Some of us have come upon butterflies, like these, and watched them do this. Once it became clear that these Spring Azure butterflies were drinking up bird ‘poop,’ our respect for such butterflies usually plummeted. If this sight made you want to know why? Why are they doing this, who is there to ask? Your friends know nothing of this, and zero of them have 1/100 of a second’s interest in it. Your friends with advanced degrees in Biology, Chemistry, Environmental Study and even your friend with a degree in Moth behavior either cannot be reached that day, or are unable to help you.
These decades of mine, pursuing butterflies, have taught me of the dearth of information out there for these good questions. In the past I’ve sought feedback from the handful of butterfly experts whose name are known, and always, yes always came up empty, none of them ever responding, not the same day nor a month later. Having been raised on the streets of a very huge eastern US city, this lack of respect, under the guise of we are too busy doing worthwhile more important works, did/does truly not sit well with me.
These Spring Azure butterflies are probably all males. They are sucking up the liquid, white nitric acid released by a bird, released along with its darker colored solid feces. Why are they doing that?
Male butterflies often fly for hours, almost without stop, seeking females. They are driven by the strong internal message: mate. This extensive, very exhausting flying wears out muscle protein. They must insure that their production of muscle protein continues, without stop, for they must constantly replenish muscle protein . . . to continue to fly and fly and fly.
Why the white, liquidy nitric acid? It is rich in the mineral Nitrogen, and nitrogen is needed to synthesize (build) new amino acid molecules, so that those same amino acid molecules can be joined together to form new butterfly muscle molecules.
I used to LOVE teaching high school Biology. I loved it.
Raccoon Creek State Park, Hookstown, Pennsylvania, west of Pittsburgh (40 minutes west of the Steel City)