Ladybugs, also known as ladybirds and lady beetles, are small, red insects with black or yellow spots. The Everything Ladybug website counts 5,000 known species, with more discovered all the time. Despite their name, ladybugs can be male or female, but telling them apart presents a challenge.
Many people erroneously think that the number of spots determines the gender. According to Everything Ladybug, the spots serve as a warning to predators, rather than an indication of the bug's sex: Male and female ladybugs can have the same number and pattern of spots. Conversely, ladybugs of the same gender may have a different spot pattern or color, even if they're of the same species.
Ladybugs vary in size, according to the Bugs and Weeds website, which recorded a one-fifth-inch long, two-spot ladybug and a one-third-inch long, seven-spot ladybug in one survey. National Geographic states on its website that ladybugs vary from one-third of an inch to two-fifths of an inch in length. While size is not a perfect indicator of an individual ladybug's gender, males are slightly smaller than females.
If you see two ladybugs in the process of mating, it's easy to tell which is male. During mating, the male ladybug will mount the female and grab her elytra -- "the outer hard shell-like wings of the ladybug," explains LadybugLady.com. In that scenario, the ladybug on top is male.
According to the Ladybug Lady website, the only way to be sure of a ladybug's gender is to see its sexual organs. Because ladybugs are so small, however, you can't see those organs with the naked eye. Under a microscope, and with an entomologist -- a scientist who studies insects -- as a guide, you could clearly see that a male ladybug has tiny, hair-like structures on the last segment of his body, whereas a female does not.