Cotesia rubecula is not common, established in only a few areas of the world.

Originally native to China, the parasite has been introduced as biological pest control in North America, specifically in New England.

Post-copulatory female mimicry by the male offers an advantage by acting as a mate-guarding mechanism.

[3] Cotesia rubecula parasitizes the cabbage worm caterpillar, generally in the stage of first instar, with the female wasp stinging and laying between 20 and 50 eggs within the host instar.

The impact on the host population can vary greatly, from a small percentage to up to 75% of the caterpillars in a given habitat.