A circadian rhythm influencing foraging behaviour in the saw-toothed grain beetle Oryzaephilus surinamensis

ABSTRACT. Adults of Oryzaephilus surinamensis (L.) (Coleoptera, Silvanidae) placed in an open arena containing a refuge showed a cyclic pattern of activity in light, dark (LD) cycles when food in the form of damaged wheat grains was placed in the arena outside the refuge. Placing food in the refuge reduced cyclic change and lowered the general activity of the beetles. Batches of fifty insects conditioned in LD 9:15 h or 15:9 h at 25°C , 65% r.h., and transferred to continuous darkness (DD) at the end of a photophase, showed a circadian rhythm of foraging activity of periodicity near 24 h. Those transferred to continuous light at the end of a scotophase showed a 6 h delay in the onset of the next peak of activity, but subsequent peaks, although damped, revealed a periodicity near that in DD. The mean number of beetles wandering in the arena ranged from about eight in LD 15:9 h with all food in the refuge to about twenty-one in LD 9:15 h with all food in the arena.     

Convergent evolution of eye ultrastructure and divergent evolution of vision-mediated predatory behaviour in jumping spiders

All jumping spiders have unique, complex eyes with exceptional spatial acuity and some of the most elaborate vision-guided predatory strategies ever documented for any animal of their size. However, it is only recently that phylogenetic techniques have been used to reconstruct the relationships and key evolutionary events within the Salticidae. Here, we used data for 35 species and six genes (4.8 kb) for reconstructing the phylogenetic relationships between Spartaeinae, Lyssomaninae and Salticoida. We document a remarkable case of morphological convergence of eye ultrastructure in two clades with divergent predatory behaviour. We, furthermore, find evidence for a stepwise, gradual evolution of a complex predatory strategy. Divergent predatory behaviour ranges from cursorial hunting to building prey-catching webs and araneophagy with web invasion and aggressive mimicry. Web invasion and aggressive mimicry evolved once from an ancestral spartaeine that was already araneophagic and had no difficulty entering webs due to glue immunity. Web invasion and aggressive mimicry was lost once, in Paracyrba, which has replaced one highly specialized predation strategy with another (hunting mosquitoes). In contrast to the evolution of divergent behaviour, eyes with similarly high spatial acuity and ultrastructural design evolved convergently in the Salticoida and in Portia.     

Lithium Chloride SCN Injection Alters the Orcadian Rhythm of Food Intake

Effect of lithium injections through chronically implanted cannulae into the bilateral suprachiasmatic nuclei (SCN) on the circadian rhythm of food intake was investigated in the rat. It was observed that the circadian rhythm was disrupted by injections of lithium at the beginning of the light as well as the dark phase of the LD cycle. In either case the percentage of the food consumed during the 12-hr light period increased while that during the dark period decreased without any significant change in the total daily intake. Disruptions in the circadian rhythm of food intake failed to show any dose-response relation. Injections of saline into the SCN or lithium into the nearby SCN area did not produce a disruption of the circadian rhythm of food intake.     

Circadian clock and prothoracicotropic hormone secretion in relation to the larval-larval ecdysis rhythm of the saturniid Samia cynthia ricini

Observations on the timing of ecdysis and neck ligation experiments on larvae of Samia cynthia ricini under various light-dark conditions show that an endogenous circadian clock controls the timing of larval ecdysis and prothoracicotropic hormone (PTTH) secretion preceding it. The clock, upon reaching a specific phase point, causes the brain to secrete PTTH provided that the brain has acquired the secretory competence. This time may vary, in relation to a previous ecdysis, according to the light-dark conditions by which the clock phase is specifically determined, but is fixed relative to a subsequent ecdysis. Thus, in the case of the ecdysis to the 5th instar, PTTH is secreted [15+nτ] hr (τ: free-running period, slightly less than 24 hr) after the clock has started when the rhythm is free-running, and in the second and third nights of the 4th instar under a photoperiod of 12 hr light and 12 hr dark. Full secretion of ecdysone occurs 6 hr after PTTH secretion and ecdysis ensues 34 hr thereafter to complete the ultimate sequence of ecdysis.     

A circadian rhythm of locomotor activity in newly emerged Ceratophyllus sciurorum

Abstract Circadian rhythm in newly emerged individuals of the Red Squirrel ( Scuirus vulgaris ) flea C.s. sciurorum was studied in a constant environment, using an insect activity monitor. Trials were run over 7 days using two start times (08.00 and 17.00 hours). The results show that, regardless of start time, the fleas display a 24 h activity rhythm. The presence of a rhythm under constant conditions gives a strong indication that C. s.sciurorum has a self-sustaining clock which is started by disturbance and is most likely to be linked to host activity patterns.     

Light and temperature entrainment of a locomotor rhythm in honeybees

Abstract. The circadian locomotor (walking) rhythms of forager honeybees (Apis mellifera ligustica L.) were entrained to eight different 24 h light-dark cycles. The phases of activity onset, peak activity, and offset were correlated with the lights-off transition, suggesting lights-off as the primary zeitgeber for the rhythm. Further support for this hypothesis was provided by LD 1:23 experiments, in which entrainment occurred when the light pulse was situated at the end, but not at the beginning, of the subjective photophase. Steady-state entrainment of the locomotor rhythm was achieved with square-wave temperature cycles of 10^oC amplitude under constant dark: most of the activity occurred within the early thermophase. Smaller amplitude temperature cycles yielded relative coordination of the rhythm. Interactions of temperature and light-dark cycles resulted in entrainment patterns different from those elicited in response to either cycle alone or those formed by a simple combination of the two separate responses. Furthermore, temperature cycles having amplitudes insufficient for entrainment of the rhythm nevertheless modified the pattern of entrainment to light - dark cycles, suggesting a synergism of light and temperature effects on the underlying circadian clock system.     

Circadian rhythm of the locomotor activity in Drosophila melanogaster and its mutants 'sine oculis' and 'small optic lobes'

ABSTRACT. The locomotor activity patterns of wildtype Drosophila melanogaster and the mutants so (sine oculis) and sol (small optic lobes) were investigated. In all strains the proportions showing circadian rhythmicity, arrhythmicity and more complex patterns which could not be thus classified were similar. The occurrence of abnormal activity patterns is thus not a property of the mutation as previously claimed (Mack & Engelmann, 1981). In flies with a distinct circadian rhythmicity, the period lengths (τ) varied between strains, τ for wildtype Italy and the mutant so was longer than for wildtype Berlin and the mutant sol. As different τ's have been reported by others, τ does not seem to be closely determined for Drosophila melanogaster. Many flies exhibited two rhythms simultaneously, one with τ shorter and one with τ longer than 24 h, apparently implying two-oscillator control of the locomotor activity. The eyeless so mutants were entrained by LD cycles, so the compound eyes are not necessary, and so must possess the relevant photoreceptor(s) elsewhere. This may therefore also be true for the wildtype. Histology of the so adults revealed no correlation between the degree of reduction in the medulla and the occurrence of abnormal activity patterns. Since the only structures common to the medulla of so and sol are known to be large tangential cells, it is concluded that either they are of importance for the rhythmic system, or the oscillator(s) controlling locomotor activity is (are) not located in the medulla.     

Effect of prey density on behaviour and development of the predatory mosquito,Toxorhynchites towadensis

The effect of prey density on feeding behaviour, killing behaviour, and development of the predatory mosquito,Toxorhynchites towadensis, was investigated in the laboratory. The number of prey consumed per larva increased toward an upper asymptote as prey density increased. Prey consumption curves during fourth instar were concave at low prey densities but convex at high prey densities. This phenomenon was not observed during other instars. Killing without consuming any part of prey occurred at prey densities of 20 per container and over. The number of prey killed but not consumed increased linearly with the number of unconsumed prey in the container. Prey acquisition behaviour was not affected by prey densities during the prepupal period. Developmental time from first instar to adult emergence decreased with increasing prey densities, but remained constant at densities of 10 per container and over. Adult size increased with increasing prey densities but there was no effect at prey densities of 20 and over.     

Prominent Orcadian Absorption of Intranasal Salmon Calcitonin (SCT) in Healthy Subjects

In young healthy subjects salmon calcitonin (SCT), intranasally administered, increased in serum as a function of the drug administration time. The serum concentration of a 400 IU SCT dose monitored 10 min after dosing was statistically more significant when inhaled at 0000 than at other, more conventional, administration times (morning or evening). Following dosing at certain times during the day, the serum SCT was less or even questionable with the dose and under the study conditions selected. Dosing without consideration of timing may lead to reduced effect or lack of effect or perhaps ambiguity or controversy regarding the possible circumstance of a “non-absorbent subject”. The circadian frequency appears to be a critical determinant of intranasal SCT absorption suggesting administration time to be an important factor in the cost/benefit ratio without the unpleasant side effects sometimes experienced through parenteral routes.     

A rapid circadian rhythm of carbon-dioxide metabolism in Bryophyllum fedtschenkoi

Leaves of Bryophyllum fedtschenkoi Hamet et Perrier maintained in a stream of normal air and at 15° C exhibit a circadian rhythm of CO₂ uptake in continuous light but not in continuous darkness. The rhythm is unusual in that it persists for at least 10 d, and has a short period of approximately 18 h. The mechanism by which this rhythm is generated is discussed.Abbreviation PEPCase phosphoenolpyruvate carboxylase     

Biological rhythm of saliva ghrelin in humans

Background: We previously reported that ghrelin in saliva, orexigenic hormone that induces NPY release, was produced and released by salivary glands in humans. The purpose of this study was to investigate a possible circadian rhythm in saliva ghrelin concentration in human subjects as a function of time and meal. Saliva samples were collected at three-hour intervals throughout a 24-h period in 12 healthy volunteer males and ten healthy volunteer females who were provided with meals on a fixed schedule, and saliva collections were made within 15 minutes after each meal. Saliva ghrelin levels were measured by using a commercial radioimmunoassay (RIA) kit that uses ¹²⁵I-labeled bioactive ghrelin as a tracer and a rabbit polyclonal antibody raised against full-length octanoylated human ghrelin. Immunohistochemical analysis of salivary glands was also performed. The results of this investigation indicated the following. (1) The saliva ghrelin level was slightly higher in female subjects in comparison with male subjects. (2) Saliva ghrelin levels were elevated before each meal and fell to trough levels after eating. (3) Saliva ghrelin levels showed a circadian rhythm that rose throughout the day to a zenith at 0300, then dropped at 0600 - 0900. (4) Saliva ghrelin also weakly correlated with BMI. (5) Immunohistochemical analysis showed that ghrelin was localized in the striated and excretory ducts of salivary glands of human. The present work is the first report of the circadian rhythm of saliva ghrelin level in human subjects as a function of time and meal. Meal plays an important role in lowering saliva ghrelin concentration in humans. However, present data did not exclude whether the circadian changes in saliva ghrelin expression were regulated by the biological clock or by food intake.     

The individual development of circadian temperature rhythm in infants

Abstract

The aim of this study was to explore the individual development of the circadian rhythm of human body temperature. Dailyperiodicchanges of body temperature were examined longitudinally in four infants from 3 to 18 months of age. At the 3rd month of life, the day‐night rhythm of the body temperature was obscure but at the 6th month it became moreevident. From the 12th month on, the circadian temperature rhythm with phase similar to that of the adult was discerned. However, the amplitude in circadian rhythm was significantly larger in children between 6 and 18 months of age than in the adult. These findings suggest that the adult type of circadian rhythm of human body temperature is established during the first year of life with regard to phase but not to amplitude.     

The ontogeny of predatory mechanisms in the fifteen-spined stickleback, Spinachia spinachia (L.)

Predatory behaviour is similar in juvenile and adult fifteen-spined sticklebacks. Despite achieving velocities up to 20.2 times faster than the prey, juvenile fish do not employ low-energy attacks. This contrasts with adults which adjust predatory behaviour according to prey-type, but may be a result of the unpredictable prey escape response.     

Reference Values for Orcadian Rhythms of 98 Variables in Clinically Healthy Men in the Fifth Decade of Life

Nine clinically healthy men, 41–47 yr of age, served as subjects in a 24-hr study conducted at the Edward Hines Jr Veterans Administration Hospital in the Chicago area in May 1988. Physiologic measurements, and blood and urine samples were collected at 3-hr intervals over a single 24-hr period beginning at 1900. The number of variables measured or calculated (total = 98) included: 6 vital signs (oral temperature, pulse, blood- and intraocular pressures); 16 in whole blood (counts and differentials); 50 in serum (SMAC-24, lipids, hormones, electrophoresis of LDH and proteins); and 26 in urine (solids, proteins, creatinine, catecholamines, melatonin, Cortisol, electrolytes and metals). Data were analyzed for time effect by analysis of variance (ANO VA) and for circadian rhythm by single cosinor. Individual rhythm characteristics for each variable were summarized for the group by population mean cosinor. The vast majority of variables revealed statistically significant within-day changes in values as validated by one-way ANOVA. All vital signs (except for intraocular pressures) and all serum hormones displayed a prominent circadian rhythm for the group, as did most variables in whole blood, while only about half of the variables in urine demonstrated a significant group rhythm. The results obtained are meant to: (a) document the circadian time structure; and (b) serve as reference values for circadian rhythm characteristics (range of change, mesor, amplitude and acrophase) for a defined group of individuals: clinically-healthy adult men in the prime of life.     

Effects of Work and Orcadian Rhythm on Bus Drivers' Oral Temperature

The results described in this paper originate from a research project aiming at the development of a useful measuring instrument which can demonstrate the effect of work and work circumstances on the task performer. Among other physiological (and psychometric) variables, oral temperature data were obtained from eight younger and eight older bus drivers working in various shifts. Measurements were performed in an experimental design under standardized conditions in a mobile laboratory before starting, during some rest intervals, and after finishing work. The same measurements were performed on the bus drivers in a control condition at corresponding times on a day off. The results indicated that only during the working days a temperature pattern could be detected resembling the data found in the literature (low in the morning, a maximum in the late afternoon, then a decline). No clear pattern was discernible on work-free days. On working days the mean oral temperature values were significantly higher at corresponding hours of the day. Upward deviations of the temperature pattern were found before starting work (but also at the beginning of the day off), while lower values were obtained after finishing work (especially in the shifts starting in the morning). These results might be interpreted in terms of interaction between circadian rhythm and activating and de-activating tendencies connected with (structured) daily activities.     

Effects of Work and Orcadian Rhythm on Bus Drivers' Oral Temperature

The results described in this paper originate from a research project aiming at the development of a useful measuring instrument which can demonstrate the effect of work and work circumstances on the task performer. Among other physiological (and psychometric) variables, oral temperature data were obtained from eight younger and eight older bus drivers working in various shifts. Measurements were performed in an experimental design under standardized conditions in a mobile laboratory before starting, during some rest intervals, and after finishing work. The same measurements were performed on the bus drivers in a control condition at corresponding times on a day off. The results indicated that only during the working days a temperature pattern could be detected resembling the data found in the literature (low in the morning, a maximum in the late afternoon, then a decline). No clear pattern was discernible on work-free days. On working days the mean oral temperature values were significantly higher at corresponding hours of the day. Upward deviations of the temperature pattern were found before starting work (but also at the beginning of the day off), while lower values were obtained after finishing work (especially in the shifts starting in the morning). These results might be interpreted in terms of interaction between circadian rhythm and activating and de-activating tendencies connected with (structured) daily activities.     

Reference Values for Orcadian Rhythms of 98 Variables in Clinically Healthy Men in the Fifth Decade of Life

Nine clinically healthy men, 41-47 yr of age, served as subjects in a 24-hr study conducted at the Edward Hines Jr Veterans Administration Hospital in the Chicago area in May 1988. Physiologic measurements, and blood and urine samples were collected at 3-hr intervals over a single 24-hr period beginning at 1900. The number of variables measured or calculated (total = 98) included: 6 vital signs (oral temperature, pulse, blood- and intraocular pressures); 16 in whole blood (counts and differentials); 50 in serum (SMAC-24, lipids, hormones, electrophoresis of LDH and proteins); and 26 in urine (solids, proteins, creatinine, catecholamines, melatonin, Cortisol, electrolytes and metals). Data were analyzed for time effect by analysis of variance (ANO VA) and for circadian rhythm by single cosinor. Individual rhythm characteristics for each variable were summarized for the group by population mean cosinor. The vast majority of variables revealed statistically significant within-day changes in values as validated by one-way ANOVA. All vital signs (except for intraocular pressures) and all serum hormones displayed a prominent circadian rhythm for the group, as did most variables in whole blood, while only about half of the variables in urine demonstrated a significant group rhythm. The results obtained are meant to: (a) document the circadian time structure; and (b) serve as reference values for circadian rhythm characteristics (range of change, mesor, amplitude and acrophase) for a defined group of individuals: clinically-healthy adult men in the prime of life.     

A note on the circadian rhythm and feeding behaviour of sheep fitted with a lightweight GPS collar

The circadian rhythm and feeding behaviour (bite rate) of 16 Scottish Blackface ewes of which eight were fitted with a lightweight (863 g) GPS collar were examined. The collar consisted of a leather harness and a 0.5 l aluminium box and represented 2.2% of the average body mass of the study ewes. No differences in circadian rhythm and bite rate were found between ewes fitted with the collars and ewes that were not. The relevance of using collar weight as a proportion of body mass as a guide to gauge its impact on the feeding behaviour of small ruminant (35–75 kg) herbivores is questioned.     

Calling behaviour in M.convecta females under different temperature and photoperiodic conditions

Abstract. . The effects of temperature and photoperiod on calling behaviour in females of the Australian common armyworm, Mythimna corwecta (Walker) (Lepidoptera: Noctuidae), were studied in the laboratory. Age at first calling was greater at 15 and 20^oC compared with 25^oC, but there were no significant differences between 25 and 30^oC. Females kept at 10^oC did not call, but if transferred at 10 days to 20^oC they called after a period similar to the pre-calling period at constant 20^oC. Onset time of calling was earlier at 15 and 20^oC compared with 25 and 30^oC, but there were no significant differences in calling duration. At 20^oC, age at first calling was increased by shorter day length (12h and 14h, compared with 16h), and there was an interaction between daylength and moth age affecting the duration of calling. Onset times advanced with longer daylength, but peak calling was later in relation to the lengtii of the scotophase. These results are discussed in connection with migration in M.convecta. Evidence for a circadian rhythm of calling was found in females entrained for 3 and 8 days after emergence under reverse-cycle conditions and then transferred to constant darkness. However, after 56 h and 80 h respectively of darkness, calling became de-synchronized. Subsequently, it appeared to re-synchronize to a different clock, which approximately correlated with the normal photoperiods the moths had experienced during larval development.