Dejan Radović

Distribution patterns and environmental determinants of European newts in the Montenegrin karst area

The distribution patterns of three European newt species (Triturus macedonicus, Lissotriton vulgaris, and Mesotriton alpestris) was determined in the Montenegrin karst region and the influence of breeding ponds, the adjacent landscape, and climate variables on distributions within the framework of allotopy vs. syntopy occurrences was tested. After surveying 145 newt breeding sites in a 10,080 km2 area, the ranges of T. macedonicus and M. alpestris were found not come into contact, while L. vulgaris, the most widely distributed species, covers the entire range of T. macedonicus and the lower part of the range of M. alpestris. Using Akaike’s Information Criterion (AIC) to evaluate the effectiveness of 70 a priori models in predicting the presence of the three newt species, it was found that: (1) elevation is the most important variable in predicting newt presence; (2) only a few elevation-dependent variables can replace elevation in the building of a good descriptive model; (3) precipitation in combination with elevation contributes significantly to the building of a better descriptive model; and (4) in comparison with allotopy, syntopy mostly occurs at intermediate elevation ranges of species in sympatry.

Efficacy of plant-derived formulation “Argus Ras” in Varroa destructor control

Abstract Varroa destructor is the most important honey bee parasite. There are various methods used in the control of this mite, but none of them meets all requested criteria, to be safe, effective and easy to apply. The objective of this study was to evaluate the varroacidal efficacy of newly created plant-derived formulation Argus Ras (mixture of extracts of Sophora flavescens, Ginkgo biloba, Gleditsia chinensis and Teucrium chamaedrys) in a field trial. The investigation was conducted on 240 Apis mellifera colonies equalized in respect of brood amount, adult bee population and food reserves. Efficiency was evaluated by applying Argus Ras consecutively with two other acaricides, amitraz and oxalic acid. Average acaricidal efficacy of Argus Ras was 80.89%, being higher of other previously tested essential oils. Besides, it showed a potential in knocking down the mites resistant to other acaricides. It should not be neglected that Argus Ras requires a smaller number of treatments and financial investments than other formulations used for the control of Varroa mites.

A survey of deformed wing virus and acute bee paralysis virus in honey bee colonies from serbia using real-time RT-PCR

Abstract In this study 55 honey bee colonies from different Serbian regions were monitored for the presence of Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV) using TaqMan-based real-time RT-PCR assay. The results revealed the presence of DWV in each sampling location, and ABPV in 10 out of 11 apiaries. High frequency of DWV (76.4%) and ABPV (61.8%) positive samples in asymptomatic colonies can be the consequence of inefficient and postponed Varroa treatment concerning the role of this mite in the transmission and activation of honey bee viruses. The real-time RTPCR technique described in this paper is proved to be the most reliable method for this kind of investigation.

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.