Observations on the larvae and pupae of Pieris brassicae (L.) in a laboratory culture

1962 ◽  
Vol 53 (2) ◽  
pp. 417-436 ◽  
Author(s):  
W. A. L. David ◽  
B. O. C. Gardiner
Keyword(s):  
Constant Temperature ◽  
Dark Period ◽  
Continuous Light ◽  
Laboratory Culture ◽  
Pieris Brassicae ◽  
Continuous Darkness ◽  
Average Width ◽  
Larval Stages ◽  
The Hours ◽  
Pass Through

The work described in this paper forms the final part of an investigation into the biology and breeding of Pieris brassicae (L.) in captivity and concerns the larvae and the pupae.The larvae of the Cambridge stock used in this investigation were found to pass through five instars in the course of their development at temperatures between 12·5 and 30°C. At the lower temperature, development was completed in 46·5 days and at the higher temperature in 11 days.The average width of the head capsules in each instar was not affected by the temperature at which the larvae were reared, it showed little variation, and it never overlapped with that of the preceding or ensuing instar and, therefore, provides a certain way of determining the instar of any larva.At 20°C., isolated larvae and larvae kept in crowded cultures completed their development in approximately the same time—19·6 and 18·8 days, respectively.The average consumption of food during the whole larval period was determined in two experiments, in which it was found to be 1·42 and 1·29 g. of fresh leaves per g. of larva per day, respectively.The duration of the pupal period ranged from 7·5 days at 30°C. to about 40 days at 12·5°C.The adults showed a definite diel rhythm of emergence. When kept at a constant temperature, with a photoperiod from 6 a.m. to 10 p.m., nearly all the insects emerged during the dark period and that immediately following it—actually between the hours of 1 a.m. and 9 a.m. If the photoperiod is displaced 12 hours, the emergence is also displaced by the same amount, to correspond with the new dark period. If, instead of keeping the temperature constant, with the photoperiod 6 a.m. to 10 p.m., it is allowed to fluctuate, as it does naturally in June, the emergence is delayed and instead of occurring in darkness and the early hours of the morning as it does at a constant temperature, it takes place mainly during the morning and the afternoon. When insects, which have been reared at a constant temperature and a photoperiod from 6 a.m. to 10 p.m., are allowed to emerge at a constant temperature, in continuous light, there is very little evidence of a diel rhythm of eclosion but if the insects are kept in continuous darkness they show a definite rhythm of emergence. If the pupae are kept in constant light but the temperature is allowed to fluctuate, most of the adults emerge during the warmer period of the cycle.Diapause in the pupa of P. brassicae is mainly determined by the photoperiod and the temperature during the larval stages. At 20°C., larvae reared in continuous darkness do not form diapause pupae; as the daily photoperiod increases, the percentage of diapause pupae formed also increases until, at a photoperiod of 12 hours, only diapause pupae are formed. Beyond this point the percentage of diapause pupae again declines until, with a photoperiod of about 18 hours, only non-diapause pupae are formed. At higher temperatures similar trends are observed but lower percentages of diapause pupae are formed at all photoperiods.In P. brassicae there is no evidence that a short, sharply defined period of a day or two exists in the course of the life of the larvae during which the photoperiod operates to influence diapause.Non-diapause pupae produced from larvae reared in continuous darkness and from larvae reared in long days (over 15 hours' light) appear to contain a growth-promoting hormone capable of causing the emergence of diapause pupae.

The development of Neomenia carinata Tullberg (Mollusca Aplacophora)

1960 ◽  
Vol 153 (951) ◽  
pp. 263-278 ◽  
Keyword(s):  
Nervous Tissue ◽  
Ventral Side ◽  
Laboratory Culture ◽  
Culture Vessel ◽  
Natural Diet ◽  
Larval Stages ◽  
Cerebral Ganglia ◽  
Locomotory Organ ◽  
Pass Through ◽  
Food Reserves

The chance finding of a single adult specimen of the solenogastre Neomenia carinata Tullberg 1875 rendered possible an embryological study of this species. Little is known concerning the ontogeny of the Aplacophora and a number of important questions, such as the fate of the larval test, the nature of the abapical depression visible during gastrulation and the presence or absence of any evidence of metamery, remain to be elucidated. Embryos, larvae and post-larvae were maintained in laboratory culture a t 10 °C. No description can be given of the early cleavage stages since the eggs when found were always well advanced. Each egg is enclosed by a single membrane. Gastrulation begins on the second day, by a process of immigration of the abapical cells; the abapical depression, often called a blastopore, is shown to be of an unusual character and is to be referred to as a pseudo -blastopore. This pseudo-blastopore is merely a relatively shallow depression marking the area at which immigration is occurring. After the completion of gastrulation, the cells lining the pseudo-blastopore are the prospective trunk ectoderm. The endoderm and mesoderm lie within the embryo and have no communication with the exterior. The remaining cells form the larval test, except for an apical quartet which will develop into the larval apical plate and for six small patches of cells which will give rise to much of the definitive nervous system. The apical/abapical axis of the gastrula is coincident with the antero-posterior axis of the adult solenogastre. The embryos leave their egg membranes on the third day and swim by means of the cilia of the larval test. This test becomes organized into a series of tiers of regularly shaped cells. The main tier is the prototroch, on which is developed a strong equatorial band of locomotory cilia. The larvae are not negatively geotactic and swim close to the bottom of a culture vessel. Proliferation of the definitive nervous tissue begins just before hatching, from six areas of larval test ectoderm on the future ventral side. Nervous elements are cut off inwards at the bases of shallow ectodermal depressions; they come to aggregate into cerebral and ventral (pedal) ganglia. By the seventh day the rudiment of the adult trunk is visible, protruding through the pseudo-blastopore. On its tip is the yolk-laden, ciliated, larval telotroch. The remainder of the trunk is 'Unciliated (except for a median longitudinal ventral ciliated band) but bears numerous pointed calcareous spicules. The length of the trunk rudiment increases by repeated division of the ectodermal cells within the pseudo-blastopore. The midgut passes down into the trunk and with it travel mesodermal elements and a pair of bands of nervous tissue which will form the ventral (pedal) cords. Proctodaeal and stomodaeal invaginations place the midgut in communication with the exterior but the larvae do not feed. The ‘ pygidial ’ development of the trunk of Neomenia resembles strongly that process as found in many annelids but it must be noted that no trace of metameric segmentation of this trunk is visible at any stage in the development of Neomenia . At no stage does the trunk bear overlapping dorsal spicules like those described by Pruvot for Nematomenia ; it seems probable on embryological grounds that the solenogastres are more closely allied to the primitive Lamellibranchia than to the Polyplacophora. Metamorphosis is considered to include only those changes occurring from the tenth to the thirteenth days, during which period the larva exchanges a pelagic for a benthic life. The trunk comes to form by far the greater proportion of the late larva and swimming becomes impossible. The larval test cells lose their orderly arrangement, the prototroch ceases to exist as a co-ordinated locomotory organ and the whole larval test becomes enclosed within the blastocoel of the trunk by the anterior extension and fusion of folds of definitive ectoderm. Similarly, the larval telotroch enters the trunk blastocoel posteriorly. From the blastocoel these yolk-laden cells of the larval locomotory and sensory apparatus pass through the midgut wall into the digestive cells; here they are broken down into small clusters of yolk granules which form the main identifiable food reserve of the post-larva. The mouth and anus, which, before metamorphosis, were directed posteriorly, are now directed ventrally; they lie at the anterior and posterior extremities of a median ventral longitudinal ciliated groove, the so-called pedal groove of the post-larva. This groove is at no stage employed as a pedal sole. The sites from which nervous elements were proliferated during larval life are obliterated at metamorphosis. In the post-larva, two new pairs of ectodermal nervous depressions develop. Both give rise to tubular strands of nervous tissue which extend to and fuse with the cerebral ganglia. Lateral (pleural) cords develop as outgrowths from the cerebral ganglia. Post-larval stages lived in the laboratory without food for up to 10 weeks; they were subsisting entirely on their food reserves. The natural diet of the species is unknown. During the ninth week after metamorphosis the atrium appeared, as a capacious invagination around the mouth. No radula, gills, cloaca, heart, coelomoducts or gonads developed before the young stages died; all but the first are known to be present in the adult Neomenia . A bibliography of works dealing with the ontogeny of Aplacophora is given.

scholarly journals DOES CHRYSANTHEMUM DISPLAY AN ENDOGENOUS CIRCADIAN RHYTHM OF STEM ELONGATION?

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1077f-1077
Author(s):  
Jason Tutty ◽  
Peter Hicklenton
Keyword(s):  
Circadian Rhythm ◽  
Constant Temperature ◽  
Dark Period ◽  
Stem Elongation ◽  
Continuous Light ◽  
Linear Displacement ◽  
Dendranthema Grandiflora ◽  
Diurnal Cycles ◽  
Diurnal Patterns ◽  
Endogenous Circadian Rhythm

The rate of internodal extension of chrysanthemum (Dendranthema grandiflora Tzvelev. cv. Envy) under various temperature and photoperiod conditions was studied to determine whether reproducible diurnal patterns of growth existed and whether any such patterns conformed to an endogenous circadian rhythm. Stem growth was monitored continuously by means of linear displacement voltage transducers. At constant temperature and under 11 h light/13 h dark photoperiod, stem elongation followed a clearly defined pattern consisting of a peak in rate immediately after the dark to light transition and then a gradual decline until the start of the dark period. During darkness, elongation rate increased and reached a maximum approximately 8 hours after the light to dark transition. This pattern differed when light period temperature was either above or below dark period temperature, but these patterns were also highly reproducible. When plants were subjected to continuous light at constant temperature, the rhythm of stem elongation initially showed a periodicity of approximately 27 hours. After 2 or 3 diurnal cycles the rhythm was less distinct and the rate became essentially constant. Furthermore, the interruption of a long period of continuous light with a 13 h dark period did not restore the rhythm. These findings do not support the existence of an endogenous circadian rhythm of stem elongation. Diurnally-cued rhythms do, however, exist and can be modified by temperature.

Semidian rhythmicity in the flowering response of Pharbitis nil to changes in temperature

1998 ◽  
Vol 25 (2) ◽  
pp. 183 ◽  
Author(s):  
O.M. Heide ◽  
R.W. King ◽  
L.T Evans
Keyword(s):  
Circadian Rhythm ◽  
Constant Temperature ◽  
Opposite Effect ◽  
Dark Period ◽  
Floral Induction ◽  
Continuous Light ◽  
The Other ◽  
Pharbitis Nil ◽  
Flowering Response ◽  
Short Day

Our earlier experiments on flowering in the short day plant Pharbitis nil involved far- red/dark (FR/D) interruptions of 90 min duration at various times during a continuous light, constant temperature period before a single inductive dark period. They revealed a rhythm with a period of 12 h, hence semidian. We concluded that the phasing of this semidian rhythm determined the length of darkness required for floral induction. This conclusion has since been challenged so we sought other pretreatments which reveal the semidian rhythm. Interruptions at 12°C–17°C for 45–90 min at various times prior to the inductive dark period were as effective as FR/D in eliciting the semidian rhythm, with significant effects on flowering persisting for at least three cycles in constant conditions in continuous light. The rhythmic response to 12°C pretreatments was 3 h out of phase with that to FR/D pretreatments. Flowering responses to the semidian rhythm exposed by 12°C pretreatments were additive to and independent of those to a circadian rhythm. Some evidence was obtained of reversal of the inhibition or promotion of flowering by FR/D or 12°C by exposure immediately afterwards to the other pretreatment at times of their opposite effect. Pretreatments at 12°C, like those with FR/D, either reduced (if promotive) or extended (if inhibitory) the length of the dark period required for floral induction in this short day plant.

‘Paradoxical Driving’ of Walking Activity in Locusts

1978 ◽  
Vol 72 (1) ◽  
pp. 1-16
Author(s):  
J. E. MOORHOUSE ◽  
I.H. M. FOSBROOKE ◽  
J. S. KENNEDY
Keyword(s):  
Walking Speed ◽  
Dark Period ◽  
Locusta Migratoria ◽  
Continuous Light ◽  
Continuous Darkness ◽  
Locusta Migratoria Migratorioides ◽  
Bout Length ◽  
Walking Activity ◽  
After Effect ◽  
Different Time Scales

Gregarious fifth-instar larvae of Locusta migratoria migratorioides were placed singly on a counterbalanced, recording treadmill providing precise measurements of (i) walking bout length, (ii) non-walking bout length, (iii) walking speed and (iv) distance walked, over periods of hours. Under constant conditions in light the walking activity was often interrupted but gradually built up to a high intensity which was then sustained for 1-2 h before finally declining; there were orderly relations between the measured behavioural components. In continuous darkness walking activity was less interrupted but less intense and quickly declined; there were less orderly relations between the components. Under alternating 10 min periods of light and darkness the relations between the behavioural components were again more orderly in the light than the dark. However, walking activity was sharply depressed in these short light periods but was promptly resumed in each subsequent dark period and grew stronger as the light-dark alternation continued. These diverse and at first sight paradoxical results are all consistent with the principle of post-inhibitory rebound (‘antagonistic induction‘). This type of behavioural after-effect, acting on different time scales, is exemplified by the surge of walking observed in the dark on the release of the experimentally applied inhibition of walking by light, as well as by the build-up and sustained walking in continuous light (‘paradoxical driving’).

scholarly journals The Biology and Behaviour of Ptinus Tectus Boie. (Coleoptera, Ptinidae), a Pest of Stored Products

1941 ◽  
Vol 18 (2) ◽  
pp. 182-195
Author(s):  
E. W. BENTLEY ◽  
D. L. GUNN ◽  
D. W. EWER
Keyword(s):  
Low Temperature ◽  
Diurnal Rhythm ◽  
Dark Period ◽  
Continuous Light ◽  
Time Of Day ◽  
Maximum Activity ◽  
Locomotory Activity ◽  
Stored Products ◽  
Fluctuating Temperature ◽  
The Hours

In alternating light and darkness at 25° C., Ptinus tectus shows a diurnal rhythm of locomotory activity with maximum activity occurring in the dark period. The rhythm is continued for a few days in continuous light. In continuous light, no inherent 24 hr. rhythm is apparent, but in subsequent alternating light and darkness, within 1 day, activity becomes practically confined to the dark period. The rhythm can be reversed by reversing the hours of light and darkness and the reversed rhythm is similarly continued in continuous light. In conditions of alternating light and darkness with fluctuating temperature (10-20° C. with low temperature in the dark periods) Ptinus shows greater activity than at 25° C., and maximum activity occurs in the cold, dark period. In constant light and daily fluctuating temperature (17-23° C.), the period of greatest activity occurs when the temperature is falling. After transfer to constant temperature, this period still occurs at the same time of day for a few days.

scholarly journals DOES CHRYSANTHEMUM DISPLAY AN ENDOGENOUS CIRCADIAN RHYTHM OF STEM ELONGATION?

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1077F-1077
Author(s):  
Jason Tutty ◽  
Peter Hicklenton
Keyword(s):  
Circadian Rhythm ◽  
Constant Temperature ◽  
Dark Period ◽  
Stem Elongation ◽  
Continuous Light ◽  
Linear Displacement ◽  
Dendranthema Grandiflora ◽  
Diurnal Cycles ◽  
Diurnal Patterns ◽  
Endogenous Circadian Rhythm

The rate of internodal extension of chrysanthemum (Dendranthema grandiflora Tzvelev. cv. Envy) under various temperature and photoperiod conditions was studied to determine whether reproducible diurnal patterns of growth existed and whether any such patterns conformed to an endogenous circadian rhythm. Stem growth was monitored continuously by means of linear displacement voltage transducers. At constant temperature and under 11 h light/13 h dark photoperiod, stem elongation followed a clearly defined pattern consisting of a peak in rate immediately after the dark to light transition and then a gradual decline until the start of the dark period. During darkness, elongation rate increased and reached a maximum approximately 8 hours after the light to dark transition. This pattern differed when light period temperature was either above or below dark period temperature, but these patterns were also highly reproducible. When plants were subjected to continuous light at constant temperature, the rhythm of stem elongation initially showed a periodicity of approximately 27 hours. After 2 or 3 diurnal cycles the rhythm was less distinct and the rate became essentially constant. Furthermore, the interruption of a long period of continuous light with a 13 h dark period did not restore the rhythm. These findings do not support the existence of an endogenous circadian rhythm of stem elongation. Diurnally-cued rhythms do, however, exist and can be modified by temperature.

Control of nitrogen assimilation in Stichococcus bacillaris by growth conditions

1987 ◽  
Vol 65 (3) ◽  
pp. 432-437 ◽  
Author(s):  
Iftikhar Ahmad ◽  
Johan A. Hellebust
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Continuous Light ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Dark Cycle ◽  
Continuous Darkness ◽  
Cell Carbon ◽  
Stichococcus Bacillaris ◽  
Mixotrophic Conditions

Stichococcus bacillaris Naeg. (Chlorophyceae) grown on a 12 h light: 12 h dark cycle divides synchronously under photoautotrophic conditions and essentially nonsynchronously under mixotrophic conditions. Photoassimilation of carbon under photoautotrophic conditions was followed by a decline in cell carbon content during the dark period, whereas under mixotrophic conditions cell carbon increased throughout the light–dark cycle. The rates of nitrogen assimilation by cultures grown on either nitrate or ammonium declined sharply during the dark, and these declines were most pronounced under photoautotrophic conditions. Photoautotrophic cells synthesized glutamine synthetase and NADPH – glutamate dehydrogenase (GDH) exclusively in the light, whereas in mixotrophic cells about 20% of the total synthesis of these enzymes during one light–dark cycle occurred in the dark. NADH–GDH was synthesized almost continuously over the entire light–dark cycle. In the dark, both under photoautotrophic and mixotrophic conditions, the alga contained more than 50% of glutamine synthetase in an inactive form, which was reactivated in vitro in the presence of mercaptoethanol and in vivo after returning the cultures to the light. The thermal stability of glutamine synthetase activity was less in light-harvested cells than in dark-harvested cells. The inactivation of glutamine synthetase did not occur in cultures growing either heterotrophically in continuous darkness or photoautotrophically in continuous light. This enzyme appears to be under thiol control only in cells grown under alternating light–dark conditions, irrespective of whether this light regime results in synchronous cell division or not.

The Daily Rhythm of Activity of the Cockroach, Blatta Orientalis L

1940 ◽  
Vol 17 (3) ◽  
pp. 267-277 ◽  
Author(s):  
D. L. GUNN
Keyword(s):  
Activity Rhythm ◽  
Continuous Light ◽  
Locomotory Activity ◽  
Continuous Darkness ◽  
Daily Cycle ◽  
Blatta Orientalis ◽  
Physical Stimuli ◽  
Inactive Phase ◽  
Set Up ◽  
Main Activity

1. In an aktograph at 25.5°C., at upwards of 75% relative humidity and with food present, the average locomotory activity of the cockroach per day does not depend on whether there is continuous light for weeks, or continuous darkness, or a daily alternation of light and darkness. 2. When temperature and humidity do not vary during the day and other factors are kept as constant as possible, the cockroach's activity can be largely concentrated into any desired half of the day, simply by suitably adjusting the time of onset of the half-day's darkness. A rhythm can thus be set up, so that the main activity occurs at the same hours each day. 3. This activity rhythm persists for some days in continuous light or continuous darkness, but eventually activity becomes much more evenly spread over the whole day, leaving only a slight residual rhythm which is unrelated to the previous conspicuous one. A new conspicuous rhythm can then be started at once by alternation of light and darkness. 4. There are indications that animal responses to physical stimuli may depend to a considerable extent on whether the animal is in the active or the inactive phase of its daily cycle. A method is suggested for making it possible to study the nocturnal phase during the daytime.

Light-induced suppression of the rat circadian system

1995 ◽  
Vol 268 (5) ◽  
pp. R1111-R1116 ◽  
Author(s):  
P. Depres-Brummer ◽  
F. Levi ◽  
G. Metzger ◽  
Y. Touitou
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Prolonged Exposure ◽  
Light Exposure ◽  
Continuous Light ◽  
Circadian System ◽  
Short Exposure ◽  
Complete Suppression ◽  
Continuous Darkness

In a constant environment, circadian rhythms persist with slightly altered period lengths. Results of studies with continuous light exposure are less clear, because of short exposure durations and single-variable monitoring. This study sought to characterize properties of the oscillator(s) controlling the rat's circadian system by monitoring both body temperature and locomotor activity. We observed that prolonged exposure of male Sprague-Dawley rats to continuous light (LL) systematically induced complete suppression of body temperature and locomotor activity circadian rhythms and their replacement by ultradian rhythms. This was preceded by a transient loss of coupling between both functions. Continuous darkness (DD) restored circadian synchronization of temperature and activity circadian rhythms within 1 wk. The absence of circadian rhythms in LL coincided with a mean sixfold decrease in plasma melatonin and a marked dampening but no abolition of its circadian rhythmicity. Restoration of temperature and activity circadian rhythms in DD was associated with normalization of melatonin rhythm. These results demonstrated a transient internal desynchronization of two simultaneously monitored functions in the rat and suggested the existence of two or more circadian oscillators. Such a hypothesis was further strengthened by the observation of a circadian rhythm in melatonin, despite complete suppression of body temperature and locomotor activity rhythms. This rat model should be useful for investigating the physiology of the circadian timing system as well as to identify agents and schedules having specific pharmacological actions on this system.

Core temperature in the female rat: effect of pinealectomy or altered lighting

1976 ◽  
Vol 231 (2) ◽  
pp. 355-360 ◽  
Author(s):  
F Spencer ◽  
HW Shirer ◽  
JM Yochim
Keyword(s):  
Core Temperature ◽  
Continuous Light ◽  
Mature Female ◽  
Female Rats ◽  
Female Rat ◽  
Light Phase ◽  
Continuous Darkness ◽  
Temperature Rhythm ◽  
Two Component ◽  
Lighting Regimen

Radiotelemetry of core temperature in unrestrained, mature female rats revealed the existence of a 24-h rhythm that was bimodal. The principal peak occurred during the night under control conditions of 14 h light and 10 h darkness, and a less pronounced, secondary peak occurred 3-4 h after the onset of the light phase. Shifts in the phase of the photoperiod or alteration of the proportion of light per day revealed that the temperature rhythm was entrained by light, but that the two component peaks were governed by different aspects of the lighting regimen. Exposure of rats to continuous darkness, continuous light, or to a 20-h photoperiod revealed that the primary rhythm was endogenous, entrained by circadian photoperiods only, whereas the secondary rhythm was exogenous, requiring a circadian light/dark rhythm. A relationship between mean core temperature and ttion pressure, end-systolic L was constant, despite variations in filling and therefore independent of initial L and delta L; moreover, the L to which the ventricle shortened was determined by the course of the systolic force L-relation. Thus, irrespective of loading, delta L occurs within the confines of the contractile state-depdendent isovolumic force-L relation and where the latter is equivalent to the end-systolic force-length relation.

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