A population-level analysis of changes in diel rhythms and sleep and their association with negative emotions during the outbreak of COVID-19 in China

Introduction: From December 2019, COVID-19 (novel coronavirus pneumonia) began spreading in China and has significantly affected the industrial economy and peoples’ daily lifestyle. Beginning on January 23, the public was asked to constantly stay at home for quarantine and community containment.Methods: To assess the effects of the changes in diel rhythms and sleep and their association with negative emotions during the COVID-19 outbreak, a questionnaire was administered to 451 responders for analysis between January 20, 2020, and January 31, 2020, in China.Results: We found that 34.6% of the participants reported diel rhythm disturbance. Moreover, 67.2% of the participants presented negative emotions regarding the pandemic situation, including worry, fear, downheartedness, anxiety, depression, and stupefaction; among them, worry was the most prevalent. Gender and age were significant factors for changes in the diel phases and emotions. There was a correlation between diel rhythm alterations and negative emotions. Three factors, i.e., the Spring Festival holiday, quarantines and concern regarding the pandemic situation, were associated with changes in diel rhythms, sleep, and negative emotions during the pandemic period. Holiday jet lag, quarantine (or community containment), and concerns regarding the pandemic situation had significant effects on diel rhythms, sleep and negative emotion in a substantial part of the population. Conclusions: Our findings suggest that diel rhythms and sleep and their association with negative emotions in COVID-19 patients and the normal population need to be considered. Moreover, the adjustment of diel rhythms could help relieve negative effects and improve the global health during the pandemic period.

Diel scent and nectar rhythms of an African orchid in relation to bimodal activity patterns of hawkmoth pollinators

Background and Aims The temporal dimensions of floral adaptation to pollinators are not yet well understood, partly because we lack accurate information on the diel rhythms of flower visitation for many pollinators. We investigated whether diel patterns of pollinator visitation to flowers of the African woodland orchid Bonatea polypodantha are synchronized with rhythms of floral anthesis, scent emission and nectar availability. Methods Direct observations and motion-activated cameras were used to identify pollinators of B. polypodantha and to document their activity periods. The timing of pollinaria removal from flowers, emission of scent and availability of nectar was also measured. Results We found that B. polypodantha is pollinated exclusively by short-tongued hawkmoths. Pollinaria of the orchid are affixed between the labial palps of the moths and brush over the protruding stigmatic arms. The flowers also receive visits by long-tongued hawkmoths, but these act as nectar thieves. Tracking of pollinaria removal from flowers confirmed that pollination occurs only at night. Camera footage revealed a striking crepuscular pattern of foraging by short-tongued hawkmoths with peaks of activity during the twilight periods at dusk and at dawn. In contrast, long-tongued hawkmoths were found to visit flowers throughout the night. Flowers of B. polypodantha exhibit unimodal peaks of anthesis, scent emission (dominated by nitrogenous aromatics) and nectar availability before or around dusk. Conclusions Flowers of B. polypodantha are pollinated exclusively by short-tongued hawkmoths, which show crepuscular foraging activity at dusk and dawn. Floral phenophases of the orchid are closely synchronized with the peak of pollinator activity at dusk.