Animals such as skunks, moles, and raccoons are known for their voracious consumption of grubs and other insects. Fortunately for those that want Japanese Beetles to go away, these vertebrates will gobble up Japanese Beetle larva in their path as well.
While the praying mantis, other mantids, and other predatory insects and arachnids will feed on adult Japanese Beetles, they are not known to significantly affect the population. This is due to the small amount that these other insects and arachnids need to consume combined with the rapid explosion of activity associated with Japanese Beetles. Insects such as ants and ground beetles that feed on the immature stages of insects have a more significant impact on Japanese Beetle populations.