Intraspecific Geographic Variation of Fragrances Acquired by Orchid Bees in Native and Introduced Populations

Male orchid bees collect volatiles, from both floral and non-floral sources, that they expose as pheromone analogues (perfumes) during courtship display. The chemical profile of these perfumes, which includes terpenes and aromatic compounds, is both species-specific and divergent among closely related lineages. Thus, fragrance composition is thought to play an important role in prezygotic reproductive isolation in euglossine bees. However, because orchid bees acquire fragrances entirely from exogenous sources, the chemical composition of male perfumes is prone to variation due to environmental heterogeneity across habitats. We used Gas Chromatography/Mass Spectrometry (GC/MS) to characterize the perfumes of 114 individuals of the green orchid bee (Euglossa aff. viridissima) sampled from five native populations in Mesoamerica and two naturalized populations in the southeastern United States. We recorded a total of 292 fragrance compounds from hind-leg extracts, and found that overall perfume composition was different for each population. We detected a pronounced chemical dissimilarity between native (Mesoamerica) and naturalized (U.S.) populations that was driven both by proportional differences of common compounds as well as the presence of a few chemicals unique to each population group. Despite these differences, our data also revealed remarkable qualitative consistency in the presence of several major fragrance compounds across distant populations from dissimilar habitats. In addition, we demonstrate that naturalized bees are attracted to and collect large quantities of triclopyr 2-butoxyethyl ester, the active ingredient of several commercially available herbicides. By comparing incidence values and consistency indices across populations, we identify putative functional compounds that may play an important role in courtship signaling in this species of orchid bee

The focus of temperature monitoring with zero-heat-flux technology (3M Bair-Hugger) : a clinical study with patients undergoing craniotomy

In the noninvasive zero-heat-flux (ZHF) method, deep body temperature is brought to the skin surface when an insulated temperature probe with servo-controlled heating on the skin creates a region of ZHF from the core to the skin. The sensor of the commercial Bair-Hugger ZHF device is placed on the forehead. According to the manufacturer, the sensor reaches a depth of 1–2 cm below the skin. In this observational study, the anatomical focus of the Bair-Hugger ZHF sensor was assessed in pre- and postoperative CT or MRI images of 29 patients undergoing elective craniotomy. Assuming the 2-cm depth from the forehead skin surface, the temperature measurement point preoperatively reached the brain cortex in all except one patient. Assuming the 1-cm depth, the preoperative temperature measurement point did not reach the brain parenchyma in any of the patients and was at the cortical surface in two patients. Corresponding results were obtained postoperatively, although either sub-arachnoid fluid or air was observed in all CT/MRI images. Craniotomy did not have a detectable effect on the course of the ZHF temperatures. In Bland–Altman analysis, the agreement of ZHF temperature with the nasopharyngeal temperature was 0.11 (95% confidence interval − 0.54 to 0.75) °C and with the bladder temperature − 0.14 (− 0.81 to 0.52) °C. As conclusions, within the reported range of the Bair-Hugger ZHF measurement depth, the anatomical focus of the sensor cannot be determined. Craniotomy did not have a detectable effect on the course of the ZHF temperatures that showed good agreement with the nasopharyngeal and bladder temperatures.Peer reviewe