Determination of insect fragments in the diet of Vespertilio murinus in the Middle Trans-Urals

Studies of bats diet are of scientific and practical interest. But in the vast territory of Russia such studies are rare. Therefore, we study the diet structure of the background and highly plastic bat species in the Middle Urals - Vespertilio murinus (Linnaeus, 1758) (Chiroptera, Vespertilionidae). The aim of the research was to study the species diet structure and to create an atlas qualifier of prey fragments, using a digital stereo microscope. We collected the material in Skorodumskoye village (Irbit district of Sverdlovsk region, 57°36N, 62°52'E) on the 11 and 16 July, 2012. We studied bat diet analyzing bat droppings. After collecting droppings, the bats were set free. In the laboratory, we selected 5-10 excrements of the close size and form for each individual. Each dropping (sample) was placed on a glass slide in a drop of glycerol. To determine and to count, the residues of arthropods were uniformly distributed on the glass surface (14 cm area), graph paper marked up into squares of 1 cm was placed under the slide. To create a photo collection of the residues we photographed the most characteristic elements, using the stereo microscope "Olympus SZ61" - 2x-4x magnification (2x front lens and 10x eyepieces). Totally, 80 samples were analyzed. For quantitative estimation of the residues we calculated the relative occurrence and abundance of various arthropod taxa. The relative occurrence is the share of samples with the taxon residues in the total number of samples (for each individual). Relative abundance is the share of squares (1 cm) with the taxon residues in the total number of squares of all found taxa (for each individual). The paper describes fragments of arthropods eaten by V. murinus, and gives photos for identification. Fragments of arthropods found in the droppings were from <0.1 to 8 mm. We identified limb and wing residues of insects most precisely which were specific in various orders. Indefinite residues predominated due to the difficulty to identify small elements. Basing on the results of the research on V. murinus diet in the plain of the Middle Trans-Urals we noted 8 orders of insects: Diptera (Nematocera, Brachycera), Trichoptera, Hymenoptera (Ichneumonidae), Homoptera (Cicadinea, Aphidina), Coleoptera, Lepidoptera, Hemiptera, Neuroptera (Hemerobiidae, Chrysopidae); and representatives of Arachnida (Acari). The most abundant and frequent were the following groups: Diptera (Nematocera) - 24.5% abundance, 98.8% occurrence, Homoptera Homoptera (Cicadinea) - 15.1% abundance, 72.7% occurrence, and Coleoptera -13% abundance, 95% occurrence. Our data agree with the data obtained by other authors in Europe and Russia, but with differences in quantitative ratios of prey (arthropod) groups.

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