Latitudinal clines for morphometrical traits in Drosophila kikkawai: a study of natural populations from the Indian subcontinent (original) (raw)
Related papers
Turkish Journal of Entomology, 2018
Literature concerning phenotypic variation among wild-caught drosophilids inhabiting varied ecological habitats is relatively rare. The present study explores pattern of body size traits along altitudinal gradients, and compensation to colder environments and reduced air pressure via adjustment of wing morphology at higher altitudes. Wild adult flies were collected in two extensive surveys during September-October 2014 and April-May 2015. All traits were measured for both the sexes to obtain data on sexual dimorphism. It was found that though these populations differed significantly in their size, as already known, they deviated from the expected reaction norms of size increase along altitudinal gradients as observed in several previous studies. This deviation from normal clinal trend can be attributed to variation in growth rates and development times at different altitudes which has important implications in overall reproductive success. Also, a significant increase in wing area of flies at higher altitude was recorded with dramatically lower wing loadings than flies that developed in comparatively warmer habitats, giving them an aerodynamic advantage at cold temperatures. Thorax width was also analyzed, possibly for the first time in wild-caught flies of Indian populations, revealing sexual dimorphism. The ratio of thorax length to width was greater than one for all species indicating that the thorax is more elongated in females, which may also influence the flight capacity of the sexes.
Scientific data, 2017
The unique geography of the Indian subcontinent has provided diverse natural environments for a variety of organisms. In this region, many ecological indices such as temperature and humidity vary predictably as a function of both latitude and altitude; these environmental parameters significantly affect fundamental dynamics of natural populations. Indian drosophilids are diverse in their geographic distribution and climate tolerance, possibly as a result of climatic adaptation. These associations with environmental parameters are further reflected in a large number of clines that have been reported for various fitness traits along these geographical ranges. This unique amalgamation of environmental variability and genetic diversity make the subcontinent an ecological laboratory for studying evolution in action. We assembled data collected over the last 20 years on the geographical clines for various phenotypic traits in several species of drosophilids and present a web-resource on I...
Journal of Genetics, 2014
In the present study, we tested the hypothesis whether flight-related traits such as wing area, flight-muscle ratio, wing loading and dispersal yield evidence of geographical variation in nine wild-collected as well as laboratory-reared (at 21 • C) latitudinal populations of Drosophila melanogaster from the Indian subcontinent. We observed positive clinal variation in the wingthorax ratio, wing aspect ratio and wing area, along a latitudinal gradient for both the sexes. In contrast, geographical changes in three parameters of flight ability, i.e. flight-muscle ratio, wing loading and dispersal, showed negative correlation with latitude. On the basis of isofemale line variability, we observed positive correlation of wing loading with flight-muscle ratio as well as dispersal behaviour in both the sexes. We also found positive correlation between duration of development and wing area. Interestingly, southern populations of D. melanogaster from warm and humid habitats exhibited higher flight-muscle ratio as well as the higher wing loading than northern populations which occur in cooler and drier climatic conditions. Laboratory tests for dispersal-related walking behaviour showed significantly higher values for southern populations compared with northern populations of D. melanogaster. Multiple regression analysis of geographical changes in flight-muscle ratio, wing loading as well as walking behaviour as a function of average temperature and relative humidity of the origin of populations in wild-collected flies have suggested adaptive changes in flight-related traits in response to steeper gradients of climatic factors in the Indian subcontinent. Finally, adaptive latitudinal variations in flight-related traits in D. melanogaster are consistent with results of other studies from different continents despite differences due to specific climatic conditions in the Indian subcontinent.
Heredity, 2000
Latitudinal variation in thorax and wing size traits was studied in wild-caught flies of the cactophilic Drosophila species, D. aldrichi and D. buzzatii, and their laboratory-reared progeny. The flies originated from five populations in Queensland, Australia, spanning an 800-km transect. The laboratory flies were reared at controlled densities and three temperatures, 20, 25, and 30 degrees C. We measured the same traits for the laboratory-reared flies as for the wild-caught flies, plus developmental time and viability. Latitudinal variation in wild-caught flies of both species followed a similar pattern for all linear size traits, with size generally increasing from north to south, but with flies from one intermediate locality markedly smaller. A drier environment at this locality and weather conditions immediately prior to collection, most likely explain the reduced size. Laboratory-reared D. aldrichi from this locality also were smaller than those from other localities, and had th...
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.
Journal of Entomology and Nematology, 2013
Post monsoon studies were conducted to analyze the altitudinal variation in a population of Drosophila (Diptera: Drosophilidae) in Brahmagiri Wildlife Sanctuary belonging to the Western Ghats of Coorg district, Karnataka State, India. A total of 4636 Drosophila flies belonging to 8 species of 3 subgenera were collected at altitudes of 800, 900 and 1000 m. The subgenus Sophophora was predominant with 5 different species, subgenus Drosophila with 2 different species and the subgenus Scaptodrosophila was least represented with only a single species. The population density varied in the above three altitudes and highest density was found at 800 m, then the density reduced at 900 m (380 flies) and once again the density increased at 1000 m. This shows that Drosophila community is affected by elevation. The diversity of the Drosophila community was also assessed by applying the Simpson and Berger-Parker indices. At 800 m, the Simpson Index was low at 0.37 and the Berger-Parker index was high at 0.47, 900 m. The distributional pattern of a species or related group of species was uneven in space and time. Drosophila kikkawai, Drosophila takahashii, Drosophila immigrans and Drosophila nigra were found in all the three altitudes suggesting that these species are dominant in this region.
Variation in wing length in Eurasian natural populations of Drosophila melanogaster
Heredity, 1994
A study of 16 natural populations of Drosophila melanogaster from Eastern Europe, the Caucasus and Central Asia has revealed a dine in wing length associated with geographical position of the populations. Wing length was shown to be positively correlated with temperature. The coefficient of variation in wing length was significantly different in town and orchard populations. The existence of a dine in wing length in the northern part of the species range and in the region where migration must be substantial suggests strong selection pressure acting in natural populations of D.
Ecography
Support for macroecological rules in insects is mixed, with potential confounding interrelations between patterns rarely studied. We here investigate global patterns in body and wing size, sexual size dimorphism and range size in common fruit flies (Diptera: Drosophilidae) and explore potential interrelations and the predictive power of Allen's, Bergmann's, Rensch's and Rapoport's rules. We found that thorax length (r2 = 0.05) and wing size (r2 = 0.09) increased with latitude, supporting Bergmann's rule. Contrary to patterns often found in endothermic vertebrates, relative wing size increased towards the poles (r2 = 0.12), a pattern against Allen's rule, which we attribute to selection for increased flight capacity in the cold. Sexual size dimorphism decreased with size, evincing Rensch's rule across the family (r2 = 0.14). Yet, this pattern was largely driven by the virilis -repleta radiation and only weakly in other lineages. Finally, range size did not correlate with latitude, although a positive relationship with latitude was present in a subset of the species investigated, providing no convincing evidence for Rapoport's rule. We further found little support for confounding interrelations between body size, wing loading and range size in this taxon. Nevertheless, we demonstrate that studying several traits simultaneously at minimum permits better interpretation in case of multiple, potentially conflicting trends or hypotheses concerning the macroecology of insects. (2018). Interrelations of global macroecological patterns in wing and thorax size, sexual size dimorphism, and range size of the Drosophilidae. Ecography, 41(10):1707-1717.