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Most organisms have an endogenous circadian clock with a period length of approximately 24h that enables adaptation, synchronization and anticipation to environmental cycles. The circadian system (circa = about or around, diem = a day) may provide evolutionary benefits when entrained to the 24-h light-dark cycle. The more the internal circadian period (τ) deviates from the external light-dark cycle, the larger the daily phase shifts need to be to synchronize to the environment. In some species, large daily phase shifts reduce survival rate. Here we tested this 'resonance fitness hypothesis' on the diurnal wasp Nasonia vitripennis, which exhibits a large latitudinal cline in free-running period with longer circadian period lengths in the north than in the south. Longevity was measured in northern and southern wasps placed into light-dark cycles (T-cycles) with periods ranging from 20 h to 28 h. Further, locomotor activity was recorded to estimate range and phase angle of entrainment under these various T-cycles. A light pulse induced phase response curve (PRC) was measured in both lines to understand entrainment results. We expected a concave survival curve with highest longevity at T=τ and a reduction in longevity the further τ deviates from T (τ/T<>1). Our results do not support this resonance fitness hypothesis. We did not observe a reduction in longevity when τ deviates from T. Our results may be understood by the strong circadian light resetting mechanism (type 0 PRC) to single light pulses that we measured in Nasonia, resulting in: (1) the broad range of entrainment, (2) the wide natural variation in circadian free-running period, and (3) the lack of reduced survival when τ/T ratio's deviates from 1. Together this indicates that circadian adaption to latitude may lead to changes in circadian period and light response, without negative influences on survival.
This article was published in the following journal.
Name: Journal of insect physiology
Volta Phase Plate (VPP) has become an invaluable tool for cryo-EM structural determination of small protein complexes by increasing image contrast. Currently, the standard protocol of VPP usage period...
Ontogenetic niche shifts are widespread. However, individual differences in size at birth, morphology, sex, and personalities can cause variability in behavior. As such, inherent inter-individual diff...
In this paper, we propose a phase measurement method for interferograms with nonuniform phase shifts. First, we measure the phase shifts between consecutive interferograms. Second, we use these values...
Electron diffraction effect associated with nano-scale periodic modulations observed in a quenched Ti-15 wt%Mo alloy within ω phase forming regime has been investigated in this study by analyzing s...
The Synchrony Respiratory Tracking System (SRTS) component of the CyberKnife Robotic Radiosurgery System (Accuray, Inc., Sunnyvale CA) enables real-time tracking of moving targets by modeling the corr...
The investigators previously shown that a rotating optokinetic stimulus results in shifts of the subjective visual vertical in healthy human subjects. However, the origin of these shifts i...
This study is designed to determine if adding daily weighted braces on the unaffected ankle may benefit to patient who have returned home compare to a placebo intervention (ankle brace wit...
A new psychological trauma treatment method is tested on a population (n 100) of adult women who have been sexually traumatized at one specific time 0-5 years before they enter the study.
The purpose of this study is to test whether shifts in the timing of the biological clock to a later hour (phase delay shifts of the human circadian system) can be produced in response to ...
An individual suffering a stroke or other brain injury may lose function on one side of the body (partial paralysis). As the individual shifts activities to favor the unaffected side, the ...
Involuntary movements of the eye that are divided into two types, jerk and pendular. Jerk nystagmus has a slow phase in one direction followed by a corrective fast phase in the opposite direction, and is usually caused by central or peripheral vestibular dysfunction. Pendular nystagmus features oscillations that are of equal velocity in both directions and this condition is often associated with visual loss early in life. (Adams et al., Principles of Neurology, 6th ed, p272)
Physiological or psychological effects of periods of work which may be fixed or flexible such as flexitime, work shifts, and rotating shifts.
Morphological or behavioral traits influenced by various living conditions that a population encounters especially as it pertains to REPRODUCTION and survival of the population (see POPULATION DYNAMICS) such as age at first reproductive event, number and size of offspring, and lifespan.
Translocation of body fluids from one compartment to another, such as from the vascular to the interstitial compartments. Fluid shifts are associated with profound changes in vascular permeability and WATER-ELECTROLYTE IMBALANCE. The shift can also be from the lower body to the upper body as in conditions of weightlessness.
Electrophoresis in which the direction of the electric field is changed periodically. This technique is similar to other electrophoretic methods normally used to separate double-stranded DNA molecules ranging in size up to tens of thousands of base-pairs. However, by alternating the electric field direction one is able to separate DNA molecules up to several million base-pairs in length.