ISSN 1062-3590, Biology Bulletin, 2017, Vol. 44, No. 10, pp. 1265–1271. © Pleiades Publishing, Inc., 2017.
Original Russian Text © O.S. Oparina, M.L. Oparin, 2016, published in Povolzhskii Ekologicheskii Zhurnal, 2016, No. 3, pp. 292–301.
Arthropod Abundance at Bustard Nesting Sites
in the Saratov Trans-Volga Region
O. S. Oparina* and M. L. Oparin
Saratov Branch of Severtsov Institute of Ecology and Evolution Problems, Russian Academy of Sciences, Saratov, 410028 Russia
Received November 24, 2015
Abstract—The results of study of the quantitative and qualitative composition of arthropod communities at
potential nesting areas of great bustard (Otis tarda) in the Saratov Trans-Volga region are reported. Specific
data collected at seven areas (two plowed fields, two fields of winter and spring wheat, two fallows of different
ages, and virgin land) in 2012 are presented. Comparative analysis of some parameters of arthropod abun-
dance and biomass on chemical-treated and untreated winter crop fields has been conducted. The results
obtained have been compared to those of previous years. The current conditions for rearing of nestlings on
natural fallow lands of different ages and on early-spring crop fields in the Saratov Trans-Volga region during
the nesting period of O. tarda are favorable. The abundance and composition of arthropods in winter crop
fields treated with a complex of chemicals do not meet the requirements for the rearing of O. tarda nestlings.
Keywords: Otis tarda, habitat, food supply, arthropods, abundance, biomass, Trans-Volga region.
Studies of the quantitative and qualitative composi-
tion of arthropod communities at potential nesting sites
of bustards provide an estimate of the suitability of cer-
tain habitats for the rearing of nestlings. As has already
been established, the survival of bustard nestlings
during the first few weeks of life is exclusively deter-
mined by the availability of arthropods. The results
obtained characterize the negative impact of the struc-
ture of land use of a specific territory on the arthropod
Earlier studies performed both in the wild and in the
laboratory showed that bustard females use arthropods
of more than 5 mm in size to feed the nestlings, and the
biomass of arthropods captured in 100 sweeps of a net
should be at least 4.5 g (Litzbarski et al., 1987, 1996).
We studied the food reserves available to bustards
during the rearing of nestlings in the Saratov Trans-
Volga region in the years 1998–2000 (Oparina et al.,
2002). The bustard population size has decreased sig-
nificantly during the past decade (Oparin et al., 2012,
Oparina et al., 2015), and therefore, collection of
material on the abundance of arthropods in the nest-
ing areas, the major indicator of breeding success, was
MATERIALS AND METHODS
This study was carried out in 2012 and 2014 in Kras-
nokutskii raion in the southwestern part of the Saratov
left-bank area at three stationary areas of 100 km
size. Arthropod samples were collected every ten days
between May 20 and July 20 by sweeping a standard
entomological net in both directions relative to the sam-
pling line for 100 strokes (one stroke per step). The
diameter of the net was 30 cm, and the length of the
handle was 50 cm, so that the width of the sampling
strip was approximately 1.5 m. The distance between
the sampling strip and the edge of the field was 100 m.
The same person collected all samples in order to
increase the reliability of data comparison. The areas
investigated at the Talovka site were located in fields of
winter wheat, spring barley, lea field (after millet), lea
field (after sunflower), middle-aged fallow (5 years),
old fallow, and virgin soil. The areas investigated at the
Lepekhinka and Komsomol’skoe sites were located in
winter wheat fields either sprayed with chemicals from
an airplane or not treated with chemicals. The data col-
lected in 2012 are presented in Table 1.
Fresh samples were placed in a freezer for 1 to
2 hours, and afterwards the arthropods were separated
from plant residues and sorted into systematic groups.
Samples that corresponded to specific systematic
groups were sorted by size (≥5 mm or <5 mm), the
number of individuals in each group was counted, and
the biomass (fresh weight) of the samples was deter-
mined. Bustards prefer large insects, and therefore, all
the quantitative parameters listed below (abundance
index and biomass per 100 sweeps of the net) refer to
arthropods of at least of 5 mm in size.