Characterization of Five New Earthworm Mitogenomes (Oligochaeta: Lumbricidae): Mitochondrial Phylogeny of Lumbricidae

Identification based on conventional morphological characteristics is typically difficult and time-consuming. The development of molecular techniques provides a novel strategy that relies on specific mitochondrial gene fragments to conduct authentication. For this study, five newly sequenced partial mitogenomes of earthworms (Bimastos parvus, Dendrobaena octaedra, Eisenia andrei, Eisenia nordenskioldi, and Octolasion tyrtaeum) with lengths ranging from 14,977 to 15,715 were presented. Each mitogenome possessed a putative control region that resided between tRNA-Arg and tRNA-His. All of the PCGs were under negative selection according to the value of Ka/Ks. The phylogenetic trees supported the classification of Eisenia and Lumbricus; however, the trees based on cox1 did not. Through various comparisons, it was determined that cox1 fragments might be more suitable for molecular identification. These results lay the foundation for further phylogenetic studies on Lumbricidae.

Integrative taxonomy of five astome ciliates (Ciliophora, Astomatia) isolated from earthworms in Central Europe

Four earthworm species, the endogeic Octolasion tyrtaeum (Savigny, 1826), the anecic Lumbricus terrestris Linnaeus, 1758 as well as the epigeic Eisenia fetida (Savigny, 1826) and Dendrobaena veneta (Rosa, 1886), were examined for the presence of astome ciliates. Based on the integrative taxonomic approach, five ciliate species were recognized in their gastrointestinal tracts: Metaradiophrya lumbrici (Dujardin, 1841), M. varians (de Puytorac, 1954), Anoplophrya lumbrici (Schrank, 1803), A. vulgaris de Puytorac, 1954 and A. nodulata (Dujardin, 1841). Their distinctness was assessed using the multivariate morphometric approach and molecular phylogenetic analyses. Although the two species of Metaradiophrya Jankowski, 2007 on the one hand and the two former species of Anoplophrya Stein, 1860 on the other, were not distinctly separated by the multivariate morphometric analyses, they were clearly delimited by the 18S rRNA gene sequences. Species within each genus also differed by their hosts, M. lumbrici and A. lumbrici occurred only in anecic earthworms while M. varians and A. vulgaris occured exclusively in epigeic earthworms. Only a single species, A. nodulata, was detected in endogeic earthworms. It was morphologically distinct from and did not cluster with the two other species of Anoplophrya but was nested within the paraphyletic assemblage containing other astomes from endogeic earthworms. This indicates that the evolution of endosymbiotic ciliates from earthworms has very likely proceeded through a specialization to various ecological groups of their host organisms.

Kitchen waste management by vermicomposting using locally available epigeic earthworm species

A large quantity of kitchen waste is generated in India which is either burnt, left in open or landfilled posing a serious problem of its safe disposal. To mitigate this problem all the kitchen waste can be converted into highly valuable nutrient rich vermicompost using the locally available epigeic earthworms. The biodegradable kitchen waste like vegetables, fruits, food waste etc can be cultured with earthworms to form the vermicompost by using vermitechnology. Since these vermicomposts are rich in nutrients which can replace the chemical fertilizers. In the present study the vermicomposting of kitchen waste has been attempted using locally available epigeic earthworm species of Jammu namely Amynthus diffringens, Metaphire houlleti and Octolasion tyrtaeum. The physico-chemical analysis of generated vermicomposts was carried out and compared with each other and with that of original soil sample that has been added in vermibeds prior to earthworm inoculation and addition of kitchen waste. The average values of macronutrients in the vermicompost produced by O. tyrtaeum were observed to be the highest among all types of vermicomposts i.e. Organic Carbon (OC)- 11.66 ± 0.34% , Nitrogen (N)- 1.17 ± 0.20%, Phosphorus (P)- 2.97 ± 0.32%, Potassium (K)- 1.18 ± 0.15%, Calcium (Ca)- 0.26 ± 0.04%, Magnesium (Mg)- 0.17 ± 0.04%.

Current knowledge of earthworm richness and distribution in Santa Fe province, Argentina

Updated list of earthworms (Oligochaeta: Lumbricina) from Santa Fe (Argentina) is presented in this work, including current data of species richness and territorial distribution status and information collected by Ljungström and collaborators 40 years ago. Field samplings were conducted between 2012 and 2015 at 23 sites, located in 11 of the 19 districts of the province. Earthworms were collected following a standard methodology (Tropical Soil Biology and Fertility). The conservation of specimens was done with 4 % formalin solution and their identification was performed according to taxonomy keys. Richness, similarity and complementarity of species between the phytogeographic provinces were analyzed. A total of 15 earthworm species were identified and grouped into ten genera and five families: Acanthodrilidae (Dichogaster bolaui, Microscolex dubius), Glossoscolecidae (Glossodrilus parecis), Lumbricidae (Aporrectodea caliginosa, Aporrectodea rosea, Aporrectodea trapezoides, Bimastos parvus, Eisenia fetida, Octolasion tyrtaeum), Megascolecidae (Amynthas gracilis, Amynthas morrisi, Metaphire californica), Ocnerodrilidae (Eukerria saltensis, Eukerria rosea, Eukerria stagnalis). From all the species found five, G. parecis, E. saltensis, E. rosea, E. stagnalis and M. dubius, are native to South America, and the rest were introduced from Asia and Europe. The Espinal presented the greatest richness of earthworms (12), while the Pampeana showed high values of complementarity (greater than 70 %) with the Chaco Húmedo and Valle de Inundación del Río Paraná. Endogeic species were present in all environments surveyed. In particular, the exotic species A. trapezoides and A. morrisi showed a wide geographical distribution, having been found at 70 and 50 %, respectively, of the total number of the studied sites. One species, E. rosea, which is in the list, was not recorded in the sampling of 40 years ago. The results of current survey show that the number of species was lower compared to study by Ljungström and collaborators (60 % of the 23 species registered). Possibly the remarkable change in the richness and distribution of earthworms could be a process associated with changes in soil use and land management developed over 40 years.

Comunidades de lombrices de tierra en sistemas agroforestales intercalados, en dos regiones del centro de México.

Se realizó un análisis de las comunidades de lombrices de tierra del sistema de cultivo milpa intercalada con árboles frutales (MIAF), en los estados de Puebla y Oaxaca. El objetivo fue conocer las especies presentes en el sistema, las diferencias entre un bosque control y los sistemas MIAF, y al interior de este entre la zona de milpa y la arbórea. En el estudio se calculó la abundancia, biomasa y diversidad de especies epigeas y endogeas. En los sistemas MIAF de Puebla se encontraron cuatro especies (una epigea y tres endogeas), mientras que en Oaxaca fueron cinco (dos epigeas y tres endógeas). En Puebla el 64% de las lombrices se concentraron en el bosque, siendo Lumbricus rubellus, Hoffmeister, 1843 y Aporrectodea trapezoides (Dugès, 1828), las dominantes; en Oaxaca el 79% de los individuos se encontraron en las áreas cultivadas, dominando las especies Octolasion tyrtaeum (Savigny, 1826), Amynthas sp., y Pontoscolex corethrurus (Müller, 1857). Las diferencias en la abundancia, la biomasa y la cantidad y clase de especies estarían relacionadas con la humedad del suelo, la intensificación agrícola y el manejo antropogénico de los materiales orgánicos (desechos de cosechas y estiércoles). Los resultados indicaron que las líneas de árboles frutales no presentaron comunidades de lombrices de tierra más diversas y abundantes, aunque esto fue más notorio en la región de Puebla. En ninguna de las dos regiones de estudio la abundancia total de lombrices alcanzó los 30 g m-2 recomendados para impactar en la fertilidad del suelo, por lo que se sugiere implementar técnicas de manejo en los sistemas MIAF que incrementen la cantidad de lombrices de talla mediana o grande.

Extrusion of earthworm coelomocytes: comparison of the cell populations recovered from the species Lumbricus terrestris, Eisenia fetida and Octolasion tyrtaeum

Coelomocytes were extruded from three earthworm species: Lumbricus terrestris, Eisenia fetida and Octolasion tyrtaeum. Featuring a simple low-vacuum holding device, the proposed methodology allows the recovery of cells with minimum risk of contamination by faecal material. The viability of O. tyrtaeum coelomocytes was highly reproducible (average 93%), with an average yield of 0.92 × 106 viable cells per earthworm. Cell viability for L. terrestris and E. fetida averaged ~68% but the cell yields were higher (respectively 1.67 × 106 and 1.28 × 106). Large inter-individual differences in cell yields were observed with L. terrestris. Flow cytometric analyses indicated species to species differences in cell populations. Coelomocytes from E. fetida were the smallest with ~57% of the total viable cells recovered being monitored between 2 and 10 µm. Large granulated cells (≥20 µm) were detected in fairly large proportions in L. terrestris and O. tyrtaeum [~52 and ~96%, respectively) while they were less abundant in E.fetida (~9%). Using the vital dye neutral red to assess functional integrity, average cellular uptakes were significantly higher for L. terrestris and O. tyrtaeum than for E. fetida (2.94, 2.66 and 0.64 µg/2 × 105 cells, respectively). In summary, the extrusion methodology herein described is applicable for the recovery of coelomocytes from a wide range of earthworm sizes and species. Moreover, this study strengthens the fact that extruded coelomocytes could be used for the evaluation of cell dysfunction and/or cell death following an in vitro and/or in vivo treatment.