Predators
The predators of C. maculatus are mostly parasitoid wasps. There are likely other generalist predators that would eat C. maculatus if the opportunity presented, but Dinarmus species, Anisopteromalus calandrae and Uscana mukerjii all specifically target C. maculatus, as well as other species in the Callosobruchus genus.
Dinarmus basalis parasitizes the early larval stage of C. maculatus and prevents the larva from developing. This limits the amount of damage C. maculatus can do to the bean, though the larva is still left inside the bean, as is the parasitoid which must also emerge. The parasitoid does not consume the bean, but gains its nutrition from the beetle larva. This leads to less damage to the bean than if the larva had developed to maturation. However, the bean is likely not viable for the next season and probably will not be used for human consumption.
Uscana mukerjii is an egg parasite and prevents the egg from hatching, thereby indirectly protecting the egg from damage.
Read more about this topic: Callosobruchus Maculatus