Vertical Distribution of Fruit Flies (Diptera: Drosophilidae) in Deciduous Forests in the Center of European Russia.

Research of Diptera in temperate forests has demonstrated uneven vertical distributions of insects. In this study, we examined the vertical distribution, seasonal fluctuations, and species diversity of Drosophilidae species in the Mordovia State Reserve. This research marks the first exploration of drosophilid vertical stratification in the European part of Russia. Using traps, we collected flies in four deciduous forest sites between early June and mid-September in 2020. A total of 27,151 individuals from 10 genera and 34 drosophilid species were identified, with 6 species from 4 genera being new to the Republic of Mordovia. Drosophila obscura Fll. and Scaptodrosophila rufifrons Lw. were the most abundant species in traps. The total highest number of drosophilid flies (10,429 individuals) was captured at a height of 1.5 m, while the lowest number (5086 individuals) was recorded at 12 m. The average number of flies was 6240 and 5387 individuals at heights of 7.5 m and 3.5 m, respectively. However, the prevalence of drosophilid numbers at the 1.5-m height was not constant during the season. We found that in the second part of July the total fly counts at heights of 7.5 m and 12 m exceeded those at 1.5 m. We have described five different types of vertical distribution of drosophilids throughout the season, which differs markedly in mycetobionts and xylosaprobionts ecological groups. Species diversity demonstrated variations across different sites and tiers during the season, with peak diversity observed in June and September.

Seasonal Dynamics of Fruit Flies (Diptera: Drosophilidae) in Forests of the European Russia.

(1) Background: Seasonal dynamics of the abundance and species diversity of various insect groups is of great importance for understanding their life cycles; (2) Methods: In our study, Drosophilidae species and their seasonal changes in Mordovia State Nature Reserve were explored. We collected the flies by crown fermental traps in five types of forests (birch, aspen, linden, pine and oak) since May to October in 2019. (3) Results: A total of 4725 individuals belonging to 9 genera and 30 species of drosophilid flies were identified, among them 15 species in 3 genera are new to the Republic of Mordovia. Drosophila obscura and D. histrio were the most abundant species in traps, the other mass species are D. kuntzei, D. testacea, D. phalerata, S. rufifrons, D. bifasciata, A. semivirgo, and L. quinquemaculata. (4) Conclusions: We found three groups of mass species with significant correlation of seasonal dynamics, e.g., D.obscura and D. bifasciata; D. histrio, D. kuntzei, D. phalerata, and D. testacea, and, finally, A. semivirgo and S. rufifrons. Apparently, the similarity observed in the seasonal dynamics of these drosophilid species is influenced at a high degree by their food preferences and rearing sites.