Sofija Pavković-Lučić

Are larger and/or more symmetrical Drosophila melanogaster (Diptera, Drosophilidae) males more successful in matings in nature?

Are larger and/or more symmetrical Drosophila melanogaster (Diptera, Drosophilidae) males more successful in matings in nature? Sexual selection in Drosophila melanogaster, related to body size and fluctuating asymmetry in wing length and number of sex comb teeth in males, was tested in natural conditions. Males collected in copula were significantly larger than those collected as a single, while no difference in mean number of sex comb teeth between copulating and single males was observed. On the other hand, single males had greater asymmetry both for wing length and number of sex comb teeth than their mating counterparts. It looks like that symmetry of these bilateral traits also may play a role in sexual selection in this dipteran species in nature.

Mating success and wing morphometry in Drosophila melanogaster after long-term rearing on different diets

Different environmental factors are important for development, physiology, behaviour and, therefore, adaptation of Drosophila species. Additionally, the presence of genetic and phenotypic variation in traits affecting mate choice forms the basis for sexual selection that may lead to isolation between populations in different nutritive environments. The aim of this research was to determine mating success and wing morphometry of Drosophila melanogaster flies after more than a decade of growing on banana and carrot substrates. Males and females reared on carrot medium were more successful in mating than flies reared on banana diet. Females originating from banana medium rather chose males originating from carrot substrate, while females developed on carrot medium equally chose males developed on both substrates. Differences in wing size and shape were observed between sexes and nutritional strains. Furthermore, the results showed absence of ethological isolation between two ‘nutritional’ strains.

'Does my Diet Affect my Perfume?' Identification and Quantification of Cuticular Compounds in Five Drosophila melanogaster Strains Maintained over 300 Generations on Different Diets.

Cuticular hydrocarbons (CHCs) in Drosophila melanogaster represent the basis of chemical communication being involved in many important biological functions. The aim of this study was to characterize chemical composition and variation of cuticular profiles in five D. melanogaster strains. These strains were reared for approximately 300 generations on five diets: standard cornmeal medium and substrates prepared with apple, banana, tomato, and carrot. Differences in quantity and/or quality in CHCs were assumed as a result of activation of different metabolic pathways involved in food digestion and adaptations to the particular diet type.

Chemical Defence in a Millipede: Evaluation and Characterization of Antimicrobial Activity of the Defensive Secretion from Pachyiulus hungaricus (Karsch, 1881) (Diplopoda, Julida, Julidae)

The chemical defence of the millipede Pachyiulus hungaricus is reported in the present paper, in which a chemical characterization is given and antimicrobial activity is determined. In total, independently of sex, 44 compounds were identified. All compounds belong to two groups: quinones and pentyl and hexyl esters of long-chain fatty acids. The relative abundances of quinones and non-quinones were 94.7% vs. 5.3% (males) and 87.3% vs. 12.7% (females), respectively. The two dominant quinones in both sexes were 2-methyl-1,4,-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone. Antibacterial and antifungal activity of the defensive secretion was evaluated in vitro against seven bacterial strains and eight fungal species. With the aid of a dilution technique, the antimicrobial potential of the secretion and high sensitivity of all tested strains were confirmed. The lowest minimum concentrations of these compounds (0.20–0.25 mg/mL) were sufficient for inhibition of Aeromonas hydrophila, Listeria monocytogenes and Methicillin resistant Staphylococcus aureus (MRSA). The growth of eight tested fungal species was inhibited by slightly lower concentrations of the secretion, with Fusarium equiseti as the most sensitive fungus and Aspergillus flavus as the most resistant. Values of MIC and MFC in the employed microdilution assay ranged from 0.10 to above 0.35 mg/mL. The given extract contains antimicrobial components potentially useful as therapeutic agents in the pharmaceutical and agricultural industries.

Behaviour and food selection of Heterocypris incongruens (Ostracoda)

In this work, the ostracod Heterocypris incongruens (Ramdohr, 1808) was used to analyse three of its behavioural activities (feeding, swimming and resting) and its food preference. The majority of the individuals spent their time swimming. However, towards the end of the experiment, the number of individuals found feeding increased. The overall time spent feeding throughout the experiment was significantly longer than the time spent swimming and resting. Spinach was the most frequently used food, followed by mosquito larvae, Cyclops (plankton mix) and Spirulina mix. The retention time spent in the compartment containing spinach was also significantly longer than the time spent on all other items.

Morphological analyses allow to separate Branchipus species (Branchiopoda, Anostraca) from different geographic regions

In Serbia, Branchipus Schaeffer, 1766 is especially common in the Pannonian lowlands, where Branchipus schaefferi and Branchipus serbicus were previously reported. In the southern parts of the country, at the foothills of the Stara Planina Mountains, a Branchipus intermedius population is reported to occur. We used multivariate analysis to assess the degree of morphological variability between Branchipus populations currently ascribed to different species. Morphometric characters contributed the most to the morphological differentiation. Populations were better defined on the basis of male morphometric characters. Our results indicate that individuals from the southeastern, mountainous part of the country had the highest level of differentiation. We confirmed that this population belongs to B. intermedius. The individuals of the presumed species B. serbicus exhibited a fairly lower level of morphological differentiation in the present study, and grouped together with other lowland Serbian populations ascribed to B. schaefferi. According to this study, B. serbicus is a junior synonym of B. schaefferi.

Sexual selection, sexual isolation and pheromones in Drosophila melanogaster strains after long-term maintaining on different diets

Evolution of reproductive isolation may be a consequence of a variety of signals used in courtship and mate preferences. Pheromones play an important role in both sexual selection and sexual isolation. The abundance of pheromones in Drosophila melanogaster may depend on different environmental factors, including diet. The aim of this study was to ascertain to which degree principal pheromones affect sexual selection in D. melanogaster. We used D. melanogaster strains reared for 14 years on four substrates: standard cornmeal substrate and those containing tomato, banana and carrot. We have previously determined that long-term maintaining of these dietary strains resulted in differences in their cuticular hydrocarbons profile (CHs). In this work, we have tested the level of sexual selection and sexual isolation between aforementioned strains. We found that the high levels of cis-vaccenyl acetate, 7-pentacosene and 7,11-nonacosadiene in the strain reared on a substrate containing carrot affected the individual attractiveness and influenced sexual isolation between flies of this strain and flies reared on a substrate containing banana. Based on these results, long-term different diets, may contribute, to sexual behaviour of D. melanogaster via the effects of principal pheromones.

BEHAVIORAL SCIENCE AT THE FACULTY OF BIOLOGY, UNIVERSITY OF BELGRADE, SERBIA

ABSTRACT Whether behavior is present in the science for many years, it is still young and very attractive discipline that needs interdisciplinar approach for studying. Large scale of experimental models makes experimental and scientific work more exciting. At the Faculty of Biology, University of Belgrade (Serbia), we have behavioral courses at all three levels of studies (bachelor, master and PhD). At the basic level, we have Animal Behavior course, than, at the master level, we offer to our students two courses, Biology of Behavior and Introduction into Behavioral Genetics. Finally, for PhD students of Neuroscience we have two courses—Cellular Basis of Behavior and Neurobiology of Behavior, while PhD students of Genetics attend course Behavior Genetics. In this way, all aspects and levels of understanding behavioral mechanisms are covered.

Teaching in Biological Sciences at Primary Schools in Serbia—An Application of the Hands on Method

ABSTRACT The project Hands on has being implemented in Serbia since 2001 in order to uplift and revitalize teaching of the natural sciences in Primary Schools and enhance a personal engagement by the pupils in different topics. In 2003, the Serbian Ministry of Education decided to put forward an optional course “Hands on—Discovering the World”, for children from 6 to 8 years old. Resources related to the biology have been occurred through seven modules, as follows: Plants, Food and digestion, Five senses, Growing and aging, Ecosystems, Environment. Knowing that topics in systematic biology are usually considered difficult and demanding, here we present the new, interesting, simple and creative way to teach systematics and classification since the early age, based on the Hands on method. New module refers to the classification of living beings, when teachers encourage their pupils to observe similar attributes, arrange the hierarchy of nested groups and classify animals discovering the evolutionary relationships of taxa.

Different responses of Drosophila subobscura isofemale lines to extremely low frequency magnetic field (50 Hz, 0.5 mT): fitness components and locomotor activity

Abstract Purpose: Extremely low frequency (ELF) magnetic fields as essential ecological factors may induce specific responses in genetically different lines. The object of this study was to investigate the impact of the ELF magnetic field on fitness components and locomotor activity of five Drosophila subobscura isofemale (IF) lines. Materials and methods: Each D. subobscura IF line, arbitrarily named: B16/1, B24/4, B39/1, B57/2 and B69/5, was maintained in five full-sib inbreeding generations. Their genetic structures were defined based on the mitochondrial DNA variability. Egg-first instar larvae and 1-day-old flies were exposed to an ELF magnetic field (50 Hz, 0.5 mT, 48 h) and thereafter, fitness components and locomotor activity of males and females in an open field test were observed for each selected IF line, respectively. Results: Exposure of egg-first instar larvae to an ELF magnetic field shortened developmental time, and did not affect the viability and sex ratio of D. subobscura IF lines. Exposure of 1-day-old males and females IF lines B16/1 and B24/4 to an ELF magnetic field significantly decreased their locomotor activity and this effect lasted longer in females than males. Conclusions: These results indicate various responses of D. subobscura IF lines to the applied ELF magnetic field depending on their genetic background.