Genetic Diversity and Wolbachia (Rickettsiales: Anaplasmataceae) Prevalence Within a Remnant Population of Regal Fritillary, Argynnis idalia (Lepidoptera: Nymphalidae), in South-Central Pennsylvania.

Eastern populations of the North American regal fritillary, Argynnis idalia Drury (1773), have been largely extirpated over the past half century. Here we report on the last remaining population of eastern regal fritillaries, located within a military installation in south-central Pennsylvania. Samples were obtained from field specimens during two years of annual monitoring, and from females collected for captive rearing over a five year period. Nuclear microsatellite and mitochondrial sequence data do not suggest subdivision within this population, but excess nuclear homozygosity indicates negative impacts on genetic diversity likely due to small population size and potential inbreeding effects. Molecular assays did not detect Wolbachia endosymbionts in field specimens of regal fritillary, but sympatric Argynnis sister species showed high prevalence of Wolbachia infected individuals. Our results inform ongoing conservation and reintroduction projects, designed to protect the last remaining regal fritillary population from extirpation in the eastern United States.

Species traits affect phenological responses to climate change in a butterfly community.

Diverse taxa have undergone phenological shifts in response to anthropogenic climate change. While such shifts generally follow predicted patterns, they are not uniform, and interspecific variation may have important ecological consequences. We evaluated relationships among species' phenological shifts (mean flight date, duration of flight period), ecological traits (larval trophic specialization, larval diet composition, voltinism), and population trends in a butterfly community in Pennsylvania, USA, where the summer growing season has become warmer, wetter, and longer. Data were collected over 7-19 years from 18 species or species groups, including the extremely rare eastern regal fritillary Speyeria idalia idalia. Both the direction and magnitude of phenological change over time was linked to species traits. Polyphagous species advanced and prolonged the duration of their flight period while oligophagous species delayed and shortened theirs. Herb feeders advanced their flight periods while woody feeders delayed theirs. Multivoltine species consistently prolonged flight periods in response to warmer temperatures, while univoltine species were less consistent. Butterflies that shifted to longer flight durations, and those that had polyphagous diets and multivoltine reproductive strategies tended to decline in population. Our results suggest species' traits shape butterfly phenological responses to climate change, and are linked to important community impacts.