Attack and defense movements involved in the interaction of <Emphasis Type="Italic">Spodoptera frugiperda</Emphasis> and <Emphasis Type="Italic">Helicoverpa zea</Emphasis> (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda (J. E. Smith) and the corn earworm, Helicoverpa zea (Boddie) are among the main pests of maize. Both species exhibit cannibalistic behavior and quite often share the same feeding guild in maize (maize ears), which can result in several interspecific and intraspecific interactions. Paired interaction scenarios of intraspecific and interspecific larvae were assessed in arenas in the presence and absence of food to characterize movements resulting from interactions of these insects. There was a difference in the frequency of behavioral movements in all the interactions, except for S. frugiperda in the presence of food. Head touching and recoiling were the predominant movements in most of the interaction scenarios. Spodoptera frugiperda exhibited a predominance of defensive movements when competing against H. zea in the same instars. Cannibalism and predation occurred frequently in interactions involving 6th instar of H. zea against opponents in 4th instar. Larvae of H. zea show a higher aggressive movement than S. frugiperda. The larvae of S. frugiperda take advantage during the interactions, although they present more defensive movements compared to H. zea. This study provides relevant information regarding the interaction of these species and intraguild interaction, which might influence the population dynamics and the competitive displacement of pest species that share the same ecological niche.     

No Evidence of Hendra Virus Infection in the Australian Flying‐fox Ectoparasite Genus Cyclopodia

Hendra virus (HeV) causes potentially fatal respiratory and/or neurological disease in both horses and humans. Although Australian flying‐foxes of the genus Pteropus have been identified as reservoir hosts, the precise mechanism of HeV transmission has yet to be elucidated. To date, there has been limited investigation into the role of haematophagous insects as vectors of HeV. This mode of transmission is particularly relevant because Australian flying‐foxes host the bat‐specific blood‐feeding ectoparasites of the genus Cyclopodia (Diptera: Nycteribiidae), also known as bat flies. Using molecular detection methods, we screened for HeV RNA in 183 bat flies collected from flying‐foxes inhabiting a roost in Boonah, Queensland, Australia. It was subsequently demonstrated that during the study period, Pteropus alecto in this roost had a HeV RNA prevalence between 2 and 15% (95% CI [1, 6] to [8, 26], respectively). We found no evidence of HeV in any bat flies tested, including 10 bat flies collected from P. alecto in which we detected HeV RNA. Our negative findings are consistent with previous findings and provide additional evidence that bat flies do not play a primary role in HeV transmission.     

Light and scanning electron microscopy of Myxobolus porofilus sp. n. (Myxosporea: Myxobolidae) infecting the visceral cavity of Prochilodus lineatus (Pisces: Characiformes: Prochilodontidae) cultivated in Brazil

Myxobolus porofilus sp. n. is described infecting the visceral cavity of Prochilodus lineatus (Valenciennes, 1836) cultivated in S?o Paulo State, Brazil. The plasmodial form of the parasite is 3-5 mm in length and appeared compressed between the wall of the visceral cavity and the pyloric caecum, reposing on this organ. The spores are small (length 5.7 +/- 0.3 microm, width 4.8 +/- 0.2 microm; mean +/- SD) and round to elliptical in frontal view. The valve surfaces are smooth and have sutural folds. The polar capsules are ovoid, small (length 1.6 +/- 0.1 microm, width 1.1 +/- 0.1 microm) and equal in size. The polar filaments have three turns aligned perpendicularly to the longitudinal axis of the capsule. A conspicuous polar filament pore is arranged at the anterior end of the spore. The only reaction observed upon histological analysis was the presence of a capsule of connective tissue surrounding the plasmodia. This is the first report of a myxosporean parasite in the Prochilodontidae.     

Spatial distribution patterns of riverine forest taxa in Brasília, Brazil

The spatial distribution of adult individuals (≥15 cm DBH) was investigated in a gallery forest of the Brasília National Park, Brazil. Four wood species, important to the Brazilian national genetic conservation programme, were chosen: Astronium fraxinifolium Schott, (Anacardiaceae); Cariniana estrellensis (Raddi) Kuntze, (Lecythidaceae); Didymopanax morototoni (Aublet) Decne. & Planch., (Araliaceae) and Hymenaea courbaril var. stilbocarpa (Hayne) Lee & Lang., (Leguminosae-Caesalpinioideae). While distribution was uneven, no relationship with gradient or togographic position could be detected, but aggregation was perceived. Stocking levels were typically low, from 0.15 to 3.31 individuals ha⁻¹.     

Death and Transfiguration of a Triple Junction in the South Atlantic

Three major lithospheric plates-Antarctic, South American, and African-meet in the South Atlantic near Bouvet Island where the Mid-Atlantic Ridge (MAR), the Southwest Indian Ridge (SWIR), and the American Antarctic Ridge converge toward a fast evolving triple junction. A major magmatic pulse has recently built a new, swollen segment of the SWIR (Spiess Ridge) that is propagating toward the MAR at a rate of 4 to 5 centimeters per year, disrupting a former ridge-ridge-ridge (RRR) triple junction. A new triple junction will be established about 70 kilometers to the north when the propagating SWIR/Spiess segment will impact with the MAR, probably within the next 1 million years. The American Antarctic Ridge will take advantage of the MAR/SWIR duel by capturing an approximately 70-kilometer stretch of MAR, whereas the Antarctic plate will increase its size.     

Geochemistry and mineralogy of southwestern Lake Superior sediments with an emphasis on phosphorus lability

Journal of Soils and Sediments - The lability of phosphorus (P) in Lake Superior sediments and its relationship with sediment mineralogy and geochemistry remains poorly understood. The purpose of...     

Evaluation of the sexual dimorphism in Mangalarga Marchador horses using discriminant analysis

This study used discriminant analysis to evaluate body measures and sexual dimorphism in Mangalarga Marchador horses. Discriminant analysis is a multivariate method that generates functions to classify animals using a prior criterion. In this study a prior criterion is male or female. The study analyzed 25 linear and 11 angular measures obtained from 25 stallions and 56 mares registered with the Mangalarga Marchador Brazilian Breeders Association. Knee girth, cannon girth, chest width, chest girth, back-loin length, hip width, distance from elbow to knee, hind limb hoof length, head width, shoulder length, and body length were found to be linear measures that provided evidence of sexual dimorphism. Angular measures with evidence of sexual dimorphism were shoulder–humerus, metacarpal–phalanx, coxae–femur, and femur–tibial angles. Stallions were larger than mares for almost all linear measures, except for back-loin length, hip width, and distance from elbow to knee. Shoulder–humerus and coxal–femur angles were larger in mares, while metacarpal–phalanx and femur–tibial angles were larger in stallions. Using linear measures, two mares were classified as stallions and three stallions were classified as mares. For angular measures, two other mares were classified as stallions and three other stallions were classified as mares. The discriminant functions can be useful for the selection of horses and to avoid registration of animals not meeting the phenotypic standards of the breed association.     

Modeling spatial variability and pattern of rust and brown eye spot in coffee agroecosystem

The advent of Precision Agriculture has made possible the analysis of complex spatial patterns of plant disease epidemiology considering statements of integrated disease management. The objective of this work was to use geostatistics, statistics and geographical information systems to characterize the structure and magnitude of spatial dependency of rust (Hemileia vastatrix) and brown eye spot (Cercospora coffeicola) incidence and severity in coffee agroecosystem cultivated with Catuai Vermelho IAC-99 (Coffea arabica L.). Evaluations of incidence and severity of rust and brown eye spot were accomplished at 67 georeferenced points arranged in 6.6202 ha of coffee crop, in the years of 2005, 2006 and 2007. Exponential models of covariance enabled the characterization of the magnitude and structure of rust and brown eye spot spatial variability in the evaluated dates. Ordinary block kriging presented satisfactory performance to map rust and brown eye spot outbreaks based on kriging error coefficients. Kriged maps enabled the visualization of intensity of rust and brown eye spot in each evaluation date. Assessments of incidence and severity presented highly statistical correlation based on linear regression models, also confirmed by the spatial variability of kriging maps. Kriging maps of rust and brown eye spot enabled to observe that intensity of disease was dispersed in foci patterns along the coffee plantation, indicating that the current strategy of disease control based in total area may be replaced by site specific disease management, with less environmental impact and sustainability of coffee crop, according to statements of integrated disease management and precision agriculture.     

Urban sediment particle size and pollutants in Southern Brazil

Background, aim and scope

Studies of particulate-associated pollutants, or PAPs, in urban areas have become necessary due to their potentially deleterious effects on the environment. However, it is not just the sediments themselves which are problematic but also their particle size composition, which has a great influence on their capacity to adsorb and transport pollutants. This paper presents the particle size distributions and concentrations of five metals (Cr, Cu, Ni, Pb and Zn) of urban sediments collected from paved streets and gully pots from 20 cities in southern Brazil. The cities have different characteristics and hence sources of PAPs associated with differing geologies, soil types and type of urbanisation. Studies of this nature enable elucidation of the relationship between diffuse sources such as streets and gully pots and the likelihood of PAPs to subsequently pollute the urban aquatic environment.

Materials and methods

Sediment samples were taken at random from paved streets and gully pots in 20 cities in Rio Grande do Sul state, southern Brazil by means of a portable vacuum cleaner to avoid loss of finer particles. The particle sizes of the samples were measured using a Cilas® 1180 laser particle analyzer, and the concentrations of five metals (Cr, Cu, Ni, Pb and Zn) were determined by wet acid digestion (HCl–HF–HClO₄–HNO₃) followed by inductively coupled plasma atomic emission spectroscopy on the <63-µm fraction.

Results

It was found that in comparison to sediments collected from the streets, gully pot sediments were more heterogeneous in terms of particle size and also that sediment samples from the gully pots were predominantly coarser than those originating on the streets. From the gully pot results, analysis of the modal particle diameter enabled the cities to be divided into three categories. The concentrations of metals in the street sediments were similar across all 20 cities, with all concentrations above background values.

Discussion

The fact that concentrations of metals in the street sediments were above statutory guideline values and that the coarser material was deposited in the gully pots suggests that the finer, more polluted sediment is not retained in the gully pots but is transported to the nearest local receiving watercourse. This finding has implications for management strategies for reducing pollution in urban environments.

Conclusions

High concentrations of Cr, Cu, Ni, Pb and Zn in the <63-µm fraction of street sediments, in combination with coarse material retained in the gully pots, indicate that metals could be transferred quite rapidly from the diffuse source of pollutants, on impermeable street surfaces, to receiving watercourses.

Recommendations and perspectives

Studies of urban sediment particle size and geochemistry enable predictions to be made of sediment behaviour in urban environments. This will inform management strategies such as the possibility of including sustainable urban drainage systems in future management plans, in which it is useful to know how efficient the drainage system is from the point of view of sediment deposition in the urban aquatic environment and the potential for pollution of receiving waters.