ISSN 1062-3590, Biology Bulletin, 2015, Vol. 42, No. 6, pp. 558–564. © Pleiades Publishing, Inc., 2015. Original Russian Text © E.S. Samoilova, N.V. Kostina, B.R. Striganova, 2015, published in Izvestiya Akademii Nauk, Seriya Biologicheskaya, 2015, No. 6, pp. 653–660. 558 INTRODUCTION Zoomicrobial relationships in the soil involve all types of biotic interactions (topical, trophic, fabric, phoric), which Beklemishev (1951) defined as the main types of symphysiological relationships. The effect of animals on the microbial population of soil communities was mainly studied with saprovores as an example, primarily earthworms and other groups of invertebrates feeding on plant waste or organic detri- tus. The main principles of zoomicrobial interactions were formulated on this basis (Anderson et al., 1985). The activity of animals was considered as a factor stimulating the mobilization and mineralization of nitrogen and other biogens. The direct impacts of zoo- genic activity (transfer of elements in trophic chains) were separated from indirect impacts (changes in the composition, abundance, and distribution of microf- lora in the soil because of the formation of zoogenic topic niches in the soil: macropores and organomin- eral aggregates). At the same time, many groups of pedobionts nei- ther make durable holes nor swallow soil together with feed objects. The animal population includes many predators and feeders on living plant tissues. Remains of plant and animal feed objects, as well as undigested feed particles mixed with metabolites, are resources for soil microflora. In addition, the movement of ani- mals in the soil involving the loosening of soil and the translocation of its particles obviously affects the water–air regime of the inhabited horizon and, hence, the structure of the microbial community. However, the zoomicrobial relationships of soil predators and phytovores, including the effect of their trophic and locomotor activities on the functional structure of microbial communities, remain still poorly under- stood. Elateridae larvae represent an obligate component of the soil animal community. They actively colonize arable lands, and many of their species are crop pests damaging plant roots. The abundance of larvae can exceed 100 individuals per 1 m 2 (Samoilova and Strig- anova, 2013). Under natural conditions, the migration and trophic activity of abundant larvae affect the aera- tion and water conditions of the inhabited horizon, as well as the composition of organic matter due to the excretion of uric acid, which is the major product of their final metabolism. The aim of the current rock was to study the effect of wireworms on the microbial population of the soil. MATERIALS AND METHODS Studies were performed on larvae of Agriotes obscu- rus (L.) and Selatosomus aeneus (L.), which are widely distributed in the soils of regions with a boreal or tem- perate climate. The larvae of both species are polyph- agous with the predominance of phytophagy; they can Effects of the Vital Activity of Soil Insect Larvae on Microbial Processes in the Soil E. S. Samoilova a , N.V. Kostina b , and B. R. Striganova a a Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninskii pr. 33/1, Moscow, 119071 Russia b Faculty of Soil Science, Moscow State University, Moscow, 119991 Russia e-mail: bellastriganova@mail.ru Received April 14, 2015 Abstract—The effects of Elateridae larvae (wireworms) on the structure, functional diversity, and tolerance of the soil microbial population in steppe ecosystems have been investigated. The trophic and locomotor activity of wireworms leads to an appreciable increase in bacterial abundance and suppression of fungal activ- ity. The fungal hyphae in the presence of wireworms are significantly damaged, which can be related to the feeding activity of Elateridae. The increase of bacterial abundance on the background of exclusion of the fun- gal component shifts the microbial succession to the acceleration of organic matter mineralization. The microbial consumption of mono- and oligosaccharides, alcohols, and water-soluble compounds increases in the presence of wireworms (multisubstrate test). The effect of Elateridae larvae on the microorganisms trans- forming nitrogen compounds is species-specific. Agriotes obscurus activity decreases their consumption of urea and creatinine by 2.1–2.5 times, and Selatosomus aeneus increases it by 1.3 and 2.5 times, respectively. The intensity of actual nitrogen fixation in the soil increases in the presence of wireworms by almost 4 times, but the losses of gaseous nitrogen do not increase because of the decrease in both the denitrification and methanogenesis rates. DOI: 10.1134/S1062359015060102 ECOLOGY