Age-dependent association between testosterone and crown UV coloration in male blue tits (Parus caeruleus)

The proximate basis of sexual traits can suggest mechanisms maintaining honesty in signalling. A central role hereby has been attributed to testosterone, although its importance for brightly coloured plumage has been questioned. We determined circulating testosterone levels in male blue tits captured at the start of breeding and demonstrated an age-dependent relationship between testosterone and male crown UV/blue coloration. In yearling males, testosterone increases with increasing ornamentation (higher UV chroma, higher chroma, more UV-shifted hue), whereas in older males, this relationship is negative, with less UV-ornamented males having higher testosterone. This pattern is robust since it occurred in 2 years, before and after egg laying, and in males sampled during the day and during the night, despite a tenfold difference in testosterone levels. Since more UV-ornamented young males gain higher within-pair paternity, while less UV-ornamented older males achieve more extra-pair matings, the results imply that higher testosterone is associated with reproductive success and attractiveness in both age classes. We hypothesise that this relationship could result from causal effects of testosterone on coloration or through associations with behaviour and suggest ways to test these hypotheses. Our results caution against premature dismissal of a potential role for testosterone in maintaining honesty of plumage signals.     

Micro-scale bromination procedure for synthesis of “2,3,7,8-substituted” brominated dibenzo-p-dioxins and dibenzofurans from [C]-labeled precursors

Brominated dibenzo-p-dioxin and dibenzofuran (BDD/BDF) isomers, specifically having from one to three halogens located in the 2,3,7,8-substituent positions, that are [¹³C]-labeled for use as analytical internal standards in mass spectrometric methods are not yet commercially available. Based upon the current availability of [¹³C]-labeled dibenzo-p-dioxin and dibenzofuran (DD/DF) precursors, we have developed a simple and efficient synthetic procedure which produces brominated congeners that are predominantly substituted in the 2,3,7, and 8-positions. The gas/solid reaction of vaporized precursor and surface-supported iron (III) bromide occurs rapidly (seconds) at temperatures ≥ 240°C and can provide total product yields in the range of 30 to 50 mole % for initial precursor amounts between 1 μg and 10 mg. In this paper we shall describe the utility of this approach to produce 5 μg quantities of [¹³C₁₂]-2,7-dibromodibenzo-p-dioxin (27-DBDD) and [¹³C₁₂]-2,8-dibromodibenzo-p-dioxin (28-DBDD).     

Development and application of protocols for the determination of response of real-time particle monitors to common indoor aerosols

Protocols have been developed and applied for the generation of aerosols that are likely to be comparable to those encountered in field settings for the calibration of easily transportable/portable real-time particle monitors. Aerosols generated were simulated environmental tobacco smoke, cedar wood smoke, cooking oil fumes, and propane stove particles. The time-integrated responses of three nephelometers and a monitor for particle-bound polynuclear aromatic hydrocarbons (PAH) were compared with gravimetric respirable suspended particulate matter (RSP) in a controlled-atmosphere chamber. In general, the monitor responses increased linearly with increasing mass concentration. However, the two monitors that reported mass per volume concentrations tended to overreport the actual RSP concentrations by factors up to 4.4. The real-time PAH monitor did not respond to cooking oil fumes, indicative of little PAH being present in the aerosol. One of the monitors that has been used in a variety of studies reported in the literature (DustTrak) was collocated with gravimetric RSP samplers in several hospitality venues in the Louisville, KY, area. Field studies indicated that the units overreported actual RSP concentrations by factors of 2.6-3.1, depending on whether the sampling was conducted in the nonsmoking or smoking sections of the facilities.     

Non-random perch selection by cryptic lizards,Amphibolurus muricatus

Behavioral Ecology and Sociobiology - Animals are often confronted with more sensory stimuli than they can attend to, and so should pay attention to stimuli that are relevant to them and habituate...     

Use of the aerodynamic particle sizer to measure ambient PM10-2.5: the coarse fraction of PM10

The Aerodynamic Particle Sizer (APS 3321, TSI, Inc., Shoreview, MN) rapidly measures particle number concentration by size from 0.5 to 20 microm. This work used simple assumptions for particle shape factor and density to estimate ambient coarse mode particulate matter, PM10-2.5, from APS number concentration data. This estimate was compared with that measured with time-integrated, filter-based federal reference method (FRM) samplers in four U.S. field studies: two in Phoenix, AZ; one in Gary, IN; and one in Riverside, CA. Near one-to-one agreement and a strong linear relationship were observed between APS-estimated and FRM-measured PM10-2.5 in the first Phoenix, AZ study (slope = 0.90, R2 = 1.00); the second Phoenix, AZ study (slope = 0.99, R2 = 0.99); and the Riverside, CA study (slope = 1.00, R2 = 0.84). In the Gary, IN study, PM10-2.5 estimates made with data from the APS tended to be less than that measured with the FRM samplers (slope = 0.57), but the linear relationship between the two methods was still strong (R2 = 0.90). Particle-bound water associated with wet atmospheric conditions may account for these differences. Additional testing is required to resolve this issue.