In our anxious times marked by the rapid pace of breaking news highlights and lowlights, the discoveries of new plant and insect species constitute truly good news stories.
Earlier this month, the United Kingdom’s Royal Botanic Gardens, Kew, announced that its intrepid plant explorers — who travelled to deserts, rainforests, woodlands and mountains in the Americas, Asia, Africa and beyond — discovered and named more than 170 brand-new plant species in 2018.
Jeffrey Marcus, associate professor of biological sciences at the University of Manitoba, and his graduate student Melanie Lalonde are explorers of another kind. Their recent identification of the grey buckeye butterfly (Junonia grisea) represents the first new butterfly species identified in North America since 2016 and the first new butterfly species found in California in decades.
Chris Rutkowski, a University of Manitoba communications director, described the discovery as the Stanley Cup of entomology in a Nov. 20 article. At the time of the announcement of the find, the forest fires in Paradise, Calif., were raging. "Some good news in a difficult time," Marcus wrote in a Nov. 15 Twitter post.
One of the great challenges faced by the scientific community, Marcus said in our phone conversation last week, is that there may be species being lost that no one even knew existed.
"As the climate changes, but also as people modify the habitats of species either through agriculture or urbanization or road construction, plant or insect species are almost certainly disappearing."
"To the extent that we can contribute to at least documenting one more species in addition to the species that are documented by other scientists," Marcus said, "the more we are able to understand the impact of human activities on species and mitigate our activities for at-risk species."
It was when Marcus sourced specimens of preserved butterflies for one of his students who was working on an unrelated scientific problem — she needed to compare butterflies from the buckeye butterfly group in the Western Hemisphere — that the first hint arose that a new species might exist.
The collection of butterflies which Marcus sourced from his network of colleagues included about 15 butterflies from California. "When we examined their DNA markers," Marcus said, "it was clear that there was something strange." While most of the buckeye butterflies from all over the Western Hemisphere have a particular gene, distinct differences were discerned in the buckeye butterflies from California.
The second clue came in 2015 when Marcus was attending a conference in California. Playing hooky from one of the conference sessions, he and a friend and her six-year-old son went to visit a park in the San Francisco Bay Area to see what types of butterflies they could catch with their butterfly nets. Marcus chose the particular area because it had been the subject of numerous research papers on butterflies by another scientist.
Marcus wondered what the site might reveal decades later, and for the first time, he witnessed California buckeye butterflies in the wild. "They didn’t look like the buckeye butterflies I was used to seeing in the eastern parts of North America," Marcus said, "nor was their behaviour similar."
Returning to the lab at the University of Manitoba with just a couple of the butterflies he caught in the park that day in 2015, Marcus began examining specimens at the Wallis Roughley Museum of Entomology. He borrowed hundreds of specimens from dozens of museums, mostly in North America and some from South America. Together, he and grad student Lalonde visited museums such as the Natural History Museum of Los Angeles County, which is the largest natural and historical museum in the western United States, and the McGuire Center for Lepidoptera and Biodiversity in Florida.
Through their extensive research, which included the rearing of the butterflies brought back to the lab, Marcus and Lalonde found that the California buckeye butterfly was a distinct species. Interestingly, Marcus said, differences in the California buckeye butterfly had been detected about two decades earlier by amateur butterfly enthusiasts who called it a subspecies of the buckeye butterfly. Their observations, though, recorded in 1998 in an obscure publication, were ignored at the time by other butterfly enthusiasts as well as the scientific community.
It is an ongoing story in butterfly taxonomy, Marcus said, that often it is the unpaid but very knowledgeable enthusiasts who make important contributions to scientific data. "Once we realized that this was a really distinctive thing, we made sure that we got our hands on their original publication so that we could appropriately acknowledge that these amateur butterfly enthusiasts were able to see before everybody else that the buckeye butterflies in California were special."
In Manitoba, buckeye butterflies are not common, Marcus said, and are only seen here every few years. An image of the common buckeye appears on the cover of Manitoba Butterflies: A Field Guide by author Simone Hebert Allard.
The food plants of the common buckeye larvae (caterpillar) include toadflax, ribgrass and snapdragon. In California, one of the important native hosts for the grey buckeye larvae, which has a startling otherworldly appearance, is Mimulus, also known as monkey flower. The larvae also feed on penstemon and snapdragon as well as plantago, an invasive weed-like plant.
Marcus said the easiest way to find a rare butterfly is to locate the plant that its caterpillar eats. "If you really know your wildflowers," he said, "sometimes you can locate populations of rare butterflies that others may have observed."
Buckeye butterflies — both the newly named grey buckeye in California and the buckeyes found in eastern North America — are especially adept at living in disturbed habitats, Marcus said. "They’re at home in vacant lots or construction areas and gravel parking lots and the like," he said. "They’re not species that are likely to be negatively affected by human activities," Marcus said. Certainly, though, he added, there are many other butterfly species that are at much greater risk because the plants they feed on aren’t able to thrive in disturbed soils.
Until very recently, Marcus said, scientists believed there were only four buckeye butterfly species in the entire Western Hemisphere. About 10 years ago, though, five new species were identified in French Guiana alone.
Lalonde now plans to study the areas of Panama and northern South America, a diverse place where the North American and South American species of buckeye butterflies meet. Her goal is to determine the exact number of different buckeye species, document the variations in their colour patterns (which vary from blue to brown and purple) and go through scientific literature to figure out which name is appropriately assigned.
Marcus has been studying buckeye butterflies for more than two decades but is also involved in other projects, including a study at the Living Prairie Museum of a group of insects called caddisflies.
Sarah Semmler, an entomologist and museum director at the Living Prairie Museum, said the discovery of new species is always exciting because it reminds us there is still so much to discover.