Infection of Chorthippus loratus (Orthoptera: Acrididae) with Liebermannia sp. (Microsporidia) in South-Western Russia

DEVELOPMENT OF MICROSPORIDIOLOGY IN RUSSIA

The study of microsporidia and microsporidioses of wild animals in Russia has been initiated in the 60-s of the past century. In the European part of country, microsporidia, infecting agricultural insect pests (All-Russian Institute of Plant Protection), freshwater arthropods and fishes (State Research Institute of Lake and River Fisheries) and the blood-sucking insects such as horseflies (Biology Institute, Karelian Scientific Center) were studied. In the Western Siberia, microsporidia of blood-sucking mosquitoes were studied (Tomsk University). As a result, by 2000, as many as 118 species and 47 genera of microsporidia were found, including 20 taxa new to science, from 100 animal species. Currently, descriptions of new taxa and taxonomic revision of the previously described taxa are performed using the molecular phylogenetic analysis. The novel data on speciation of microsporidia have been obtained, and the coevolution of parasites and their host insects have been confirmed for microsporidia of blood-sucking mosquitoes. During the study of the structure and physiology of microsporidia, it has been demonstrated, that the secretory proteins of microsporidia migrate into the nucleus of the host cell; the factors of parasites suppressing host cell apoptosis and the presence of specific organelles related to the energy metabolism have been revealed; the mitosomes have been found in the spores and not the prespore stages of microsporidia. The role of the Golgi complex in the formation of the extrusion apparatus, as well as the absence of the vesicular secretory transport in microsporidia, has been shown for the first time. For the first time in Russia, cases of microsporidia infection in HIV-infected patients have been identified. Currently, attention is paid to the development of a new universal taxonomic system of microsporidia combining molecular characteristics with a description of the structural and developmental features of each taxon of the parasites. Microsporidia possess many remarkable structural and functional differences from any other organisms thus substantiating an independent field of biological research: “microsporidiology”.

Entomopathogenic microorganisms in locusts and grasshoppers populations and prospects for their use for control of this pest group

Brief information on the main groups of microorganisms parasitizing on locusts and grasshoppers is given. It has been shown that viral and most bacterial infections have no practical prospects, both as natural regulators of density populations and as potential producers of bioinsecticides. Alpha-proteobacteria, entomophthoralean fungi and microsporidia may make some contributions as natural mechanisms of population dynamics. The most significant group as producers of biopesticides are anamorphic ascomycetes from the genera Metarhizium and Beauveria.

Prevalence rates of microsporidia in locusts and grasshoppers in South-Western Russia

Locusts and grasshoppers are dangerous polyphagous pests of agricultural crops. In the present paper, results of screening of Acridoidea populations in the South-Western Russia for microsporidia infections including locusts Locusta migratoria, Dociostaurus maroccanus, and Calliptamus italicus and grasshoppers Chorthippus loratus, Oedipoda caerulescens, and Acrida bicolor, are presented. Microsporidia prevalence rates were estimated using light microscopy of fresh smears. Out of 179 specimens of L. migratoria sampled between 2002 and 2019 in Krasnodar Territory, Astrakhan and Rostov Regions, none was infected with microsporidia. Similarly, 95 specimens of D. marrocanus from Krasnodar Territory (2017) and Dagestan Republic (2009) were also negative for microsporidia. Meanwhile, one positive case was detected for C. italicus corresponding to 0.5 % for the total amount of 192 exemplars collected from 2002 to 2019 in Krasnodar Territory, Astrakhan and Rostov Regions. As for grasshoppers, all Ch. loratus samplings in Krasnodar Territory in 2017-2019 were infected at the prevalence rates of 2.2-15 %, though no infection was found in 40 specimens in Crimea in 2019. In 56 individuals of O. caerulescens collected from Rostov Region and Krasnodar Territory, the microsporidia prevalence rate was 1.8 %. Among 96 specimens of A. bicolor, none was infected. In total, the microsporidia prevalence rates were higher in grasshoppers as compared to locusts, the difference being statistically significant at p<0.01.