Variation in locomotor behaviour of Drosophila bipectinata and Drosophila malerkotliana with altitude

Abstract

The locomotor rhythm is an innate, ubiquitous and complex biological phenomenon. This activity rhythm makes an organism to adapt to daily light cycles and other environmental cues. This is controlled by robust and self-sustained oscillators. Such robust rhythm is altered by many physical factors such as temperature, light/dark cycles etc. Several studies have shown that locomotor activity in different species varies with changes in altitude and latitudes altered the locomotor activity in different species. In the present study, flies were collected from Chamundi Hill, Mysore, at two different altitudes such as 910 m altitude and 740 m altitude. The locomotor activities of these strains were compared to the activity of laboratory population (LP) (640 m). Result revealed that there is a significant variation in the activity of two species. Drosophila bipectinata showed bimodal activity, whereas in Drosophila malerkotliana showed unimodal activity pattern. It is reverse in the 740 m altitude. LPs of D. bipectinata showed a continuous photo-phase activity, whereas in D. malerkotliana exhibit unimodal activity pattern. The periods of all the six populations were closer to 24 h. The statistical analysis revealed that there is significant difference in the locomotor activity rhythm of two species.

Keywords:

• locomotor activity rhythm
• altitude
• D. bipectinata
• D. malerkotliana

Acknowledgement

We are grateful to the UGC-New Delhi for the financial assistance and Chairman, Department of Studies in Zoology for the facility.