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Simple Summary: In insects distributed in temperate and cold zones, cold hardiness during overwintering crucially affects the distribution, including range shifts due to climate change. Our previous work on the genus Erebia, a cold-adapted and species-rich group of the sub-family Satyrinae (Nymphalidae), disclosed unexpected diversity of cold hardiness strategies, with closely related species surviving or not surviving freezing of larval body fluids. Asking whether this diversity is peculiar to this genus, or may be common in the Satyrinae clade, we investigated supercooling ability, contents of sugars and polyols in overwintering larvae tissues, and evolutionary signal of these traits of eight European Satyrinae species (from seven genera) and compared them with the Erebia representatives investigated earlier. We show that cold hardiness strategies are indeed diverse in the group and that high mountain and continental steppe species employ similar cryoprotection mechanisms, differing from those employed by species of more mesic environments. 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. gardetta contained high ribitol and trehalose; lowland species contained high saccharose, maltose, fructose, and sorbitol. SCP, TSPC, and glycerol concentrations were affected by phylogeny. Species of mountains or steppes tend to be freeze-avoidant, overwinter as young larvae, and contain high concentrations of trehalose, while those of mesic environments tend to be freeze-tolerant, overwinter as later instars, and rely on compounds such as maltose, saccharose, and fructose. [ABSTRACT FROM AUTHOR]

SYNOPSIS. Lepidopteran juvenile hormone (JH) esterase appears to have a functional role in the regulation of embryogenesis, larval growth and development, and adult reproduction. In preovipositional and newly laid eggs of the tobacco hornworm, , JH esterase activity was elevated presumably to metabolize maternal JHs, and then declined after blastoderm formation. Also, a single peak in hemolymph JH esterase activity was found prior to ecdysis in the second through the fourth instar of , the function of which is unclear. However, in the last instar, elevated hemolymph JH esterase activity was noted prior to wandering and again prior to ecdysis to scavenge the last traces of JH necessary for normal development. The hemolymph JH esterase is likely of multiple tissue origin for the prewandering peak with the fat body excluded as a source for the prepupal peak; an inhibitory factor from the brain and JH regulate JH esterase biosynthesis. In adult cabbage loopers, , elevated hemolymph JH esterase activity appeared to be important in reducing the JH titer and preventing egg maturation. Structure/activity data with trifluoromethylketones were incorporated into the design of a novel, JH esterase inhibitor, the sulfone and hydrate of octylthio-1,1,1- trifluoropropan-2-one, with selective and persistent, inhibitory activity. The topical application of this compound to last instar larvae and virgin adults of produced juvenizing effects (delayed pupation and induced egg maturation/oviposition, respectively) providing direct evidence of a functional role for JH esterase in lepidopteran development. [ABSTRACT FROM PUBLISHER]

The fine structure of the dorsal longitudinal flight muscle of the monarch butterfly, Danaus plexippus (L.), is described. The high actin: myosin filament ratio in this fast muscle is likely related to extensive actin-myosin filament interaction which must occur when tension is increased and maintained by repeated nervous stimulation as demonstrated by Kammer (1967) during the long downstroke of the wingbeat cycle. Glycogen particles are present in the granular fraction of the interfibrillar sacroplasm and among the myofilaments of the flight muscle of young butterflies. The distribution of the granules appears to be related to spatial forces within the muscle fibril for in resting butterflies the intermyofilament particles are generally located in rows parallel to the myofilaments, while they are in transverse bands in the H and I zones of animals fixed immediately after flight. Since the glycogen particles were not depleted during flight, this redistribution does not appear to be related to glycogen metabolism. Glycogen in the flight muscle was depleted during eight days of adulthood in butterflies fed on honey solutions, but lipid reserves increased in the same period. [ABSTRACT FROM AUTHOR]