I just took these photos of a pair of mating monarchs in Ann Arbor, MI. I looked through the Bug Love pages and didn’t see any monarchs, so I hope these are a useful addition to your site. One question: one of these butterflies has been patrolling my garden for the past week or more, chasing away all the other monarchs until tonight. I’m assuming that’s the male? Just curious.
We actually do have other mating Monarch Butterflies buried in the archives of our numerous Bug Love pages, but your beautiful image is still a welcome addition to our site. The behavior you describe is consistant with that of a territorial male butterfly trying to attract a mate. The male Monarch butterfly, like the open winged individual in your photo, can be identified by the conspicuous black scent glands on his lower wings. According to a Monarch website we found: “Males use the pheromones produced by this gland to make themselves attractive to females.” This is a bit of a role reversal among Lepidopterans. Most female moths release pheromones to attract the male, and the male has bushier antennae to better sense the pheromones. In the case of the Monarch, based on your description, we would deduce that the male located a likely food source and staked out the territory. He then released his pheromones and attracted a mate. Thanks for the wonderful account of your observation.