Trait-mediated effects on flowers: artificial spiders deceive pollinators and decrease plant fitness

Although predators can affect foraging behaviors of floral visitors, rarely is it known if these top-down effects of predators may cascade to plant fitness through trait-mediated interactions. In this study we manipulated artificial crab spiders on flowers of Rubus rosifolius to test the effects of predation risk on flower-visiting insects and strength of trait-mediated indirect effects to plant fitness. In addition, we tested which predator traits (e.g., forelimbs, abdomen) are recognized and avoided by pollinators. Total visitation rate was higher for control flowers than for flowers with an artificial crab spider. In addition, flowers with a sphere (simulating a spider abdomen) were more frequently visited than those with forelimbs or the entire spider model. Furthermore, the presence of artificial spiders decreased individual seed set by 42% and fruit biomass by 50%. Our findings indicate that pollinators, mostly bees, recognize and avoid flowers with predation risk; forelimbs seem to be the predator trait recognized and avoided by hymenopterans. Additionally, predator avoidance by pollinators resulted in pollen limitation, thereby affecting some components of plant fitness (fruit biomass and seed number). Because most pollinator species that recognized predation risk visited many other plant species, trait-mediated indirect effects of spiders cascading down to plant fitness may be a common phenomenon in the Atlantic rainforest ecosystem.     

Toxicity testing of pesticides in zebrafish—a systematic review on chemicals and associated toxicological endpoints

The use of zebrafish (Danio rerio) has arisen as a promising biological platform for toxicity testing of pesticides such as herbicides, insecticides, and fungicides. Therefore, it is relevant to assess the use of zebrafish in models of exposure to investigate the diversity of pesticide-associated toxicity endpoints which have been reported. Thus, this review aimed to assess the recent literature on the use of zebrafish in pesticide toxicity studies to capture data on the types of pesticide used, classes of pesticides, and zebrafish life stages associated with toxicity endpoints and phenotypic observations. A total of 352 articles published between September 2012 and May 2019 were curated. The results show an increased trend in the use of zebrafish for testing the toxicity of pesticides, with a great diversity of pesticides (203) and chemical classes (58) with different applications (41) being used. Furthermore, experimental outcomes could be clustered in 13 toxicity endpoints, mainly developmental toxicity, oxidative stress, and neurotoxicity. Organophosphorus, pyrethroid, azole, and triazine were the most studied classes of pesticides and associated with various toxicity endpoints. Studies frequently opted for early life stages (embryos and larvae). Although there is an evident lack of standardization of nomenclatures and phenotypic alterations, the information gathered here highlights associations between (classes of) pesticides and endpoints, which can be used to relate mechanisms of action specific to certain classes of chemicals.     

Funneliformis mosseae and Invasion by Exotic Legumes in a Brazilian Tropical Seasonal Dry Forest

Russian Journal of Ecology - Parkinsonia aculeata and Prosopis juliflora are two of the most problematic invasive plant species in the Brazilian tropical seasonal dry forest, but the mechanisms...     

Integrated hydro- and wind power generation: a game changer towards environmental flow in the Sub-middle and Lower São Francisco River Basin?

Many renewable resources for the generation of electricity, such as hydropower and wind power, are dependent on climatic factors. Reservoirs have been created to overcome the stochastic nature of river flows and to make water supply more reliable. However, reservoirs are affecting the ecological status of river ecosystems, e.g., by modifying the flow regime, triggering discussions regarding the discharge of reservoirs. In Brazil’s northeast region, the installed capacity for wind power generation has increased substantially in recent years. Setting up a modeling system for simulating wind power and hydropower generation in this study, it is analyzed whether wind power generation, peaking in the dry season, can help to achieve a more environmentally oriented flow regime in the Sub-middle and Lower São Francisco River Basin. Simulated higher discharges from reservoirs during the rainy season and lower discharges during the dry season, representing a more natural flow regime, will reduce hydropower generation in the dry season. Under recent conditions, the resulting gap in electricity generation can only be partially covered by wind power. A large share needs to be generated by thermal power plants or be imported from other regions in Brazil. The planned future increase in installed wind power capacity can change this picture; the demand for electricity generated by thermal power plants and imported will decrease. Adopting an integrated approach for hydropower and wind power generation, the flow regime in the Sub-middle and Lower São Francisco River Basin can be modified to improve the ecological status of the river system.     

Mice exposure to tannery effluents changes their olfactory capacity,and their response to predators and to the inhibitory avoidance test

Environmental Science and Pollution Research - The current study has assessed whether the oral and/or dermal exposure of C57Bl/6 J mice to tannery effluent (a complex pollutant consisting of...     

Identification of protein biomarkers of mercury toxicity in fish

Bioaccumulative metals such as mercury are found in increasing amounts in fish and their consumers. In the region of the Madeira River, in the Brazilian Amazon, mercury (Hg) is a predominant contaminant in the aquatic ecosystem. There is therefore a need to find specific biomarkers of mercury toxicity in fish to monitor contaminations. Here, mercury-bound proteins were identified in the liver tissues of fishes Mylossoma duriventre and Brachyplatystoma rousseauxii. Mercury was quantified in liver tissue, pellets and protein spots by graphite furnace atomic absorption. Proteins were fractionated by two-dimensional polyacrylamide gel electrophoresis and identified by mass spectrometry with electrospray ionization. We identified nine proteins linked to mercury and that presented biomarker characteristics of mercury. Among the proteins identified, isoforms of parvalbumin, ubiquitin-40S ribosomal protein S27a, brain-specific angiogenesis inhibitor 1-associated protein 2-like protein 2 and betaine–homocysteine S-methyltransferase 1 are notable for having the molecular function of binding to metallic ions.     

A data-based model to locate mass movements triggered by seismic events in Sichuan, China

Earthquakes affect the entire world and have catastrophic consequences. On May 12, 2008, an earthquake of magnitude 7.9 on the Richter scale occurred in the Wenchuan area of Sichuan province in China. This event, together with subsequent aftershocks, caused many avalanches, landslides, debris flows, collapses, and quake lakes and induced numerous unstable slopes. This work proposes a methodology that uses a data mining approach and geographic information systems to predict these mass movements based on their association with the main and aftershock epicenters, geologic faults, riverbeds, and topography. A dataset comprising 3,883 mass movements is analyzed, and some models to predict the location of these mass movements are developed. These predictive models could be used by the Chinese authorities as an important tool for identifying risk areas and rescuing survivors during similar events in the future.     

Assessment of trace metal concentration in feathers of seabird (Larus dominicanus) sampled in the Florianópolis, SC, Brazilian coast

Cd, Co, Cr, Cu, Mn, Ni, Zn, and Pb were measured in feather samples of adult, subadult, and juvenile of Larus dominicanus, sampled in the Florianólis, SC, in the south of Brazil in December 2005, by flame atomic absorption spectrophotometry. The average of the distribution of Cd concentration in adult feathers (0.072 μg g^???1) was significantly different than that found in juvenile feathers (0.021 μg g^???1). Cu concentration averages were not significantly different between adults (13.30 μg g^???1), subadults (9.67 μg g^???1), and juveniles (13.76 μg g^???1). For adults and juveniles there was significant difference in feather concentrations for Cd, Co, Cr, Ni, and Pb. The distribution of Mn concentration averages in feathers differs between adults (11.36 μg g^???1) and juveniles (1.184 μg g^???1). Ni concentration averages of adults (5.92 μg g^???1) were significantly higher than those of juveniles (2.23 μg g^???1). For Pb, concentration averages were significantly higher in adults (7.53 μg g^???1) than in juveniles (1.47 μg g^???1). The concentration of Co and Cr in juvenile and subadults are statistically different when compared with the adults. In the present study, levels of Cd, Co, Cr, Mn, Ni, Zn, and Pb increased with age. The concentrations of essential trace elements in L. dominicanus were generally comparable to values reported in other studies. With non-essential metals (Cd, Pb, and Ni), in our study, L. dominicanus had lower values than those reported for their northern Atlantic counterparts.     

Assessment of groundwater quality in a region of endemic fluorosis in the northeast of Brazil

The aim of this study was to estimate the risk for caries and fluorosis in a desertification area, applying the calcium/fluoride concentration ratio of underground water and the quality of water in a selected geographical region. This study was performed in the municipality of São João do Rio do Peixe, located in the tropical semiarid lands of Brazil. A total of 111 groundwater samples were collected. Fluoride concentration varied from 0.11 to 9.33 mg/L. Thirty percent of all samples analyzed showed values above 1.5 mg/L, while 64 % were above the ideal limit of 0.7 mg/L. Mean calcium concentration was 47.6 mg/L, and 14.4 % of all samples presented values above the WHO acceptable limits. The proportional value of calcium/fluoride in water showed that only 12 % of the samples were suitable for dental caries prevention with minimal risk for dental fluorosis. Mapping of the fluoride distribution indicated that approximately 2,465 people could be affected by dental fluorosis and 1,057 people might be affected by skeletal fluorosis. It can be concluded that, in addition to fluoride, many water parameters were not suitable for the drinking water. Mapping out calcium/fluoride ratio may indicate areas of water suitability for caries control, whereas the fluoride concentration solely can indicate the areas with the risk for fluorosis. This approach can be relevant for health authorities for identifying communities where dental caries or dental fluorosis is prevalent.     

Potentially toxic elements (PTEs) in soils from the surroundings of the Trans-Amazonian Highway,Brazil

The Trans-Amazonian Highway (TAH) is located in the northern region of Brazil, comprising a border region where agricultural, mining, and logging activities are the main activities responsible for fostering economic development, in addition to large hydroelectric plants. Such activities lead to environmental contamination by potentially toxic elements (PTEs). Environmental monitoring is only possible through the determination of element contents under natural conditions. Many extraction methods have been proposed to determine PTEs’ bioavailability in the soil; however, there is no consensus about which extractor is most suitable. In this study, we determined the contents of PTEs in soils in the surroundings of TAH after mineral extraction with diethylenetriaminepentaacetic acid-triethanolamine (DTPA-TEA), Mehlich I, and Mehlich III solutions. Soil samples were collected in areas of natural vegetation in the vicinity of TAH in the state of Pará, Brazil. Chemical attributes and particle size were determined, besides concentrations of Fe, Al, Mn, and Ti by sulfuric acid digestion, Si after alkaline solution attack, and poorly crystalline Fe, Al, and “free” Fe oxides. Mehlich III solution extracted greater contents from Fe, Al, and Pb as compared to Mehlich I and DTPA-TEA and similar contents from Cd, Mn, Zn, and Cu. Significant correlations were found between concentrations of PTEs and the contents of Fe and Mn oxides as well as organic carbon and soil cation exchange capacity. Contents of Cu, Mn, Fe, and Zn by the three methods were positively correlated.