Identifying Male Monarch Butterflies

Monarch butterfly photographed by Jeff Zablow at Raccoon Creek State Park

You will always be asked, “How can you tell whether a Monarch Butterfly is a male or a female?” It is asked each and every time I show photographs before groups of adults and children.

It’s August 17th and this butterfly is resting on a Common milkweed leaf (Asclepias Syriaca) at Raccoon Creek State Park in Hookstown, Pennsylvania.

This powerfully built butterfly demonstrates how to discern the sex of male and female Monarchs. Do you see that black patch on his left hindwing vein? Only males have these scent glands, one on each hindwing. If you see a Monarch and it doesn’t have two black scent patches, it’s a female. If it does have a black scent patch on each hindwing, it’s a male.

2013 has got to be a bummer for male Monarchs. With so few females about in the 48 continental U.S. states, males have more than the usual patrolling to do to find a mate, and begin the Monarch butterfly life cycle all over again. No time to waste!

Jeff