At the beginning of the 20th century, a train line opened in Nishiyama, Tokyo. But in 1920, the train crew found themselves blocking traffic due to abnormal reasons. The train tracks passing through the dense forest were submerged by thousands of millipedes, and each arthropod was white like a ghost. These creatures are not insects and emit cyanide when attacked by predators. Even if they fall into dead leaves and soil, they are still in a mysterious state.
The train resumed service, and the millipede was not seen for a long time. But about ten years later, they reappeared like elves rising from the ground, devouring train tracks and mountain roads. They seem to follow this pattern time and time again.
Now, Niijima, Yoshimura, and Momoka Nii of Shizuoka University are also in the paper published in the journal “Royal Society Open Science” on Wednesday. They are also members of Shizuoka University. They elaborated on these millipedes, especially The subspecies Parafontaria laminata armigera is indeed periodic. This behavior was first observed in non-insect animals, and its life cycle lasted eight years from birth to death. However, they also reported that the number of millipedes is no longer as large as before.
Dr. Yoshimura said that when the millipedes stood up, they were heading to a new breeding ground. Adult adults are almost always found on the move. When these creatures reach the fresh bed of rotting leaves for food, they will eat, mate, lay eggs and die.
Dr. Niijima and many of her colleagues who submitted millipede infestation reports also carefully collected invertebrates from the soil near the discovery group. They want to confirm the time scale of millipede development-if there are new larvae in the same place every year, these creatures are unlikely to be periodic. However, if they have grown slowly over the years, they will better adapt to the situation.
As time passed, it became clear that not only did they develop in eight years, but there were also many different populations or broods that lived in different places in the mountains. The researchers identified seven brooding groups. They wrote that the 1920 event was the rise of the sixth brooding group, which was discovered again almost every eight years thereafter. The only gap in Brood VI’s record was in 1944, when Japan suffered chaos after its defeat in World War II, which meant that no group was recorded.
In earlier work, Dr. Yoshimura and collaborators reported that during periods of global cooling, the cyclicality of cicadas may have evolved during periods of global cooling, and all available adults are immediately mixed together. Although it is worth noting that all brooders live at relatively high altitudes, it is not clear what causes the millipede to adopt its own unique laws. Perhaps the extremes of the mountain lifestyle make them cyclical.
However, one of these broods has not been discovered for many years. Others seem to be shrinking.
Dr. Yoshimura said: “For many years, we have never seen a train jam.” “Things are changing.”
He suspected that climate change might affect the life cycle of millipedes, and pointed out that they seem to be a year later than in the past. He also wanted to know whether the reduction in numbers would hinder successful mating and thus accelerate its decline.
He said: “We still want to know the main reason for the reduction.”