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22
August
2022
ZOOLOGISTS TOOK A CLOSER LOOK AT TROPICAL MOLLUSCS AND DESCRIBED 4 NEW SPECIES
A team of biologists from the IEE RAS and the Faculty of Biology of Moscow State University studied the common tropical nudibranch mollusc Coryphellina rubrolineata. Molecular genetic analyzes, as well as a study of the external and internal structure of animals, showed that this is not one species, but at least five. As a result, the authors described four new species of nudibranch mollusks that differ in mitochondrial and nuclear genes, as well as body stripes. The study was supported by a grant from the Russian Science Foundation (RSF), the results were published in the journal Diversity. Molecular genetic methods have allowed scientists to better identify cryptic (similar in appearance, but genetically different) and pseudocryptic (different in appearance, but this becomes clear only after applying genetic methods) species and species complexes. With their spread in taxonomy, the hypothesis of the leading role of geographical barriers and spatial isolation in speciation began to dominate. Often, remote populations of the same species with a wide range began to be divided into several species, based solely on genetic comparison data, which is not always justified. Recent studies in the field of evolution and phylogeny emphasize the great role of the ecological factor in speciation: organisms can diverge into different ecological niches within the same geographical area, acquiring new characters and isolating according to their "way of life."
22
August
2022
SCIENTISTS OF THE IEE RAS TOGETHER WITH MATHEMATICIANS FROM INM RAS AND MIPT DEVELOPED A MODEL FOR STUDYING THE ECOLOGICAL PROPERTIES OF PATHOGENIC FUSARIAN FUNGI
Existing methods of combating pathogenic species of Fusarium fungi are not effective enough due to the high variability and specificity of the biology of these phytopathogenic microorganisms. The aim of our work was to reconstruct the kinetic mechanisms that determine the biomass of Fusarium species in the agroecosystem to minimize the risk of the spread of Fusarium. Using dynamic modeling, a system consisting of three components was studied: soil fungieating nematodes, Fusarium fungi and winter wheat seedlings. Based on the results of the parameter estimation and global sensitivity analysis, scientists identified three model parameters that have the strongest impact on the biomass of Fusarium species: (1) the rate of reproduction of mushroom-eating nematodes due to feeding on Fusarium fungi, (2) the rate of natural death of fungi-eating nematodes, and (3) tank size media for Fusarium fungi. According to the results of stochastic modeling, the internal variability of the dynamics of the biomass of Fusarium species was two orders of magnitude higher than the internal variability of the dynamics of the abundance of fungi-eating nematodes. The developed model made it possible to obtain fundamentally new information about the main mechanisms of interaction between Fusarium species, fungi-eating nematodes, and winter wheat plants, as well as to identify the most promising mechanisms that can reduce the biomass of Fusarium species in the soil.