Altered light conditions during spring: effects on timing of migration and reproduction in migratory redheaded bunting (Emberiza bruniceps)

Abstract

Photoperiod is the most consistent environmental cue, and therefore, any change in anticipated light environment may affect subsequent response under long days. To test this hypothesis, photosensitive migratory redheaded buntings (Emberiza bruniceps) were exposed to altered photoperiods for 4 weeks [short days (SP, 8L:16D, group 1; control), short days alternated with constant dim light (SP/LL_dim; group 2), constant dim light (LL_dim; group 3) and constant bright light (LL_bright; group 4)] before being transferred to long days (LP; 16L:8D) for 15 weeks. Group differences in long-day-induced responses were observed. The onset of migratory restlessness (Zugunruhe) was earliest in LL_bright but persisted for maximum period in LL_dim group. The LL_dim group attained peak testis size significantly delayed and had more food consumption under long days. The results suggest that the altered photoperiodic exposure during photosensitive stage affects the seasonal phenotypes such as migration and reproduction in migratory buntings.

Keywords:

• photosensitive bunting
• migratory restlessness
• altered photoperiods

Acknowledgements

Financial supports from Department of Science and Technology, New Delhi, through IRHPA Center for Excellence in Biological Rhythm Research grant is gratefully acknowledged. Neha Agarwal is a recipient of UGC Senior Research Fellowship.

Disclosure statement

No potential conflict of interest was reported by the authors.