For me, it was the summer of swallowtail butterflies. The Rappahannock county butterfly count broke their previous record for eastern tiger swallowtails, hitting 3,081 this year (see sidebar for more butterfly count highlights).
Among the many caterpillars I saw throughout the summer were eastern tigers and spicebush swallowtails, both of which have pupated on or near my house. I also found larvae of the black swallowtail, which I had never seen here before in any form. They were munching away on a potted parsley on my deck. While this was a nonnative plant, the parsley family (Apiaceae), the host of this butterfly species, also includes Queen Anne’s lace and poison hemlock.
Knowing that these cats were probably of the generation that overwinters as pupae, emerging as adults in the spring, I decided to foster them through the winter. Moving off the parsley after they went through their final instar (larval stage), they pupated on twigs I’d placed in a mesh cage with the pot of parsley. I removed the pot, put the larvae in separate cages. I placed the cages under the eaves of my deck so the pupa would be able to experience normal weather conditions while overwintering without the threat of being eaten by the wrens and phoebes that often hunt bugs there that time of year.
Last Thursday (Sept. 19), Bruce Jones reported in an email thread that monarch butterflies had started migrating through his naturalized property, which attracts a variety of wildlife. He estimated 40-50 monarchs were visiting the goldenrod and sunflowers there. From F.T. Valley, Jane Smith reported seeing more than 60 at her place — a “thrilling” sight, she wrote in the thread. Noting the annual fall hawk migration is also underway, Bruce also wrote that hawk-watching stations had reported large numbers of monarchs now coming south.
On Friday, I went to Big Meadows, in Shenandoah National Park, hoping to see the monarch migration. It was a beautiful day, and the small part of the meadows I walked through to take photos had dozens of monarchs, along with some buckeyes, red admirals and other pollinators. They were nectaring on the prolific asters and goldenrod there, along with thistle and anything else in bloom. I could see monarchs flying around all over the meadows — hundreds, perhaps more, fueling up before continuing their journey south.
As summer was ending, I started seeing more moth caterpillars. Among them were ailanthus webworm moths, which pupated in the silken web they’d woven in an ailanthus sapling near the house. But the big find for me was my first sighting of a saddleback caterpillar. Some moth cats, like this species, have spines that carry a chemical that stings; the saddleback is believed to deliver the nastiest sting. It’s hard to imagine, considering how cute it looks — like a tiny Scottish terrier wearing a bright green sweater.
The spines with the chemical are clustered on the cat’s head. Even though I knew this cat was dangerous to touch, so was careful in photographing it, I generally avoid picking up wild critters — no matter how tiny and cute — until I know picking them up won’t harm me or them. Even some walking-stick species can spray chemicals into a predator’s eyes when threatened, although the most common walking stick here, the northern walking stick, is harmless and is often kept as a pet. A male and female of the species recently showed up on my recently, and another on my exterior wall, as they often do this time of year.
Beyond the amazing number of eastern tiger swallowtails, the big bug news this summer was the huge swarms of common green darner dragonflies (with other dragonfly species likely mixed in) showed up in Rappahannock, as Lyt Wood wrote about in the in this paper on Sept. 20. Swarms of them were being reported all over the state and at least as far as West Virginia, as I found out from a friend in the panhandle.
As Lyt noted, the dragonflies were feeding on swarms of other flying insects that had appeared, many so small I didn’t see them until I looked at the photos I’d attempted to take of the dragonfly swarms (with little success). In the dark areas, the tiny insects formed what looked like a snowstorm. By the end of last week, the dragonfly swarms were dissipating in some locations, including Bruce’s property, but “what a show” it was, as he aptly put it. On Tuesday (Sept. 24), Lyt reported in an email that “lots of dragonflies” were still moving through where he lives, south of Sperryville, but in numbers “more typical migration at its peak.”
The final insect swarm I witnessed, as summer came to an end, was from a huge nest of what appear to wasps in the Vespa family (yellowjackets) that my landlady found in her yard. What was likely a bear had excavated a huge hole to get at the nest, which was wedged in among rocks underground. Now exposed, the nest was swarming with wasps trying to manage the damage. Although nests of such hymenopterans (which includes ants, bees and wasps) are frequently targeted by bears because the insects provide a rich source of protein, the bears pay a price for disturbing them.
The summer ended, as it has here for almost a decade, with swarms of brown marmorated stink bugs arriving on the exterior of my house, seeking winter shelter. This annual invasion, thought to be triggered by the waning daylight, usually peaks around the autumnal equinox. The numbers of the bug have declined here, likely because many have dispersed further south and west. Native predators have also warmed up to them. (See the slideshow below for photos of invertebrates I photographed from August through the end of summer.)
While summer may have ended officially, invertebrate activity is likely to continue for some time, thanks in part to global warming. Dreading the silence of the coming winter, I have been sitting outside as much as possible to enjoy the choruses of cicadas, katydids and crickets while I can.
© 2019 Pam Owen
Butterfly count 2019 highlights
The Rappahannock County butterfly count (officially, the “Washington, VA” count) once again set a record for the number of eastern tiger swallowtails recorded. In doing so, it broke its previous local record, set in 2013, and the national record for the 45-year North American Butterfly Association (naba.org/butter_counts.html) annual July Fourth count. Whether it’s a new North American record won’t be known officially until a few months from now, when NABA publishes its annual report. I heard a rumor that some other count in Virginia may have almost double that number of eastern tigers, so I’m looking forward to seeing the official results.
In hitting the highlights of this year’s count, I’ve excluded last year’s data because it rained last year, and although the count has been conducted in rainy weather before, one site that usually has high numbers was not counted, so would skew the overall totals. The totals at other sites in the Rappahannock count were not notable, according to count leaders.
Female eastern tiger swallowtails have a dark morph (form), which makes them hard to distinguish from the other swallowtails that are predominantly black, especially from a distance. This is particularly true for the spicebush swallowtail, which also usually scores high in the count, but also the pipevine swallowtail, the black swallowtail and even the giant swallowtail. In 2013, 607 butterflies were reported only down to the genus level (“swallowtail spp”), while only 137 were in 2019. In any given year, likely 80-90 percent of the butterflies lumped into the “swallowtail spp” category are these dark-morph tigers, so the actual number of tigers in 2013 may not be that far off from this year, although still lower.
With the boost from eastern-tiger numbers Rappahannock recorded a new overall high for the total number of butterflies counted: 5,543. Totals for the previous years (excluding 2018) were 2,377 (2017), 1,478 (2016), 2,123 (2015), 1,291 (2014), 4,798 (2013), 2,380 (2012) and 1,254 (2011). Although the nine years of count data are not enough to clearly show trends, booms and busts in some species, especially eastern tigers, do seem occur.
Other counts nearby did not report relatively high numbers for the eastern tiger this year. Bert Harris, the institute’s executive director of the Clifton Institute, which manages the Airlie count in Fauquier County, reported they had “a great count this year.” Although the number of eastern tigers was not that high, Harris said the clouded skipper and juniper hairstreak seemed to be “having a good flight this year.” Two other counts that include parts of Shenandoah National Park also did not report particularly high numbers for the eastern tiger but did report new high numbers for sleepy orange, American snout, common buckeye and common wood-nymph.
Along with the eastern tiger, several other species broke the Rappahannock count’s record for previous years, most notably the spicebush swallowtail, common buckeye, red-spotted purple, red admiral, monarch and eastern comma. The data showed no species in serious decline, although some species have fluctuated in number over the nine years of the count, and others have experienced slow rises and declines (think bell curves). Even nine years of data is not enough to clearly determine trends, but it’s a start.