I love the hairs sticking out from the thorax of the top monarch. Now that it is mating season and many of the monarchs are down closer or on the ground, I am getting some great close up shots. I am also seeing things that i never noticed before, like the tactile setae, aka hairs.
I got the following information from MonarchWatch.org -Adults have tactile setae on almost all of their body parts. In both adults and larvae, the setae play an important role in helping the butterfly sense the relative position of many body parts (e.g., where is the second segment of the thorax in relation to the third segment). This is especially important for flight, and there are several collections of specialized setae and nerves that help the adult sense wind, gravity, and the position of head, body, wings, legs, antennae, and other body parts. In monarchs, setae on the adult's antennae sense both touch and smell.
This one on top is actually the female with the male on the bottom. however, the male will be trying to get the female folded into submission. That way he can easily fly up into the trees. And easily is only meant that it would be almost impossible in the female's correct pose.
I did not see these two take off. They stayed in this tree for many minutes before I got fixated on something else and when i checked back, they were gone.