Abstract: Genetic variation is the fuel of evolution, with standing genetic variation especially important for short-term evolution and local adaptation. To date, studies of spatiotemporal patterns of genetic variation in natural populations have been challenging, as comprehensive sampling is logistically difficult, and sequencing of entire populations costly. Here, we address these issues using a collaborative approach, sequencing 48 pooled population samples from 32 locations, and perform the first continent-wide genomic analysis of genetic variation in European Drosophila melanogaster. Our analyses uncover longitudinal population structure, provide evidence for continent-wide selective sweeps, identify candidate genes for local climate adaptation, and document clines in chromosomal inversion and transposable element frequencies. We also characterize variation among populations in the composition of the fly microbiome, and identify five new DNA viruses in our samples.
Keywords: Population genomics, adaptation, demography, selection, clines, SNPs, structural variants

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Abstract: Lipocalin genes NLaz, GLaz, and Karl are evolutionarily conserved genes in Drosophila melanogaster. There are studies on lipocalin gene expression differences under diverse diet conditions, but these studies have focused mainly on age-dependent expression profiles of these genes. The main aim of our study is to determine lipocalin expression in the developmental period by nutritional manipulation with an isofemale-based design. Three larval developmental periods have been researched under normal and restricted diets. We found significant differences between lines during their developmental time-related lipocalin expression. Here, we demonstrate that upregulations in the early developmental stages of lipocalin genes under stressful conditions resulted in unaffected developmental time. The possible reason for high expression is the activation of stress signal pathways in order to buffer the harmful effects of nutritional restriction. Our data showed that the early developmental period (48-72 h) is especially crucial to tolerate the dietary stress with respect to GLaz and NLaz expression. Results of this experiment have shown that the expression profiles of lipocalin genes have line-specific pathways to nutritional stress. Their expression depends on the genetic background corresponding to development time results. Our results highlight the transcriptional changes of lipocalins associated with developmental time in larvae, developed in a dietary-restricted medium.
Keywords: Dietary stress, lipocalin gene family, ApoD, developmental time, Drosophila melanogaster. 
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Abstract: Studies of altitudinal changes in phenotype and genotype can complement studies of latitudinal patterns and provide evidence of natural selection in response to climatic factors. In Drosophila melanogaster, latitudinal variation in phenotype and genotype has been well studied, but altitudinal patterns have rarely been investigated. We studied populations from six different altitudes varying between 35m and 2173m in the Firtina Valley in northeastern part of Turkey to evaluate clinal trends in lifespan under experimental conditions. Lifespan in the D. melanogaster populations was examined in relation to altitude, sex, temperature (25°C and 29°C), and dietary yeast concentration (5g/L and 25g/L). As expected high temperature decrease lifespan in all populations. However, it was shown that lifespan was slightly affected by dietary stress. We found that lifespan decreases significantly under thermal stress conditions with increasing altitude. Moreover, there was a slightly negative relationship between altitude and lifespan, which was closely associated with climatic factors such as temperature and precipitation, may suggest local adaptation to climate.

Keywords: Altitudinal gradient; Clinal variation; Food stress; Lifespan; Local adaptation; Temperature stress
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Abstract: Drosophila suzukii  (Matsumura, 1931) (Diptera: Drosophilidae) is native to East Asia and invasive on the European and American continents. The first records in both Europe and the United States were in 2008. Since that year, it has widely moved across these continents. As D. suzukii females lay eggs in healthy ripening fruits of several species, particularly in small soft fruits and berries, the species causes agricultural damage. The soft thin-skinned fruit pest, identified as D. suzukii, has been found in Erzurum, Turkey, where damaged strawberry crops were observed and cultured in the middle of August and September 2014. Initially, 2 adults, 3 pupae, and several larvae were observed. Emergence of male and female adults continued for 10 more days. Here we report the first finding of D. suzukii in Turkey.
Keywords: Spotted-wing drosophila, Anatolia, invasive species, small-fruit crop pest.
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Abstract: Environmental stress effects on life history traits have been shown by many studies up to the present. Organisms are frequently affected by nutritional stress in nature. Nutritional restriction has been used as an artificial environmental stress by scientists since 1935. As a result of such studies, it is known that nutritional intake during developmental stages can affect many life history traits as a response to environmental stress in Drosophila melanogaster. In this study, we used 15 different diet regimes with variable yeast and sugar concentrations to test the effects of dietary changes on viability, developmental time, and wing size. Our data showed no specific relationship between yeast-sugar concentrations and larva-to-pupa or larva-to-adult viability. However, over 90% of all larvae that achieved the pupal stage could develop to the adult stage. As expected, the developmental time was moderately affected with respect to yeast-sugar concentrations and their interactions. In addition, the developmental time was extended with decreases in yeast and sugar concentrations. When calculating the pupation and larval times, we came up with the result that longer larval developmental time was buffered under restricted conditions by a shorter pupation period. In other words, dietary stress extended the larval development period and shortened the pupation period to make up for the developmental time delay. Our study indicated that sugar-free larval nutrition reduced the common positive effects between nutrition and body size. Measurement of wing lengths presented sex-specific fluctuations with increased sugar concentration, which showed variable interaction with yeast concentration.
Keywords: Larval nutrition, wing size, developmental time, viability, Drosophila melanogaster.
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Abstract: In order to study P element dynamics in natural populations of Drosophila melanogaster, 88 isofemale lines were examined from the Firtina Valley, Turkey. The P-M gonadal dysgenesis characteristics and the molecular patterns of P and KP elements were analyzed. Gonadal dysgenesis tests showed a slight variation both for P activity and P susceptibility, however the results showed a predominant M' phenotype for this region. The P and KP element were also characterized by polymerase chain reaction. The molecular analyses showed that all the populations examined had the entire 1.15 kb KP element. The molecular patterns of KP elements were the same for the populations studied. No clear relationship was found between phenotype and genomic P element composition. The correlations between the level of gonadal dysgenesis percentage (as an index for P activity and P susceptibility) and several geoclimatic factors were tested, and no general effects of altitude, temperature, rainfall, or humidity were found. The theoretical P' strain, which is very rare in natural populations, was also recorded for this region.

Keywords: geoclimatic variables, transposable elements.
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Abstract: We analyzed the P-M gonadal dysgenesis characteristics and the molecular patterns of P and KP elements of 35 populations from distinct locations of Turkey and Cyprus to find out P element dynamics in natural populations of Drosophila melanogaster. The results of Gonadal dysgenesis (GD) tests showed a predominat M′ phenotype for this region. Besides Q populations were also found in less numbers. It was also noticed that there is a strong tendency for the presence of a Q type “buffer zone” in the Western part of Turkey. The variation in GD percentage (as a index for P element activity and susceptibility) observed among the populations did not show any clear relationship with some geoclimatic variables, but a significant correlation was found between longitude, and P element susceptibility. The P and KP element were also characterized by polymerase chain reaction amplification. The molecular analyses showed that all the populations examined have the entire of 1.15 kb KP element. The molecular patterns of KP elements have been found similar between the populations studied.

Keywords: Transposable Element, Buffer Zone, Population, Gonadal Dysgenesis.
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Abstract: Effects of dietary conditions on many life history traits have been studied for a long time with Drosophila. However, many laboratories use different diets and techniques, which make it difficult to compare the results obtained from various studies. For this reason an optimization protocol for dietary restriction (DR) studies seems to be necessary and in fact recently an optimization protocol published by Bass et al. [1]. In our study we compared the standard diet (S) that we use in our laboratory and the proposed diet (P) with the restricted groups of both diets. In our work, differences between two different dietary protocols with respect to egg-to-adult viability and developmental time were investigated. The P diet did not show any significant differences between the groups with respect to developmental time. On the contrary, the S diet showed significant differences in the yeast and yeast + sugar restricted groups when compared with the respective control and sugar restricted groups. 

Keywords: Drosophila melanogaster, Dietary restriction, Developmental time, Viability.
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Abstract: Abstract: We investigated developmental time difference in response to dietary restriction (DR) in two sibling species, Drosophila melanogaster and Drosophila simulans, which were collected at the same time from two different localities in Turkey. Different diets used in this experiment were: standard (C), sugar reduced (DR-S), yeast reduced (DR-Y), and sugar with yeast reduced (DR-SY) diets. When the species developmental times in response to different DR were analyzed, both of the species showed the same pattern. We did not observe significant difference in relation to developmental time between different populations of D. melanogaster whereas two D. simulans populations showed significant developmental time differences. As a major result, egg-to-pupa developmental time was observed to be prolonged-mostly due to yeast restriction. 
Keywords: Larval nutrition, developmental time, Drosophila melanogaster, Drosophila simulans.
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Abstract: In the study presented, we compare the effects of food restriction variation on longevity in Drosophila melanogaster and its sibling species D. simulans in natural populations in a sex based experimental design. Our data show that rate of increase in age specific mortality parameter (b, from the classical logistic equation) and mean longevity are affected differently by the restriction. However, both age specific mortality parameter and the mean longevity are contributed by species, sex and population specific effects at different levels in response to food restriction variation. We conclude that this non-universal phenomena could be expected on the fact that longevity, as a life history trait likely to be influenced by many genes is not independent of various background effects.
Keywords: Drosophila, food restriction, longevity.
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Abstract: The effect of high temperature stress on mating success is investigated in three natural populations of Drosophila melanogaster from different geographical origins. In this experiment, the males of the control group were continuously kept at 25°C while the males of the second and third groups were kept at 36°C and 38.5°C respectively for 1 h before mating to evaluate the male mating success. One group of males exposed to short-term high thermal stress were immediately put into the vials to mate with females, while males of the second group were kept in the vials for a
relaxation period for 1 h before mating. I found that mating success which was measured as the number of offsprings
was higher in the group which was mated immediately after short-term high thermal stress. Also it is seen that the
individuals exposed to 38.5°C were much more successful than the individuals which were kept at 25°C. There is also
some variation between the populations of different origins as a respond to thermal stress. This results show us that
genotype environment interaction is higher for male mating success and the relaxation period after short-term thermal
stress has a negative effect on male mating success.
Keywords: Heat-shock response, Male mating success, Relaxation period, Drosophila melanogaster
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