Testosterone and helping behavior in the azure-winged magpie (Cyanopica cyanus): natural covariation and an experimental test

In this study, we investigated patterns of natural covariation between testosterone and reproductive status in a cooperatively breeding bird species, the azure-winged magpie (Cyanopica cyanus). To assess the relationship between testosterone and breeding behavior, we also manipulated testosterone (T) levels early in the season (before breeding started) using testosterone-filled or empty implants. Our results do not support the hypothesis that circulating testosterone levels affect the occurrence of helping behavior in the azure-winged magpie. Helping males had similar T levels to breeding males. Furthermore, experimentally augmented plasma T did not affect the likelihood of becoming either a helper or a breeder. Overall, these results are consistent with previous findings in other bird species and only give some support to the behavioral suppression hypothesis, suggesting that helping in the azure-winged magpie is a flexible behavioral option moderated in the short-term by social and ecological factors. Experimentally elevated testosterone levels, however, reduced the reproductive success of male breeders because of markedly lower levels of paternal care, had similar effects on their mates, but had the contrary effect on helpers, which raised levels of parental effort. We suggest increases in the share of paternity and in social prestige as possible explanations for these results.Communicated by: A. Cockburn     

A pest is a pest is a pest? The dilemma of neotropical leaf-cutting ants: Keystone taxa of natural ecosystems

Leaf-cutting ants of the generaAcromyrmex andAtta are considered the principal polyphagous pests of the Neotropics Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests ofAtta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems Likewise, the pest species can be used to detect environmental disturbance As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs     

Recycling of iron foundry sand and glass waste as raw material for production of whiteware.

The purpose of this study was to evaluate the production feasibility of triaxial whiteware using sand from cast iron moulds as a raw material instead of silica, and recycled glass in place of feldspar. Formulations were prepared using sand, glass waste, and white-firing clay such that only 50% of the composition was virgin material (clay). The ceramic bodies were formed by pressing and fired at different temperatures (between 1100 and 1300 degrees C). Specimens were characterized in terms of green density prior to firing; and their flexural strength, linear shrinkage, and water absorption were measured after firing. The microstructure was determined by scanning electron microscopy. Possible environmental impacts of this recycling process were also evaluated, through solubility and leaching tests, according to Brazilian standards. Gaseous emissions during the firing process were also analysed. The results showed that it is possible to produce triaxial ceramics by using such alternative raw materials.     

Mantle-to-shell CaCO<Subscript>3</Subscript> transfer during shell repair at different hydrostatic pressures in the deep-sea vent mussel <Emphasis Type="Italic">Bathymodiolus azoricus</Emphasis> (Bivalvia: Mytilidae)

Calcium carbonate transfer was experimentally examined in hydrothermal mussels Bathymodiolus azoricus, which were collected from 850 m depth at Menez Gwen hydrothermal vent site (31°31′W, 37°50′N) on the Mid Atlantic Ridge in May 2007. In each of four 10-day experiments, groups of mussels were maintained at atmospheric pressure or re-pressurised to depths relevant to their site of occurrence, i.e. 850 m depth at Menez Gwen, 1,750 m at Lucky Strike (31°31′W, 37°18′N) and 2,300 m at Rainbow (31°31′W, 36°13′N). The shells of experimental mussels were perforated and mantle tissue was fixed for light and TEM studies at days 7 and 10 following the injury. Simultaneously, haemocytes from the extrapallial fluid (EPF) at the site of induction were studied. At day 7 the response was most intense in the middle fold of the mantle margin and possibly proportional to hydrostatic pressure. At day 10 the epithelial cells on the mantle surface facing the body cavity produced copious organic secretions that avidly bound calcium. Haemocyte migration was noted within the mantle tissue, and the haemocytes at the mantle surface facing the shell had a Ca-positive granular content. Large haemocytes were detected in the EPF at the injury site, and some showed evidence of an immune reaction while others showed Ca-positive granular content. These results suggest that haemocytes are involved in shell repair in these deep-sea mussels just as in some freshwater and shallow marine molluscs.     

Tween 20 and Its Major Free Fatty Acids as Carbon Substrates for the Production of Polyhydroxyalkanoates in Pseudomonas aeruginosa ATCC 27853

The ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize polyhydroxyalkanoates (PHAs) using Tween 20 as the sole carbon source was investigated. Tween 20 could support cell growth and PHA production. The polymer produced from Tween 20 was compared with those produced from its major free fatty acids components: lauric (C₁₂), myristic (C₁₄), and palmitic (C₁₆) acids. Gas-chromatographic analysis of methanolyzed samples and ¹³C-Nuclear Magnetic Resonance (NMR) showed that the PHAs obtained are composed of even carbon atoms 3-hydroxyalkanoates ranging from C₆ to C₁₄, with C₈ and C₁₀ as the predominant components. The nature of the carbon sources used had little influence on the composition, but was found to be important in determining the average molecular weight, shorter chain fatty acids yielding higher molecular weight products. Fast Atom Bombardment-Mass Spectrometry (FAB-MS) of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers.     

Genetic Variability in mtDNA of the Silvery Gibbon: Implications for the Conservation of a Critically Endangered Species

Abstract: The silvery gibbon (   Hylobates moloch ), endemic to the island of Java, relies on closed-canopy, lowland evergreen forest for its survival. Because Java has lost over 91% of its original forest, silvery gibbons currently occupy small, isolated forest fragments and are threatened with extinction. To contribute to a comprehensive conservation strategy for this species, we analyzed the mtDNA control region of 31 silvery gibbons representing most remaining populations. Our results suggest the presence of at least two genetically differentiated lineages: a "western" lineage, represented by the largest remaining natural population in Gunung Halimun National Park and a "central" lineage, consisting of smaller, more isolated populations in and around the Gunung Masigit/Simpang/Tilu complex, Gunung Gede/Pangrango, and Gunung Slamet. These two lineages, at a minimum, represent different management units that should, except in the most dire circumstances, be managed separately.     

Identification of Enteric Viruses in Foods from Mexico City

Foodborne viruses are a common and, probably, the most under-recognized cause of outbreaks of gastroenteritis. Among the main foods involved in the transmission of human enteric viruses are mollusks, and fruits and vegetables irrigated with wastewater and/or washed with non-potable water or contaminated by contact with surfaces or hands of the infected personnel during its preparation. In this study, 134 food samples were analyzed for the detection of Norovirus, Rotavirus, and Hepatitis A virus (HAV) by amplification of conserved regions of these viruses. From the 134 analyzed samples, 14 were positive for HAV, 6 for Norovirus, and 11 for Rotavirus. This is the first report in Mexico where emphasis is given to the presence of HAV and Norovirus on perishable foods and food from fisheries, as well as Rotavirus on frozen vegetables, confirming the role of vegetables and bivalve mollusks as transmitting vehicles of enteric viruses.