Factors affecting survival and dispersal of the comma butterfly in a high mountain deciduous forest habitat

Population and community dynamics of butterflies are relatively well known in Europe thanks to citizen science and academic efforts to cover large spatio–temporal scales. However, there are still gaps of knowledge about which life–history traits have a large influence on the dynamics of particular species and the ecological factors that influence those traits. We conducted a capture–recapture demographic study on the comma butterfly Polygonia c–album in a high mountain deciduous forest. We estimated daily survival in breeding adults caught while foraging on thistles and we calculated the probability of dispersal between two close sites. Thistle growth was enhanced by nitrification in cattle grazing in the study area. Local survival was higher for males (0.920, 95 % CI: 0.851–0.959) than for females (0.869, 95 % CI: 0.799–0.917). Short–range dispersal mostly occurred in absence of wind. Light winds and high levels of solar radiation likely enhanced foraging activity. In contrast with findings in most butterfly demographic studies, recapture rates were significantly higher in females than in males, likely due to the latter moving each afternoon to establish territories along sunny forest edges away from the foraging habitat. Further demographic studies are needed to assess the effects of climate stochasticity and habitat transformation caused by changes in extensive cattle grazing on the population dynamics of the comma butterfly.

Effects of growth hormone in patients receiving total parenteral nutrition following major gastrointestinal surgery

The purpose of the present study was to determine whether the administration of a biosynthetic human growth hormone was capable of enhancing the efficacy of total parenteral nutrition. Patients (n = 38) who had undergone major gastrointestinal surgery were randomly divided into two groups. Group I (n = 20) treated only with PN, and Group II (n = 18) treated as in Group I plus human growth hormone (4 IU daily). Our study shows that the administration of human growth hormone produces a statistically significant increase in serum levels of growth hormone, somatomedin-C, transferrin, albumin and total proteins. It also causes a positive nitrogen balance from the first 24 hours onward. These findings suggest that the administration of human growth hormone produces an increase in protein synthesis, perhaps through somatomedin-C as mediator.