15 research outputs found

    The triatomines of northern Peru, with emphasis on the ecology and infection by trypanosomes of Rhodnius ecuadoriensis (Triatominae).

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    Information on the distribution and synanthropic behaviour of triatomines is essential for Chagas disease vector control. This work summarises such information from northern Peru, and presents new data on Rhodnius ecuadoriensis - an important local vector infesting 10-35% of dwellings in some zones. Three species are strongly synanthropic and may be suitable targets for chemical control of domestic/peridomestic bug populations. Panstrongylus herreri, the main domestic vector in the area, is probably present in sylvatic ecotopes in the Marañón river system. R. ecuadoriensis and Triatoma dimidiata seem exclusively domestic; biogeographical and ecological data suggest they might have spread in association with humans in northern Peru. Confirmation of this hypothesis would result in a local eradication strategy being recommended. Presence of trypanosome natural infection was assessed in 257 R. ecuadoriensis; Trypanosoma rangeli was detected in 4% of bugs. Six further triatomine species are potential disease vectors in the region (T. carrioni, P. chinai, P. rufotuberculatus, P. geniculatus, R. pictipes, and R. robustus), whilst Eratyrus mucronatus, E. cuspidatus, Cavernicola pilosa, Hermanlentia matsunoi, and Belminus peruvianus have little or no epidemiological significance. A strong community-based entomological surveillance system and collaboration with Ecuadorian public health authorities and researchers are recommended

    Toxicity of AMPA to the earthworm Eisenia andrei Bouché, 1972 in tropical artificial soil

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    Aminomethylphosphonic acid (AMPA) - one of glyphosate’s main metabolites - has been classified as persistent in soils, raising concern regarding the widespread use of glyphosate in agriculture and forestry. Glyphosate may have negative or neutral effects on soil biota, but no information is available on the toxicity of AMPA to soil invertebrates. Therefore our aim was to study the effect of AMPA on mortality and reproduction of the earthworm species Eisenia andrei using standard soil ecotoxicological methods (ISO). Field-relevant concentrations of AMPA had no significant effects on mortality in acute or chronic assays. Except at the highest concentration tested, a significant biomass loss was observed compared to controls in the chronic assay. The number of juveniles and cocoons increased with higher concentrations of AMPA applied, but their mean weights decreased. This mass loss indicates higher sensitivity of juveniles than adults to AMPA. Our results suggest that earthworms coming from parents grown in contaminated soils may have reduced growth, limiting their beneficial roles in key soil ecosystem functions. Nevertheless, further research is needed to better understand the mechanisms underlying the sublethal effects observed here

    Effects of regular and irregular temporal patterns of disturbance on biomass accrual and species composition of a subtidal hard-bottom assemblage

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    Assessing patterns of species distribution and abundance is important to understand the driving processes of, and predict future changes in, biodiversity. To this date, ecological studies have been mainly designed to investigate the effects of the mean magnitude of predictor variables, although ecological factors naturally vary in space and time. In a nine month long field experiment, we tested the effects of different temporal patterns (regular, lowly and highly irregular) in biomass removal (=disturbance event) on the diversity, species composition, and biomass accrual of macrobenthic assemblages grown on 15 × 15 cm2 PVC-panels. For each pattern of disturbance, disturbance events were timed at three sequences to control for possible confounding effects with recruitment patterns. Disturbance intensity was kept identical among treatments. Assemblages developed in the absence of disturbance for 3 months prior to a 150-day manipulation period, during which the biomass from 20% of the panel area was removed at each of ten disturbance events. Additional undisturbed settlement panels were deployed in the field to assess monthly recruitment rates and species succession over a one year period. Disturbance (i) reduced biomass and total species cover, (ii) changed species composition during the first half of the manipulation period significantly, and (iii) was without effect on species richness and evenness. Irregular disturbance regimes enhanced the abundance of the ascidian Ciona intestinalis, biomass accrual, and total species cover of assemblages relative to the regular disturbance regime, but had either no or only transient effects on diversity and species composition, respectively. Neither the degree of irregularity in disturbance nor the sequence of disturbance events affected any of the response variables significantly. Recruitment of species was strongly seasonal with almost only diatoms recruiting during winter, while recruitment was most intense during summer. Our results suggest that the temporal patterns of predictor variables might be of low explanatory power for the variance of responses in communities with seasonal recruitment patterns that are exposed to a high level of disturbance. Thus the need to include temporal patterns of predictor variables in experimental designs may depend on community dynamics and the characteristics of the process under investigation

    Benthic Estuarine Assemblages of the Southeastern Brazil Marine Ecoregion (SBME)

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    We assess the current knowledge of the benthic assemblages in the Southeastern Brazil Marine Ecoregion (SBME), which extends for approximately 1200 km of coastline and includes seven major estuarine systems from Guanabara Bay in Rio de Janeiro to Babitonga Bay (or Sao Francisco do Sul) in Santa Catarina. The high ecosystem diversity of SBME putatively accounts for the high levels of endemism of the regional marine invertebrate fauna. However, until more taxonomical and biogeographical evidence is available, the SBME should be treated as a working biogeographical hypothesis rather than a cohesive unit identified by endemic fauna. As a consequence of urban, agricultural, and industrial development, the coastal areas from the SBME have been the most altered in the country over the last 500 years. Some of the largest cities and busiest harbors of the country are in or near the regional estuarine areas. The rapid environmental changes over the last several decades do not allow for the assessment if current similarities and dissimilarities in the benthic assemblages express pristine conditions or if they are already the result of major human interventions, especially in the case of the Guanabara, Sepetiba, and Santos estuaries.Univ Fed Parana, Ctr Estudos Mar, Pontal Do Sul, Parana, BrazilUniv Fed Sao Paulo, Inst Mar, Santos, SP, BrazilUniv Catolica Norte, Millennium Nucleus Ecol & Sustainable Management, Fac Ciencias Mar, Dept Biol Marina, Coquimbo, ChileUniv Estadual Paulista, Inst Biociencias, Campus Litoral Paulista, Sao Vicente, SP, BrazilUniv Fed Fluminense, Dept Biol Marinha, Campus Valonguinho, Niteroi, RJ, BrazilUniv Estadual Paulista, Inst Biociencias, Campus Litoral Paulista, Sao Vicente, SP, Brazi
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