Patterns of Genetic Variation in the Eisenia nordenskioldi Complex (Oligochaeta: Lumbricidae) along an Elevation Gradient in Northern China

Eisenia nordenskioldi is the dominant earthworm species in many tundra and boreal habitats. Nothing is known about the genetic diversity of this species along the elevation gradient in China. This study sampled 28 individuals in the E. nordenskioldi complex from Wuling Mountain, northern China, to examine their external morphology and genetic diversity. Mt. Wuling is the southern limit of the distribution of the E. nordenskioldi complex. The specimens from Mt. Wuling were classified into three groups along an elevation gradient. Mismatch distribution analysis suggested that the Pleistocene glaciations possibly did not significantly affect the distribution of earthworm species in this region. We also found that elevation affected the genetic diversity, but not the external morphology of E. nordenskioldi. Given the altitudinal genetic diversity within the E. nordenskioldi complex, the phylogeography of this species provides important information for the zoogeographic reconstruction of the mountains in northern China. With the relatively limited sample size, the result is not conclusive, and further studies need to be conducted in the future to verify the results.

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.

Variation in nuclear genome size within the Eisenia nordenskioldi complex (Lumbricidae, Annelida)

The size of the nuclear genome in eukaryotes is mostly determined by mobile elements and noncoding sequences and may vary within wide limits. It can differ significantly both among higher-order taxa and closely related species within a genus; genome size is known to be uncorrelated with organism complexity (the so-called C-paradox). Less is known about intraspecific variation of this parameter. Typically, genome size is stable within a species, and the known exceptions turn out be cryptic taxa. The Eisenia nordenskioldi complex encompasses several closely related earthworm species. They are widely distributed in the Urals, Siberia, and the Russian Far East, as well as adjacent regions. This complex is characterized by significant morphological, chromosomal, ecological, and genetic variation. The aim of our study was to estimate the nuclear genome size in several genetic lineages of the E. nordenskioldi complex using flow cytometry. The genome size in different genetic lineages differed strongly, which supports the hypothesis that they are separate species. We found two groups of lineages, with small (250–500 Mbp) and large (2300–3500 Mbp) genomes. Moreover, different populations within one lineage also demonstrated variation in genome size (15–25 %). We compared the obtained data to phylogenetic trees based on transcriptome data. Genome size in ancestral population was more likely to be big. It increased or decreased independently in different lineages, and these processes could be associated with changes in genome size and/or transition to endogeic lifestyle.

LUMBRICIDAE SPECIES COMPOSITION IN THE SOILS OF THE FOOTHILL BEYOND ILE ALATAU REGION

This article discusses the species composition of earthworms in the soils of the beyond Ile Alatau region. The role of earthworms in the soil is quite large. First of all, it is worth noting their loosening and structuring activities. During the movement process, these soil invertebrates mix a huge number of small fractions of soil. The loosening activity promotes moisture and sufficient oxygen. The most important is the destructive activity and enrichment of soils with active substances, as enzymes. The study of lumbricides began from the time of Charles Darwin, and is still of great importance the essence of such invertebrates in zoology. Scientific researchers had been carried out over two years (2018-2020) during the active vegetation of plants on the soils of the highest point of the beyond Ile Alatau region - in the peak of Talgar. As a result of the conducted research, the following earthworm species from the Lumbricidae family were found: Octolasium lacteum, Eisenia foetida, Eisenia nordenskioldi, Nicodrilus caliginosus, Nicodrilus longus, Lumbricus rubellus, Lumbricus terrestris, Dendrobaena octaedra. The most common species are Lumbricus rubellus and Nicodrilus caliginosus, and the rest are less common. In the seasonal dynamics of earthworm numbers, two peaks of activity were observed - in early June and at the end of August.

Species Delimitation of the Eisenia nordenskioldi Complex (Oligochaeta, Lumbricidae) Using Transcriptomic Data

Eisenia nordenskioldi (Eisen, 1879) is the only autochthonous Siberian earthworm with a large distribution that ranges from tundra to steppe and broadleaved forests. This species has a very high morphological, ecological, karyological, and genetic diversity, so it was proposed that E. nordenskioldi should be split into several species. However, the phylogeny of the complex was unclear due to the low resolution of the methods used and the high diversity that should have been taken into account. We investigated this question by (1) studying the diversity of the COI gene of E. nordenskioldi throughout its range and (2) sequencing transcriptomes of different genetic lineages to infer its phylogeny. We found that E. nordenskioldi is monophyletic and is split into two clades. The first one includes the pigmented genetic lineages widespread in the northern and western parts of the distribution, and the second one originating from the southern and southeastern part of the species' range and representing both pigmented and non-pigmented forms. We propose to split the E. nordenskioldi complex into two species, E. nordenskioldi and Eisenia sp. 1 (aff. E. nordenskioldi), corresponding to these two clades. The currently recognized non-pigmented subspecies E. n. pallida will be abolished as a polyphyletic and thus a non-natural taxon, while Eisenia sp. 1 will be expanded to include several lineages earlier recognized as E. n. nordenskioldi and E. n. pallida.

Invertebrate animals of landscape gardening lawn cenoses of the city of Karaganda (area of the South-East)

Urbanization of territories leads to the formation of ecosystems that are significantly different from natural ones. Invertebrates are the most effective and promising group of bioindicators of anthropogenic impact on natural and urban ecosystems. However, very little work has been done to study the fauna of urban ecosystems in Kazakhstan. The article presents research data on invertebrates of the Karaganda region by specialists of the Department of Zoology of Karaganda State University, carried out in different years and during periods of field practice. Analysis of invertebrate lawn communities showed the dominance of insects, in particular hymenopteran genera Formica, Myrmic, Camponotus. In second place in terms of numbers are coleoptera,among which ground beetles and staphilins prevail, as characteristic inhabitants of the city. The predominance of insects is a zonal sign. Among them there are dangerous pests: larvae of nutcracker beetles, black beetles, and lamellar beetles. Soil worms include earthworms: Lumbricus rubellus, Eisenia nordenskioldi, Appropriateode caliginosa f. typica. Predators dominate the trophic structure of lawn inhabitants, which is very characteristic of urban cenoses. The high number of predatory forms, the diversity of orders and families testifies to the favorable ecological regime of the studied lawn cenoses as a result of their long existence.