Every 8 years, tracks in Japan are literally blocked by the invasion of millipedes, which have even been nicknamed "train" for this reason. Working together, these small creatures (about 3 cm long), which play a huge role in the nitrogen cycle in the local larch forests, simply make the trains stop. Until now, however, scientists were not sure what causes such behavior and why it occurs with such regularity - after 50 years of research, we finally got to know the answer, namely Parafontaria laminata armigera, because this is the species we are talking about, characterized by an exceptional 8-year cycle life. This is an extremely exciting discovery for the scientific community, because so far the only known perennial species with such a long life cycle were perennial cicadas.
They inhabit the eastern and central parts of North America and have a 13- and 17-year development cycle - most of the time they mature, because after pupation they only live 30 days, during which they reproduce. However, when it is time to mow, they begin to appear as much as 1.5 million per acre, which is why they are commonly called the 17-year-old locust in the US. A similar phenomenon occurs in Japan: - These millipedes spend 7 years shifting from egg to adult form, and then 1 more years to mature. 8-year life cycle confirmed by tracking the complete life of individuals in two different locations, the authors of the study explain.
Interestingly, cybernews.world on this phenomenon began in 1972 in two different places, so knowledge about the species appeared gradually. As the work progressed, it turned out that Parafontaria laminata armigera has 7 stages of development, which remain in the ground, hibernate in winter and molt in summer: - Draft millipedes molt every summer and have 7 stages of development. They become adults by eight, eight years after laying the egg, the researchers explain.
Then they massively come to the surface in September and October, sometimes traveling as much as 50 meters for breeding purposes, hibernating for winter and mating again in late spring. By August, females are laying 400-1,000 eggs and all adults die, making room for the next 8-year-old generation. Interestingly, as with cicadas, the 8-year cycle is not synchronized everywhere, and researchers in central Japan suspect there are probably 7 places where millipedes mature at different times. And since these do not move too much, specific trains have a problem in the same places every 8 years.