Ivica Radovic

Population Genetic Analysis of Serbian Red Foxes (Vulpes vulpes) by Means of Mitochondrial Control Region Sequences

A population genetic analysis based on sequences of the mitochondrial control region in 110 red foxes from five sampling localities in northern Serbia was carried out. The analysis yielded nine different haplotypes. Neither haplotype phylogeny nor their distribution was in accordance with the geographic location of the populations. In particular, the data failed to detect an unequivocal influence of the two big rivers, the Danube and the Tisza, separating the populations studied. Population differentiation was altogether low, without any relationship to the rivers as possible migration barriers. Although the possibility of foxes crossing the rivers over bridges or by swimming, thus keeping up gene flow, cannot be ruled out, it is most probable that the control region sequences are not sensitive enough to resolve small-scale population relationships but rather show patterns determined by stochastic processes such as genetic drift or lineage sorting.

Morphological, biochemical and hematological characterization of endangered Balkan donkey breed.

Abstract The aim of the study was to establish morphometric, biochemical and hematological values for the endangered Balkan donkey breed (Serbia) and to explore the possible age dependence of the parameters tested. Inter-breed similarity of morphometric parameters was assessed by comparing the data obtained for the Balkan donkey with morphometric measurements of several previously characterized domestic donkey breeds. The study population included 74 donkeys, divided in two age groups (group A ≤ 3 years; group B > 3 years). In total, 18 morphometric, 13 hematological and 14 biochemical parameters were assessed. Significant morphometric differences (p<0.05) in body length, head length, chest circumference and body weight were found between the two age groups. Significant differences in morphological parameters were revealed among the Balkan donkey and other donkey breeds (Catalonian, Croatian and Albanian), but results of cluster analysis demonstrated the smallest distance between the Balkan donkey and Albanian donkeys. The results of morphometric analyses showed consistency of the obtained values within the breed, and diversity as compared to other donkey breeds, and, thus, could be taken as referent for the Balkan donkey. Hematological and biochemical profiles obtained for the Balkan donkey were consistent with previous reports and within the recommended reference ranges. White blood cell, mid cell and granulocyte counts, showed significantly higher (p<0.05) values in donkeys under 3 years of age, while the only biochemical parameter affected by age was alkaline phosphatase. The information gained through characterization of the Balkan donkey breed provides a basis for conservation and development of the breed standard.

Stimulating effect of sugar dusting on honey bee grooming behaviour

The aim of this research was to investigate whether or not sugar dusting can stimulate the grooming behaviour in Apis mellifera L. (Hymenoptera: Apidae), an important defensive mechanism against Varroa destructor Anderson & Trueman (Acari: Varroidae), and to assess the most effective dose and frequency of treatment. The criterion for evaluation of grooming potential was the percentage of damaged mites (PDM) among the total number collected on the bottom boards of the hives. In each sugar‐treated group PDM was significantly higher in comparison both with the negative control (no treatment) and with the values preceding the treatment. The results point to a stimulating effect of sugar on the grooming behaviour at all doses and frequencies tested. Treatment frequency influenced the stimulating effect of sugar: treatments at 3‐ and 7‐day intervals with 30 and 40 g resulted in significantly higher PDMs than the least frequent treatment (every 14 days); dusting with 20 g influenced PDM only when repeated at 3‐day intervals. Because treatments at 3‐day intervals are time‐consuming, those with 40 or 30 g repeated every 7 days may be recommended. In the positive control (hives treated with amitraz), average PDM was significantly lower than in the negative control and all sugar‐treated groups. Possible causes of the stimulating effect of sugar dusting on bee grooming behaviour are discussed.

Further evidence of the Asian mud-daubing wasps in Europe (Hymenoptera : Sphecidae)

We report the further south‐eastward range extension of the invasive Asian mud‐daubing wasp, Sceliphron curvatum (Smith), initially introduced into Austria in the late 1970s. We document its presence in the central Balkan Peninsula from 1997 onwards, and we discuss the circumstances and course of its recent expansion in the area. We also report the first finding of another Asian species, Sceliphron deforme (Smith), in Europe, and we consider various aspects of this case, given the possibility that the record from southern Montenegro represents a successful introduction.

The effect of Agaricus brasiliensis extract supplementation on honey bee colonies

This study was done to discover any beneficial effect of a medicinal mushroom Agaricus brasiliensis extract on the honey bee. Firstly, a laboratory experiment was conducted on 640 bees reared in 32 single-use plastic rearing cups. A. brasiliensis extract proved safe in all doses tested (50, 100 and 150 mg/kg/day) irrespective of feeding mode (sugar syrup or candy). Secondly, a three-year field experiment was conducted on 26 colonies treated with a single dose of A. brasiliensis extract (100 mg/kg/day) added to syrup. Each year the colonies were treated once in autumn and twice in spring. The treatments significantly increased colony strength parameters: brood rearing improvement and adult population growth were noticed more often than the increase in honey production and pollen reserves. These positive effects were mainly observed in April. In conclusion, A. brasiliensis extract is safe for the bees and helps maintaining strong colonies, especially in spring.

Physical and Geographical Description of the Boka Kotorska Bay

Compared to other parts of the Adriatic Sea, the Boka Kotorska Bay represents a unique and specific entity with its geographical position and geomorphological, climatological, hydrological and biotic characteristics. The sea deeply penetrates into the continent making it a unique fjord with the Mediterranean climate. The bay coastline length is 105.7 km, and the entire bay can be divided by its geographic–hydrographic properties into three entities: (1) the Kotor–Risan Bay, (2) the Tivat Bay and (3) the Herceg Novi Bay.