Monday, Dec. 30, 2002
* Japanese name: Yotsu boshi hiratashide mushi
* Scientific name: Dendroxena sexcarinat
* Description: The full name of this insect is the Japanese four-spotted carrion beetle. It is 15 mm long, with a flat, orange body with four black spots. The body is unusually flexible for a beetle. Carrion beetles belong to the family Silphidae.
* Where to find them: Carrion beetles are common in mountainous temperate regions, forests and woodlands, and urban areas. A good place to find them is in the carcasses of roadkill (not that poking around in dead animals is a pleasant thing to do), although the adults can also be seen on bushes and trees. The adults are attracted to light. Carrion beetles are sometimes found in human corpses that have been exposed to the elements.
* Food: The adults and larvae feed on fly maggots and the rotting flesh of dead animals, but adults have also been known to hunt and eat caterpillars. The carrion beetle's body is flexible because the insect needs to squirm through the decomposing tissues of small carcasses. Eggs are laid on the carcass, and the life cycle after hatching goes through the three stages common to all insects which undergo metamorphosis: larva, pupa and adult.
* Special features: As soon as a bird, mouse or other small animal dies, its body is up for grabs by a range of different creatures. Probably the first to arrive at the site of a carcass are the blowflies, but ants, fungi and bacteria will all quickly establish themselves. Carrion beetles are highly sensitive to the odors released by rotting flesh, and can pick up the scent from a kilometer or more away. They have special olfactory organs on their antennae, which are flattened and shaped into clubs to increase the surface area and so improve their ability to smell. The beetles arrive at a carcass during the early to middle stages of decomposition, which is why the larvae of carrion beetles often get to feed on fly maggots.
If a male arrives at a carcass and finds himself alone, he will release a pheromone to attract a female. Some males release pheromones without having found a carcass. But even though these males manage to copulate with the duped female, they probably don't father many of the eggs she will lay, because when she finds a carcass she will copulate with another male, and it is the last male to mate who fathers most of her eggs.