Altitudinal and Seasonal Variation inDrosophilaSpecies on Mount Japfu of Nagaland, a Sub-Himalayan Hilly State of India

Abstract

Drosophila (L.) (Diptera: Drosophilidae) has richly contributed to the understanding of patterns of inheritance, variation, speciation, and evolution. Drosophila, with its cosmopolitan nature and complexities in species compositions, is an excellent model for studying the eco-distributional patterns of various species. This study analyzed the altitudinal and seasonal variation in Drosophila species of Mount Japfu in Nagaland, a sub-Himalayan hilly state of northeast India, over the course of one year. A total of 4,680 Drosophila flies belonging to 19 species of 4 subgenera were collected at altitudes of 1500, 1800, 2100, 2400, and 2700 m a.s.l. The subgenus Sophophora Sturtevant was predominant, with 10 species, followed by subgenus Drosophila, with 4 species. Subgenus Dorsilopha and subgenus Scaptodrosophila were represented by 1 species each. The remaining 3 species were not identified. Cluster analysis and constancy methods were used to analyze the species occurrence qualitatively. Altitudinal changes in the population densities and relative abundances of the different species at different seasons were also studied. The diversity of the Drosophila community was assessed by applying Simpson's diversity index. At 1800 m a.s.l., the Simpson's index was low (0.09301), suggesting high Drosophila diversity at this altitude. The density of Drosophila changed significantly during different seasons (F = 26.72; df = 2; p < 0.0001). The results suggest the distributional pattern of a species or related group of species was uneven in space and time.

The abundance and diversity of fruit flies and their parasitoids change with elevation in guava orchards in a tropical Andean forest of Peru, independent of seasonality

“…Although seasonal fluctuations in tropical regions are not as drastic as in other latitudes, climatic changes due to seasonality can also affect insect abundance and diversity in the tropics [ 7 ], particularly because of seasonal differences in precipitation [ 11 , 13 ]. For example, Achumi et al [ 11 ] showed a positive correlation of Drosophila fly population density with rainfall. Still, this is not true for all dipterans because several species of flies respond differently to seasonal variation [ 1 ].…”

“…Environmental conditions associated with higher elevation are known to influence insect communities [1]. For example, it is widely accepted that there is a decrease in the abundance and diversity of many insect groups at higher elevations, including beetles (Coleoptera) [2][3][4][5], moths and butterflies (Lepidoptera) [6][7][8], wasps (Hymenoptera) [9,10], and flies (Diptera) [1,11,12]. In addition, insect communities change according to season.…”

Impact of Wild Yeast Added to Culture Media on Drosophila Abundance in and Around a Banana Market, Daranggiri, Assam, India

“…However, the Drosophila diversity is least influenced simply by species richness. (Torres andMadi-Ravazzi 2006 andAchumi et al, 2013). The dominance recorded for the total taxa of six at 0.3464 in the monsoon.…”

Population assemblage of the small fruit flies (Diptera, Drosophilidae) in the North Western Ghats of Karnataka (India) with special report on the dominant species

“…In this region, researchers have extensively studied the effect of several factors such as precipitation, temperature, humidity, habitat, habitat loss, and global warming, with pioneering survey by Dobzhansky and Pavan (1950) from Brazil and subsequent studies by other researchers such as Benado & Brncic (1994) in forests of Chile, other localities of Brazilian forests (De Toni & Hofmann, 1995;Martins, 2001;Tidon, 2006;Torres & Madi-Ravazzi, 2006;Mata et al, 2008;Gottschalk et al, 2008;Schmitz et al, 2007Schmitz et al, , 2010De Toni et al, 2007;Bizzo et al, 2010;Poppe et al, 2012Poppe et al, , 2014Penariol & Madi-Ravazzi, 2013;Garcia et al, 2014;Cavasini et al, 2014;Monteiro et al, 2016;Oliveira et al, 2016;Coutinho-Silva et al, 2017;Duarte et al, 2018). Population assemblage of Drosophilidae from India are poorly understood (Hegde et al, 2001), except few studies (Guruprasad et al, 2010;Achumi et al, 2013;Srinath & Shivanna, 2014b). All these studies have analysed drosophilid population with respect to variations in temperature, rainfall, seasons, and altitude.…”