Photoperiod modifies circadian resetting responses in sparrows

Binkley, Sue; Mosher, Karen

doi:10.1152/ajpregu.1986.251.6.r1156

Cited by 13 publications

(16 citation statements)

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“…In a detailed analysis of the PRC in both species of the cockroaches we studied, the advance phase shifts were smaller than the phase delay shifts regardless of the length of the circadian period (Table 1). This finding coincides with ones on various animals thus far studied (8,9,16,22,29). Since it is more difficult to adjust to phase advance, lengthening the circadian period provides an alternative way to accelerate synchronization to environmental cycles ( Fig.…”

Section: Discussionsupporting

confidence: 88%

“…The shapes of the photic PRCs reported above are similar to those found for other insects and animals (7,8,16,17,22,23). Since the topological features of PRCs are crucial in determining the entrainability of circadian pacemakers to the daily light-dark cycle (9,10), significant differences in the magnitude of phase shifting between the two species of cockroaches reflect potential differences in their entrainment mechanisms and ability to adjust to various ecological situations.…”

Section: Discussionsupporting

confidence: 69%

“…This sensitivity is best characterized by a phaseresponse curve (PRC), which plots the magnitude and direction of phase shifts induced by a zeitgeber (for example, light pulses) presented at different circadian times in animals housed under constant conditions (9,10,(14)(15)(16). PRCs help explain how the circadian pacemaker adjusts its phase to synchronize animals to its environment.…”

Section: Introductionmentioning

confidence: 99%

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ADJUSTABILITY OF THE CIRCADIAN CLOCK IN THE COCKROACHES: A COMPARATIVE STUDY OF TWO CLOSELY, RELATED SPECIES,BLATTELLA GERMANICAANDBLATTELLA BISIGNATA

Wei

Lee

2001

Chronobiology International

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A single 2h light pulse (250 lux) was given at various times to phase shift the locomotor circadian rhythm of two species of closely related cockroaches, Blattella bisignata and Blatella germanica. The phase-response curve (PRC) of both species showed a similar pattern. Phase delays and advances were induced by light pulse during the early and late subjective night, respectively, while no clear phase shifting was elicited during the subjective day. However, the magnitude of the phase delay (1.89h +/- 0.66h) and advance (0.69h +/- 0.36h) of B. bisignata was significantly larger than that of B. germanica (0.78h +/- 0.38h and 0.35h +/- 0.18h, respectively). This result indicates the superior adjustability of the circadian clock in B. bisignata. The period-response curve (PdRC) was also constructed for both species. Although both species did not show great flexibility in circadian period changes, the phase shifts were significantly correlated with the period changes in the advance zone of B. bisignata (r = 0.72, P < .1). This allowed the circadian clock of B. bisignata to display better entrainability since the phase advance adjustment was significantly more difficult than that of phase delay. The results indicate the overall adjustability of the circadian clock of B. germanica is inferior to that of B. bisignata. The significance of this finding is discussed from an ecological perspective.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

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ADJUSTABILITY OF THE CIRCADIAN CLOCK IN THE COCKROACHES: A COMPARATIVE STUDY OF TWO CLOSELY, RELATED SPECIES,BLATTELLA GERMANICAANDBLATTELLA BISIGNATA

Wei

Lee

2001

Chronobiology International

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“…Ref. 3), yielding an average "advance" of ϩ0.45 h in controls. By plotting and analyzing our data relative to nonpulsed controls, we find significant delays rather than advances for LD animals.…”

Section: Discussionmentioning

confidence: 99%

“…Likewise, the circadian rhythm of light responsiveness in hamsters is altered by SD entrainment so that light induces phase shifts over a longer fraction of the circadian cycle, enhancing the magnitude of both advances and delays (31). In house sparrows, a similar SD-induced increase in phase delay magnitude augments overall photic PRC amplitude (3). Finally, the most definitive indicator of pacemaker function, endogenous period length, can be altered by prior entrainment conditions (32).…”

Section: Discussionmentioning

confidence: 99%

Photoperiod differentially modulates photic and nonphotic phase response curves of hamsters

Evans¹,

Elliott²,

Gorman³

2004

American Journal of Physiology-Regulatory, Integrative and Comp

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Circadian pacemakers respond to light pulses with phase adjustments that allow for daily synchronization to 24-h light-dark cycles. In Syrian hamsters, Mesocricetus auratus, light-induced phase shifts are larger after entrainment to short daylengths (e.g., 10 h light:14 h dark) vs. long daylengths (e.g., 14 h light:10 h dark). The present study assessed whether photoperiodic modulation of phase resetting magnitude extends to nonphotic perturbations of the circadian rhythm and, if so, whether the relationship parallels that of photic responses. Male Syrian hamsters, entrained for 31 days to either short or long daylengths, were transferred to novel wheel running cages for 2 h at times spanning the entire circadian cycle. Phase shifts induced by this stimulus varied with the circadian time of exposure, but the amplitude of the resulting phase response curve was not markedly influenced by photoperiod. Previously reported photoperiodic effects on photic phase resetting were verified under the current paradigm using 15-min light pulses. Photoperiodic modulation of phase resetting magnitude is input specific and may reflect alterations in the transmission of photic stimuli.

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Short‐time exposure to light at night affects incubation patterns and correlates with subsequent body weight in great tits (Parus major)

Strauß,

Bosma,

Visser

et al. 2024

J Exp Zool Pt A

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Artificial light at night (ALAN) widely affects wildlife by blurring light‐dark differences, including transitions such as sunrise and sunset, thereby affecting regulation of diel rhythms. As a result, activity onsets in many wild diurnal songbirds advance under ALAN. From chronobiological studies, it is known that the direction and strength of the response to light depends on when during the night exposure takes place. However, these experiments are mostly done under continuous light conditions, when animals have free‐running rhythms. It remains unclear whether phase‐dependence also holds in entrained, wild songbirds; i.e., does the effect of ALAN on activity patterns differ between exposure in the morning compared to the evening? This information is essential to assess the effects of mitigation measures by limiting ALAN to selected times of the night. We exposed incubating great tits (Parus major) inside the nest‐box to 4 h of dim light, of which 1 h overlapped with dawn before sunrise or dusk after sunset. We found a small advancing effect of morning‐light on activity onset and of evening‐light on offset compared to dark controls but not vice versa. Breeding success and chick condition were unaffected by the light treatments. However, light‐treated females had lower weights 9–18 days after the end of the treatment compared to the controls, independent of whether ALAN occurred in the morning or the evening, indicating possible costs of ALAN. Despite the weak behavioral response, ALAN might have affected the females' circadian clock or physiology resulting in lower body condition.

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Photoperiod modifies circadian resetting responses in sparrows

Cited by 13 publications

References 0 publications

ADJUSTABILITY OF THE CIRCADIAN CLOCK IN THE COCKROACHES: A COMPARATIVE STUDY OF TWO CLOSELY, RELATED SPECIES,BLATTELLA GERMANICAANDBLATTELLA BISIGNATA

ADJUSTABILITY OF THE CIRCADIAN CLOCK IN THE COCKROACHES: A COMPARATIVE STUDY OF TWO CLOSELY, RELATED SPECIES,BLATTELLA GERMANICAANDBLATTELLA BISIGNATA

Photoperiod differentially modulates photic and nonphotic phase response curves of hamsters

Short‐time exposure to light at night affects incubation patterns and correlates with subsequent body weight in great tits (Parus major)

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