A resource on latitudinal and altitudinal clines of ecologically relevant phenotypes of the Indian Drosophila (original) (raw)
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Genetical Research, 1998
Natural populations of Drosophila kikkawai were collected in India and Sri Lanka, along a latitudinal transect ranging from 6·8° to 31·8° N latitude. Six morphometrical traits were analysed: wing and thorax length, body weight, ovariole number, and abdominal and sternopleural bristle numbers. Significant clines were observed for the three size-related traits and for ovariole number, corresponding to a regular increase in the mean value with latitude, but not for bristle numbers. Due to the utilization of two types of laboratory food, data were distributed into two separate data sets. A low-nutrient food produced smaller flies on average because of more intense crowding. The two rearing conditions produced significant clines but with significantly different slopes. The wing/thorax ratio, which is inversely related to wing loading, also increased with latitude. The analysis of Indian climatic conditions suggested that winter temperature, decreasing from south to north, could be more e...
Abstract: Drosophilahasbeen a good model system to understand fundamental principles of genetics, biodiversity, evolution and human disease(s). Genus Drosoplila with its vast diversity of species composition (about 2240 species have been described fror.n all bver the world) serves as an excellent tool in order to understand above mentioned principles ofbiology. However status ofmembers ofgenus Drosophila in north eastern part oflndian subcontinent has not been studied comprehensively, particularly of Nagaland, which is a beautiful sub Himalayan hilly state bearing . diverse climatic conditions and rich biodiversity. Herice we are making a pioneering effort to reviewthe status ofmembers ofgenus Drosophila ofNagaland state. Twenty two species including one newly discovered species (Drosophila hegdii) have been reported so far from Nagaland. A check list of Drc,sophila species ofall the districts ofNagaland state has been prepared and presented here. The results'of the eco-geographic distribution of Drosophila reveals that the species of Drosophila are not evenly distributed in nature. The occurrence and distributional pattem can be conelated not only with type of vegetation and climate of Nagaland but also with the colonizing abilities of species concerned. According to the constant, accessory and accidental species indicates several species that coexisted had similar ecological preferences. Prevalence of Sophophora and, Drosophila sub genera in Nagaland populations reaffirms the observation made by Bock and Wheeler (1972) lhat melanogaster and immigrans species group might have originated in South EastAsia and then colonized in other regions. Drosophila fauta ofNagaland state exhibits geographical convergence pattems by exhibiting similarity not only with SouthAsia but also with that of East Asia that can be explained from geographical location of this scenic north eastern state.
Pattern of Distribution of Drosophila Species: A Global Scenario
Drosophila belongs to the order Diptera and family Drosophilidae. In this brief report we have reviewed the Taxodros geographical search page (https://stockcentre.ucsd.edu/info/geography.php) to analyze global distribution of Drosophila species. Worldwide there are about 4000 known species. The maximum numbers of Drosophila species (811) have been reported from the North American Countries. Of those Hawaii topped the list with 335 species and the least number of species (132) has been reported from Mexico. The available record revealed 317 Drosophila species from Asian countries that included 70 species from Indian subcontinent. The Antarctic is the continent from where not a single species of Drosophila has been reported so far. In this brief report we have highlighted the global distribution of Drosophila species with a note on the species that we have collected from Chhattisgarh. The Chhattisgarh is one of the most unexplored regions of the Indian subcontinent.
Genetica, 2000
We analyzed natural populations of Zaprionus indianus in 10 Indian localities along a south-north transect (latitude: 10-31 degrees 3 N). Size traits (body weight, wing length and thorax length) as well as a reproductive trait (ovariole number) followed a pattern of clinal variation, that is, trait value increased with latitude. Wing/thorax ratio, which is inversely related to wing loading, also had a positive, but non-significant correlation with latitude. By contrast, bristle numbers (sternopleural and abdominal) exhibited a non-significant but negative correlation with latitude. Sex dimorphism, estimated as the female/male ratio, was very low in Z. indianus, contrasting with results already published in other species. Genetic variations among populations were also analyzed according to other geographic parameters (altitude and longitude) and to climatic conditions from each locality. A significant effect of altitude was found for size traits. For abdominal bristles, a multiple re...
Meta-analysis of geographical clines in desiccation tolerance of Indian drosophilids
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2013
Tropical fruit flies (Drosophilidae) differ from temperate drosophilids in several ecophysiological traits, such as desiccation tolerance. Moreover, many species show significant differences in desiccation tolerance across geographical populations. Fruit flies from the tropical and subtropical Indian subcontinent show a clinal pattern for desiccation tolerance which is similar for more than a dozen species studied so far, suggesting adaptation to climatic differences. We performed a meta-analysis to investigate which particular climatic patterns modulate desiccation tolerance in natural populations of drosophilids. Latitude of the sampling site explained most of the variability. Seasonal thermal amplitude (fluctuations in temperature expressed as coefficient of variation) was the strongest climatic factor shaping desiccation tolerance of flies, while factors measuring humidity directly were not important. Implications for survival of flies after future climate change are suggested.
Five Indian geographical populations of Drosophila melanogaster were analyzed for their genetic divergence of life history traits. Clinal variations were observed for body weight, ovariole number, and four pre-life history traits (i.e., fecundity, hatchability, viability, and duration of development). Rearing populations at different growth temperatures shows that the variations among wild flies are likely to reflect variations in the environmental conditions under which they developed. The results of cold assay suggest that the northern populations were cold resistant as compared to southern populations. Significant correlations of the mean monthly coefficients of variation of temperature with these fitness related traits can best explain the observed clinal variations under natural selection.
Physiological limits determine susceptibility to environmental changes and can be assessed at the individual, population, or species/lineage levels. Drosophila nepalensis could serve as an indicator species for analyzing range changes under changing climatic conditions. Ectothermic Drosophilids are profoundly affected by thermal selection (i.e., genetic effects) or through induced effects on phenotypes (i.e., plastic effects). Climatic data for the last fifty years involves a significant change in average temperature (T ave) of Western Himalayas, which has affected the distribution and boundaries of various Drosophilids in this region. There is a significant decline in the number of D. nepalensis from lower ranges. D. nepalensis is more abundant under colder and drier montane habitats in the western Himalayas, but the mechanistic basis of such a climatic adaptation is largely unknown. Here we discuss the physiological levels in D. nepalensis and consider implications for determining species susceptibility to climate change. Thus, temperature-specific divergence in waterbalance-related traits in this species is consistent with its adaptations to cold and dry habitats of Western Himalayas. Our results suggest that D. nepalensis from lowland localities seems vulnerable due to acclimation potential in the context of global climate change in the Western Himalaya. Finally, this is the first report on higher desiccation resistance of D. nepalensis due to developmental plasticity of cuticular melanisation when grown at 15°C, which is consistent with its abundance in temperate regions. Abbreviations: 'D', Desiccation resistant strains; I.F., Isofemale; J/mg, Joules/mg; RWL, Rate of water loss.
Evolution, 1998
Desiccation and starvation tolerance were measured along latitudinal transects in three Drosophilid species (Drosophila ananassae, D. melanogaster, and Zaprionus indianusy of the Indian subcontinent. In each case, significant latitudinal clines were observed; desiccation tolerance increased with latitude while starvation tolerance decreased. Such field observations suggest that desiccation and starvation tolerance are fitness related traits that are independently selected in nature and genetically independent. It was, however, difficult to relate these genetic changes with precise climatic variables, except winter temperature. The overall negative correlation between the two traits, which was evidenced in natural populations, contrasts with a positive correlation generally observed in various laboratory selection experiments and that also seems to exist between different species. These observations point to the difficulty of interpreting correlations among fitness-related traits when different evolutionary levels are compared, and also different sets of data, that is, field versus laboratory studies.