These Hungry Animals Eat Their First Meal Before Birth

Newsweek

28-05-2025

Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
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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.
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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). https://doi.org/10.1093/pnasnexus/pgaf132