According to media reports, recently, citizens of Harbin discovered some unusual "plant seeds" on the roadside.
They look like chili seeds but are a bit plumper and green. Occasionally, they jump up and down, bouncing as high as 5 centimeters, making crackling sounds.
These "chili seeds" are piled up under trees, densely clustered together.
Citizens are quite curious about this. An elderly gentleman remarked, "I've lived in Harbin for nearly 60 years, and I've never seen anything like this before. It can bounce around without feet, truly remarkable!"
Some brave souls even treat the "chili seeds" as toys, holding them in their hands and discovering they bounce even more joyfully there than on the ground.
But let me advise you, if you don't know why it jumps, it's best not to touch it. I fear you'll regret knowing the truth!
The Poplar Leaf Beetle Larva Hiding in Leaves
If you take a closer look, you'll notice that the round disc-shaped object wrapped in leaf material has leaf veins on its surface and appears semi-transparent.
Inside, you can see a wriggling larva.
Some have opened up "pepper seeds" and found a white larva inside, about less than 5 millimeters long, with wrinkles on its body, curled up in a circular leaf bract, resembling a corn borer.
This insect is scientifically known as the poplar leaf beetle larva, commonly referred to as the rubber worm. The jumping motion of the entire circular leaf is caused by its wriggling.
Belonging to the family Chrysomelidae, the rubber worm thrives on trees such as poplars and elms.
It enjoys feasting on leaves, burrowing beneath the epidermis of the leaf and parasitizing the leaf tissue for sustenance.
After the leaf is cut
The caterpillar, before dining, outlines its territory, creating a circular tunnel inside which it selectively consumes leaf tissue.
Once the circular portion of the leaf inside the tunnel is devoured, that part of the leaf withers and falls to the ground, resembling what we commonly see as "pepper seeds" on the sidewalk.
After a period of time, the larvae within these "pepper seeds" progress to the next stage of growth, emerging from their shells as adult insects, ready to reproduce and continue the cycle of life.
The Parachuting Leaf Beetle
Many wonder why the parachuting leaf beetle hops and jumps, seeking refuge underneath leaves. Isn't it just for safety?
From our perspective, jumping seems unsafe. It could easily draw attention from other animals, and the direction of each leap appears random, leaving the beetle unaware of where it might land.
So, why the jumps?
Scientists have found answers to this question by studying another creature, the Mexican jumping bean.
The Mexican jumping bean, just like its counterpart, the rubber tree seed, jumps for survival!
The mechanism behind Mexican jumping beans is similar to that of rubber tree seeds: both involve the parasitic action of small insects causing the jumping, albeit with some differences in species.
These small insects are called jumping bean moth larvae. In spring, the jumping bean moth begins to seek out trees to lay its eggs, with a preference for a certain tree species in the spurge family, which produces very large seeds with three segments.
After hatching, the jumping bean moth larvae burrow into the pods of the seeds while they are still immature. Larvae can parasitize any of the three segments of the seed.
Hidden within the seed, the larvae feed on its contents, eventually hollowing it out. When the seed falls to the ground, the Mexican jumping bean phenomenon is triggered.
Open a runner bean pod and you'll find that the larvae of the Mexican bean beetle spit out silk and then attach themselves inside the seeds.
Their hopping movements are also accomplished by pulling silk with their bodies.
In 2023, physicists from the University of Seattle published a paper in a journal where they documented the movement trajectories of 37 runner beans.
The results revealed that the jumping of Mexican beans is irregular; they "blindly" jump around mainly to evade high temperatures and seek cooler spots.
Place these little insects on your hand, and they'll jump more actively—it's because the temperature of the palm is high, and the bugs dislike warm environments.
However, since the jumps are irregular, the efficiency of seeking shade through jumping is low. Nevertheless, they keep jumping nonetheless. For them, encountering high temperatures means there's a chance of survival through jumping; worst-case scenario, they jump a few more times until they find a satisfactory spot. But not jumping guarantees death!
Similarly, for rubber tree caterpillars, it's the same story. They jump to find a more suitable environment for continued growth and development.
In the end, the surviving jumping bean moth larvae, after the pupal stage, hatch into jumping bean moths. They then emerge from the jumping beans, starting the next cycle of life.
Last
Abroad, Mexican jumping beans are famous novelties, considered a specialty of the town of Álamos in the Mexican state of Sonora, which dubs itself the "World Capital of Jumping Beans."
Foreigners have mixed opinions about this "toy." Some cherish Mexican jumping beans as a fond childhood memory, while others oppose the notion of deriving amusement from the "torment" of larvae, seeing handling the beans as animal "cruelty."
The game with this "toy" follows a simple rule: the higher the temperature, the higher it jumps, bringing joy to the players!
But regardless of how you define it, Mexican jumping beans have always been available as "commodities" for sale, both locally in Mexico and online.
For those tempted to buy, take note: many countries prohibit the importation of this commodity, including ours.
This is because the beans contain living organisms and are considered invasive species, posing a significant risk of ecological disaster.
