Genetic uniformity of widely separated populations of the coral reef starfishLinckia laevigata from the East Indian and West Pacific Oceans,revealed by allozyme electrophoresis

Gene flow among 18 widely separated populations of the starfishLinckia laevigata was investigated using allozyme electrophoresis at seven polymorphic enzyme loci. Little genetic differentiation was observed among East Indian-West Pacific populations separated by thousands of kilometres. Gene flow was estimated to be of the same order of magnitude as that found in the highly connected Great Barrier Reef region. The absence of genetic structure over such a broad geographic range is consistent with any of three conclusions: (1) there is extensive dispersal among widely separated populations across the range examined, (2) there has been a rapid expansion of the East Indian-West Pacific populations in the recent past, or (3) the loci surveyed are under the influence of balancing selection. The first two conclusions are not totally exclusive, since a recent expansion over several thousand generations would also require rapid dispersal at some stage, although present-day levels of dispersal need not be of the same order. With the available data, it is not possible to distinguish which of these mechanisms is the most likely. The most parsimonious conclusion is that extremely low levels of population differentiation are consistent with the existence of a large, homogeneous, panmictic population, with extensive dispersal occurring throughout the East Indian-West Pacific.     

Prenatal diagnosis of PORCN-related developmental syndrome in a fetus: A novel phenotype

We report a case of a female fetus born to an unrelated couple with a complex fetal phenotype of a pleural effusion, a cardiac malformation, and syndactyly of the toes. Prenatal exome sequencing identified a variant of uncertain significance in the PORCN gene that was upgraded to likely pathogenic following postnatal clinical examination. The phenotype described in cases with variants in the PORCN gene is often associated with findings that cannot be prospectively diagnosed by ultrasonography. This is the first report of a prenatal phenotype involving a fetal effusion associated with variants in the PORCN gene, with skeletal findings identified later in gestation on ultrasonography. The diagnosis was confirmed on neonatal examination.     

Contaminants of Emerging Concern in Fish from Western U.S. and Alaskan National Parks — Spatial Distribution and Health Thresholds

Remote national parks of the western U.S. and Alaska are not immune to contaminants of emerging concern. Semivolatile organic compounds (SOCs) such as pesticides and PCBs can selectively deposit from the atmosphere at higher rates in cold, high‐elevation and high‐latitude sites, potentially increasing risk to these ecosystems. In the environment, SOCs magnify up food chains and are known to increase health risks such as cancer and reproductive impairment. One hundred twenty‐eight fish in 8 national parks in Alaska and the western U.S. were analyzed for contaminant concentrations, assessed by region, and compared to human and wildlife health thresholds. SOC concentrations from an additional 133 fish from a previous study were also included, for a total of 31 water bodies sampled. PCBs, endosulfan sulfate, and p,p′‐DDE were among the most frequently detected contaminants. Concentrations of historic‐use pesticides dieldrin, p,p′‐DDE, and/or chlordanes in fish exceeded USEPA guidelines for human subsistence fish consumers and wildlife (kingfisher) health thresholds at 13 of 14 parks. Average concentrations in fish ranged from 0.6‐280 ng/g lipid (0.02‐7.3 μg/g ww). Contaminant loading was highest in fish from Alaskan and Sierra Nevada parks. Historic compounds were highest in Alaskan parks, while current‐use pesticides were higher in the Rockies and Sierra Nevada. This study provides a rigorous analysis of CECs in fish from national parks and identifies regions at potential risk.     

An experimental test of alternative population augmentation scenarios

Human land use is fragmenting habitats worldwide and inhibiting dispersal among previously connected populations of organisms, often leading to inbreeding depression and reduced evolutionary potential in the face of rapid environmental change. To combat this augmentation of isolated populations with immigrants is sometimes used to facilitate demographic and genetic rescue. Augmentation with immigrants that are genetically and adaptively similar to the target population effectively increases population fitness, but if immigrants are very genetically or adaptively divergent, augmentation can lead to outbreeding depression. Despite well‐cited guidelines for the best practice selection of immigrant sources, often only highly divergent populations remain, and experimental tests of these riskier augmentation scenarios are essentially nonexistent. We conducted a mesocosm experiment with Trinidadian guppies (Poecilia reticulata) to test the multigenerational demographic and genetic effects of augmenting 2 target populations with 3 types of divergent immigrants. We found no evidence of demographic rescue, but we did observe genetic rescue in one population. Divergent immigrant treatments tended to maintain greater genetic diversity, abundance, and hybrid fitness than controls that received immigrants from the source used to seed the mesocosms. In the second population, divergent immigrants had a slightly negative effect in one treatment, and the benefits of augmentation were less apparent overall, likely because this population started with higher genetic diversity and a lower reproductive rate that limited genetic admixture. Our results add to a growing consensus that gene flow can increase population fitness even when immigrants are more highly divergent and may help reduce uncertainty about the use of augmentation in conservation.     

Prospects for repellent in pest control: current developments and future challenges

The overall interest in environmentally safe pest control methods and the rise of insecticide resistance in pest populations have prompted medical and agricultural entomology research on insect repellents in recent years. However, conducting research on repellent is challenging for several reasons: (1) the different repellent phenomena are not well defined; (2) it is difficult to test for and quantify repellent; (3) the physiological mechanisms are poorly known; (4) the field efficacy appears to be highly variable. Here, we identified five different types of repellent: expellency, irritancy, deterrency, odor masking and visual masking, and described behavioral bioassays to differentiate between them. Although these categories are currently defined by their behavioral response to different stimuli, we suggest new definitions based on their mechanism of action. We put forward three main hypotheses on the physiological mechanism: (1) a dose effect that modifies the behavior, (2) a repellent mechanism with specific receptors, or (3) inhibition of the transduction of neural information.     

A very unusual ‘groin’, the MV River Princess,Goa, India and its impacts upon tourism

On June 6, 2000, the Merchant Vessel River Princess – dead weight 114,645 tonnes and 261 m in length, grounded on the beach off the Candolim-Sinquerim coast, Goa, India, spilling some 40 tonnes of oil. In the past 10 years it has settled some 10 m into the sea bed and taken in circa 40,000 tonnes of sand. Until the ‘60’s the Goan economy centered on agriculture and fishing with very low key recreation. Over the last three decades it has become heavily reliant upon recreation, with 13 % of GDP arising from this sector. Nine million cubic metres of littoral drift occurs off this beach per annum, with the longshore current broken by rips into a series of circulating cells. The vessel acts as a massive groin so much so that downdrift, erosion of approximately 5 to 10 m/annum (dependent on the monsoon strength) is occurring at the Taj hotel site. Satellite imagery has shown that some 0.13 km² beach loss has occurred since 2001. Downdrift, the beach is circa 20 m wide compared to updrift areas where it exceeds 100 m. Embryo tombola growth has now commenced between shore and ship. In addition to this, the dune system is now seriously out of equilibrium and sand bags, geotextiles etc. are currently in use to combat dune foot erosion. Questionnaires (n?=?111) showed that 37 % of beach users ranked erosion as the top coastal problem. Sixty seven percent of beach users rated scenery as the most important quality of a beach and due to the grounded ship, >60 % rated the scenery as below average, as well as viewing the ship as a source of danger for swimming purposes.