The purpose of the research is to test blood-sucking dipterans collected in the Tyumen Region for genetic material of viruses that cause dangerous diseases in live-stock animals.Materials and methods. From May to October 2021, blood-sucking insects of the Diptera order whose species membership was established by tabular keys were collected on pastures and farms in ten Tyumen Region districts. In 60 samples formed from the captured insects according to the taxonomic affiliation and the period and place of collection, the presence of genetic material of the leukemia provirus and the dermatitis nodularis virus of cattle (bovine) and the African swine fever virus was evaluated by polymerase chain reaction (PCR) in real time.Results and discussion. Adult insects collected for the PCR analysis were blood-sucking flies (family Muscidae, genus Stomoxys), mosquitoes (family Culicidae, genus Aedes), midges (family Simuliidae, genera Byssodon and Schoenbaueria), horseflies (family Tabanidae, genera Hybomitra, Tabanus and Haematopota), and biting midges (family Ceratopogonidae, genus Culicoides). As a result of the PCR testing of the samples for the bovine leukemia provirus DNA, 1 out of 13 samples of Stomoxys spp. (7.7%) and 1 of 13 samples of Hybomitra spp. (7.7%) were positive. The bovine leukemia provirus DNA detected in blood-sucking insects indicates the presence of this pathogen in the insect collection area as well as their possible involvement in its spread. Further research is needed on the Stomoxys spp. and Hybomitra spp. vector competence in vivo, considering natural and climatic features of the Tyumen Region.

Pesticide resistance has become one of the pressing problems of ecology and agriculture because it makes it difficult to deal with pests and ectoparasites while increasing the chemical load on the environment. This paper focuses on the importance of studying insecticidal resistance in agricultural, veterinary, and medical insects. Brief information is given concerning the resistance of ectoparasites and crop insect pests in different world regions to commonly used insecticides. The main approaches for identifying insecticide resistance in field insect populations are listed. The progress achieved in understanding the molecular basis of insecticidal resistance in insects is briefly described, and the primary areas of recent research are outlined. The importance of assessing the resistance profile and the potential for insecticide resistance developing in field insect populations are emphasized. The study of molecular mechanisms of insecticidal resistance to specific compounds is important for searching for new active agents and developing strategies for their application.

The study of changes that occurred in insect organisms in response to insecticidal exposure and their species-specific characteristics is important for a fuller understanding of the environmental and evolutionary patterns of pesticidal resistance. For chlorfenapyr from the pyrrole group of insecticides, the mechanism underlying the resistance in insects is not quite clearly described. This study evaluated the activity of acetylcholinesterase (AChE) in adults of the house fly Musca domestica of the chlorfenapyrresistant (selected with chlorfenapyr) strain (ChlA). Also, we assessed the kinetic parameters of AChE in females and males of the ChlA strain compared to these of the unselected strain (Lab) of M. domestica for the first time. Specimens of Lab and ChlA strains had no statistically significant differences in specific AChE activity. The percentage remaining activities of propoxur-inhibited AChE was 3.81 times less (р < 0.05) and values of Vmax and Km were 43.3% and 46.9% (р < 0.05), respectively, less in females of the ChlA strain compared to these in females of the Lab strain. For both Lab and ChlA strains M. domestica, the catalytic efficacy of AChE based on Vmax/Km in males was more than that in females. In general, the results obtained suggest that the affinity of AChE to specific ligands (like a substrate acetylthiocholine and an inhibitor propoxur) increased without a rise of the catalytic activity in females of the ChlA strain M. domestica that was under selection with chlorfenapyr during 23-24 generations.