What are two black caterpillars with red in the middle?

According to the information you provided, the two caterpillars in the middle, black and red, may be the larvae of the blue-footed orange borer.

Blue-footed moth is an important leaf-eating pest, which mainly harms Podocarpus and bamboo cypress. The body of the larva is black and white, the head and feet are orange, and there are orange stripes on the side, which is a warning color. Mature larvae are about 5 cm long and then dive into the soil to pupate. Adults appear from June to September and live in flat land and low-altitude mountainous areas. During the outbreak, this caterpillar will eat all the leaves of the host, leaving only bare poles, which is of great significance for pest control in forestry and gardens.

The above information is for reference only. If more detailed information is needed, it is recommended to consult relevant websites or professionals.