Effects of Food Availability Cycles on Phase and Period of Activity-rest Rhythm in Drosophila melanogaster

Abstract

Foraging and feeding are indispensable for survival and their timing depends not only on the metabolic state of the animal but also on the availability of food resources in their environment. Since both these aspects are subject to change over time, these behaviors exhibit rhythmicity in occurrence. As the locomotor activity of an organism is related to its disposition to acquire food, and peak feeding in fruit flies has been shown to occur at a particular time of the day, we asked if cyclic food availability can entrain their rhythmic activity. By subjecting flies to cyclic food availability, that is, feeding-starvation (FS) cycles, we provided food cues contrasting to the preferred activity times and observed if this imposed cycling in food availability could entrain the activity-rest rhythm. We found that phase control, which is a property integral to entrainment, was not achieved despite increasing starvation duration of FS cycles (FS 12:12, FS 10:14, and FS 8:16). We also found that flies subjected to T21 and T26 FS cycles were unable to match period of the activity rhythm to short or long T-cycles. Taken together, these results show that external food availability cycles do not entrain the activity-rest rhythm of fruit flies. However, we find that starvation-induced hyperactivity causes masking which results in phase changes. In addition, T-cycle experiments resulted in minor period changes during FS treatment. These findings highlight that food cyclicity by itself may not be a potent zeitgeber but may act in unison with other abiotic factors like light and temperature to help flies time their activity appropriately.

Studying food entrainment: Models, methods, and musings

“…Honey bees (A. mellifera) have been shown to entrain to restricted feeding schedules and exhibit phase differences in expression of cryptochrome2 (cry2) and period (per) with timerestricted foraging (8,9). By contrast, studies in D. melanogaster show that restricted food availability is not able to entrain activity cycles (10,11). Food anticipation has also been welldocumented in fish.…”

Reorganisation of circadian activity and the pacemaker circuit under novel light regimes

“…While the waveform of locomotor activity is considered a reasonably close reflection of the state of the underlying circadian machinery, factors such as startle responses or timing of food availability are also known to influence it [1][2][3]. Thus, it is crucial to understand clock and non-clock factors regulating activity waveform.…”

“…Among all the behavioural rhythms exhibited by metazoans, daily rhythmicity in locomotion has garnered significant interest due to its apparent utility in providing insights into waveform regulation. While the waveform of locomotor activity is considered a reasonably close reflection of the state of the underlying circadian machinery, factors such as startle responses or timing of food availability are also known to influence it [1–3]. Thus, it is crucial to understand clock and non-clock factors regulating activity waveform.…”

Reorganization of circadian activity and the pacemaker circuit under novel light regimes

“…Among all the behavioural rhythms exhibited by metazoans, daily rhythmicity in locomotion has garnered significant interest owing to its apparent utility in providing insights into waveform regulation. While the waveform of locomotor activity is considered a reasonably close reflection of the state of the underlying circadian machinery, factors such as startle responses or timing of food availability are also known to influence it [1][2][3]. Thus, it is crucial to understand clock and non-clock factors regulating activity waveform.…”