It is generally thought that insects inhabiting lower latitudes are more severely impacted by changes in their thermal environment than are high latitude species. This is attributed to the wider range of temperatures ...It is generally thought that insects inhabiting lower latitudes are more severely impacted by changes in their thermal environment than are high latitude species. This is attributed to the wider range of temperatures to which high-latitude species are exposed. By contrast, low-latitude species have typically evolved in more thermally stable environments with a narrower range of temperature variation. However, deviation from this pattern can occur and here we report that under variable winter conditions a higher latitude species may be more sensitive to thermal variation than its lower latitude sister species. Using split broods, we examined the survival and adult emergence success of diapausing pupae of Papilio canadensis and P. glaucus, as well as a unique, recombinant hybrid population （＂late-flight＂） to short periods of mid-winter cold and heat stress. Our results indicate that the higher latitude, univoltine populations （P. canadensis and late-flights） exhibit lower pupal survival than the lower latitude, facultative diapauser （P. glaucus） for all mid-winter thermal stress treatments, both high and low. Size differences alone do not appear to account for the observed differences in survival or metabolic costs in these three pheno- types, as late-flight individuals are similar in size to R glaucus. We attribute the observed differences in survival and weight loss to potential metabolic differences and variation in the intensity of diapause, in addition to divergent adaptation to winter precipitation levels （e.g. snow cover） and the influences this may have on microhabitat temperature moderation.展开更多
基金Acknowledgments This research was supported in part by the Michigan Agricultural Experiment Station （Project #01644）, and the National Science Foundation （DEB-0716683 DEB- 0918879）. Awards from NSF research experience for un- dergraduates （REU DEB- 0821958） partially supported Matthew Aardema, and Emily Maher. For assistance in the field and/or laboratory we thank Becky Aslakan, Bill Houtz, Angeline Kosnik, Matt Lehnert, Jim Maudsley, Michelle Oberlin, Gabe Ording and Howard Romack. Matthew Aardema was supported in part by College of Natural Sciences undergraduate research award and a Scriber Scholars award in Butterfly Biology and Con- servation （Dept. of Entomology, MSU）.
文摘It is generally thought that insects inhabiting lower latitudes are more severely impacted by changes in their thermal environment than are high latitude species. This is attributed to the wider range of temperatures to which high-latitude species are exposed. By contrast, low-latitude species have typically evolved in more thermally stable environments with a narrower range of temperature variation. However, deviation from this pattern can occur and here we report that under variable winter conditions a higher latitude species may be more sensitive to thermal variation than its lower latitude sister species. Using split broods, we examined the survival and adult emergence success of diapausing pupae of Papilio canadensis and P. glaucus, as well as a unique, recombinant hybrid population （＂late-flight＂） to short periods of mid-winter cold and heat stress. Our results indicate that the higher latitude, univoltine populations （P. canadensis and late-flights） exhibit lower pupal survival than the lower latitude, facultative diapauser （P. glaucus） for all mid-winter thermal stress treatments, both high and low. Size differences alone do not appear to account for the observed differences in survival or metabolic costs in these three pheno- types, as late-flight individuals are similar in size to R glaucus. We attribute the observed differences in survival and weight loss to potential metabolic differences and variation in the intensity of diapause, in addition to divergent adaptation to winter precipitation levels （e.g. snow cover） and the influences this may have on microhabitat temperature moderation.
