When black cutworm adults mate at night, the sexual impulse behavior changes with moth age. 4-day-old moths have the most sexual impulses (up to 2 1) and the longest duration (up to 1.77min on average) every night. Most of them mate 1 ~ 2 times, and a few mate 3 or 4 times. Generally, the time of each sexual impulse is about1min; After 6 ~ 7 days of age, mating gradually stopped and entered the peak of spawning.

The spawning habits of adult ground tigers are as follows:

Black cutworms can't be parthenogenetic. Although you can lay eggs without mating, there are few eggs and you can't hatch. Female moths mostly lay eggs at night, and their spawning sites vary with seasons, plant species and topography. Weeds or crops are mostly produced on clods or hay stalks before emergence; When host plants are abundant, they usually lay eggs on the back of plant leaves. Most eggs are scattered, and several eggs are laid together at the peak of spawning. And have the habit of feeding supplementary nutrition while laying eggs. It was observed that adults selectively laid eggs, mainly in fields with many weeds, especially in Chenopodiaceae. In addition, it is also selective for leaf characteristics; Anyone with a rough and hairy surface has a large number of eggs. Therefore, it is advocated in the forecast to cut sacks into small pieces and put them in the ground to lure them to lay eggs. The number of eggs laid by black cutworm is mostly 800 ~ 1000, and the highest number can reach more than 2000.