Ecology and Vulnerability

Regal Fritillary

Insects, including lepidoptera, play an integral role in ecosystems as pollinators and food sources, and studying their interactions and indirect effects of climate change on them is critical (Harvey et al., 2022). Lepidoptera are extremely sensitive to changes in their environment and are being threatened by herbicides, insecticides, habitat loss, pollution, and direct and indirect effects of climate change (Wagner 2021). As ectotherms, climate change can be a major physiological stressor that can cause changes to misalignment with Lepidoptera host plant and emergence, shifts in range, behavior, development and more (Hellmann et al., 2016, Patterson et al., 2019). Species with longer developmental overwintering stages, narrower diets, or restricted ranges may be more at risk of decline or extinction due to changing temperatures and precipitation compared to generalist species (Patterson et al., 2019). Temperature increases have led to many species emerging earlier than host plants, with spring species advancing faster than summer species. Phenological mismatch can reduce survival due to emerging before their host plant or after the host plant senesces (Patterson et al., 2019). Early emergence of adult butterflies could mean limited nectar resource availability, and exposure to late snowstorms and freezing temperatures (Patterson et al., 2019). Asynchrony in some lepidoptera larvae has shown increased rates of parasitism and predation (including cannibalism) due to mismatched timing of host plant emergence and the butterfly’s life cycle (Despland 2018). Research on the effects of climate change on Lepidoptera species is still largely understudied and little is known about the response of many of the RCGN species listed above. More research is needed at both the fine scale and large scale, temporally and spatially.

Shifts in Range, Elevation, or Depth

The Regal Fritillary historically has had a distribution range expanding from the western state of Colorado to the eastern coast of the United States, primarily occupying native tall-grass and mixed-grass prairies. Over the past 30 years, their range has greatly declined due to habitat loss from haying, burning, mowing, and other grassland conversions, limiting them to patchy prairie habitat in the central plains of the United States (Post Van Der Burg et al., 2022). The distribution of Regal Fritillary in the southern portion of their range could experience a population decline as average temperatures continue to rise and precipitation stays the same (Post Van Der Burg et al., 2022). Changes in temperature and lack of precipitation in the spring and early summer could lead to early larval emergence and host plant desiccation, which has 96 been noted in other fritillary species, like the Glanville fritillary (Tack et al., 2015; Post Van Der Burg et al., 2022) This increase in temperature in the Great Plains and Midwest could lead to a shift northward in the distribution of the regal fritillary which Swengel and Swengel (2017) has soon a range expansion northward (Post Van Burg et al., 2022).