Earthworm species occurrence in agroecosystems in the Midlands, KwaZulu-Natal, South Africa

Little is known about the species composition of earthworms in agroecosystems in South Africa even though earthworms provide soil ecosystem services and are useful biological indicators of changes in the habitats. Given the land use and management impact biodiversity, the aim of this study was to document earthworm species that occur under cultivated land in the KwaZulu-Natal Midlands. A survey of nine farms that practise conservation agriculture was carried out between 2018 and 2020. Twelve earthworm species belonging to four introduced families: Acanthodrilidae (Dichogaster bolaui), Rhinodrilidae (Pontoscolex corenthrurus), Lumbricidae (Aporrectodea caliginosa, Aporrectodea rosea, Aporrectodea trapezoides, Lumbricus rubellus, Octolasion cyaneum, Octolasion lacteum), Megascolecidae (Amynthas aeruginosus, Amynthas corticis, Amynthas gracilis, Amynthas rodericensis) and juveniles from an indigenous family Tritogeniidae were recorded from cultivated fields. The type of crop (habitat) affected both species richness and abundance of earthworms significantly. However, post hoc results showed differences in species richness between the soya and the maize only, with greater species richness in the maize. Our results demonstrate that habitat type has a major influence on communities of earthworms in agroecosystems.

In vivo Assessment of APPJ Discharge on the Earthworm: Coelomic TAC and MDA Levels, Cell Death and Tissue Regeneration

The cold atmospheric pressure plasma jet (APPJ) is one of the effective tools with medical applications that its positive effects have been reported by various researchers, including sterilization of liquid and solid surfaces, treatment of chronic wounds, treatment of cancer tumors, and blood clots. This study investigated the effects of APPJ discharge on the two species of Earthworms (Aporrectodea trapezoides and Eisenia fetida). The APPJ discharge for different time durations, zero as a blank, 5, 10, 20, and 30 seconds, on these two species. Then some of these effects on the worms, including regeneration ability to miss segments, Malondialdehyde (MDA), catalase activity (CAT), total antioxidant capacity (TAC), cell death, total proteins, and protein profile in the coelomic fluid were investigated. Results showed levels of TAC and CAT increased after plasma treatment. In addition, a significant change was not observed in MDA levels and cell death. In summary, it can be concluded that APPJ exposure up to 40 seconds didn’t inhibit effects on the TAC levels of the earthworms and the defense system was able to fight oxidative stress and by increasing the expression of some proteins APPJ lead to better regeneration.

Integrative taxonomy of some Iranian peregrine earthworm species using morphology and barcoding (Annelida: Megadrili)

Despite the biological and economic importance of earthworms, the taxonomic status and evolutionary relationships of most lumbricid genera are still under debate. Further complications arise from the recognition that earthworms also show a high cryptic diversity. Past and current field studies of Iranian earthworm fauna have resulted in the identification of a total number of 28 earthworm species. However, many specimens do not fully fit into their original descriptions, making the species assignation very difficult. In this study, we evaluated the genetic diversity using mitochondrial markers as a tool to assess the species occurrence of some problematic species in Iran. Four species with high morphological variation were selected: Aporrectodea caliginosa (Savigny, 1826), Aporrectodea trapezoides (Dugès, 1828), Dendrobaena byblica (Rosa, 1893) and Dendrobaena veneta (Rosa, 1886). Morphological identification was contrasted with the molecular information generated through COI and 16S barcoding and the COI and 16S sequences stored in the Genbank. The results of this first integrative taxonomic analysis revealed that D. veneta consisted of two separated clades and that a number of species assigned to D. byblica showed very close relationships with those belonging to the genus Philomontanus. The lack of taxonomic expertise and identification characters providing a clear and unambiguous identification of earthworms highlights the urgent need of new tools to identify species unequivocally. Therefore, it is concluded that more taxonomical studies are needed to clarify the diagnostic characters and taxonomic status of the species belonging to two genera, Aporrectodea and Dendrobaena (Lumbricidae), in Iran.

Earthworm diversity in Rio Grande do Sul, Brazil

The knowledge regarding earthworm species richness in subtropical Brazil is limited, particularly in the state of Rio Grande do Sul (RS), where only a few sites have been sampled. In this study we assessed earthworm richness in different ecosystems of RS, prioritizing un-sampled regions. Fifteen ecosystems, including native vegetation and other ecosystems with variable levels of disturbance were sampled in 30 counties in RS, totaling 77 sampling points, mainly in the Pampa biome. Qualitative sampling was performed by handsorting soil monoliths and fixing the earthworms in 4% formalin solution. Species identification was based on morphological characters, and species richness and Shannon (H) and McIntosh (U) diversity indices were calculated for each ecosystem. Twenty-one earthworm species were identified, belonging to seven families: Glossoscolecidae (8), Rhinodrilidae (2), Ocnerodrilidae (4), Megascolecidae (4), Acanthodrilidae (1), Lumbricidae (1) and Criodrilidae (1). From these, ten are new species belonging to the genera: Glossoscolex (6), Fimoscolex (1), Kerriona (1), Eukerria (1), and one aquatic species of the Criodrilidae family, belonging to a new genus. Most of the native species (Urobenus brasiliensis, Fimoscolex n.sp.1 and the Glossoscolex spp.) predominated in ecosystems little altered by human activity, while exotic (Amynthas gracilis, Amynthas rodericensis, Metaphire californica, Aporrectodea trapezoides) and peregrine species (Pontoscolex corethrurus) predominated in areas with more human disturbance. Native ecosystems with lower disturbance, particularly forests and native pastures had higher diversity than disturbed sites. This is the first record of A. rodericencis for Brazil and most sites represent new collection records for the known species in RS.

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.

Las lombrices de tierra de zonas boscosas y agroecosistemas del municipio de San Antonio Sacatepéquez, departamento de San Marcos, Guatemala

La riqueza de lombrices de tierra fue determinada en dos tipos de ecosistemas: bosques (naturales) y agroecosistemas con cultivos anuales de San Antonio Sacatepéquez. Se muestrearon 16 sitios; estos fueron determinados sobreponiendo los mapas -shapes- de zonas de vida (De la Cruz, 1982); serie de suelos (Simmons et al., 1959) y cobertura forestal municipal, utilizando el software Quantum Gis; con el fin de zonificar aquellas áreas que difieren por esas variables ecológicas y por tipo de ecosistema. Los muestreos fueron realizados en septiembre y octubre de 2014, de acuerdo con el Método del programa internacional de Biología y Fertilidad de Suelos Tropicales (TSBF), la unidad básica de muestreo fue un cubo -monolito- de 25 x 25 x 30 cm de profundidad. Se realizaron cinco cubos por sitio, sin estratificar por capas la tierra extraída. En total se determinaron seis especies de lombrices de tierra, cuatronativas: Ramiellona aff vulcánica, Ramiellona sp, Kaxdrilus parkus y Kaxdrilus sp, de la familia Acanthodrilidae; y dosexóticas: Aporrectodea trapezoides y Octalasión tyrtaeum de la familia Lumbricidae. La mayor riqueza fue encontrada en bosque con tres especies nativas y una exótica: R. aff vulcánica, K. parkus, K. sp, O. tyrtaeum; y en agroecosistemastres especies (Ramiellona sp y ambas exóticas). El estudio contribuyó con cinco nuevos registros para Guatemala. Es importante continuar estudiando la oligoquetofauna guatemalteca y aprovecharla en la generación devermicomposteo, o reproducirlas e introducirlas a los sistemas agrícolas y forestales en proyectos que intenten elevarla fertilidad de los suelos y su restauración.

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.