Growing up along Colorado’s Front Range, as a young lepidopterist, the last warm days of the season were always special opportunities, to see how late the toughest butterflies could persist into the shortening and progressively colder days of November.  On a typical year, up to a dozen butterfly species can usually still be found here on warm days in early November, with that number dwindling to nearly or exactly zero by the end of the month.  Adults of only five butterfly species have ever been found in nature in December in Colorado, including the Orange Sulphur Colias eurytheme (late date of 4 December), Clouded Sulphur Colias philodice eriphyle (15 December), Dainty Sulphur Nathalis iole iole (5 December), Painted Lady Vanessa cardui (4 December) and the Mourning Cloak Nymphalis antiopa (31 December).  Of these, only the Mourning Cloak passes the winter here as an adult, though along with other nymphalid butterflies that overwinter as adults, it usually resists the temptation to fly around on warm winter days until late February or early March.  Remaining adults of the other four species will inevitably perish with the onset of winter, but they hang on for as long as they can!

Of all the adult butterflies that have persisted into December in Colorado, all are year-round residents here, except for the Dainty Sulphur.  The tiny Dainty Sulphur cannot survive the long winters in Colorado, and freezes out of the state on an annual basis.  But starting in April each year, these diminutive butterflies begin to arrive, from Texas and the desert southwest, probably due to winds more than their own dispersal abilities, and by the end of the season, they can literally be found everywhere in the state, even on alpine tundra above 13,000′ elevation!  There are several larval foodplants for them here in warm months, and the Dainty Sulphur can produce two or three generations in Colorado before it is finally frozen out at the end of the season.  But the late-season adults come equipped with an unusually dark, greenish ventral coloration, for taking in the early winter rays, and prolonging late-season life.

I arrived back in Colorado for the holidays two days ago, and did not expect the unseasonably warm conditions awaiting me!  It was 62 degrees F yesterday, and it reached 64 today!  Of course, such conditions mandate field work (and postponement of holiday shopping), to see what is still out!  After the recent frigid low of -14 degrees F a couple weeks ago, I did not expect to find many insects, but have been pleasantly surprised!

Today at about 11:00 hrs, on a ridge at 6400′ elevation, I was astonished to scare up a male Dainty Sulphur!  Shortly after taking flight, he settled on a dead plant a few feet away, so I moved in for photos! Here’s the first good shot I got of him:

I spent the next several minutes getting photos.  In the persistent breeze and warm morning sun, he did not sit still in any one place for long, and most of the time, after taking flight, he would land in places that were not conducive for photography.  But, finally, he landed in a clearing where I could get several crisp photos.  As you can see below, he was in excellent condition, not missing a scale!

This is the latest a non-overwintering adult butterfly has ever been found in Colorado!  Judging from his immaculate condition, he most likely survived the recent frigid weather as a pupa, and probably eclosed in yesterday’s unseasonable afternoon warmth.  While there is little or no chance of this guy finding a mate or surviving even a week (cold weather predicted to return soon), his appearance today is testament to the toughness of this tiny butterfly!

It’s easy to think of small butterflies as delicate or fragile, but in fact, the smallest butterflies are some of the toughest! Today, on this early December day in northern Florida, most butterflies are in dry-season mode, that is, hibernating. However, a few butterflies here are as abundant as ever. The Eastern Pygmy-Blue (Brephidium pseudofea), one of the smallest North American butterflies, is taking full advantage of our unusually warm December weather, despite a recent freeze on Thanksgiving morning. I spent a couple hours with this tiny but mighty butterfly today, and want to share the experience with you!

The Eastern Pygmy-Blue lives in salt marsh habitats, where its larval foodplants grow in abundance. While these environments are quite scenic, they are subject to harsh conditions on a regular basis. At times, all the low vegetation is completely inundated by sea water, especially during storms. And it freezes here. Yet for a few organisms, such conditions are ideal…

The Eastern Pygmy-Blue lives in coastal salt marshes in the southeastern United States, from eastern Texas to South Carolina. In northwestern Florida, the favored larval foodplants of the Eastern Pygmy-Blue are Saltwort (Batis maritima) and especially, Perennial Glasswort (Sarcocorina perennis). Wherever the latter plant is found, Eastern Pygmy-Blues are usually common.

Everything in the intertidal zone must tolerate regular exposure to salt water. This makes survival difficult for many plants and animals! Yet there are some, including our tiniest of butterflies, that feel very much at home in the ever-changing intertidal environment, egg, larva, and adult.

Males of the Eastern Pygmy-Blue spend most of their time cruising the canopy of larval foodplants, searching for females. When it is sunny and not too windy, males are in continuous flight above the foodplants, and rarely stop to pose for a photo. Normally, you have to follow a male for several minutes before he will pause, briefly (as above), for a chance of a close look or to capture his image!

I spent about 30 minutes in a “grove” of S. perennis today, around noon, following the various males as they landed, rarely, in their search for females (photo above).  Then, along the edge of the salt marsh, I saw a female blue fluttering above the foliage. She flew differently- slower, and less determined. I headed towards her, as she was settling on some glasswort.

I spent a couple minutes photographing this female, as she displayed her underside against the late morning sky (above). Then, she became restless and moved on…

I caught up with her a couple minutes later, when she landed on some Sarcocorina, with her wings spread partly open, signaling for attention from nearby males. It only took a few seconds for a male blue to arrive on the scene!

The male blue (above) pursued the female for several minutes, but all attempts at mating ended in failure. She then flew a few feet away and landed on an especially lush-looking Sarcocorina twig.

As I watched, she twisted her abdomen around the twig, and placed an egg at the junction of two branches.  I could not see the egg from where I was watching, but then changed my view (yes, sand spurs and cactus spines in my left knee), and could see the egg clearly!

After ovipositing, the female Eastern Pygmy-Blue rested briefly, before taking flight once again.

As she flew away, a breeze kicked in, and I lost sight of her. Thus, I headed along the edge of the salt marsh, to another area where I often find these blues.  Upon arriving at the site, I saw a female perched, signaling for males.  Just as I crouched down, ready to take photos, a male blue arrived, and the two immediately began to court.  Before I knew it, the two were in copula, and luckily, I was able to get a few shots.  Their union only lasted a few minutes, before they flew off in different directions, but I felt very lucky to have been there at the right moment…

I’ll share more about these awesome blues in a future post (there is so much more to tell about them), so stay tuned!