Reproductive endocrine disruption in smallmouth bass (Micropterus dolomieu) in the Potomac River basin: spatial and temporal comparisons of biological effects

A high prevalence of intersex or testicular oocytes (TO) in male smallmouth bass within the Potomac River drainage has raised concerns as to the health of the river. Studies were conducted to document biomarker responses both temporally and spatially to better understand the influence of normal physiological cycles, as well as water quality and land-use influences. Smallmouth bass were collected over a 2-year period from three tributaries of the Potomac River: the Shenandoah River, the South Branch Potomac and Conococheague Creek, and an out-of-basin reference site on the Gauley River. The prevalence of TO varied seasonally with the lowest prevalence observed in July, post-spawn. Reproductive maturity and/or lack of spawning the previous spring, as well as land-use practices such as application of manure and pesticides, may influence the seasonal observations. Annual, seasonal, and site differences were also observed in the percentage of males with measurable concentrations of plasma vitellogenin, mean concentration of plasma vitellogenin in females, and plasma concentrations of 17β-estradiol and testosterone in both sexes. Bass collected in the South Branch Potomac (moderate to high prevalence of TO) had less sperm per testes mass with a lower percentage of those sperm being motile when compared to those from the Gauley River (low prevalence of TO). An inverse relationship was noted between TO severity and sperm motility. An association between TO severity and wastewater treatment plant flow, percent of agriculture, total number of animal feeding operations, the number of poultry houses, and animal density within the catchment was observed.     

Putting the cart before the horse: Water governance and IWRM

Water governance has emerged as perhaps the most important topic of the international water community in the 21^st century, and achieving “good” water governance is now a focus of both policy discourse and innumerable development projects. Somewhat surprisingly in light of this attention, there is widespread confusion about the meaning of the term “water governance”. This paper reviews the history of the term's use and misuse to reveal how the concept is frequently inflated to include issues that go well beyond governance. Further, it highlights how calls to improve water governance often espouse predetermined goals that should instead be the very function of water governance to define. To help overcome this confusion, the paper suggests a more refined definition of water governance and related qualities of good water governance that are consistent with broader notions of the concepts. In light of the substantial resources allocated in its name, this paper's findings show there is significant potential to strengthen efforts at improving water governance.     

Invasive Microstegium populations consistently outperform native range populations across diverse environments

Plant species introduced into novel ranges may become invasive due to evolutionary change, phenotypic plasticity, or other biotic or abiotic mechanisms. Evolution of introduced populations could be the result of founder effects, drift, hybridization, or adaptation to local conditions, which could enhance the invasiveness of introduced species. However, understanding whether the success of invading populations is due to genetic differences between native and introduced populations may be obscured by origin x environment interactions. That is, studies conducted under a limited set of environmental conditions may show inconsistent results if native or introduced populations are differentially adapted to specific conditions. We tested for genetic differences between native and introduced populations, and for origin x environment interactions, between native (China) and introduced (U.S.) populations of the invasive annual grass Microstegium vimineum (stiltgrass) across 22 common gardens spanning a wide range of habitats and environmental conditions. On average, introduced populations produced 46% greater biomass and had 7.4% greater survival, and outperformed native range populations in every common garden. However, we found no evidence that introduced Microstegium exhibited greater phenotypic plasticity than native populations. Biomass of Microstegium was positively correlated with light and resident community richness and biomass across the common gardens. However, these relationships were equivalent for native and introduced populations, suggesting that the greater mean performance of introduced populations is not due to unequal responses to specific environmental parameters. Our data on performance of invasive and native populations suggest that post-introduction evolutionary changes may have enhanced the invasive potential of this species. Further, the ability of Microstegium to survive and grow across the wide variety of environmental conditions demonstrates that few habitats are immune to invasion.     

Pre-migratory life history stages of juvenile Arctic birds: costs, constraints, and trade-offs

Many young birds on the Arctic tundra are confronted by a challenging task: they must molt their feathers and accumulate fat stores for the autumn migration before climatic conditions deteriorate. Our understanding of the costs and constraints associated with these stages is extremely limited. We investigated post-juvenal molt and premigratory fattening in free-ranging juvenile White-crowned Sparrows (Zonotrichia leucophrys gambelii) on the Arctic tundra. We found evidence for trade-offs between premigratory fat accumulation and molt: heavily molting birds had significantly less fat. Birds increased the rate of fat accumulation as the season progressed, but we found no evidence of a similar increase in rate of molt. Using a controlled captive study to isolate the energetic costs of body feather replacement, we found no difference in fat or size-corrected mass of birds actively growing body feathers as compared to controls. Molting birds, however, consumed 17% more food than controls, suggesting a significant cost of body feather growth. Our results provide evidence of significant costs, constraints, and trade-offs associated with post-juvenal molt and premigratory fat accumulation in young Arctic birds.     

Worker policing in the bee Apis florea

Apis florea is a single-combed, open-nesting, dwarf honeybee indigenous to Asia. In common with other species of this genus, A. florea is highly polyandrous, and is therefore predicted to curtail worker reproduction by mutual policing mechanisms that keep worker reproduction at an extremely low level. Policing mechanisms could involve destruction of workers' eggs or offspring, or aggression toward those workers that are reproductively active. We show that in A. florea, worker-laid eggs are eliminated approximately twice as fast as queen-laid eggs, indicating that A. florea uses oophagy of worker-laid eggs as a mechanism of worker policing. Genetic analysis of four colonies indicated that all males produced were sons of queens, not workers. Dissections of 800 workers, from four colonies, did not reveal any significant levels of ovary activation. These results suggest that worker policing is an effective component of the mechanisms that maintain worker sterility in this species. Furthermore, they suggest that worker policing via oophagy of worker-laid eggs is pleisiomorphic for the genus.     

Stable lead isotope profiles in smelter and general urban communities: a comparison of environmental and blood measures

High-precision lead isotope ratios and lead concentrations have been compared statistically and graphically in women of child-bearing age (n = 77) from two smelter communities and one general urban community to evaluate the relative contributions to blood lead of tissue lead stores and lead from the contemporaneous environment (soil, floor dust, indoor airborne dust, water, food). Blood lead (PbB) contents were generally low (e.g. <10 g dL^–1). Statistically significant isotopic differences in blood and environmental samples were observed between the three cities although isotopic differences in blood for individual subjects living in close proximity (200 m radius) was as large as the differences within a city. No single environmental measure dominated the biological isotope profile and in many cases the low levels of blood lead meant that their isotopic profiles could be easily perturbed by relatively small changes of environmental exposure. Apportioning of sources using lead isotopes is possibly not feasible, nor cost effective, when blood lead levels are <5 g dL^–1. Interpretations based on statistical analyses of city-wide data do not give the same conclusions as when the houses are considered individually. Aggregating data from multiple subjects in a study such as this obscures potentially useful information. Most of the measures employed in this study, and many other similar studies, are markers of only short-to-medium integration of lead exposure. Serial sampling of blood and longer sampling times, especially for household variables, should provide more meaningful information.     

Occurrence of naproxen,ibuprofen, and diclofenac residues in wastewater and river water of KwaZulu-Natal Province in South Africa

The present paper reports a detailed study that is based on the monitoring of naproxen, ibuprofen, and diclofenac in Mbokodweni River and wastewater treatment plants (WWTPs) located around the city of Durban in KwaZulu-Natal Province of South Africa. Target compounds were extracted from water samples using a multi-template molecularly imprinted solid-phase extraction prior to separation and quantification on a high-performance liquid chromatography equipped with photo diode array detector. The analytical method yielded the detection limits of 0.15, 1.00, and 0.63 μg/L for naproxen, ibuprofen, and diclofenac, respectively. Solid-phase extraction method was evaluated for its performance using deionized water samples that were spiked with 5 and 50 μg/L of target compounds. Recoveries were greater than 80% for all target compounds with RSD values in the range of 4.1 to 10%. Target compounds were detected in most wastewater and river water samples with ibuprofen being the most frequently detected pharmaceutical. Maximum concentrations detected in river water for naproxen, ibuprofen, and diclofenac were 6.84, 19.2, and 9.69 μg/L, respectively. The concentrations of target compounds found in effluent and river water samples compared well with some studies. The analytical method employed in this work is fast, selective, sensitive, and affordable; therefore, it can be used routinely to evaluate the occurrence of acidic pharmaceuticals in South African water resources.     

Sperm viability staining in ecology and evolution: potential pitfalls

The causes and consequences of variation in sperm quality, survival and ageing are active areas of research in ecology and evolution. In order to address these topics, many recent studies have measured sperm viability using fluorescent staining. Although sperm viability staining has produced a number of interesting results, it has some potential pitfalls that have rarely been discussed. In the present paper, I review the major findings of ecology and evolution studies employing sperm viability staining and outline the method’s principle limitations. The key problem is that the viability assay may itself kill sperm, which is likely to confound many common experimental designs in addition to producing artificially low estimates of sperm viability. I further suggest that sperm number should be routinely measured in sperm viability studies, as it may be an important but overlooked source of spurious results. I provide methodological advice on sperm viability staining aimed at minimising artefacts and producing robust conclusions, and discuss possible avenues for future research. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Assumptions beyond the science: encouraging cautious conclusions about functional magnetic resonance imaging research on organizational behavior

Functional magnetic resonance imaging (fMRI) is likely to become the major tool for studying the neural underpinnings of organizational behavior. It is a technique for brain imaging that, according to advocates, provides information about which areas of the brain are activated during organizational processes (e.g., leadership and decision‐making). In this article, we take a critical look at this tool from a technical perspective. In particular, we take the reader through the assumptions that must be made at the three main steps of the research process (study design, data capture, and interpretation of results) in order to draw conclusions about organizational phenomena from fMRI research. Applying this analysis to three case studies demonstrates the gap between what fMRI can actually tell us and the claims often made about the contribution of fMRI to understanding and improving organizational behavior. Our discussion provides researchers with a series of recommendations oriented toward optimizing the use of fMRI to help it live up to its potential in the field of organizational behavior and consumers with a means of evaluating fMRI research in order to draw appropriate and warranted conclusions. Copyright © 2016 John Wiley & Sons, Ltd.