It started with this photo:
|Photo by Marty Horowitz 4/30/2017
And these questions from Marty:
I think it’s a Palmer’s Metalmark (FRED - please confirm/correct). The very short story: I scooped it out of the pool, along with many others (why do butterflies drown themselves?). I put the skimmer down in the sun and when I returned in a few minutes, this one twitched (so I took its portrait). In another couple of minutes it few off!
It is certainly a Palmer’s Metalmark. There is a intermittent rocky stream at the top of Garden Canyon in Fort Huachuca that has a few persistent pools carved out of solid granite. We refer to these pools as the dead pools as we can find numerous dead butterflies and other insects. These pools are usually best (or worst from the insect’s perspective) in the fall, when we find many Chiricahua Whites, Arizona Sisters and numerous hairstreaks and blues.
|Photo by Fred Heath 4/23/2017
Sunday, a week ago [4/23/2017], we decided to check out the pools and sure enough they were filled with insects (see photo above) with numerous (maybe 25-30) Arizona Hairstreaks (the bright blue creature in the middle). We were able to scoop a few AZ Hairstreaks and a Juniper Hairstreak which were at the edge of the pool and watched them walk and then fly away as they dried out. We had seen no AZ Hairstreaks other than the ones in the pool that day.
We have many theories as to why they end up in these pools (and your swimming pool), but we think that some initially get trapped as they land on the surface thinking they can get a drink doing the typical puddling behavior. Once some of a particular species get stuck, we believe others of that species may be attracted to butterflies in the water.
We’ve noticed a similar thing when a mantis on the ground catches a butterfly (usually coming to wet soil) and eats the body allowing the wings to flutter to the ground. After a while, there are numerous consumed individuals, all of the same species and as more wings are piled up, the more the site begins to be attractive to others of that species. I can imagine the “poor” mantis, thinking, “Darn, I’m getting sick of eating only Bordered Patches today!”
Last year, Fred took the photo below at the same place.
|Mixed Gender Synchronized Swimming Team
These are all Chiricahua Whites (orange female and white males).
Thanks, Fred and Marty, for this in-depth story. Ha!