Occurrence and insecticide susceptibility of the grain aphid Sitobion avenae in northern Mongolia

A survey was carried out to determine the prevalence of Sitobion avenae (S. avenae) in the central agriculture zone of northern Mongolia (including Darkhan-Uul, Selenge, Tuv, and Erdenet aimags). Bioassays were used to assess the pest's susceptibility to three regularly used insecticides (deltamethrin, fenvalerate, and imidacloprid). DNA sequencing was used to look into the genotypes of codons 918 and 1014 of the Voltage-gated sodium channel (VGSC) gene in S. avenae. The findings revealed that in 2019, the population density of S. avenae was low in 159 fields and medium in 31, and the infestation rate was low in 73 fields, medium in 117 fields. Even at a concentration of 0.005%, high mortality rates (>84 per cent) of S. avenae nymphs were detected after 72 hours of exposure to the three insecticides, indicating that this pest was susceptible to all three insecticides tested. In our grain aphid samples, the pyrethroid resistance-causing mutations (M918L and L1014F) in the voltage-gated sodium channel were not detected

Spatial variations in larch needle and soil δ15N at a forest–grassland boundary in northern Mongolia

The spatial patterns of plant and soil δ15N and associated processes in the N cycle were investigated at a forest–grassland boundary in northern Mongolia. Needles of Larix sibirica Ledeb. and soils collected from two study areas were analysed to calculate the differences in δ15N between needle and soil (Δδ15N). Δδ15N showed a clear variation, ranging from −8‰ in the forest to −2‰ in the grassland boundary, and corresponded to the accumulation of organic layer. In the forest, the separation of available N produced in the soil with 15N-depleted N uptake by larch and 15N-enriched N immobilization by microorganisms was proposed to cause large Δδ15N, whereas in the grassland boundary, small Δδ15N was explained by the transport of the most available N into larch. The divergence of available N between larch and microorganisms in the soil, and the accumulation of diverged N in the organic layer control the variation in Δδ15N

Sequencing, Analysis and Organization of the Complete Genome of a Novel Baculovirus <i>Calliteara abietis</i> Nucleopolyhedrovirus (CaabNPV)

Baculoviridae, a virus family characterized by a single large double stranded DNA, encompasses the majority of viral bioinsecticides, representing a highly promising and environmentally friendly pesticide approach to insect control. This study focuses on the characterization of a baculovirus isolated from larvae of Calliteara abietis (Erebidae, Lymantriidae) collected in Mongolian pinaceae forests. This new isolate was called Calliteara abietis nucleopolyhedrovirus (CaabNPV). CaabNPV exhibits an irregular polyhedron shape, and significant variation in the diameter of its occlusion bodies (OBs) was observed. Nucleotide distance calculations confirmed CaabNPV as a novel baculovirus. The CaabNPV genome spans 177,161 bp with a G+C content of 45.12% and harbors 150 potential open reading frames (ORFs), including 38 core genes. A comprehensive genomic analysis categorizes CaabNPV within Group II alphabaculovirus, revealing a close phylogenetic relationship with Alphabaculovirus orleucostigmae (OrleNPV). Additionally, repeat sequence analysis identified three highly repetitive sequences consisting of 112 bp repeat units, known as homologous regions (hrs). This research contributes valuable insights into CaabNPV’s phylogenetic placement, genomic structure, and its potential applications in insect biocontrol

Range-Wide Phylogeography and Ecological Niche Modeling Provide Insights into the Evolutionary History of the Mongolian Racerunner (<i>Eremias argus</i>) in Northeast Asia

The Mongolian racerunner, Eremias argus, is a small lizard endemic to Northeast Asia that can serve as an excellent model for investigating how geography and past climate change have jointly influenced the evolution of biodiversity in this region. To elucidate the processes underlying its diversification and demography, we reconstructed the range-wide phylogeographic pattern and evolutionary trajectory, using phylogenetic, population genetic, landscape genetic, Bayesian phylogeographic reconstruction and ecological niche modeling approaches. Phylogenetic analyses of the mtDNA cyt b gene revealed eight lineages that were unbounded by geographic region. The genetic structure of E. argus was mainly determined by geographic distance. Divergence dating indicated that E. argus and E. brenchleyi diverged during the Mid-Pliocene Warm Period. E. argus was estimated to have coalesced at~0.4351 Ma (Marine Isotope Stage 19). Bayesian phylogeographic diffusion analysis revealed out-of-Inner Mongolia and rapid colonization events from the end of the Last Interglacial to the Last Glacial Maximum, which is consistent with the expanded suitable range of the Last Glacial Maximum. Pre-Last Glacial Maximum growth of population is presented for most lineages of E. argus. The Glacial Maximum contraction model and the previous multiple glacial refugia hypotheses are rejected. This may be due to an increase in the amount of climatically favorable habitats in Northeast Asia. Furthermore, E. argus barbouri most likely represents an invalid taxon. The present study is the first to report a range-wide phylogeography of reptiles over such a large region in Northeast Asia. Our results make a significant contribution towards understanding the biogeography of the entire Northeast Asia

Spatial variations in larch needle and soil δ¹⁵N at a forest–grassland boundary in northern Mongolia

<p>The spatial patterns of plant and soil δ¹⁵N and associated processes in the N cycle were investigated at a forest–grassland boundary in northern Mongolia. Needles of <i>Larix sibirica</i> Ledeb. and soils collected from two study areas were analysed to calculate the differences in δ¹⁵N between needle and soil (Δδ¹⁵N). Δδ¹⁵N showed a clear variation, ranging from −8 ‰ in the forest to −2 ‰ in the grassland boundary, and corresponded to the accumulation of organic layer. In the forest, the separation of available N produced in the soil with ¹⁵N-depleted N uptake by larch and ¹⁵N-enriched N immobilization by microorganisms was proposed to cause large Δδ¹⁵N, whereas in the grassland boundary, small Δδ¹⁵N was explained by the transport of the most available N into larch. The divergence of available N between larch and microorganisms in the soil, and the accumulation of diverged N in the organic layer control the variation in Δδ¹⁵N.</p