Reduced avian predation on an ultraviolet-fluorescing caterpillar model

Many caterpillars exhibit patterns of ultraviolet (UV) fluorescence, although its purpose is unclear. We used realistic plasticine models of a fluorescing caterpillar species, the Polyphemus moth, Antheraea polyphemus (Lepidoptera; Saturniidae), adorned with fluorescent paint treatments and unpainted controls to quantify bird predation in two hardwood forested regions of New York State, United States of America. In separate field studies, significantly more birds struck deployed model caterpillars that had no UV fluorescence. More strikes on unpainted and clear paint treatments suggest paint itself did not impact predation, whereas similar predation attempts on bird and human-visible fluorescent dummies suggest that UV fluorescence and not UV reflectance was responsible for the observed effect. A second study found the dummy’s location on the tree was also important, but the low number of bird strikes limited analyses. Although our results do not identify a mechanism, fluorescence may function to deter or avoid predation. Our study contributes to a growing body of work investigating the importance of UV patterns in arthropods and highlights a potentially fruitful area of future research on predator–prey relations.

Assessing Thermal Maturity through a Multi-Proxy Approach: A Case Study from the Permian Faraghan Formation (Zagros Basin, Southwest Iran)

This study focuses on the thermal maturity of Permian deposits from the Zagros Basin, Southwest Iran, employing both optical methods (Thermal Alteration Index, Palynomorph Darkness Index, Vitrinite Reflectance, UV Fluorescence) and geochemical analyses of organic matter (Rock Eval Pyrolysis and MicroRaman spectroscopy) applied to the Faraghan Formation along two investigated Darreh Yas and Kuh e Faraghan surface sections. Furthermore, an integrated palynofacies and lithofacies analysis was carried out in order to integrate the few studies on the depositional environment. The Faraghan Formation, which is widely distributed in the Zagros area, generally consists of shale intercalated with sandstones and pebble conglomerates in the lower part, followed by a succession of sandstone, siltstone and shaly intercalations and with carbonate levels at the top. The integrated palynofacies and lithofacies data confirm a coastal depositional setting evolving upwards to a shallow marine carbonate environment upwards. Rock Eval Pyrolysis and Vitrinite Reflectance analysis showed that the organic matter from samples of the Darreh Yas and Kuh e Faraghan sections fall in the mature to postmature range with respect to the oil to gas generation window, restricting the thermal maturity range proposed by previous authors. Similar results were obtained with MicroRaman spectroscopy and optical analysis such as Thermal Alteration Index and UV Fluorescence. Palynomorph Darkness Index values were compared with Rock Eval Pyrolysis and vitrinite reflectance values and discussed for the first time in the late stage of oil generation.

Paper Foxing Stains on a Historic Manuscript from the Early Qajar Era: Abiotic or Biotic Foxing?

The aim of this study was to identify the nature and cause of foxing spots in a historical manuscript. This manuscript was a Holy Quran from the beginning of the Qajar period and the end of the 18th century. Samples were incubated for 14 days and were evaluated for the presence of fungal activity. UV fluorescence photography, micro X-ray fluorescence spectroscopy and Fourier transform infrared spectroscopy were also used to investigate the characteristics and causes of foxing spots. The results showed that there was no fungal activity in the foxing spots of this manuscript. Based on the morphology of the stain in UV fluorescence photography, these foxing stains are of the Bullseye type, usually associated with metal ions. µXRF spectroscopy also showed a high accumulation of iron and copper at the site of these spots. This indicates abiotic foxing in this manuscript. Based on FTIR spectroscopy and peak deconvolution and fitting by Gaussian function, abiotic foxing increases the cellulose oxidation rate. Intensification of cellulose oxidation in foxing stains can be considered as one of the reasons for paper discoloration.