Breaking: Mexican Silverspot Butterfly Sighted in Colorado

Right place, right time, and with a little help from your friends. That is how discoveries are made. All of those factors came together to verify the spotting of a Mexican Silverspot butterfly, Dione moneta on the eastern edge of Colorado Springs, Colorado on April 18, 2017.

Sharon Milito is a geology lecturer at University of Colorado, Colorado Springs, and a retired Colorado Springs School district eleven teacher. She has also been a volunteer with the city for ten years, doing paleontology surveys and acting as a science education consultant. She has, in her volunteer capacity, access to places not open to the public, including Jimmy Camp Creek Park on the very eastern edge of the city.

Sharon and I went scouting on Tuesday, April 18, and she took me to specific locations that seem to have a slightly greater biological diversity in the sprawling former ranch. It is a unique composite of many different habitats including mostly shortgrass prairie punctuated with sandstone bluffs. Some of the bluffs are covered in Ponderosa Pine forest. There is also Jimmy Camp Creek itself, a drainage fed by numerous springs within the property. There is almost always water in the creek, and some surprisingly deep pools in the sandstone bed. Otherwise, lots of mud trampled by cattle that still graze the park.

One of the areas we went to boasted a grove of wild plum, Prunus americana, in full bloom. It was like walking into a fairy tale. Hundreds of butterflies were sipping nectar from the blossoms. Most were Painted Lady, Vanessa cardui, but there were also Red Admiral (Vanessa atalanta), Milbert's Tortoiseshell (Nymphalis milbertis), Gray Hairstreak (Strymon melinus), Marine Blue (Leptotes marina), and several Monarchs (Danaus plexippus). Most of the Monarchs seem to have had a rough migration up from the south. The whole morning scene was mesmerizing and enchanting.

Eventually, Sharon called me over to ask "what about this one here?" and pointed out a butterfly that had me perplexed initially. At first I thought it was a Variegated Fritillary, which would be expected at this time of year. The wing shape was a little odd, though, and when I glimpsed the underside, it was studded with large, silver spots. Wow, a Gulf Fritillary. That is not a very common butterfly in these parts. I got several images of the insect and we went our merry way. Later, I posted what I thought was our somewhat significant find to the Facebook group "Arthropods Colorado" for more folks to enjoy.

Enter Robb Hannawacker. He raised the stakes substantially higher by proposing that the butterfly was in fact a Mexican Silverspot, Dione moneta. I was embarrassed to admit that until he mentioned it I was not even aware of the species at all, let alone where it is supposed to occur. Robb mentioned the identifying markings, and how our specimen matched them, and it is now pretty obvious that is what we have.

According to my copy of the Kaufman Field Guide to Butterflies of North America, the Mexican Silverspot "Strays to south Texas, rarely to southwest and Big Bend region. More at home in mid-elevation tropical woodlands but reported to breed sporadically in lower Rio Grande Valley....Recorded late spring to late fall (multiple broods in Mexico." The butterfly['s normal range extends from Mexico through Central America to Brazil. The larval foodplants are passion vines, which do not occur in Colorado.

The most recent northern record for the species in the online database of Butterflies and Moths of North America was on May 8, 2005 in Roosevelt County, New Mexico, by Christopher Rustay. As near as I can tell, this is the first record for Colorado, at least of recent vintage. Please alert me to additional historical records. Thank you. Now, go forth and see what amazing species you can find.

Filigree Skimmer State Record for Colorado

Earlier this month, on July 3, I was fortunate enough to be in the right place at the right time to make an important observation and documentation of a male Filigree Skimmer, Pseudoleon superbus, in Colorado Springs. This represents the first confirmed state record for the species as well as a significant northern range extension.

There is a vast series of vacant lots up the hill from my home that includes a narrow, deep riparian corridor through the otherwise degraded shortgrass prairie habitat of the hills. The channel carries water dependably throughout the year, and trickles into Sand Creek, a wide, mostly dry riverbed that sometimes runs in very shallow, meandering rivulets (except during storms when the volume is much greater).

The Filigree Skimmer was frequenting the large pond shown in the habitat shot above, repeatedly perching on the rockwork between forays up and down the watercourse. At first I assumed it was probably a Common Whitetail, Plathymis lydia, but something about those wing markings looked a bit off. Noting where it was repeatedly perching, I worked my way into a position where I could get the images shown here, taken with a Canon Powershot SX50. That powerful zoom sure comes in handy at times like this.

The near pristine condition of the specimen makes me wonder if perhaps the species does breed here rather than migrate up from the species' usual range of southern and central Arizona, New Mexico, and western and central Texas. This is essentially a subtropical species found as far south as Costa Rica, though mostly in dry uplands there.

Male specimens have the wings mostly blackish, especially the hind wings. Females have much less black, arranged in an abstract, reticulated pattern. Both genders have the "pinstripes" on the eyes. The total body length varies from 38-45 millimeters, and the length of the hind wing averages 30-35 millimeters.

The preferred habitat for the Filigree Skimmer is a rocky stream or river with a slow or moderate current, usually in an open setting. The little creek where I found it certainly fits the bill. Females lay their eggs by hovering and dipping the tip of their abdomen into the water, usually in the vicinity of algal mats or piles of detritus. There is plenty of both in this location, too.

Bill Maynard, our local authority on Odonata, asked for directions to the spot where I saw the skimmer, and he visited on July 4 but had no luck. Ironically, he did observe several species of damselflies that I had not yet documented for the area. He also got a lovely image of a Gulf Fritillary butterfly, as likely to be seen this far north as the Filigree Skimmer.

My record of the Filigree Skimmer is awaiting confirmation at Odonata Central. I encourage my readers to consult that website to see what species have been recorded in their state or county, and add their own observations as they deem appropriate.

Just because you have "never seen this (insert name of insect or other arthropod here) before in (your) life," and you have "lived here for (insert number of decades or years)," does not mean that it is something rare or exotic or otherwise novel. BUT, sometimes it really is a unique find worthy of note. That is your take-home lesson for today: Be observant and don't assume anything. It helps me to have some knowledge of what should and should not be here in Colorado, but you, too, can make significant contributions to our collective scientific knowledge.

Source: Paulson, Dennis. 2009. Dragonflies and Damselflies of the West. Princeton, New Jersey: Princeton University Press. 535 pp. I highly recommend this reference, well worth the price.

More Beetle Excitement

I got some exciting news this past week that I thought I would share. It involves a species of beetle that I collected while on a photo outing on the Fourth of July near the Quabbin Reservoir in Franklin County, Massachusetts.

While in a forest clearing (well, more of a slash pile of logging residue, actually), I saw a metallic woodboring beetle in the family Buprestidae. It seemed non-descript, much less brilliant in color than others I have seen, but I took its picture anyway. I wanted more images, though, so I captured it alive in a vial and took it home.

After chilling this highly active animal in the refrigerator, I placed it on the kitchen table and took more images. I was finally able to see that it was more or less metallic purple, the granular violet nature of its exoskeleton reflecting the light from my camera flash. It looked like the beetle had perhaps hatched out of a geode rather than a pine tree.

I posted my two images, one “in the wild” and the other “staged,” to Bugguide.net in the hopes of confirming my identification of it as Buprestis striata. Much to my surprise, the consensus among the experts is that this is actually a specimen of Buprestis sulcicollis, a much less commonly-encountered species. It was, in fact, previously unrecorded for the state of Massachusetts, though long suspected of occurring here.

Getting a state record is reasonably remarkable, but considering that I have been here in Massachusetts for a grand total of two months, it feels pretty spectacular. It would be great if it translated to a wage increase, but alas, I suspect all I will get out of it is “this stupid t-shirt” equivalent. As luck (good or bad depending on your viewpoint) would have it, the beetle subsequently died before I got around to releasing it. I will get to decide where the specimen will be deposited, which is a reward unto itself, I think.

The beetle deserves a bit of notoriety, too, but very little is known about Buprestis sulcicollis. Adult beetles measure from eleven to 15.5 mm. The recorded hosts for the larvae are pitch pine and eastern white pine. Its distribution is mostly from the Great Lakes to the Atlantic seaboard, but there are records as far west as Alberta and the Northwest Territories.

I encourage each of you to not assume that whatever creature you encounter is common, known from your area, or even already known to science. Take pictures, note the habitat, any behaviors you observe, and record the date and precise location you found the organism in. You never know what may become of your patient and careful study.