What was done
The authors "inferred the phylogeography of the alpine butterfly Colias meadii Edwards (Pieridae) and compared its genetic structure with that of another high elevation, co-distributed butterfly, Parnassius smitheus Doubleday (Papilionidae), to test if the two Rocky Mountain butterflies responded similarly to the palaeoclimatic cycles of the Quaternary," i.e., to the recurring cycles of glacial and interglacial climates, in the hope of "establishing a baseline for predicting the effects of future climate change."

What was learned
It was determined, among several other things, that the two butterfly species "experienced similar cycles of expansion and contraction," suggesting that "populations persisted across the geographic range throughout the climate cycles, experiencing isolation on 'sky islands' during interglacial periods and becoming connected as they migrated down-slope during cool, wet climates."

What it means
In the words of the authors, "inferences from our study suggest that the general response of alpine taxa in the Rocky Mountains to palaeoclimatic oscillations of the Quaternary fits an expanding-contracting archipelago model," whereby "populations persisted across the latitudinal range of the Rockies throughout the climate cycles by expanding down-slope during glacial periods, and contracting upslope into a fragmented archipelago of sky islands during warm interglacials."  This (or something very close to it) being the case, we can conclude that all species currently inhabiting the Rocky Mountains are likely immune to the extinctions climate alarmists claim will occur in response to IPCC-predicted global warming; for all indigenous species found throughout the Rocky Mountains today had to have survived the high temperatures of all prior interglacials, the last four of which were more than 2°C warmer, in the mean, than the abnormally cool interglacial in which we currently live (Petit et al., 1999).

Reference
Petit, J.R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, M.., Delaygue, G., Delmotte, M., Kotlyakov, V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., Pepin, L., Ritz, C., Saltzman, E. and Stievenard, M.  1999.  Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica.  Nature 399: 429-436.