RESUMO

Bananas and plantains are major commodity/food crops that represent an important habitat for earthworms, although so far, no review is available on earthworm communities associated with banana/plantain crops worldwide. The Vale do Ribeira region is among the largest banana producing areas in Brazil, but little is known of the earthworms living there. Hence, the present study assessed earthworm populations and species in three banana plantations and adjacent Atlantic forest fragments along the Ribeira de Iguape River using standard (hand sorting) methodologies. Furthermore, we review earthworm populations reported in banana/plantain plantations worldwide. Only two species (Pontoscolex corethrurus, Amynthas gracilis) belonging to two families (Rhinodrilidae, Megascolecidae) were found in the Ribeira River valley, occurring concurrently. Abundance was low (< 13 indiv. m-2) compared with other banana plantations worldwide, that frequently surpassed 100 indiv. m-2. More than 70 studies reported earthworms from >200 banana plantations in 28 countries, and mean species richness was 2.7 per site, ranging from 1 to 10 species. Exotics predominated in most sites and P. corethrurus was the most prevalent species encountered. Overall, more than 104 species from 10 families were reported, with around 61 native and 43 exotic widespread species, mainly of the Megascolecidae, Lumbricidae and Acanthodrilidae families. Richness was highest in India (27 spp.) and the Canary Islands (25 spp.), but native species dominated only in a few countries and sites, while exotics were prevalent especially in island countries and Brazil. Lower-input practices appear to be important for earthworm communities and banana plantations can have large earthworm populations in some cases, which may be contributing to soil processes and plant production, topics that deserve further attention. However, many important banana-producing countries have not yet been evaluated, so further work is warranted, both in terms of applied ecology and biodiversity.

RESUMO

Pontoscolex corethrurus (Müller, 1857) plays an important role in tropical soil ecosystems and has been widely used as an animal model for a large variety of ecological studies in particular due to its common presence and generally high abundance in human-disturbed tropical soils. In this study we describe the complete mitochondrial genome of the peregrine earthworm P. corethrurus. This is the first record of a mitochondrial genome within the Rhinodrilidae family. Its mitochondrial genome is 14 835 bp in length containing 37 genes (13 protein-coding genes (PCG) 2 rRNA genes and 22 tRNA genes). It has the same gene content and structure as in other sequenced earthworms but unusual among invertebrates it hasseveral overlapping open reading frames. All genes are encoded on the same strand. Most of the PCGs use ATG as the start codon except for ND3 which uses GTG as the start codon. The A+T content of the mitochondrial genome is 59.9% (31.8% A 28.1% T 14.6% G and 25.6% for C). The annotated genome sequence has been deposited in GenBank under the accession number KT988053.

RESUMO

Mercury (Hg) is one of the most toxic nonessential trace metals in the environment, with high persistence and bioaccumulation potential, and hence of serious concern to environmental quality and public health. Emitted to the atmosphere, this element can travel long distances, far from emission sources. Hg speciation can lead to Hg contamination of different ecosystem components, as well as biomagnification in trophic food webs. To evaluate the effects of atmospheric Hg deposition in tropical forests, we investigated Hg concentrations in earthworm tissues and soils of two Forest Conservation Units in State of Rio de Janeiro, Brazil. Next, we performed a laboratory study of the biological responses (cast analysis and behavioral, acute, chronic and bioaccumulation ecotoxicological tests) of two earthworms species (Pontoscolex corethrurus and Eisenia andrei) to Hg contamination in tropical artificial soil (TAS) and two natural forest soils (NS) spiked with increasing concentration of HgCl2. Field results showed Hg concentrations up to 13 times higher in earthworm tissues than in forest soils, while in the laboratory Hg accumulation after 91-days of exposure was 25 times greater in spiked-soils with 128mgHgkg-1 (dry wt) than in control (unspiked) soils. In all the toxicity tests P. corethrurus showed a higher adaptability or resistance to mercury than E. andrei. The role of earthworms as environmental bioremediators was confirmed in this study, showing their ability to greatly bioaccumulate trace metals while reducing Hg availability in feces.

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RESUMO

The objective of the present work was to determine the incidence of Meloidogyne paranaensis galls in the roots of Solanum lycopersicum, after inoculation with Amynthas spp. and Pontoscolex corethrurus. The experiment was performed in the greenhouse in a randomised block experimental design was adopted, with four treatments and five repetitions: T1. M. paranaensis; T2. M. paranaensis + Amynthas spp. T3. M. paranaensis +P. corethrurus; T4. M. paranaensis + Amynthas spp. + P. corethrurus. Initially, six adult worms of Amynthas spp. or P. corethrurus, isolated or in the same proportion (3:3), with the previously determined fresh biomass. After one week, tomato seedlings (cultivar “Rutgers”) were transplanted to the pots and inoculated with 5 mL of a suspension of M. paranaensis containing 5,000 eggs and/or juveniles per pot. Sixty-five days after inoculation, the number of remaining worms was counted after manual collection; the fresh biomass was determined by direct weighing, and the number of galls on the roots of the tomato was counted directly in a stereomicroscope. The results demonstrated a reduction in the number of galls per plant with treatments involving inoculation with worms, varying between 26,7% and 63,3%, respectively, for Amynthas spp. and P. corethrurus. Meanwhile, the combination of worms lead to a reduction of 50,0% in the incidence of galls. The results demonstrate that the use of worms in the biological control of nematodes, during tomato cultivation, has great potential that requires further investigation.(AU)

O presente trabalho teve como objetivo avaliar a eficiência de Amynthas spp. e Pontoscolex coretrhrurus na redução de galhas de Meloidogyne paranaensis em raízes de Solanum lycopersicum. O experimento foi conduzido em casa de vegetação do Laboratório de Nematologia do Centro de Diagnóstico “Marcos Enrietti”, da Secretaria de Estado da Agricultura e do Abastecimento do Paraná (SEAB), em delineamento experimental blocos ao acaso, com quatro tratamentos e cinco repetições: T1. M. paranaensis; T2. M. paranaensis + Amynthas spp. T3. M. paranaensis + P. corethrurus; T4. M. paranaensis + Amynthas spp. + P. corethrurus. Inicialmente, seis minhocas adultas de Amynthas spp. ou P. corethrurus, isoladas ou na mesma proporção (3:3), com a biomassa fresca previamente determinada, foram inoculadas em vasos de polietileno com capacidade para 4 L, contendo três litros de solo esterilizado. Após uma semana, foram transplantadas, para os vasos, mudas de tomate (cultivar ‘Rutgers) e inocularam-se 5 mL de uma suspensão de M. paranaensis contendo 5.000 ovos e/ou juvenis por vaso. Aos 65 dias de inoculação foram avaliados o número de minhocas remanescentes, por catação manual, a biomassa fresca, por pesagem direta e o número de galhas nas raízes do tomate, por contagem direta em microscópio estereoscópio. Os resultados demonstraram que houve redução na quantidade de galhas/planta, nos tratamentos que foram inoculadas minhocas, variando de 39,2% a 55,2%, respectivamente, para Amynthas spp. e P. corethrurus. Já a combinação das minhocas apresentou redução de 50,0% de incidência de galhas. A taxa de remanescência das minhocas oscilou de 26,7% a 63,3%, com superioridade para o gênero Amynthas. Os resultados demonstram que a utilização de minhocas no controle biológico de nematoide, na cultura do tomate, apresenta grande potencial a ser entendido e explorado.(AU)

Assuntos

RESUMO

The objective of the present work was to determine the incidence of Meloidogyne paranaensis galls in the roots of Solanum lycopersicum, after inoculation with Amynthas spp. and Pontoscolex corethrurus. The experiment was performed in the greenhouse in a randomised block experimental design was adopted, with four treatments and five repetitions: T1. M. paranaensis; T2. M. paranaensis + Amynthas spp. T3. M. paranaensis +P. corethrurus; T4. M. paranaensis + Amynthas spp. + P. corethrurus. Initially, six adult worms of Amynthas spp. or P. corethrurus, isolated or in the same proportion (3:3), with the previously determined fresh biomass. After one week, tomato seedlings (cultivar “Rutgers”) were transplanted to the pots and inoculated with 5 mL of a suspension of M. paranaensis containing 5,000 eggs and/or juveniles per pot. Sixty-five days after inoculation, the number of remaining worms was counted after manual collection; the fresh biomass was determined by direct weighing, and the number of galls on the roots of the tomato was counted directly in a stereomicroscope. The results demonstrated a reduction in the number of galls per plant with treatments involving inoculation with worms, varying between 26,7% and 63,3%, respectively, for Amynthas spp. and P. corethrurus. Meanwhile, the combination of worms lead to a reduction of 50,0% in the incidence of galls. The results demonstrate that the use of worms in the biological control of nematodes, during tomato cultivation, has great potential that requires further investigation.

O presente trabalho teve como objetivo avaliar a eficiência de Amynthas spp. e Pontoscolex coretrhrurus na redução de galhas de Meloidogyne paranaensis em raízes de Solanum lycopersicum. O experimento foi conduzido em casa de vegetação do Laboratório de Nematologia do Centro de Diagnóstico “Marcos Enrietti”, da Secretaria de Estado da Agricultura e do Abastecimento do Paraná (SEAB), em delineamento experimental blocos ao acaso, com quatro tratamentos e cinco repetições: T1. M. paranaensis; T2. M. paranaensis + Amynthas spp. T3. M. paranaensis + P. corethrurus; T4. M. paranaensis + Amynthas spp. + P. corethrurus. Inicialmente, seis minhocas adultas de Amynthas spp. ou P. corethrurus, isoladas ou na mesma proporção (3:3), com a biomassa fresca previamente determinada, foram inoculadas em vasos de polietileno com capacidade para 4 L, contendo três litros de solo esterilizado. Após uma semana, foram transplantadas, para os vasos, mudas de tomate (cultivar ‘Rutgers’) e inocularam-se 5 mL de uma suspensão de M. paranaensis contendo 5.000 ovos e/ou juvenis por vaso. Aos 65 dias de inoculação foram avaliados o número de minhocas remanescentes, por catação manual, a biomassa fresca, por pesagem direta e o número de galhas nas raízes do tomate, por contagem direta em microscópio estereoscópio. Os resultados demonstraram que houve redução na quantidade de galhas/planta, nos tratamentos que foram inoculadas minhocas, variando de 39,2% a 55,2%, respectivamente, para Amynthas spp. e P. corethrurus. Já a combinação das minhocas apresentou redução de 50,0% de incidência de galhas. A taxa de remanescência das minhocas oscilou de 26,7% a 63,3%, com superioridade para o gênero Amynthas. Os resultados demonstram que a utilização de minhocas no controle biológico de nematoide, na cultura do tomate, apresenta grande potencial a ser entendido e explorado.

Assuntos

RESUMO

Soil burning has been used in agricultural and forestry systems as a fundamental technique to clean the land and add some nutrients to the soil. In addition, earthworms are known to promote various soil functions since they contribute to aeration and organic matter and nutrients availability to other soil organisms. This study evaluated the effects of tropical forest crops management with presence-absence of Eucalyptus grandis on earthworm population in Huimanquillo, Tabasco, Mexico. Three sites (average area of 1-1.5ha each) with different management conditions were considered for soil and earthworm sampling (two depths and six replicates): without vegetation (SV) and recent slash-burned (38 days), forest crops of five years of production of E. grandis (Euc), and secondary vegetation of 15 years (Acah). Soil physico-chemical properties (apparent density, humidity, texture, pH, Ntot, OM, P, K, cationic capacity) were also evaluated, and earthworms were collected at the end of the rainy season (august-october 2007). We found that the sites soil is an acrisol acid, with pH 3.0-4.5 in the first 30cm depth. Organic matter content (OM) and total nitrogen (Ntot) in the recently burned sites were significantly lower (6-8% y 0.19-0.22%, respectively) than in sites with vegetation (OM=9-11%; el Ntot=0.27-0.33%). Only one species (P. corethrurus) was found in all the sampled areas, where most of the individuals were at juvenile stage (80%). The highest densities and biomass were found in Euc. treatment (166.4ind/m² y 36.8g/m²) followed by Acah (138.7ind/m² y 19.1g/m² respectively), while the SV treatment showed of about an 80% reduced earthworm populations when compared to other treatments. Even though 15 years have passed over the secondary vegetation (Acah) still some perturbations were observed as the low abundance of the oligochaeta group. We concluded that the management used to culture E. grandis produces negative effects over the abundance and diversity of earthworms and soil nutrient availability.

La presencia de oligoquetos en los ecosistemas puede indicar fertilidad del suelo, ya que estos organismos transportan, mezclan y entierran los residuos vegetales de la superficie al interior del suelo. Se caracterizó la comunidad de oligoquetos bajo sitios con diferentes periodos de establecimiento y manejo de plantaciones de Eucalyptus grandis, sin vegetación (SV), con cinco años en producción (Euc) y vegetación secundaria con 15 años (Acah) que han pasado por el proceso de tumba y quema en suelos de Acrisol en Huimanguillo, Tabasco; y se analizaron las propiedades físico-químicas del suelo (D.A., humedad, textura, pH, Ntot, MO, P, K, CIC). La recolecta de lombrices se realizó al finalizar las lluvias (agosto-octubre 2007). Se muestreó en tres parcelas con seis réplicas en cada una. Se encontró que los suelos tenían pH de 3.0-4.5 en los primeros 30cm de profundidad. Los contenidos de materia orgánica (MO) y nitrógeno total (Ntot) fueron significativamente menores en los sitios SV (6-8% y 0.19-0.22% respectivamente) que en Euc y Acah (MO=9-11%; el Ntot=0.27-0.33%). La especie Pontoscolex corethrurus domino en toda el área, presentando mayores densidades y biomasas en Euc (164.4ind/m² y 36.8g/m² respectivamente) y Acah (138.7ind/m² y 19.1g/m² respectivamente), mientras que en SV sus poblaciones fueron reducidas en un 80%. Se encontró que el sistema Acah sigue presentando rasgos de un sistema perturbado, al no recuperar fácilmente la diversidad de oligoquetos y las concentraciones de nutrientes disponibles en el suelo.

Assuntos