The Autumn Darter (Sympetrum frequens) is a species of dragonfly endemic to Japan.
Both male and female Sympetrum frequens are yellow in the immature adult stage, but males turn into red upon maturation (like most Sympetrum species). 
It lives near grasslands and can grow up to 40 mm in length.
The Autumn Darter is regarded as a migratory species.
Most individuals breed in the lowlands in autumn, the eggs overwinter and hatch the next spring and the larvae grow up in early summer.
After moulting they migrate to the highlands, spending time there to maturate.
And when they are mature, they return to the lowlands to breed.

Shirakawago, Gifu Prefecture, Japan, 26 September 2018