‘Bistability’ experiments and the photoperiodic clock in the spider mite <i>Tetranychus urticae</i>

Nunes, Marlies Vaz; Veerman, A.

doi:10.1046/j.1570-7458.1997.00215.x

Cited by 7 publications

(2 citation statements)

References 10 publications

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“…In this way, it was shown that the spider mite's clock resembles an hourglass, and the observed positive results of NandaHamner and Bünsow experiments were assumed to be due to the resonance effect of the circadian system on the counter (Model 3). The negative results of bistability experiments agreed with this model (Vaz Nunes and Veerman, 1997).…”

Section: Experimental Tests Of Clock Models and Their Use In Guiding supporting

confidence: 81%

Photoperiodic Time Measurement in Insects: A Review of Clock Models

Nunes¹,

Saunders²

1999

J Biol Rhythms

119

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Based on analyses of responses of insects and mites to a wide range of diel and nondiel experimental light-dark schedules, a variety of models have been developed for the photoperiodic clocks in these species by nearly as many investigators. According to some of these models, the photoperiodic clock is based on a mechanism separate from the circadian system, that is, a so-called "hourglass." According to other models, the clock is based on one or more circadian oscillators that may be coupled to each other and that may or may not show a certain degree of damping. In this context, a rapidly damping oscillator could be regarded as an hourglass. The present article gives an overview of the many different clock models and their philosophies, and it makes comparisons among them to provide a better understanding about how these models are related, if at all, and why the double circadian oscillator model is the most favored model at present.

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Section: Experimental Tests Of Clock Models and Their Use In Guiding supporting

confidence: 81%

Photoperiodic Time Measurement in Insects: A Review of Clock Models

Nunes¹,

Saunders²

1999

J Biol Rhythms

119

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“…T‐experiments and symmetrical skeleton photoperiods in the ‘zone of bistability’ (see above) have failed to provide evidence, in T. urticae , for a circadian involvement in photoperiodism (Vaz Nunes & Veerman, 1997). However, this may have been due to the relatively weak (short) 1‐h pulses of light used in these experiments.…”

Section: Damping Circadian Oscillator(s) As Photoperiodic Clocksmentioning

confidence: 99%

Photoperiodic induction of diapause: opening the black box

Saunders

Lewis²,

Warman

2004

Physiological Entomology

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Abstract. Over several decades, formal experiments measuring diapause responses to variable light inputs have indicated that photoperiodic time measurement in insects is accomplished either by a nonoscillatory 'hourglass-like' mechanism or by oscillatory components of the circadian system. Although both are possible given the present state of our knowledge, a substantial body of evidence strongly suggests that night-length measurement is a function of the circadian system, and that 'hourglass-like' clocks are manifestations of damping circadian components. The two types of time measurement, 'hourglass' and circadian, are therefore parts of a spectrum of mechanisms differing in their damping coefficients. If this view is correct, it may follow that genes and proteins involved in circadian timing are also involved in photoperiodism, although additional genes, or known 'clock' genes used in novel ways, may also play a part. This review outlines the experimental evidence for the oscillator clock theory of photoperiodism and suggests ways in which further progress may be made.

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References A man will turn over half a library to make one book. Samuel Johnson

2002

Insect Clocks

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‘Bistability’ experiments and the photoperiodic clock in the spider mite Tetranychus urticae

Abstract: Link to publication Citation for published version (APA):Vaz Nunes, M., & Veerman, A. (1997). "Bistability" experiments and the photoperiodic clock in the spider mite tetranychus urticae. Entomologia Experimentalis et Applicata, 84,[195][196][197]

Cited by 7 publications

References 10 publications

Photoperiodic Time Measurement in Insects: A Review of Clock Models

Photoperiodic Time Measurement in Insects: A Review of Clock Models

Photoperiodic induction of diapause: opening the black box

References A man will turn over half a library to make one book. Samuel Johnson

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