Dollar stores/100-yen shops are selling plastic cages/boxes for summer time pets, the stag beetle (“kuwagata”) and the rhinoceros beetle (“kabuto”) in particular. They also sell special dirt for the beetles as well as food. Beetle food is a kind of sweet syrup that they suck up.
The containers can be used for any kind of insect collection, which is a common summer pastime in Japan. Some insects can be very expensive, and competitions for size and races among competing owners and their bugs are not unknown.
Some families go to the forested countryside to hunt for beetles while others go to pet shops and buy the larvae which they care for until the beetles hatch.
Like many Asian countries, Japan’s summer is steamy and humid. It’s good for insect breeding. The stag beetle and rhinoceros beetle are popular for their size, their unique shapes, and the ability of children to witness their life cycles from larva and pupa through to adult insect make them a real-time science project.
The cicada (“semi”) is especially renown in these parts in August, when the air is so thick with their chirruping you think you can cut it with a knife, and the immensity of their sound strikes you when you open the door in the morning. In English all insect noise is habitually described as “Buzzzzzzzzzzz.” In Japan the cicada’s sound is rendered “Miii-miii-miii-miii-miii” or something like that.
Part of what accounts for the place of noisome insects in Japanese culture is the curious assertion that insect chirruping makes Japanese feel cool in the summer heat. It’s not about the insects themselves so much as their high-pitched noise. The popularity of wind chimes (“fuurin”) tinkling on the balcony has the same root. Maybe it’s because the sounds are distracting.