Ecology and Vulnerability

Karner Blue

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.

Changes in Population

Karner Blue Butterflies are particularly vulnerable to changes in their habitat and specifically the effects of climate change on their singular host plant, Wild Blue Lupine (Lupinus perennis (Patterson et al., 2019; Eskildsen et al., 2015; Miller-Rushing et al., 2010). Increased temperatures can induce early larval hatching before the emergence of the Wild Blue Lupine, leading to a higher larval mortality rate in late spring or early summer (Patterson et al., 2019). Along with mismatched emergence between host plants and larvae, drought and increased summer temperatures can cause lupine to senesce early in the season, limiting the survival rate of the second generation of Karner Blues (Patterson et al., 2019).