It is easy to observe the gender differences between male and female luna moths while they are still in cocoons by looking at the markings on the outside of the cocoon. Once a luna moth has hatched, you can tell the female from male Luna months by looking at the antennae, body shape and color of the bodies.
Antenna Size and Body Color
The main method for discerning the sex of adult luna moths is antennae size. Males have larger and bushier antennae than females. Female luna moths have more of a blue-green cast to their coloring compared to males who tend to have a yellow-green color.
Examining the cocoons of the luna moths can allow you to determine the gender of the moths before they emerge. If two luna moth cocoons were started around the same time, if you look at the belly side of a cocoon, you will notice that some cocoons will have two notches located on the fourth and fifth abdominal segments. These cocoons contain female luna moths. Cocoons without these notches are male. You also can tell the difference between male and female moths when they emerge from their cocoons. Males often emerge several days before the females begin to emerge.
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