Cold hardiness and deacclimation of overwintering Papilio zelicaon pupae (original) (raw)
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Insects
The cold hardiness of overwintering stages affects the distribution of temperate and cold-zone insects. Studies on Erebia, a species-rich cold-zone butterfly genus, detected unexpected diversity of cold hardiness traits. We expanded our investigation to eight Satyrinae species of seven genera. We assessed Autumn and Winter supercooling points (SCPs) and concentrations of putatively cryoprotective sugars and polyols via gas chromatography–mass spectrometry. Aphantopus hyperantus and Hipparchia semele survived freezing of body fluids; Coenonympha arcania, C. gardetta, and Melanargia galathea died prior to freezing; Maniola jurtina, Chazara briseis, and Minois dryas displayed a mixed response. SCP varied from −22 to −9 °C among species. Total sugar and polyol concentrations (TSPC) varied sixfold (2 to 12 μg × mg−1) and eightfold including the Erebia spp. results. SCP and TSPC did not correlate. Alpine Erebia spp. contained high trehalose, threitol, and erythritol; C. briseis and C. gar...
Journal of Insect Physiology, 1994
Migrants of the eastern North American population of the monarch butterfly, Danaus plexippus, are often subjected to subzero temperatures, heavy dews and frost in late September and October during the autumn migration to overwintering sites in Mexico. Adults of this generation had the capacity to rapidly increase their cold-hardiness. A chilling period of 1 h at +4OC before exposure to-4OC for 24 h significantly improved the survival (> 80%) of monarchs over those with no chilling prior to-4OC exposure (~40%). This is the first report of rapid cold-hardening in Lepidoptera, and the capacity to rapidly cold-harden may protect monarchs against cold injury during diurnal changes in temperature. An extended period of progressively lower temperature acclimation enhanced cold-hardiness to a greater extent than did the rapid cold-hardening treatment. When exposed to-4'C, migrants collected in the field from Ohio were less tolerant (LT, = 37.5 h) than migrants gradually acclimated over several weeks from 20 to 25OC in the field to overwintering conditions of +4OC in the laboratory (LT,, = 85.8 h). External moisture on the exoskeleton significantly raised supercooling points (SCPs) of acclimated monarchs from-8.2 to-4.7OC. In addition, external moisture decreased the supercooling capacity and triggered internal ice formation at subzero temperatures above the SCP of dry monarchs. No monarchs survived internal ice formation associated with SCP determination, evidence that the monarch butterfly is a freeze-susceptible insect. Supercooling point Cold tolerance Freezing temperatures Danaus plexippus
Journal of Insect Physiology, 1996
We examined seasonal changes in the cold hardiness of summer reproductive and fall migrant cohorts of the monarch butterfly in southwest Ohio in 1994. Reproductive and migrant butterflies were distinguished on the basis of lipid content and whether the female had mated. We compared crystallization temperatures (the temperature at which ice forms inside the body) and the capacity to resist chilling injury (i.e. injury due to subzero chilling in animals which supercooled but did not freeze) between reproductives and migrants. Very low crystallization temperatures (<-10°C) were found only in the migrants. Among reproductives there was a significant positive correlation between lipid content and crystallization temperature. Chilling injury occurred frequently among reproductives, in contrast to migrants which survived subzero exposure until ice began to form in their tissues. Records of microhabitat and ambient temperatures from field data loggers and meteorological stations indicate that the monarch migrants in this region infrequently encounter temperatures low enough to promote extensive cold acclimation, and that subzero temperatures are very rare during the time we observed migrants. Data from previous studies of monarchs at the overwintering site or acclimated in a laboratory cold room indicate that this species is capable of greater cold hardiness than we observed in freshly-caught field specimens. We conclude that the increased cold hardiness we observed in migrants was due almost entirely to physiological changes accompanying reproductive diapause and migration, and that cold acclimation played little if any role.
Insect Science, 2012
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 phenotypes, as late-flight individuals are similar in size to P. 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.
Journal of Insect Physiology, 1987
Laboratory manipulations of ambient temperature were used to investigate the role of temperature in triggering or modulating cold-hardiness adaptations, supercooling-point depression and cryoprotectant accumulation, in larvae of the goldenrod gall moth, Epibfemu scudderiuna (Clemens), a freeze-intolerant species. Low temperature strongly facilitated cryoprotectant synthesis; larvae subjected to a 1°C per day decrease in temperature showed a major increase in the rate of glycerol synthesis when temperature fell below 5°C with highest rates of synthesis, greater than 90 nmol gg' d-i, at temperatures between 0 and -10°C. Conversely, abrupt rewarming of larvae from -18 to 23°C in mid-November stimulated a rapid loss of glycerol (from a starting level of 1763 + 278 pmol/g wet weight) with a half time of only 1.5 days. Supercooling-point depression was not keyed to ambient temperature but appeared to be an endogenous event occurring over the same time interval in laboratory animals held at warm or cold temperatures, as well as in outdoor animals. Rewarming of cold-adapted larvae in November resulted in only a small rise in supercooling point (and did not break diapause) but rewarming in February resulted in a 19°C increase in supercooling point in 4 days, followed rapidly by pupation.
Journal of Insect Physiology, 1989
Abstraract-Two species of nymphalid butterflies, Agluis urticae and Inachis io were exposed to four different temperature regimes (10, 2, -Y'C, and cycling -S/lWC) during diapause to determine patterns of cold hardiness and overwintering survival. Supercooling ability increases in all groups from cessation of feeding to 100 days in diapause, but the lowest temperature regime does not produce the lowest mean crytallisation temperature. Pre and post-diapause feeding reduce supercooling as does surface water. Fresh weight loss follows a temperature-dependent pattern with greatest weight loss at 10" and least at -5°C in both species. Mortality is highest at lo" accounting for 80% of I. io after 100 days and 75% of A. urticae after 170 days.
Journal of Insect Physiology, 1989
The metabolic responses to repeated cycles of temperature change, alternating 24 h at -16 and +3"C, wer': compared for a freeze-tolerant (Eurosta soliduginis) vs a freeze-avoiding (Epiblema scudderiuna) insect. The two species differed most strongly in the response by cellular energetics. ATP content and energy charge were depressed in E. scudderiana larvae with each -16°C exposure but rebounded with each return to + 3°C; after 12 such cycles, final energy status at + 3°C was not significantly different than cc'ntrol values. By contrast, E. soliduginis larvae maintained a high energy charge (at the expense of a decrease in the total adenylate pool) over the first two cycles of freeze/thaw only. Subsequently energy stress was cumulative, with no recovery in the +3"C half of each cycle, and energy charge fell to 0.70-0.75.
European Journal of Entomology, 2007
Seasonal variations in the supercooling point, survival at low temperatures and sugar content were studied in fieldcollected codling moth larvae. The supercooling point of field-collected larvae decreased significantly from a mean value of-13.4°C in August 2004 (feeding larvae) to-22.0°C in December 2004 (overwintering larvae). Survival at-20°C/24 h was 0% during early autumn, whereas it increased to approximately 60% during winter. The survival at low temperature was well correlated with the supercooling point. The supercooling point of the diapause destined larvae decreased from-16.9 to-19.7°C between September and October as the larvae left the food source and spun a cocoon. For early-diapause larvae, exposure to 5°C/30 days has an additional effect and decreased the supercooling point from-19.7 to-21.3°C. One-month exposure of overwintering larvae to 5°C led to a mortality of 23% in early diapause larvae, while only 4% of diapause larvae died after acclimation. Overwintering larvae accumulated trehalose during winter. There was approximately a threefold increase in trehalose content between larvae at the onset of diapause (5.1 mg/g fresh weight) and larvae in a fully developed diapause (18.4 mg/g fresh weight) collected in January. Trehalose content was correlated with supercooling capacity, survival at low temperatures and chilling tolerance, suggesting that trehalose may play some role in the development of cold tolerance in this species.