Dragonflies
Dragonflies are usually associated with ditches, rivers, ponds, or other damp places where their nymphs (larvae) live. However, adult dragonflies can also be found on mountaintops or in grasslands and forests, and those environments are often equally important to their life cycles. Depending on the species, a newly matured dragonfly may make short trips from the water, spend weeks away, or even leave the water entirely, returning only to breed.
All this migration, combined with the wide variety of environments preferred by different species, means that dragonflies can be found in many places around Mt. Sanbe. Those that prefer rivers are generally found near cold, fast-flowing streams where foliage hangs over the bank. Their nymphs hide beneath rocks and logs in the riverbed. Rice fields, which are flooded for part of the growing season, are a favorite habitat for members of the genus Sympetrum, known as “darters” or “meadowhawks.” The autumn darter gains its wings in July, then relocates to the grassy summit of Mt. Sanbe. In autumn, it returns to its birthplace to breed and turns bright red.
Around roads and grasslands, visitors might come across oniyanma (Anotogaster sieboldii), Japan’s largest dragonfly species, which flit between roads and nearby rivers from July to October. These areas are also home to another autumn resident, Lestes temporalis, a damselfly identifiable by its metallic green body and large green eyes.
Once mature, most dragonflies live only for a season, then die off by winter. One Sanbe species can be seen year-round: the damselfly Indolestes peregrinus, which hibernates through winter and breeds in spring. This is the origin of its Japanese name, “thin-bodied dragonfly who greets the new year” (hosomi otsunen tonbo).
