The Best Year for Butterflies..Ever!

Posted by Mark Conboy

Though the butterfly season is not yet entirely over, it’s certainly not too early to declare 2012 one of the best years ever for observing butterflies in Ontario. Though most of the excitement was to be found in southwestern Ontario, we here in eastern Ontario were not without some great butterflying of our own.

Common Buckeye. Photo by Brian Penney.

At QUBS, like in much of the province’s south, the excitement came in the form of several waves of “invading” migratory species starting with red admirals (Vanessa atalanta), American ladies (V. virginiensis), painted ladies (V. cardui), question marks (Polygonia interrogationis) and common buckeyes (Junonia coenia) at record early dates and in unprecedented numbers during the March heat wave. Though red admirals, American ladies and question marks occur good numbers during most years, painted ladies and common buckeyes are rather rare species at QUBS. During this initial invasion we also had two grey hairstreaks (Strymon melinus) in a remote part of the Pangman Tract. Grey hairstreaks are yet another rare species at the station having been recorded on only a few occasions.

A second wave of migrants arrived a few weeks later. This second invasion had most of the above mentioned species plus mourning cloaks (Nymphalis antiopa), little yellows (Eurema lisa; rare at QUBS) and unusually high numbers of early season clouded (Colias philodice) and orange (C. eurytheme) sulphurs. In just the last few weeks even more invaders have arrived. Recently fiery skippers (Hylephila phyleus), at least one sachem (Atalopedes campestris) and two white-M hairstreaks (Parrhasius m-album) have reached the Kingston Region but none have yet been found at QUBS. In other parts of southern Ontario funereal duskywings (Erynnis funeralis), cloudless sulphurs (Phoebis sennae), dainty sulphurs (Nathalis iole), American snouts (Libytheana carinent) and variegated fritillaries (Euptoieta claudi) have all been recorded in greater abundance than usual.

Gian swallowtail. Photo by Mark Conboy.

In addition to migrants this has been a notable year for breeding giant swallowtails (Papilio cresphontes). Giant swallowtails have are now a common component of our butterfly fauna, but this is a fairly new species QUBS. The expansion of giant swallowtails out of southwestern Ontario and into our area started in 2008 when there were a few recorded along Opinicon Road; in 2009 there were about a dozen observations throughout QUBS lands; in 2010 they had become a little more common and more regularly encountered. By the spring of 2011 giant swallowtails were all of a sudden very common, especially on the Pangman and Hughson Tracts where we also found our first caterpillars. This spring, they were more abundant than ever; it was not unusual to count up to 20 adults on a single outing. By mid-summer the number of adults had decreased so that only a few were being daily, but caterpillars were abundant and widespread on northern prickly-ash (Zanthoxylum americanum) along field edges in sunny patches of forest. The large caterpillars which look like big droppings, smell like citrus and display a range of intriguing anti-predator behaviours when disturbed have caught the attention of many non-biologists too. I’ve had over a dozen inquiries about the “huge strange worms” from local residents and cottagers.

Another species of formerly southern butterfly may be found breeding at QUBS in the coming years. Wild indigo duskywings (Erynnis baptisiae) have recently arrived along the Lake Ontario shoreline near Bath and in Prince Edward County. We haven’t found any for certain yet at QUBS but several patches of one of this species’ larval food plants, crown-vetch (Securigera varia), are found on the roadsides near the station and could potentially support a small population of this drab little skipper. Identification of this species is rather complicated because it is virtually identical to columbine duskywing (E. lucilius), a very common species at QUBS. These two species are not reliably told apart in the field except when you can see what plant the females are ovipositing on (baptisiae on crown-vetch, lucilius on red columbine [Aquilegia canadensis]) With some careful observations and a little luck we may yet add wild indigo duskywing to our station list which presently stands at 79 species.