsweek
These Hungry Animals Eat Their First Meal Before Birth
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. Forget The Very Hungry Caterpillar—scientists have discovered that another notoriously ravenous insect can eat its very first meal before it is even born. Entomologist Koutaro Ould Maeno of the Japan International Research Center for Agricultural Sciences and colleagues report that, in dry conditions, undersized desert locusts can hatch from oversized eggs with a little bit of the egg's yolk already in their guts. This little snack, the team believes, gives the young locusts the extra time and energy to find food to eat after hatching—allowing them to survive longer than their regular counterparts. The extra yolk, the researchers wrote, "functions as a 'lunch box'"; as they explain, "producing large eggs is advantageous under harsh conditions." A swarm of locusts A swarm of locusts Michael Wallis/iStock / Getty Images Plus The desert locust—Schistocerca gregaria—is a species of short-horned grasshopper found in parts of Africa, Arabia and southwest Asia that lives in one of two phases based on environmental conditions. Ordinarily, the insects live solitary lifestyles, moving independently and typically sporting a coloration that allows them to blend in with the background vegetation. When droughts cause food supplies to dwindle and locust populations to become more dense, the insects undergo both bodily and behavioral changes into a gregarious form. This sees the locusts switch to a more yellow coloration and emit pheromones that attract each other—encouraging group movements and swarm formation. These swarms, which can contain a staggering 390 million locusts per square mile, may travel long distances to reach new areas and form plagues that consume vast swathes of vegetation, making them a major agricultural pest. In their study, Maeno (who also goes by the moniker "Dr. Locust") and his colleagues raised desert locus in both isolated and crowded conditions, as well as in dry and wet settings. When reared in crowds, female locusts were found to lay fewer but larger eggs than those raised in isolation. Larger offspring are expected to have an advantage in competing for food. Meanwhile, dry conditions caused both solitary and gregarious locusts to have smaller offspring than in dry conditions—and both these hatchlings from small and large eggs were found to have residual yolk within their guts after birth. Pictured: Sample Locusts from the experiments; those from dry conditions were found to have yolk in their guts (black arrows). Pictured: Sample Locusts from the experiments; those from dry conditions were found to have yolk in their guts (black arrows). PNAS Nexus 2025. DOI: 10.1093/pnasnexus/pgaf132 "We show that larger progeny survive longer than smaller ones, which is expected," the researchers explained. "However, hatchlings from desiccated large eggs are abnormally small but have more yolk as energy—and survive longer under starved conditions than hatchlings from normal eggs." In fact, among solitary locusts reared in dry conditions, small hatchlings lived 65 percent longer in the absence of food than their normal-sized counterparts. And small gregarious hatchlings birthed in dry conditions survived a whopping 230 percent longer than solitary eggs produced in wet conditions. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about locusts? Let us know via science@ Reference Maeno, K. O., Piou, C., Leménager, N., Ould Ely, S., Ould Babah Ebbe, M. A., Benahi, A. S., & Jaavar, M. E. H. (2025). Desiccated desert locust embryos reserve yolk as a "lunch box" for posthatching survival. PNAS Nexus, 4(5).
Times of Oman
02-03-2025
- Science
- Times of Oman
Scientists crack the code for why locusts swarm
Berlin: After months of building, the biggest locust swarm recorded in 70 years swept across 10 countries in East Africa in spring 2020. The damage to crops was estimated at $8.5 billion (€8.1 billion) in a region where 23 million people face severe food insecurity. During these invasions, desert locusts (Schistocerca gregaria) eat their own weight in food every day. The biblical-scale plague ate through 160,000,000 kilograms of food a day — enough to feed 800,000 people for a year. Scientists have been trying to understand how individual locusts gather in swarms for decades. Knowing their behaviour would help with predicting and managing outbreaks. A new model, published today in the journal Science, casts light on the hive mind of locusts. The study describes how individual locusts transition from behaving as solitary animals to giant swarms with collective motion. "Our work provides a new perspective for considering collective motion in animals, and robotics too," lead author Iain Couzin, a neurobiologist at Centre of the Advanced Study of Collective Behaviour, Konstanz, Germany. "One application is a new class of predictive models of how and where swarms move. Future research on this could impact the livelihoods of 1 in 10 people on the planet," Couzin told DW. A new model of swarming, using insect VR Locusts swarms have threatened food security for millennia and have played their part in history — locusts were one of the 10 plagues brought upon Egypt as retold in the Book of Exodus. For decades scientists have been trying to understand how individual locusts move en masse. In 2006, Couzin developed a model explaining how locusts would march together in a line when they swarm. "This model came from particle physics and suggested that individuals bump into each other randomly, then flow together all in the same direction if there is a high density of individuals," said Couzin. Study author Sercan Sayin began probing this model in locusts using a virtual reality (VR) stage set for locusts. Sayin had the insects walk on a ball surrounded by panoramic views on screens. These landscapes reconstructed the world in 3D to make the locusts think they were in a swarm, Sayin said. But he couldn't replicate the 2006 findings that animal density was responsible for locusts forming swarms. Vision cues swarming behaviours Field experiments in Kenya during the huge 2020 swarm showed certain visual cues caused locusts to behave with collective movements when swarming. "Previously we'd thought that bumping into each other caused swarms, but our experiments showed that it's vision that's important," said Couzin. "We found instead that [swarm behaviours] are triggered by the type of sensory information around them, not how many locusts they're surrounded by." Jan Ache, a neurobiologist at the University of Wuerzburg, Germany, who was not involved in the study, said the research expands a mathematical model of swarms which acknowledges the individuality of locusts. "In order for locusts to have collective motion, they need very basic forms of cognitive processing — where insects integrate their own position relative to the position of those around them, then actively follow other locusts," he said. This occurs in individual locusts, but when they come together in crowds it creates the emergent effect of a swarm. How the brain makes decisions Ache said locusts are fascinating to study because they exist in two different states: solitary or swarming. Normally avoidant, the insects switch into marching bands after several hours of crowding. "When they change from one type to the other, the brain is in two different states. In each state, the same neurons drive very different behaviors — like being attracted to or repelled by other locusts," Ache said. Ultimately, the findings are about decisions-making in neuronal systems, Couzin said. "At the basic level, there's competition between groups of neurons in the brain. The brain must come to a consensus and make a decision about movement," Couzin said. In other words, when there's a conflict in the brain, neuronal pathways compete until a decision is made when one pathway "wins" over the other. In their experiments, the visual cues of other locusts in front acted as a target causing the navigation systems to pull the organism in the same direction. "This is very similar to opinion dynamics in humans, where people adopt similar opinions to others and dismiss other opinions," said Couzin. Predicting swarms and crowds? Couzin said the new model has important implications for predicting swarms in the real world. "If we were able to create a model predicting how swarms move, we were using the wrong model before. The implication is new ways to predict how and where swarms move based on a biological understanding of collective motion," said Couzin. It could also help to understand how fish move in schools; birds move in flocks and potentially how mammals move in herds. Couzin is also applying their research in robots, creating collective motion in autonomous vehicles. Couzin said their findings are worth considering in human crowds too, perhaps to help prevent crowd crushes, but "it's too early to make any claims as those experiments haven't been done."
