Seasonal and Altitudinal Changes in Population Density of 20 Species ofDrosophilain Chamundi Hill

Abstract

A year long study was conducted to analyze the altitudinal and seasonal variation in a population of Drosophila (Diptera: Drosophilidae) on Chamundi hill of Mysore, Karnataka State, India. A total of 16,671 Drosophila flies belonging to 20 species of 4 subgenera were collected at altitudes of 680 m, 780 m, 880 m and 980 m. The subgenus Sophophora was predominant with 14 species and the subgenus Drosilopha was least represented with only a single species. Cluster analysis and constancy methods were used to analyze the species occurrence qualitatively. Altitudinal changes in the population density, and relative abundance of the different species at different seasons were also studied. The diversity of the Drosophila community was assessed by applying the Simpson and Berger-Parker indices. At 680 m the Simpson Index was low at 0.129 and the Berger- Parker index was high at 1.1 at 980 m. Linear regression showed that the Drosophila community was positively correlated with rainfall but not elevation, Furthermore the density of Drosophila changed significantly in different seasons (F = 11.20, df 2, 9; P<0.004). The distributional pattern of a species or related group of species was uneven in space and time. D. malerkotliana and D. nasuta were found at all altitudes and can be considered as dominant species.

The changing biodiversity of Alabama Drosophila: important impacts of seasonal variation, urbanization, and invasive species

“…Several previous studies reported no significant correlation between abundance of Drosophila and seasonal temperature variation (Guruprasad et al., ; Srinath & Shivanna, ; Torres & Madi‐Ravazzi, ). The reason for the difference in our results relative to theirs could be due, in part, to the different approach in statistical analyses.…”

“…The Drosophilidae family consists of about 4,000 species distributed in approximately 65 genera, including Drosophila (Brake & Bächli, ; da Mata, Valadão, & Tidon, ; Srinath & Shivanna, ). Members of Drosophila genus are widely used in genetic, developmental, and molecular biology studies (e.g., Guruprasad, Hegde, & Krishna, ; da Mata et al., ; Strickberger, ). However, relatively little is known about the ecology of Drosophila (da Mata et al., ; Shorrocks, ).…”

“…Members of Drosophila genus are widely used in genetic, developmental, and molecular biology studies (e.g., Guruprasad, Hegde, & Krishna, 2010;da Mata et al, 2015;Strickberger, 1962). However, relatively little is known about the ecology of Drosophila (da Mata et al, 2015;Shorrocks, 1975).…”

“…The influence of seasonal changes on Drosophila abundance and biodiversity has been surveyed mostly in tropical and temperate climatic zones (Dobzhansky & Pavan, 1950;Levitan, 1954;da Mata et al, 2015;Patterson, 1943;Shorrocks, 1975). The abundance of Drosophila species is influenced primarily by precipitation in tropical regions (Dobzhansky & Pavan, 1950;Guruprasad et al, 2010;Srinath & Shivanna, 2014;Torres & Madi-Ravazzi, 2006), while in temperate climate regions, seasonal changes in abundance and biodiversity of Drosophila are better explained by temperature variation (da Mata et al, 2015;Patterson, 1943;Poppe, Valente, & Schmitz, 2013).…”

A survey ofDrosophilaspecies on Santa Catalina Island with an emphasis on the repleta species group (Diptera: Drosophilidae)

“…An informal island-wide insect survey conducted April 2011 produced data that suggests that species distribution on the island is not uniform or ubiquitous despite the prevalence of host cacti on the island. We returned to the island in June and July of 2012 to carry out an in depth island-wide survey of Drosophila species sampling at many sites across the island with a standardized trapping procedure that included noting the location coordinates and elevation of the collection sites, as altitudinal factors are known to play a role in population density (Guruprasad et al, 2010). We also conducted seasonal collections at two select island locations to assay how fly populations change over the course of a year in terms of population density and what species were present in the population (Dobzhansky and Pavan, 1950;Guruprasad et al, 2010;Patterson, 1943;Torres and Madi-Ravazzi, 2006).…”