Oviposition site selection and oviposition stimulation by conspecifics in the golden egg bug (<Emphasis Type="Italic">Phyllomorpha laciniata</Emphasis>): implications for female fitness

Phyllomorpha laciniata Vill. (Heteroptera, Coreidae) females lay eggs on the host plant and on the backs of conspecifics. Since egg survival is greater when eggs develop on the backs of conspecifics than when laid on plants, we predict that females should prefer to lay eggs on conspecifics. In addition, because conspecifics are a high-quality site that represents a limiting resource, females should experience oviposition stimulation upon an encounter with a conspecific. Our results reveal that, when both the host plant and conspecifics are available simultaneously, females lay eggs preferentially on conspecifics. The results also support the second prediction, since females housed with conspecifics lay more than twice the number of eggs than isolated females. Isolated females do not seem to retain eggs, suggesting that oviposition stimulation is the result of an acceleration of egg-maturation rates. Other studies have found oviposition stimulation by mating and have suggested that it is the result of male strategies to increase short-term male reproductive success at some cost to females. The evolutionary scenario of our model organism seems to be quite different since females benefit greatly from increasing egg laying when there are conspecifics, because the advantages in terms of offspring survival are likely to translate into substantial increases in female reproductive success.     

大型水母爆发对东海生态系统中上层能量平衡的影响

通过建立东海生态系统ECOPATH模型,并将大型水母作为一个独立的功能组,从能量平衡的角度探讨近年来东海大型水母爆发对生态系统的影响,并在此基础上提出抑制大型水母爆发加剧的控制机制的假说。模型分析结果表明:大型水母对中上层生物资源普遍具有显著不利影响;在大型水母、浮游动物和鲳鱼等小型中上层鱼类之间可能存在一个由大型水母爆发引发的生态系统中上层能量反馈循环;大型水母爆发初期将破坏生态系统中上层能量平衡;浮游动物生物量的波动可能是抑制大型水母爆发加剧的自然控制机制之一。     

Hepatitis A Virus: State of the Art

Hepatitis A is the most common among all hepatitis worldwide in spite of an efficient vaccine and improved hygiene. Shellfish-borne outbreaks are still of major concern causing hundreds of cases and huge economical losses in the present context of global food trade. Hepatitis A virus (HAV) is a unique picornavirus with many differences in its molecular biology including both its incapacity to induce the inhibition of the cellular protein synthesis and a highly biased and deoptimized codon usage with respect the cell. The final goal of this intriguing strategy seems to be the need for a fine-tuning control of the translation kinetics, particularly at the capsid coding region, and the underlying mechanism is the use of a right combination of common and rare codons to allow a regulated ribosome traffic rate thus ensuring the proper protein folding. Capsid folding is critical to warrant a high environmental stability for a virus transmitted through the fecal–oral route with long extracorporeal periods.     

Determining indoor air quality and identifying the origin of odour episodes in indoor environments

A methodology for identifying volatile organic compounds (VOC) and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive odorous and/or discomfort episodes. Glass multi-sorbent tubes are connected to the pump samplers for the retention of VOC. The analysis is performed by automatic thermal desorption (ATD) coupled with gas chromatography-mass spectrometry (GC/MS). This methodology can be applied in cases of sick building syndrome (SBS) evaluation, in which building occupants experience a series of varied symptoms that appear to be linked to time spent in the building. Chemical pollutants concentrations (e.g., VOC) have been described to contribute to SBS. To exemplify the methodology, a qualitative determination and an evaluation of VOC present were performed in a dwelling where the occupants experienced the SBS symptoms. Higher total VOC (TVOC) value was detected in episodes in indoor air (1.33 ( 1.53 mg/m3) compared to outdoor air (0.71 ( 0.46 mg/m3). The concentrations of individual VOCs, such as ethanol, acetone, isopropanol, 1-butanol, acetic acid, acetonitrile and 1-metoxy-2-propanol, were also higher than the expected for a standard dwelling. The external source of VOC was found to be a not declared activity of storage and manipulation of solvents located at the bottom of a contiguous building.     

Reverse positional orientation in a neotropical orb-web spider, <Emphasis Type="Italic">Verrucosa arenata</Emphasis>

Most orb-web spiders face downwards in the web. A downward orientation has been proposed to be the optimal strategy because spiders run faster downwards and thus can catch prey quicker. Consequently, orb-web spiders also extend their web in the lower part, leading to top-down web asymmetry. Since the majority of orb-web spiders face downwards, it has been difficult to test the effect of orientation on prey capture and web asymmetry. In this study, we explored the influence of reverse orientation on foraging efficiency and web asymmetry in Verrucosa arenata, a neotropical orb-web spider that faces upwards in the web. We show that reverse orientation does not imply reverse web asymmetry in this species. V. arenata spiders captured more prey in the lower part of the web but more prey per area on the upper part. The average running speeds of spiders did not differ between upward and downward running, but heavier spiders took longer to capture prey while running upwards. We discuss these findings in the context of foraging efficiency and web asymmetry.     

Movements and environmental preferences of the shortfin mako, <Emphasis Type="Italic">Isurus oxyrinchus</Emphasis>, in the southeastern Pacific Ocean

Nine individuals of shortfin mako, Isurus oxyrinchus, were tracked in the southeastern Pacific Ocean, off northern Chile, by means of pop-up satellite archival tags. No common pattern was observed in their trajectories, apart from a movement onshore of all the fish tracked during June–August. The average estimated rate of movement was of c. 27 km day⁻¹. Data were collected and processed for a total of 341 days, including 33 days for one recaptured fish specimen, allowing high-resolution archived data to be downloaded. The fish spent most of their time in the mixed layer but undertook dives down to 888 m. Ambient temperatures ranged between 4.6 and 24.1°C, and the sea surface temperatures recorded ranged from 13.4 to 24.1°C during the study period. No clear diel pattern in depth behavior was observed, but mean vertical distribution was deeper during the daytime. Moreover, a foraging pattern, consisting of rapid descents below the thermocline followed by slower ascents, was generally observed during daylight hours. Dissolved oxygen concentration and water temperature seem to be the main factors affecting the vertical range of the species in the area. This is the first study on electronic tagging of the shortfin mako in the southeastern Pacific Ocean and covers the longest total tracking period reported so far for this species.     

Impact of harmful algal blooms on wild and cultured animals in the Gulf of California

Historical documents and classic works together with recent specialized literature have described Harmful Algal Blooms (HABs) in the Gulf of California. This is a review of HABs impact (qualitative and quantitative) during the last decades in the Gulf of California on wild (mammals, birds, fishes, and invertebrates) and cultured animals (shrimps and fishes). Microalgal species responsible of noxious effects are Noctiluca scintillans, Cochlodinium polykrikoides, Gymnodinium catenatum, Prorocentrum minimum, Akashiwo sanguinea, Chattonella subsalsa Ch. marina, Chattonella sp., Heterocapsa sp., Dinophysis sp., Fibrocapsa japonica, Heterosigma akashiwo, Thalassiosira sp., Chaetoceros spp., Pseudo-nitzschia australis, P fraudulenta, Pseudo-nitzschia sp., Trichodesmium erythraeum and ScSchizotrix calcicola. Emphasis is given to the necessity to continue with interdisciplinary studies in oceanography, ecology, toxicology and toxinology interrelated with biomedical sciences such as physiology, pathology, epidemiology and animal health.     

Landscape--wildfire interactions in southern Europe: implications for landscape management

Every year approximately half a million hectares of land are burned by wildfires in southern Europe, causing large ecological and socio-economic impacts. Climate and land use changes in the last decades have increased fire risk and danger. In this paper we review the available scientific knowledge on the relationships between landscape and wildfires in the Mediterranean region, with a focus on its application for defining landscape management guidelines and policies that could be adopted in order to promote landscapes with lower fire hazard. The main findings are that (1) socio-economic drivers have favoured land cover changes contributing to increasing fire hazard in the last decades, (2) large wildfires are becoming more frequent, (3) increased fire frequency is promoting homogeneous landscapes covered by fire-prone shrublands; (4) landscape planning to reduce fuel loads may be successful only if fire weather conditions are not extreme. The challenges to address these problems and the policy and landscape management responses that should be adopted are discussed, along with major knowledge gaps.     

Bottom-up control of consumers leads to top-down indirect facilitation of invasive annual herbs in semiarid Chile

The abundance of exotic plants is thought to be limited by competition with resident species (including plants and generalist herbivores). In contrast, observations in semiarid Chile suggest that a native generalist rodent, the degu (Octodon degus), may be facilitating the expansion of exotic annual plants. We tested this hypothesis with a 20-year data set from a World Biosphere Reserve in mediterranean Chile. In this semiarid environment, rainfall varies annually and dramatically influences cover by both native and exotic annual plants; degu population density affects the composition and cover of exotic and native annual plants. In low-rainfall years, cover of both native and exotic herbs is extremely low. Higher levels of precipitation result in proportional increases in cover of all annual plants (exotic and native species), leading in turn to increases in degu population densities, at which point they impact native herbs in proportion to their greater cover, indirectly favoring the expansion of exotic plants. We propose that bottom-up control of consumers at our site results in top-down indirect facilitation of invasive annual herbs, and that this pattern may be general to other semiarid ecosystems.     

Assessment of enrichment factors and grain size influence on the metal distribution in riverbed sediments (Anll��ns River, NW Spain)

The metals distribution in the bed sediments of the Anllóns River was studied, with special emphasis on the evaluation of the metal distribution as a function of the granulometric fraction chosen for the analysis. Statistical significant differences between the distribution of K, Ca, Cr, Mn, As, Rb, Sr and Nb in the bulk (<2 mm) and fine fraction (<63 μm) were not found. Fe, Ni, Cu, Ga, Zr, Zn and Pb commonly appear in higher concentrations in the fine fraction, whereas Ti appears in higher concentrations in the bulk fraction. In general, it was observed that contamination phenomena tend to equalise the concentrations of both fractions, and this was mainly explained as the result of two processes. First, the formation of coatings over sands and, second, the formation of large aggregates (pseudo-sands) at sites located over basic rocks, whose chemical behaviour is closer to that of clays and could be responsible for significant adsorption processes. Normalisation techniques to evaluate contamination were applied by testing Nb, Sr, Rb or Ga as normaliser elements and by using crustal or shale average values for background concentrations. The most satisfactory result was obtained when using shale average values and Ga as the normaliser element. Arsenic was identified as the main contaminant of the basin, exceeding in all cases the low-effect reference values proposed by sediment quality guidelines and in two cases the medium-effect reference values. These sites were identified by multivariate techniques, which allow differentiating site 10 as affected by anthropogenic inputs related to past mining activities.