Sawtooth stag

Characteristics

A stag beetle representative of Japan, characterized by its large jaw with saw-like teeth. They are reddish brown to dark brown, and there are large individual differences. The shape of the male's jaw varies from highly curved to short and straight. Large males can exceed 7 cm. Mandibles are thought to have evolved to fight other males over females. Females are about 2-4 cm in size and reddish.

Ecology

It gathers in the sap of sawtooth oaks and konara oaks in broad-leaved forests from early summer to autumn. They are nocturnal and active at night, but can be seen during the day. They may also use their jaws to fight other stag beetles and beetles. Most saw beetles do not survive the winter as adults and die in the fall.

Stag beetle larvae

Stag beetles lay their eggs in the ground of broad-leaved forests or under dead trees. The larva grows while eating rotten wood, molts twice, and takes 1 to 3 years to mature. Before becoming a pupa, it creates a space called a pupal chamber and takes about a month to emerge.

Breeding Stag beetles

Since it is a stag beetle that can be found all over Japan, it has long been raised by children.

The breeding method is the same as other stag beetles, laying mats such as rotted wood in a breeding box such as an insect cage, and putting perches and insect jelly as food. If it is a pair, you can spawn by putting a piece of rotting wood in it.

Habitat

A newly hatched male emerged from the bark of a konara oak tree in Hachioji, Tokyo. It was about five centimeters in size and had a loosely curved jaw. It's hard to see in the picture, but there was a female under the male, and they were mating.

In addition to near trees with sap, you can see saw stag beetles that fly to screen doors and streetlights at night.