Loss of functional cryptochrome 1 reduces robustness of 24-hour behavioral rhythms in monarch butterflies

Samantha E Iiams; Guijun Wan; Jiwei Zhang; Aldrin B Lugena; Ying Zhang; Ashley N Hayden; Christine Merlin

doi:10.1016/j.isci.2024.108980

Loss of functional cryptochrome 1 reduces robustness of 24-hour behavioral rhythms in monarch butterflies

iScience. 2024 Jan 20;27(2):108980. doi: 10.1016/j.isci.2024.108980. eCollection 2024 Feb 16.

Authors

Samantha E Iiams^{1

2}, Guijun Wan^{1

3}, Jiwei Zhang¹, Aldrin B Lugena¹, Ying Zhang¹, Ashley N Hayden¹, Christine Merlin^{1

2}

Affiliations

¹ Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843, USA.
² Genetics Interdisciplinary Program, Texas A&M University, College Station, TX 77843, USA.
³ Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.

Abstract

Light is one of the strongest cues for entrainment of circadian clocks. While some insect species rely only on visual input, others like Drosophila melanogaster use both the visual system and the deep-brain blue-light photoreceptor cryptochrome for entraining circadian rhythms. Here, we used the monarch butterfly Danaus plexippus (dp), which possesses a light-sensitive cryptochrome 1 (dpCry1), to test the conservation of mechanisms of clock entrainment. We showed that loss of functional dpCry1 reduced the amplitude and altered the phase of adult eclosion rhythms, and disrupted brain molecular circadian rhythms. Robust rhythms could be restored by entrainment to temperature cycles, indicating a likely functional core circadian clock in dpCry1 mutants. We also showed that rhythmic flight activity was less robust in dpCry1 mutants, and that visual impairment in dpNinaB1 mutants impacted flight suppression at night. Our data suggest that dpCRY1 is a major photoreceptor for light-entrainment of the monarch circadian clock.

Keywords: Entomology; Natural sciences; Neuroscience; Zoology.