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Sexual selection by mate choice is a powerful force that can lead to evolutionary change, and models of why females choose particular mates are central to understanding its effects. Predominant mate choice theories assume preferences are determined solely by genetic inheritance, an assumption still lacking widespread support. Moreover, preferences often vary among individuals or populations, fail to correspond with conspicuous male traits, or change with context, patterns not predicted by dominant models. Here, we propose a new model that explains this mate choice complexity with one general hypothesized mechanism, "Inferred Attractiveness." In this model, females acquire mating preferences by observing others' choices and use context-dependent information to infer which traits are attractive. They learn to prefer the feature of a chosen male that most distinguishes him from other available males. Over generations, this process produces repeated population-level switches in preference and maintains male trait variation. When viability selection is strong, Inferred Attractiveness produces population-wide adaptive preferences superficially resembling "good genes." However, it results in widespread preference variation or nonadaptive preferences under other predictable circumstances. By casting the female brain as the central selective agent, Inferred Attractiveness captures novel and dynamic aspects of sexual selection and reconciles inconsistencies between mate choice theory and observed behavior., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 DuVal et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

In Brazil, sucrose-rich broths (cane juice and/or molasses) are used to produce billions of liters of both fuel ethanol and cachaça per year using selected Saccharomyces cerevisiae industrial strains. Considering the important role of feedstock (sugar) prices in the overall process economics, to improve sucrose fermentation the genetic characteristics of a group of eight fuel-ethanol and five cachaça industrial yeasts that tend to dominate the fermentors during the production season were determined by array comparative genomic hybridization. The widespread presence of genes encoding invertase at multiple telomeres has been shown to be a common feature of both baker's and distillers' yeast strains, and is postulated to be an adaptation to sucrose-rich broths. Our results show that only two strains (one fuel-ethanol and one cachaça yeast) have amplification of genes encoding invertase, with high specific activity. The other industrial yeast strains had a single locus ( SUC2 ) in their genome, with different patterns of invertase activity. These results indicate that invertase activity probably does not limit sucrose fermentation during fuel-ethanol and cachaça production by these industrial strains. Using this knowledge, we changed the mode of sucrose metabolism of an industrial strain by avoiding extracellular invertase activity, overexpressing the intracellular invertase, and increasing its transport through the AGT1 permease. This approach allowed the direct consumption of the disaccharide by the cells, without releasing glucose or fructose into the medium, and a 11% higher ethanol production from sucrose by the modified industrial yeast, when compared to its parental strain.

Abstract: The traffic in international animal products can become a public health hazard when legal import sanitary procedures are not followed. In Brazil, due to its extensive border area, the importation of animal products is a common practice in many areas, especially in Rio Grande do Sul, a state that borders Argentina and Uruguay. The objective of this study was to evaluate the presence of veterinary drug residues (antibiotics and antiparasitics) in animal products consumed in Rio Grande do Sul. The presence of residues of veterinary antibiotics and antiparasitics was assessed in 189 meat (beef, pork, and chicken), processed dairy, and meat product samples bought in Argentina (n = 90) and Uruguay (n = 99). Residues of these veterinary drugs were detected in 50 (26.45%) of the samples; 28 samples (14.81%) had antibiotic residues, and 22 samples (11.64%) had antiparasitic residues. Of the 50 positive samples, 40% (15 from Argentina and 5 from Uruguay) had residues above the maximum residue limits (MRLs). Of these 20 samples, 12 had antiparasitic residues above the MRLs (11 beef samples had ivermectin and 1 pork sample had ivermectin and doramectin) and 8 had antibiotic residues above the MRLs (2 pork and 2 sausage samples had doxycycline, 2 cheese samples had doxycycline and chlortetracycline, 1 poultry meat sample had chloramphenicol, and 1 cheese sample had monensin). Because of the potential toxic effects on humans and the potential for pathogens to develop antibiotic resistance, the presence of these residues above the MRLs is a potential risk to public health. The negative impact of consumption of imported animal products can be reduced by implementation of an effective surveillance system and educational campaigns for the general population., (Copyright ©, International Association for Food Protection.)

Body size mediates life history, physiology and inter- and intra-specific interactions. Within species, sexes frequently differ in size, reflecting divergent selective pressures and/or constraints. Both sexual selection and differences in environmentally mediated reproductive constraints can drive sexual size dimorphism, but empirically testing causes of dimorphism is challenging. Manakins (Pipridae), a family of Neotropical birds comprising approximately 50 species, exhibit a broad range of size dimorphism from male- to female-biased and are distributed across gradients of precipitation and elevation. Males perform courtship displays ranging from simple hops to complex aerobatic manoeuvres. We tested associations between sexual size dimorphism and (a) agility and (b) environment, analysing morphological, behavioural and environmental data for 22 manakin species in a phylogenetic framework. Sexual dimorphism in mass was most strongly related to agility, with males being lighter than females in species performing more aerial display behaviours. However, wing and tarsus length dimorphism were more strongly associated with environmental variables, suggesting that different sources of selection act on different aspects of body size. These results highlight the strength of sexual selection in shaping morphology-even atypical patterns of dimorphism-while demonstrating the importance of constraints and ecological consequences of body size evolution.

In cooperatively breeding species, subordinates forgo reproduction to assist breeders in raising offspring. When cooperative breeding is facultative, breeders from the same population may differ in whether they are assisted by non-breeding helpers. Predation risk is a major source of nest failure and assistance during nest defense is often an overlooked, yet important, way helpers assist breeders. A breeder's aggressive response to a nest predator could have important implications for whether they form cooperatively breeding groups. We investigated the hypothesis that breeder aggression towards a nest predator is related to current and future helper recruitment. We tested the prediction that less aggressive breeders were more likely to form cooperative groups, which could occur if these breeders benefit from helper assistance during nest defense. We also considered the possibility that more aggressive breeders were more likely to form cooperative groups. We assessed the effects of partnerships and tested whether aggression exhibited by breeding partners was correlated. We conducted this work in the facultative, cooperatively breeding brown-headed nuthatch ( Sitta pusilla ). We measured breeder aggression in response to a taxidermy model of a nest predator to determine whether breeders' aggression correlated with their current or future helper recruitment. We found no evidence of a sex difference in aggression among breeders and aggression scores of breeding partners were not significantly correlated. Aggression scores for both breeding males and breeding females were unrelated to whether they formed cooperative groups in the current year. We followed most of the breeding males, though not breeding females, across years and found that breeding males' aggression scores were unrelated to helper recruitment the following year. Our results suggest that breeders' responses to nest predators are not related to cooperative group formation in this species and that males and females showed comparable levels of aggression towards a nest predator., Competing Interests: Conflict of Interest: The authors declare no conflict of interest.

When vertebrates are exposed to stressors, the subsequent acute increase in glucocorticoids by the hypothalamic-pituitaryadrenal (HPA) axis triggers a suite of adaptive responses, including mobilization of stored energy and repression of non-essential processes. However, chronic exposure to high concentrations of glucocorticoids can lead to metabolic dysregulation, impaired immune function, and cognitive decline. In developing young, this hormonal stress response shows considerable variation. Generally, the physiological stress response of young of precocial species is comparable to that of adults, whereas offspring of altricial species exhibit an attenuated response compared to adults. The developmental hypothesis of the HPA axis proposes that the dampened stress response in dependent offspring is an adaptive response to avoid the negative effects of elevated glucocorticoids, particularly in altricial species where young lack the ability to mitigate stressful stimuli.We aimed to test the developmental hypothesis in a tropical avian species, the lance-tailed manakin (Chiroxiphia lanceolata). We predicted that nestlings of this altricial species should have a dampened corticosterone response, in both magnitude and duration, compared to that of adults. We also predicted that recently fledged hatch-year birds would display a response intermediate to that of adults and nestlings. We quantified circulating corticosterone levels in adults, recently fledged hatch-year birds, and 11-day-old nestlings using a standardized capture and restraint protocol. Nestlings showed a lower maximal corticosterone response and faster negative feedback compared to adults. Further, five post-fledging hatch-year birds showed a feedback response intermediate to those of nestlings and adults. However, we caution against generalizing about fledgling responses beyond this study due to the small sample (n = 5). Interestingly, lance-tailed manakin nestlings appear to return to baseline concentrations faster than nestlings of temperate species. These results support the developmental hypothesis of the HPA axis explaining variation in stress response. This study is the first to assess the development of the hormonal stress response in nestlings of a tropical bird, which is of interest because of our still-developing understanding of how tropical and temperate species differ physiologically. Finally, findings here underscore the importance of validating and adjusting sampling protocols that quantify nestling stress responses, as sampling timelines identified for adults may underestimate the magnitude of the nestling stress response., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Multiple mating by females is common and often driven by social constraints on female mate choice. However, females mate with multiple males even in systems without these social constraints and rates of multiple mating tend to be highly variable within and between populations. In lek mating systems, females are able to assess multiple males and their choice is unrestricted by pair bonds or the need for biparental care, yet some females mate with multiple males. To better understand the factors affecting variation in multiple mating, we investigated the occurrence of multiple paternity within clutches in a highly polygynous lek mating system. Using long-term data on genetic paternity, survival, social status and individual age from a population of lance-tailed manakins Chiroxiphia lanceolata, a species where males lek in cooperative alpha-beta pairs, we tested five non-exclusive hypotheses about the causes of variation in multiple mating and its benefits in females. We found that inexperienced males, including new alphas and rare beta sires, were disproportionately likely to share paternity when they sired any chicks. In contrast, female age (experience) was unrelated to multiple paternity. Multiple mating did not result in higher reproductive success or reduced variance in success for females, and there were neither consistently promiscuous females nor males that consistently shared paternity. The occurrence of multiple paternity in this lek mating system was best explained by female choice related to male characteristics that change with male experience. Our results support the hypothesis that there is a developmental component to the occurrence of multiple mating, and suggest females choose to mate multiply when their choices are not optimal., (© 2019 British Ecological Society.)

Many microorganisms from various sources may be present in ejaculates of bulls. This study identified and isolated bacteria from bull sperm samples in a commercial stud and evaluated their resistance to antibiotics. The number of colony-forming units was determined in semen samples collected at distinct steps during freezing and thawing. The minimum inhibitory concentration and the minimum bactericidal concentration were determined for four antibiotics commonly used in commercial studs. A total of 135 microorganisms from 25 genera were isolated. After a sensitivity test, all evaluated microorganisms (n = 55) were resistant to penicillin and most of them were resistant to tylosin and lincomycin (n = 54). Resistance to all tested antibiotics was observed in 22% of all isolates, whereas only 3.9% of the isolates were inhibited by the tested antibiotics at the concentrations recommended by the international legislation. As the isolated microorganisms presented high resistance to frequently used antibiotics, sensitivity tests should be periodically conducted in commercial bull semen studs to prevent the use of contaminated semen in artificial insemination., (© 2020 Blackwell Verlag GmbH.)

The El Niño Southern Oscillation (ENSO) is a global phenomenon that influences climate variation and, in turn, the ecological processes affecting the abundance and distribution of populations across taxa. For example, the ENSO can profoundly influence the development and survival of pelagic species, but the extent to which the ENSO affects offspring of terrestrial species is less well known. We used piecewise structural equation modeling to investigate the direct and indirect relationship between the ENSO and offspring development and survival in a terrestrial tropical passerine, the lance-tailed manakin (Chiroxiphia lanceolata). The Oceanic Niño Index (ONI), a measure of the ENSO, was negatively related to individual growth rate, maximum number of lesion developed by nestlings, and hatching day-of-year; which in turn mediated indirect effects on fledging success and recruitment. Further the ONI was a better predictor of nestling development compared to local temperature and rainfall. Our study establishes a link between the ENSO and the development and survival of young of a terrestrial species and underscores the need to better understand how offspring cope with global climate variation.

The aim of this study was to investigate hepatitis A virus (HAV), hepatitis E (HEV), and rotavirus (RV) in fresh and processed meat traded on the border of Brazil with Argentina and Uruguay. In total, 159 samples of raw and processed foods of animal origin were collected in Paso de los Libres, Argentina (n = 53 raw meat, n = 24 processed meat) and Rivera, Uruguay (n = 55 raw meat, n = 18 processed meat), or were seized by the Brazilian International Agricultural Surveillance System-VIGIAGRO (Brazil-Argentina border) (n = 8 raw meat, n = 1 bush meat). All samples were tested for the presence of HAV, HEV, and RV genomes. HAV genes were detected in 18.23% of samples and RV genes in 23.89%. No HEV-positive samples were detected. HAV was also detected in two of the VIGIAGRO samples. Processed meats from Argentina and Uruguay had a higher rate of HAV and RV than raw meat (P > 0.05). The median HAV in the Argentinian and Uruguayan samples was 6.9 × 10 4 and 3.5 × 10 3  copies/g, respectively. The presence of RV viral genes in raw meats from Argentina was significant, and this was not observed in processed meats. The presence of HAV and RV genes in a significant portion of products from Argentina and Uruguay is a potential source of human infection. This also indicates precarious conditions of acquisition, processing, and manipulation, which could be improved by improved regulation of food across borders.

This study aimed to evaluate the presence of pathogens in, and the hygienic-sanitary quality of, commercialized foods of animal origin at the international border region of Rio Grande do Sul, Brazil. In total, 270 samples of raw and processed foods of animal origin were collected in Paso de los Libres, Argentina (n = 65 raw meat, n = 47 dairy products, n = 28 processed meat) and Rivera, Uruguay (n = 60 raw meat, n = 31 dairy products, n = 29 processed meat), or were seized by the Brazilian International Agricultural Surveillance System (Brazil-Argentina border) (n = 9 raw meat, n = 1 bush meat). The samples were subjected to the enumeration of aerobic mesophilic bacteria, enterobacteria, and coagulase-positive staphylococci, and were tested for Salmonella spp., Listeria monocytogenes, and Escherichia coli O157:H7. The virulence genes for Salmonella spp. (hilA, invA, spvC, pefA, and sefA), L. monocytogenes (prs, inlA, inlC, and inlJ) and E. coli O157:H7 (uspA, eae, rfb O157 , fliC H7 , stx1, stx2, and hlyA) were investigated using PCR assays. Raw products showed higher counts of aerobic mesophiles and enterobacteria compared to processed products (P < 0.05). There were no significant differences in aerobic mesophile or in enterobacterial counts between identical products according to origin (Argentina vs. Uruguay, P > 0.05). Escherichia coli O157:H7 was not detected in any of the samples tested. Salmonella spp. was detected in six (8%) raw products from Argentina. Listeria monocytogenes was isolated from five (6.66%) raw products originating in Argentina and 20 (16.66%) raw products from Uruguay. All 52 E. coli isolates carried the uspA gene, but only one carried the eae gene. The rfb O157 , fliC H7 , stx1, stx2, and hlyA genes were not detected. All Salmonella spp. isolates carried hilA and invA genes, but spvC, pefA, and sefA were not found. All L. monocytogenes isolates carried the prs gene; however, inlA, inlC, and inlJ genes were found in 20% of the isolates from Argentina and 95% of those from Uruguay. To our knowledge, this is the first microbiological study into the hygienic-sanitary quality of animal products in Brazil's land border region. Salmonella spp. and L. monocytogenes were detected in products of animal origin, constituting a public health concern and emphasizing the need for an active surveillance system to reduce the risk of foodborne pathogen introduction into Brazil., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Bull Semen Collection and Processing Centers (SCPC) have satisfactory control of sperm quality, but commonly lack standardized quality control of hygiene procedures. This study assessed the impact of implementing a Hazard Analysis and Critical Control Points (HACCP) system in a bull SCPC, comparing microbial counts on various steps of semen processing, semen quality and costs across two periods (before and after the HACCP implementation). After surveying all routine activities of the SCPC, control points were identified, preventive measures were designed and corrective actions were employed, whenever necessary. Six months after HACCP implementation, the system was audited and production data covering two similar periods of two consecutive years were compared. Counts of colony forming units in samples collected from artificial vaginas, flexible tubes from the straw filling machine and from fresh and frozen semen after HACCP implementation were lower than during the previous period (P < 0.05). Improved post-thawing sperm motility, membrane integrity and acrosome integrity (P < 0.0001) and reduced rejection of semen batches and frozen doses were observed after HACCP implementation (P < 0.01), resulting in reduced opportunity costs. Thus, the implementation of a HACCP system in a bull SCPC allowed low-cost production of high-quality semen doses with reduced microbial contamination., Competing Interests: Conflicts of interest
The authors have no conflict of interest to declare.

International food transit is a risk to public and animal health when not subject to legal importation sanitation procedures. Due to the extensive border area, illegal food import in Brazil is a common practice, especially in Rio Grande do Sul (RS), a state that borders with Argentina and Uruguay. The objective of this study was to evaluate the profile of Brazilians living in cities in RS that border with Argentina (BR-AR) or Uruguay (BR-UR) regarding the practice of illegal import of products of animal origin and to determine associations between the population characteristics and illegal import. A questionnaire with information related to the personal profile, habits of acquisition of imported food, and knowledge of health risks deriving from the consumption of the imported products was elaborated. The questionnaire was administered in six cities in RS (three cities bordering Argentina and three cities bordering Uruguay) and responses were obtained from 744 individuals. The variables city, sex, level of education, and knowledge were subjected to the chi-square test to verify the association between these variables and food import. Part of the interviewees admitted to illegally importing products of animal origin at both BR-AR (65.17%) and BR-UR (76.28%) borders. Dairy products were the main imported goods, followed by raw and processed meat. The study revealed that illegal import is common at the frontier region of RS, especially that of products of animal origin, dairy, and raw and processed meat. Although illegal importation occurs at all the cities under study, it was higher at the BR-UR border. Also, knowledge of the health risks influences the decision to import food or not.

Intense manipulation during beef jerky production increases the possibility of contamination with pathogenic microorganisms. This study evaluated the contamination by thermotolerant coliforms, Escherichia coli and Salmonella spp., on processing surfaces and raw materials during beef jerky production, as well as in the final product. Thermotolerant coliforms were found on all surfaces tested and in the raw material. Escherichia coli was identified in 6.7% of the surface samples, while Salmonella spp. was found in 3.3% of the surface samples and 8.6% of raw material samples. Virulence genes were detected in Salmonella spp. isolates. One Salmonella spp. isolate was resistant to sulfonamide, while one E. coli isolate was multiresistant, including the presence of resistance genes sul2, strA, strB, tetA and tetB. The presence of coliforms demonstrates failings in hygienic-sanitary procedures. The presence of pathogenic microorganisms causing foodborne diseases in the production line indicates persistent contamination in the production plant. Although the drying process applied to beef jerky should guarantee the safety of the final product, the presence of multiresistant pathogenic microorganisms, presenting virulence genes, should be a matter of concern. Because beef jerky is a ready-to-eat product, a failure in the production process may cause such microorganisms to pose a public health risk., (© FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The need for cleaner sources of energy has stirred research into utilising alternate fuel sources with favourable emission and sustainability such as biodiesel. However, there are technical constraints that hinder the widespread use of some of the low cost raw materials such as pork fatty wastes. Currently available technology permits the use of lipolytic microorganisms to sustainably produce energy from fat sources; and several microorganisms and their metabolites are being investigated as potential energy sources. Thus, the aim of this study was to characterise the process of Staphylococcus xylosus mediated fermentation of pork fatty waste. We also wanted to explore the possibility of fermentation effecting a modification in the lipid carbon chain to reduce its melting point and thereby act directly on one of the main technical barriers to obtaining biodiesel from this abundant source of lipids. Pork fatty waste was obtained from slaughterhouses in southern Brazil during evisceration of the carcasses and the kidney casing of slaughtered animals was used as feedstock. Fermentation was performed in BHI broth with different concentrations of fatty waste and for different time periods which enabled evaluation of the effect of fermentation time on the melting point of swine fat. The lowest melting point was observed around 46°C, indicating that these chemical and biological reactions can occur under milder conditions, and that such pre-treatment may further facilitate production of biodiesel from fatty animal waste., (Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.)

Considering the specific biochemical composition of buffalo (Bubalus bubalis) meat (high iron content, high biological value proteins and essential fatty acids, low amounts of fat and cholesterol), we evaluated the influence of cutting and deboning operations on the microbiological quality and shelf-life of vacuum-packed buffalo meat stored under refrigeration. On the processing day, samples were collected from carcass, deboning room surfaces and meat cuts. Samples from meat cuts were evaluated weekly for two months. On the processing day, higher counts of Pseudomonas spp. were observed in samples from meat cuts compared with the hindquarters and the processing surfaces. For thermotolerant coliform scores, the averages were -0.5 log MPN·cm(-2), -0.4 log MPN·cm(-2) and 0.9 log MPN·g(-1), respectively. Higher counts of Pseudomonas spp. and LAB in meat cuts were observed on the processing day and after the first week of storage, respectively, remaining constant during shelf life. Listeria grayi was identified in two samples of hindquarters and meat cuts during storage. Listeria innocua was identified in one meat cut. In conclusion, cutting and deboning operations influence the microbiological quality and shelf life of vacuum-packed buffalo meat stored under refrigeration., (Copyright © 2016. Published by Elsevier Ltd.)

The increasing rise in the production of meat around the world causes a significant generation of agro-industrial waste--most of it with a low value added. Fatty wastes have the potential of being converted into biodiesel, given the overcome of technological and economical barriers, as well as its presentation in solid form. Therefore, the aim of this work was to investigate the capacity of Staphylococcus xylosus strains to modify the chemical structure of chicken fatty wastes intending to reduce the melting points of the wastes to mild temperatures, thereby breaking new ground in the production of biodiesel from these sources in an economically attractive and sustainable manner. The effects in time of fermentation and concentration of the fat in the medium were investigated, assessing the melting point and profile of fatty acids. The melting temperature showed a decrease of approximately 22 °C in the best operational conditions, due to reduction in the content of saturated fatty acids (high melting point) and increase of unsaturated fatty acids (low melting point).

Indirect benefits of mate choice result from increased offspring genetic quality and may be important drivers of female behaviour. 'Good-genes-for-viability' models predict that females prefer mates of high additive genetic value, such that offspring survival should correlate with male attractiveness. Mate choice may also vary with genetic diversity (e.g. heterozygosity) or compatibility (e.g. relatedness), where the female's genotype influences choice. The relative importance of these nonexclusive hypotheses remains unclear. Leks offer an excellent opportunity to test their predictions, because lekking males provide no material benefits and choice is relatively unconstrained by social limitations. Using 12 years of data on lekking lance-tailed manakins, Chiroxiphia lanceolata, we tested whether offspring survival correlated with patterns of mate choice. Offspring recruitment weakly increased with father attractiveness (measured as reproductive success, RS), suggesting attractive males provide, if anything, only minor benefits via offspring viability. Both male RS and offspring survival until fledging increased with male heterozygosity. However, despite parent-offspring correlation in heterozygosity, offspring survival was unrelated to its own or maternal heterozygosity or to parental relatedness, suggesting survival was not enhanced by heterozygosity per se. Instead, offspring survival benefits may reflect inheritance of specific alleles or nongenetic effects. Although inbreeding depression in male RS should select for inbreeding avoidance, mates were not less related than expected under random mating. Although mate heterozygosity and relatedness were correlated, selection on mate choice for heterozygosity appeared stronger than that for relatedness and may be the primary mechanism maintaining genetic variation in this system despite directional sexual selection., (© 2014 John Wiley & Sons Ltd.)

The differential allocation hypothesis predicts increased investment in offspring when females mate with high-quality males. Few studies have tested whether investment varies with mate relatedness, despite evidence that non-additive gene action influences mate and offspring genetic quality. We tested whether female lekking lance-tailed manakins (Chiroxiphia lanceolata) adjust offspring sex and egg volume in response to mate attractiveness (annual reproductive success, ARS), heterozygosity and relatedness. Across 968 offspring, the probability of being male decreased with increasing parental relatedness but not father ARS or heterozygosity. This correlation tended to diminish with increasing lay-date. Across 162 offspring, egg volume correlated negatively with parental relatedness and varied with lay-date, but was unrelated to father ARS or heterozygosity. Offspring sex and egg size were unrelated to maternal age. Comparisons of maternal half-siblings in broods with no mortality produced similar results, indicating differential allocation rather than covariation between female quality and relatedness or sex-specific inbreeding depression in survival. As males suffer greater inbreeding depression, overproducing females after mating with related males may reduce fitness costs of inbreeding in a system with no inbreeding avoidance, while biasing the sex of outbred offspring towards males may maximize fitness via increased mating success of outbred sons.

Experience improves individual performance in many tasks. Pre-breeding cooperation may provide important experience that improves later success as a breeder, offering one compelling explanation for why some individuals delay reproduction to help others breed (the 'skills hypothesis'). However, confounding effects of age, quality and alternative selective benefits have complicated rigorous tests of this hypothesis. Male lance-tailed manakins perform cooperative courtship displays involving partnerships between unrelated alpha and beta males, and alphas monopolize resulting copulations. Beta males therefore do not receive immediate direct or indirect fitness benefits, but may gain skills during cooperation that increase their later success as an alpha. To date, however, the effect of cooperative experience on later success as a breeder has never been tested in any cooperatively displaying taxon. The effects of prior cooperative experience on reproductive success of alpha lance-tailed manakins were analysed in a mixed model framework using 12 years of information on cooperative experience and annual and lifetime genetic reproductive success for 57 alpha males. Models included previously identified effects of age and alpha tenure. Individual-level random effects controlled for quality differences to test for an independent influence of beta experience on success. Males accumulated up to 5 years of beta experience before becoming alphas, but 42·1% of alphas had no prior beta experience. Betas became alphas later in life, and experienced significantly lower reproductive success in their final year as alpha than males that were never beta, but did not have higher lifetime success or longer alpha tenures. Differences in patterns of annual siring success were best explained by age-dependent patterns of reproductive improvement and senescence among alphas, not beta experience. Cooperative experience does not increase relative breeding success for male lance-tailed manakins. Importantly, beta cooperation seems to be an alternative reproductive tactic that yields fitness payoffs equivalent to a non-cooperative route to alpha status, if population growth rate is stable., (© 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.)

The extent and importance of female mate fidelity in polygynous mating systems are poorly known. Fidelity may contribute to high variance in male reproductive success when it favors attractive mates or may stabilize social interactions if females are faithful to mating sites rather than males. Using 12 years of data on genetic mate choice in the cooperatively lekking lance-tailed manakin (Chiroxiphia lanceolata), I investigated the frequency of fidelity within and between years, whether females were faithful to individual males or to mating sites across years, and whether fidelity favored attractive males. Mate fidelity occurred in 41.7% of 120 between-year comparisons and was observed for 41.1% of 73 individual females that had the opportunity to mate faithfully. Females were not more likely to mate at prior mating sites when previous mates were replaced. Faithful females mated with the same male in up to four consecutive years but were not disproportionately faithful to attractive partners. Mating history influences current mate choice, and fidelity in this lekking system apparently represents active mate choice by females but little is not cited in the text. Please provide a citation or mark this reference for deletion.consensus in mate choices among faithful females. This study underscores the prevalence of mate fidelity in polygynous mating systems and emphasizes the need to consider the larger context of lifetime reproductive behavior when interpreting patterns of female choice.

The causes of variation in individual reproductive success over a lifetime are not well understood. In long-lived vertebrates, reproductive output usually increases during early adulthood, but it is difficult to disentangle the roles of development and learning on this gain of reproductive success. Lekking lance-tailed manakins provide an opportunity to separate these processes, as the vast majority of male reproduction occurs after a bird obtains alpha status and maintains a display area in the lek, but the age at which males achieve alpha status varies widely. Using 11 years of longitudinal data on age, social status and genetic siring success, I assessed the factors influencing variation in siring success by individuals over their lifetimes. The data show increases in annual reproductive success with both age and alpha experience. At advanced ages, these gains were offset by senescence in fecundity. Individual ontogeny, rather than compositional change of the population, generated a nonlinear relationship of breeding tenure with lifetime success; age of assuming alpha status was unrelated to tenure as a breeder, or success in the alpha role. Importantly, these findings suggest that social experience can mitigate the negative effects of senescence in older breeders.

Evolutionary biologists have developed several indices, such as selection gradients (β) and the opportunity for sexual selection (I(s) ), to quantify the actual and/or potential strength of sexual selection acting in natural or experimental populations. In a recent paper, Klug et al. (J. Evol. Biol.23, 2010, 447) contend that selection gradients are the only legitimate metric for quantifying sexual selection. They argue that I(s) and similar mating-system-based metrics provide unpredictable results, which may be uncorrelated with selection acting on a trait, and should therefore be abandoned. We find this view short-sighted and argue that the choice of metric should be governed by the research question at hand. We describe insights that measures such as the opportunity for selection can provide and also argue that Klug et al. have overstated the problems with this approach while glossing over similar issues with the interpretation of selection gradients. While no metric perfectly characterizes sexual selection in all circumstances, thoughtful application of existing measures has been and continues to be informative in evolutionary studies., (© 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.)

Though cooperative behavior has long been a focus of evolutionary biology, the proximate hormonal mechanisms underlying cooperative interactions remain poorly understood. Lance-tailed manakins (Chiroxiphia lanceolata) are tropical passerines that form long-term male-male partnerships and cooperate in paired male courtship displays. To elucidate patterns of natural hormonal variation in relation to cooperation and reproductive behavior, we examined circulating androgen levels of male lance-tailed manakins in relation to social status, display behavior, and time of year. We found significantly higher circulating androgen levels in alpha-ranked (breeding) males compared to non-alpha adult males in the population. Beta males, which participated in courtship displays but did not copulate, had androgen levels indistinguishable from those of unpaired adult males that never displayed for females, suggesting that an elevated concentration of plasma testosterone in tropical lekking birds may be associated primarily with copulatory behavior or other status-specific traits, and not the performance of courtship display. Androgens decreased throughout the breeding season for males of all status categories. Interestingly, alphas that displayed for females in the observation session prior to sampling had lower androgen levels than alphas that did not display for females. This pattern may result from female discrimination against alpha males at display areas with high levels of social conflict among males, as social disruption is linked to elevated testosterone in many species. However, recent change of a display partner was not related to alpha androgen levels. We discuss alternative explanations and the possible implications of these results, and generate several testable predictions for future investigations., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Aims: We performed an analysis of maltotriose utilization by 52 Saccharomyces yeast strains able to ferment maltose efficiently and correlated the observed phenotypes with differences in the copy number of genes possibly involved in maltotriose utilization by yeast cells., Methods and Results: The analysis of maltose and maltotriose utilization by laboratory and industrial strains of the species Saccharomyces cerevisiae and Saccharomyces pastorianus (a natural S. cerevisiae/Saccharomyces bayanus hybrid) was carried out using microscale liquid cultivation, as well as in aerobic batch cultures. All strains utilize maltose efficiently as a carbon source, but three different phenotypes were observed for maltotriose utilization: efficient growth, slow/delayed growth and no growth. Through microarray karyotyping and pulsed-field gel electrophoresis blots, we analysed the copy number and localization of several maltose-related genes in selected S. cerevisiae strains. While most strains lacked the MPH2 and MPH3 transporter genes, almost all strains analysed had the AGT1 gene and increased copy number of MALx1 permeases., Conclusions: Our results showed that S. pastorianus yeast strains utilized maltotriose more efficiently than S. cerevisiae strains and highlighted the importance of the AGT1 gene for efficient maltotriose utilization by S. cerevisiae yeasts., Significance and Impact of the Study: Our results revealed new maltotriose utilization phenotypes, contributing to a better understanding of the metabolism of this carbon source for improved fermentation by Saccharomyces yeasts., (© 2010 The Authors. Journal compilation © 2010 The Society for Applied Microbiology.)

Fuel ethanol is now a global energy commodity that is competitive with gasoline. Using microarray-based comparative genome hybridization (aCGH), we have determined gene copy number variations (CNVs) common to five industrially important fuel ethanol Saccharomyces cerevisiae strains responsible for the production of billions of gallons of fuel ethanol per year from sugarcane. These strains have significant amplifications of the telomeric SNO and SNZ genes, which are involved in the biosynthesis of vitamins B6 (pyridoxine) and B1 (thiamin). We show that increased copy number of these genes confers the ability to grow more efficiently under the repressing effects of thiamin, especially in medium lacking pyridoxine and with high sugar concentrations. These genetic changes have likely been adaptive and selected for in the industrial environment, and may be required for the efficient utilization of biomass-derived sugars from other renewable feedstocks.

Leks are classic models for studies of sexual selection due to extreme variance in male reproductive success, but the relative influence of intrasexual competition and female mate choice in creating this skew is debatable. In the lekking lance-tailed manakin (Chiroxiphia lanceolata), these selective episodes are temporally separated into intrasexual competition for alpha status and female mate choice among alpha males that rarely interact. Variance in reproductive success between status classes of adult males (alpha versus non-alpha) can therefore be attributed to male-male competition whereas that within status largely reflects female mate choice. This provides an excellent opportunity for quantifying the relative contribution of each of these mechanisms of sexual selection to the overall opportunity for sexual selection on males (I males). To calculate variance in actual reproductive success, we assigned genetic paternity to 92.3% of 447 chicks sampled in seven years. Reproduction by non-alphas was rare and apparently reflected status misclassifications or opportunistic copulations en route to attaining alpha status rather than alternative mating strategies. On average 31% (range 7-44%, n=6 years) of the total I males was due to variance in reproductive success between alphas and non-alphas. Similarly, in a cohort of same-aged males followed for six years, 44-58% of the total I males was attributed to variance between males of different status. Thus, both intrasexual competition for status and female mate choice among lekking alpha males contribute substantially to the potential for sexual selection in this species.

Male lance-tailed manakins (Chiroxiphia lanceolata) cooperate in complex courtship displays, but the dominant (alpha) partner monopolizes mating opportunities. This raises the question of why subordinates (betas) cooperate. Three nonexclusive hypotheses explain the adaptive basis of helping behavior by subordinate males: cooperation may increase (1) subordinates' immediate reproductive success, (2) the reproductive success of close relatives, or (3) subordinates' chances of future reproduction. I demonstrated that beta males rarely sired chicks and were unrelated to their alpha partners but received delayed direct benefits from cooperation; betas had an increased probability of becoming an alpha when compared to males that had not been betas. To investigate the mechanism by which betas attain these adaptive benefits, I examined betas' success in replacing their alpha partners both in natural turnover events and when alphas were experimentally removed. Beta males did not consistently inherit alpha roles in the same territories where they served their beta tenure, arguing that queuing for status does not fully explain the benefits of cooperation for betas. Instead, betas may be apprenticing to develop effective and appropriate displays that enhance their subsequent success as alphas. Complex social affiliations appear to mediate selective pressure for cooperation in this species.

The objective of this work was to study the occurrence of Listeria species in feces and on dressed and cooled carcasses of lambs at a packing plant in Brazil. Listeria spp. were recovered on Oxford and Palcam agars. The 35 fecal samples yielded Listeria welshimeri (20%) and Listeria innocua (8.6%). The 69 carcass samples yielded L. innocua (34.8%), Listeria monocytogenes (4.3%), and Listeria ivanovii (1.5%). More Listeria spp. were recovered with two selective agars than with either agar alone.