How do you know what sex a ladybug is?

Answer

The easiest way to determine the sex of a ladybug is when you see two ladybugs mating. The male is then on top, the female below (as with tortoises).

If you don’t see them mating, distinguishing between males and females is very difficult. Usually both sexes are colored the same, so color or number of dots does not matter. Females are usually slightly larger than males, but that is not a reliable point of difference either.

The abdomen of a ladybug consists of 6 segments (pieces that hinge). The shape of the posterior edge of the segments allows to distinguish females from males. There is no general rule, each species has different differences between the sexes. All males have one characteristic in common: they have thin membranes between the abdominal segments (so that when they sit on a female, the abdomen can be curled more). To see these things you need a loupe or a binocular microscope and some experience.