Arabis mosaic nepovirus coat protein in transgenic tobacco lessens disease severity and virus replication

Tobacco plants expressing the coat protein of a lilac isolate of arabis mosaic virus (ArMV) poorly supported the replication of this virus and did not display any of the signs of systemic invasion produced in their untransformed counterparts or in transgenic plants expressing a different gene (β-glucuronidase). These effects, were manifest whether the inoculum was virions or RNA. This is the first report of such coat protein protection with a nepovirus.     

Geographical and seasonal gradients in hatching failure in Eastern Bluebirds Sialia sialis reinforce clutch size trends

Eggs untended during the laying phase can lose viability if exposed to high temperatures, such as those common at lower latitudes and late in the nesting season. The egg‐viability hypothesis states that constraints on viability during the laying phase could account for latitudinal and seasonal gradients in clutch size. We used 7 years’ worth of data collected by volunteers (The Birdhouse Network, co‐ordinated by the Cornell Laboratory of Ornithology) to look simultaneously at populations across the temperate breeding range of Eastern Bluebirds Sialia sialis in order to test three predictions of the egg‐viability hypothesis: the probability of hatching failure decreases at higher latitude and increases later in the season, and that these trends are strongest among large clutches. The overall average number of unhatched eggs relative to the total number of eggs laid was similar to that found by other studies (7.8%; range 6.8–8.9% annually; n = 32 567 eggs from 7231 nests from 530 study sites). Using generalized linear mixed models that controlled for the non‐independence of eggs within a clutch, we found that the ‘per‐egg’ probability of hatching failure was highest late in the season, highest at lower latitudes, and highest for both small (three‐egg) and large (six‐egg) clutches. The seasonal and geographical gradients in egg hatching failure reinforce documented seasonal and geographical trends in clutch size. Loss of egg viability prior to incubation currently provides the most parsimonious and consistent explanation of the observed patterns of hatching failure. However, alternative explanations for large‐scale patterns, particularly those not consistent with the egg‐viability hypothesis, warrant further research into other causes of hatching failure, such as microbes and infertility (related to extra‐pair mating). Our results demonstrate that investigating causes of variation in demography among local populations across a geographical gradient provides a potential means of identifying selection pressures on life‐history traits.     

A spatial analytical approach for selecting reintroduction sites for burbot in English rivers

1. Availability of suitable habitat is a prerequisite for species reintroduction success, and to ensure population persistence, investigations of a species’ habitat utilisation throughout its life history should be conducted as part of a feasibility study. 2. Habitat utilisation models for burbot, Lota lota, developed using data from field studies conducted in France and Germany and information from the literature were used to assess the feasibility of reintroducing burbot into rivers of its former native range in eastern England. 3. Per cent tree roots, aquatic vegetation and flow types were important predictors of adult burbot abundance. Furthermore, the habitat utilisation models were supplemented with information from the literature, which suggested that off‐channel habitat such as wetlands and backwaters is important for spawning and nursery stages. 4. An assessment of the habitat availability in the rivers of the burbot’s former native range using variables related to spawning and nursery and adult life stages showed that although adult habitat was widely distributed, the availability of spawning and nursery habitat was less abundant, potentially limiting successful reestablishment. 5. Potential suitable habitat was concentrated in the central and southern areas of the species’ former English distribution. Overall, rivers of the burbot’s former range potentially afford suitable habitat to sustain a reintroduced population. However, sites should be preferentially selected on the basis of having appropriate spawning and nursery areas.     

Supplemental Feeding of Northern Bobwhite Affects Red-Tailed Hawk Spatial Distribution

ABSTRACT Supplemental feeding is a widely used management practice in areas managed for northern bobwhite (Colinus virginianus; hereafter quail). Although food provisioning is intended to benefit quail directly, it may also indirectly affect predators by allowing them to focus on the increased concentration of prey. We studied the effects of food supplementation for northern bobwhite on red-tailed hawk (Buteo jamaicensis) space use in a longleaf pine (Pinus palustris) ecosystem in southwestern Georgia. We used radiotelemetry to determine whether hawks were attracted to areas where supplemental feeding occurred. We found hawks almost 3 times closer to feeding sites (224 ± 96 m; x̄ ± SE) than expected (638 ± 96 m). Our data provide an example of a common game management practice having an unintended influence on a top predator.     

Tropical acid streams – the chironomid (Diptera) response in northern Australia

1. Chironomidae, sampled by interception of drifting cast pupal exuviae, responded to inputs of acid, heavy metal-rich waters in a seasonally flowing tropical stream in northern Australia.
2. Responses included gain of distinctive (indicative) taxa, loss of some species typical of pristine conditions, and increase in species richness.
3. Experimental manipulation (upstream diversion) of a mine adit entry showed that these responses were the result of change in water quality.
4. The higher species richness at low pH, which is contrary to temperate studies, may be explained by the large tropical (Australian and south-east Asian) pool of species tolerant of naturally occurring acidic aquatic habitats.
5. The structure and responses of the exuvial-assessed chironomid community matched long-term larval data.     

Redescription, palaeobiogeography and palaeoecology of Coniasaurus crassidens Owen, 1850 (Squamata) from the Lower Chalk (Cretaceous; Cenomanian) of SE England

Type and referred specimens of Coniasaurus crassidens from the Lower Chalk (Upper Cretaceous; Cenomanian) of southeast England, are re-described. The type is a left maxilla associated with 14 dorsal vertebrae. The maxilla is elongate, bears a low ascending process, and has a long and posteriorly positioned external narial margin. The first maxillary tooth is pointed and bears a groove on the labial face; more posterior maxillary teeth are increasingly rounded and bulbous, and have a single groove on the labial face. Mandibles assigned to Coniasaurus cf. C. crassidens possess teeth of similar form; mandibular bones include the dentary, splenial, angular, coronoid, prearticular, and surangular. A number of features show important similarities to later mosasaurs and contemporaneous groups such as dolichosaurs. These new data provide a very different picture of coniasaurs and their mode of life in the early Upper Cretaceous. The functional morphology of coniasaur teeth is unique and shows occlusion between the lingual platforms of the upper teeth with the crowns of the lower teeth. Coniasaurs can be considered as analgous to small sauropterygians in terms of general morphology, habitats, and trophic structure. Coniasaur distributions in the Cenomanian and Turonian of Europe and North America are similar to the palaeobiogeographic patterns of other organisms living in the Tethys and SuperTethys Seaway.     

Louisiana waterthrushes (Seiurus motacilla) and habitat assessments as cost-effective indicators of instream biotic integrity

1. Benthic stream animals, in particular macroinvertebrates, are good indicators of water quality, but sampling can be laborious to obtain accurate indices of biotic integrity. Thus, tools for bioassessment that include measurements other than macroinvertebrates would be valuable additions to volunteer monitoring protocols. 2. We evaluated the usefulness of a stream‐dependent songbird, the Louisiana waterthrush (waterthrush, Seiurus motacilla) and the Environmental Protection Agency Visual Habitat Assessment (EPA VHA) as indicators of the macrobenthos community in headwater streams of the Georgia Piedmont, U.S.A. We sampled macrobenthos, surveyed waterthrushes and measured habitat characteristics along 39 headwater reaches across 17 catchments ranging from forested to heavily urbanised or grazed by cattle. 3. Of the indicators considered, waterthrush occupancy was best for predicting relative abundances of macrobenthic taxa, while the EPA VHA was best for predicting Ephemeroptera–Plecoptera–Trichoptera (EPT) richness. Individual components of EPA VHA scores were much less useful as indicators of EPT richness and % EPT when compared with the total score. Waterthrushes were found along streams with higher % EPT, a lower Family Biotic Index (FBI) values and greater macrobenthos biomass. 4. While macroinvertebrates remain one of the most direct indicators of stream water quality, stream bird surveys and reach‐scale habitat assessments can serve as cost‐effective indicators of benthic macroinvertebrate communities. Using stream‐dependent birds as an early warning signal for degradation of stream biotic integrity could improve the efficacy of catchment monitoring programmes in detecting and identifying perturbations within the catchment.