Effect of electromagnetic field (50 Hz, 0.25 mT) on fitness components and wing morphometrics of Drosophila subobscura Collin, 1936 (Insecta, Diptera)

Od svog nastanka život na Zemlji se odvijao u prisustvu prirodnih elektromagnetnih polja (EMP) koja su relativno jednostavna i potiču od malobrojnih emitera elektromagnetne energije. Živa bića su se tokom svoje evolucije prilagodila ovom konstantnom sredinskom faktoru, ali su danas pored prirodnih, u sve većoj meri izložena EMP poreklom od izvora koje je stvorio čovek. Intenzitet i frekvencija ovih polja su daleko veći u odnosu na polja prirodnog porekla, a tu spadaju najvećim delom EMP mrežne frekvencije (u okviru dela spektra ekstremno niske frekvencije (ENF) od 50 ili 60 Hz), polja koji potiču od uređaja masovnih (RTV predajnici, 100-500 MHz) i mobilnih komunikacija (800-900 MHz i 1800-2200 MHz). EMP ENF imaju veliki biofizički značaj jer su sveprisutna u životnoj sredini usled prenosa i upotrebe električne energije. Elektromagnetna polja antropogenog porekla predmet su izučavanja različitih bioloških disciplina, ali pre svega sa aspekta zdravlja ljudi. Izlaganje organizama ELM ENF, čak i tokom kraćeg vremenskog perioda, ima za posledicu narušavanje ravnoteže bioloških sistema, kao i poremećaje na različitim nivoima organizacije, ali još uvek ne postoji opšte prihvaćena teorija o mehanizmima dejstva EMP ENF u biološkim sistemima. Pored toga, sredinske promene, usled prisustva EMP ENF, mogu imati uticaj na ekološke i evolucione procese koji utiču na stepen i obim promena u genetičkoj strukturi i evoluciji populacije. Stoga je od suštinskog značaja dublje razumevanje mehanizama koji omogućavaju organizmima da se manje ili više uspešno prilagođavaju sredinskim izazovima, kao i mogućnost da se predvide i prate odgovori populacija na promene u životnoj sredini koja ih okružuje. Tokom poslednje tri decenije izvedene su brojne studije na Drosophila sa ciljem ispitivanja bioloških efekata EMP ENF. Eksperimentalno izlaganje individualnih genotipova Drosophila EMP ENF tokom različitih faza životnog ciklusa, rezultuje različitim odgovorima koji su često oprečni, jer efekat delovanja EMP ENF na rast i metabolizam organizama, bilo inhibitorni, bilo stimulativni, zavisi od kompleksnih veza između frekvencije, jačine polja, dužine izlaganja, i stanja i tipa ćelija ili organizama..

Adaptive significance of amylase polymorphism in drosophila, XV: Examination of genotype-by-environment interactions on the viability, developmental time and stability of drosophila subobscura homozygous for Amy during exposure to nutritional changes

Due to the direct interaction between enzyme and substrate, the amylase system can provide valuable information on the relationship between homozygosity and developmental homeostasis under a changing environment in several Drosophila species, The adaptive significance of the relationship between genetic variability and environmental change manifests through the well-known polymorphism of the amylase locus (Amy). We examined the effect of gradual and abrupt changes in starch concentration in the nutritional substrate, on the developmental time, egg-to-adult viability and phenotypic plasticity in the progeny of Drosophila subobscura that was homozygous for 'fast' (AmyF/AmyF) and 'slow' (AmyS/AmyS) Amy alleles. Our findings show that gradual and abrupt nutritional changes exert a significant effect on developmental time and viability. A high heterogeneity among genotypes in fluctuating asymmetry (FA) and no direct association between FA and fitness components under the two experimental regimes of environmental change were observed.Projekat ministarstva br. 17301

Variability of fluctuating asymmetry in ovariole number of Drosophila subobscura caused by microclimatic difference

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Adaptive significance of amylase polymorphism in drosophila, XV: Examination of genotype-by-environment interactions on the viability, developmental time and stability of drosophila subobscura homozygous for Amy during exposure to nutritional changes

Due to the direct interaction between enzyme and substrate, the amylase system can provide valuable information on the relationship between homozygosity and developmental homeostasis under a changing environment in several Drosophila species, The adaptive significance of the relationship between genetic variability and environmental change manifests through the well-known polymorphism of the amylase locus (Amy). We examined the effect of gradual and abrupt changes in starch concentration in the nutritional substrate, on the developmental time, egg-to-adult viability and phenotypic plasticity in the progeny of Drosophila subobscura that was homozygous for 'fast' (AmyF/AmyF) and 'slow' (AmyS/AmyS) Amy alleles. Our findings show that gradual and abrupt nutritional changes exert a significant effect on developmental time and viability. A high heterogeneity among genotypes in fluctuating asymmetry (FA) and no direct association between FA and fitness components under the two experimental regimes of environmental change were observed.Projekat ministarstva br. 17301

Local adaptation at fine spatial scale through chromosomal inversions and mito-nuclear epistasis: Findings in Drosophila subobscura (Diptera: Drosophilidae)

To explore local adaptation in wild populations at a fine spatial scale we characterized the genetic variability of eight closely located populations of Drosophila subobscura and its associations with microhabitat environmental conditions. Three different genetic markers were assessed: chromosomal inversions, a SNP of mitochondrial ND5 gene and nuclear microsatellites. Population genetic analyses of chromosomal variability revealed significant genetic differentiation between these populations. Gene arrangement frequencies on the E chromosome contributed most to these differences. We also investigated role of mito-nuclear epistasis in mitochondrial genome differentiation and revealed weak linkage disequilibrium (LD) exclusively between O3+4 inversion arrangement and mitochondrial DNA haplotype I in two populations. In addition, the trend in the LD between OST chromosomal arrangement and haplotype II was general in the total sample. Microsatellite analysis revealed an absence of stochastic processes, like census reduction, upon population differentiation. Only a small amount of the genetic variation is related to geographic distance, while most (97%) is attributable to other factors and in some degree to microhabitat variables (temperature, humidity). The analysis of these factors revealed they effect inversion arrangement frequencies, especially E1+2+9, EST and OST. Even though this model organism is known for its high mobility and mostly large effective population size, the results presented here reveal that local adaptations can occur even at a small spatial scale. We propose that locally adapted alleles within chromosomal inversions, as well as joint selective pressures acting on mitochondrial and nuclear genomes, are responsible for the observed adaptation to microhabitat conditions

Life-history variation of drosophila subobscura under lead pollution depends on population history

Contamination represents environmental stress that can affect genetic variability of populations, thus influencing the evolutionary processes. In this study, we evaluate the relationship between heavy metal contamination (Pb) and phenotypic variation, assessed by coefficients of variation (CV) of life-history traits. To investigate the consequences of population origin on variation of life history traits in Drosophila subobscura in response to different laboratory conditions we compared populations from relatively polluted and unpolluted environments. Prior to experiment, flies from natural populations were reared for two generations in standard Drosophila laboratory conditions. Afterwards, all flies were cultured on three different media: one medium without lead as the control, and the other two with different concentrations of lead. Coefficients of variation (CV) of life- history traits (fecundity, egg-to-adult viability and developmental time) were analyzed on flies sampled in generations F2, F5 and F8 from these three groups. In later generations samples from both polluted and unpolluted environments showed the increased fecundity variation on media with lead. This increase is expressed more in population from unpolluted environment. On contrary, population from unpolluted environment had increased variation of developmental time in earlier, F2 generation, compared to the population from polluted environment. Our results showed that the response to heavy metal contamination depends on the evolutionary history of the populations regarding habitat pollution. [Projekat Ministarstva nauke Republike Srbije, br. 173012

Adaptive significance of amylase polymorphism in drosophila, XV: Examination of genotype-by-environment interactions on the viability, developmental time and stability of drosophila subobscura homozygous for Amy during exposure to nutritional changes

Due to the direct interaction between enzyme and substrate, the amylase system can provide valuable information on the relationship between homozygosity and developmental homeostasis under a changing environment in several Drosophila species, The adaptive significance of the relationship between genetic variability and environmental change manifests through the well-known polymorphism of the amylase locus (Amy). We examined the effect of gradual and abrupt changes in starch concentration in the nutritional substrate, on the developmental time, egg-to-adult viability and phenotypic plasticity in the progeny of Drosophila subobscura that was homozygous for “fast” (AmyF/AmyF) and “slow” (AmyS/AmyS) Amy alleles. Our findings show that gradual and abrupt nutritional changes exert a significant effect on developmental time and viability. A high heterogeneity among genotypes in fluctuating asymmetry (FA) and no direct association between FA and fitness components under the two experimental regimes of environmental change were observed

Life-history variation of Drosophila subobscura under lead pollution depends on population history

Contamination represents environmental stress that can affect genetic variability of populations, thus influencing the evolutionary processes. In this study, we evaluate the relationship between heavy metal contamination (Pb) and phenotypic variation, assessed by coefficients of variation (CV) of life-history traits. To investigate the consequences of population origin on variation of life history traits in Drosophila subobscura in response to different laboratory conditions we compared populations from relatively polluted and unpolluted environments. Prior to experiment, flies from natural populations were reared for two generations in standard Drosophila laboratory conditions. Afterwards, all flies were cultured on three different media: one medium without lead as the control, and the other two with different concentrations of lead. Coefficients of variation (CV) of lifehistory traits (fecundity, egg-to-adult viability and developmental time) were analyzed on flies sampled in generations F2, F5 and F8 from these three groups. In later generations samples from both polluted and unpolluted environments showed the increased fecundity variation on media with lead. This increase is expressed more in population from unpolluted environment. On contrary, population from unpolluted environment had increased variation of developmental time in earlier, F2 generation, compared to the population from polluted environment. Our results showed that the response to heavy metal contamination depends on the evolutionary history of the populations regarding habitat pollution.Ministry of Education, Science and Technological Development, Republic of Serbia {[}173012

The impact of extremely low frequency electromagnetic field (50 hz, 0.25 mt) on fitness components and wing traits of Drosophila subobscura

Over the past century, man-made electromagnetic fields (EMF) have changed the natural environment, representing one of the most common and rapidly increasing environmental factors as technology advances. Numerous studies of biological effects of exposure to EMF have been performed on Drosophila during the last 30 years, showing contrasting results. In an attempt to determine whether EMF exposures might affect the development of Drosophila, the present study examines phenotypic variations through direction and range of changes in several fitness components and wing length and width, of Drosophila subobscura isofemale lines, affected by 50 Hz EMF. Embryonal and early post-embryonal stages were exposed to homogeneous sinusoidal 0.25 mT EMF of 50 Hz. The EMF exposure caused a significantly prolonged developmental time and significantly increased the wing size with the opposite direction of directional asymmetry compared to the control group. These results shows that even such a weak EMF has the potential to modulate, through developmental pathways, some of the fitness-related traits, wing size, and wing asymmetry in D. subobscura even after one generation of exposure, showing that extremely low frequency (ELF) EMFs have relevant consequences on development, adult morphology, and fitness.Ministry of Education, Science and Technological Development, Republic of Serbia {[}173012

The impact of extremely low frequency electromagnetic field (50Hz, 0.25 mT) on fitness components and wing traits of Drosophila subobscura

Over the past century, man-made electromagnetic fields (EMF) have changed the natural environment, representing one of the most common and rapidly increasing environmental factors as technology advances. Numerous studies of biological effects of exposure to EMF have been performed on Drosophila during the last 30 years, showing contrasting results. In an attempt to determine whether EMF exposures might affect the development of Drosophila, the present study examines phenotypic variations through direction and range of changes in several fitness components and wing length and width, of Drosophila subobscura isofemale lines, affected by 50 Hz EMF. Embryonal and early post-embryonal stages were exposed to homogeneous sinusoidal 0.25 mT EMF of 50 Hz. The EMF exposure caused a significantly prolonged developmental time and significantly increased the wing size with the opposite direction of directional asymmetry compared to the control group. These results shows that even such a weak EMF has the potential to modulate, through developmental pathways, some of the fitness-related traits, wing size, and wing asymmetry in D. subobscura even after one generation of exposure, showing that extremely low frequency (ELF) EMFs have relevant consequences on development, adult morphology, and fitness. [Projekat Ministarstva nauke Republike Srbije, br. 173012