Moving through the meadows: Team studies butterfly dispersal in mountain fields

Dr. Stephen Matter, PhD (University of Cincinnati), has been studying the Rocky Mountain Apollo butterfly (Parnassius smintheus) for almost 20 years, along with colleagues Dr. Nusha Keygobadhi, PhD (University of Alberta), and Dr, Jens Roland, PhD (University of Alberta). This summer, Matter was joined by graduate student Jennifer Goff and undergraduate student Max Lackey at the University of Calgary Barrier Lake Field Station to continue ongoing field work in Kananaskis Country. One main focus of their research is the movement and dispersal patterns of Parnassius smintheus and the connections between movement and the larger landscape matrix.

The Rocky Mountain Apollo is an alpine butterfly species which primarily lays its eggs on the larval host plant Sedum lanceolatum but can also use other Sedum species. The host plant, and therefore the butterfly, are found in dry and rocky areas, like ridges, throughout the alpine and subalpine. The ridges and meadows of the Jumpingpound area of Kananaskis are ideal places to find this species.

Over time, due to both natural and human-caused disturbances, the meadows that these butterflies depend on have been losing connectivity, meaning the meadows are separated by forests, roads, and other barriers. One of the main goals of the field work this year was to use mark-recapture techniques to monitor if butterflies are migrating between different meadows despite reduced habitat connectivity.

The work involves patrolling alpine meadows, watching for the characteristic colouration and flight pattern of Parnassius smintheus, and then capturing the butterflies in a net. Once captured, the butterflies are marked with an ID code on each of their two hind wings, and a small tissue sample is taken from their forewing. The sample will be used for genetic analysis in the lab to gain a better understanding off how landscape connectivity is impacting genetic diversity in the species.

The removal of a small sample from the forewing has a negligible impact on the butterfly as it mimics the natural wing damage that occurs over time due to predators, harsh environmental conditions and general wear and tear. For her master’s project, Jennifer Goff is specifically focused on the effect that changing temperatures have on Parnassius smintheus dispersal throughout the meadows.  

Another student in Matter’s lab, PhD candidate Justine Samuel, also spent the summer at the Barrier Lake Field Station but took a more laboratory-based approach to studying Parnassius butterflies. Her work focuses on volatile compounds released by Parnassius, which appear to play a role in sexual selection. Her work focuses on measuring the volatiles released by females throughout their lifespan, including in larval and pupal stages.

She is hoping to identify the specific volatiles released and gain a deeper understanding of scent communication in the species. There is emerging scientific evidence that certain species of butterflies begin releasing volatiles to attract a mate while still in their pupal form and may even be able to mate in this form.

For Parnassius smintheus females, this would be a logical adaptation as this species exhibits a role reversal from the more common female-led sexual selection. For Parnassius, it is the males who choose their mates and the females who compete with one another for the opportunity to mate with a male.  

Although the field season for studying Parnassius smintheus wrapped up in August, there is plenty of work to be done during the fall and winter months. Before finishing their field season, researchers placed data loggers in the meadows, which will measure light intensity and temperature throughout the winter.

Sealed packages of eggs have also been left to overwinter at the sites. The hatching success of the eggs, combined with data about winter conditions will provide valuable insights into the ability of Parnassius smintheus to survive changing conditions throughout the entire year.

Winter is also the time when data collected in the field will be analyzed and interpreted for trends. After a winter spent sheltered in a lab, or in the case of the butterflies, under the snow, spring will signal a return to the meadows for researchers and butterflies alike.