Insights into differential activity patterns of Drosophilids under semi-natural conditions

• DOI: 10.1242/jeb.092270
• Publication Date: 2013-10-19T03:56:59Z
• Authors: Priya M. Prabhakaran; Vasu Sheeba
• Keywords: Male; 0301 basic medicine; Sympatry; 03 medical and health sciences; Light; Photoperiod; Animals; Drosophila; Seasons; Environment; Circadian Rhythm

Summary We showed recently that Drosophila ananassae (DA), a closely related and sympatric species of the commonly studied fruitfly D. melanogaster (DM), shows distinctly deviant pattern in circadian activity/rest rhythm from the latter, under a variety of laboratory conditions. To examine whether such differences extend to more natural conditions where a variety of time cues and similar environmental pressures might force different species to adopt similar temporal patterns we examined these two species under semi-natural conditions over a span of 1.5-yrs. Furthermore, we asked to what extent features of activity/rest rhythm of flies are conserved across species under changing environmental conditions encountered across seasons, and to do so, we studied two more Drosophilid species. We found that while each species exhibits seasonality in activity patterns, it is marked by interesting inter-species differences. Similar to laboratory studies DA showed activity mostly during the day, while DM and D. malerkotliana (DK) exhibit almost similar activity patterns across seasons with predominantly two peaks of activity, one in the morning and another in the evening. Throughout the year Z. indianus (ZI) displayed very low levels of activity compared to DM, yet, compared to that seen in standard laboratory assays this species exhibited more robust rhythm under semi-natural conditions. We hypothesise that different ecological factors may have influenced these species to adopt different temporal niches.