Metamorphic rate as a function of the light/dark cycle in Rana pipiens larvae

1. The rate of development of Rana pipiens tadpoles in spontaneous and thyroxine (T4)-induced metamorphosis was studied on light/dark (LD) cycles in which the photophase was held constant while the scotophase was progressively extended or vice versa. 2. Metamorphic rate fluctuated in both types of experiments as the LD cycle lengthened. However, the pattern of resonance differed with the length of the photophase. For example, with an 8 hr light phase, development rate slowed and then increased as the cycle was extended from 24 to to 36 hr, whereas with a 12 hr photophase the reverse took place. 3. The findings are compatible with the occurrence of a rhythm of light sensitivity in photoperiodic time measurement in this amphibian. 4. From the viewpoint of hormonal mechanisms, it is suggested that photoperiodic effects on metamorphic rate result from different patterns of melatonin secretion under the various LD cycles, since melatonin can modify the action of T4 in metamorphosis.     

温周期对不同地理种群棉铃虫幼虫发育及蛹滞育的影响

为了探明不同地理种群棉铃虫Helicoverpa armigera (Hiibner)对温周期的反应,本研究系统调查了棉铃虫广东广州种群(23.08°N,113.14°E)、江西水修种群(29.04°N,115.82°E)、山东泰安种群(36.15°N,116.59°E)和辽宁喀佐种群(41.34°N,120.27°E...     

Diurnal locomotion and feeding activities of two rice-ear bugs,Trigonotylus caelestialium and Stenotus rubrovittatus (Hemiptera: Heteroptera: Miridae)

Diurnal locomotion and feeding activities of Trigonotylus caelestialium (Kirkaldy) and Stenotus rubrovittatus (Matsumura) were investigated using a video camera and electrical penetration graph. Diurnal locomotion activity of T. caelestialium was higher in photophase than in scotophase, whereas that of S. rubrovittatus was higher in scotophase than in photophase. No difference was observed in the locomotion activity of T. caelestialium between mated and unmated bugs or between males and females. Locomotion activity of S. rubrovittatus was different between the sexes. The activity of females was higher than that of males. Diurnal rhythms of feeding activity were obscure compared with those of the locomotion activities in both mirids. The feeding behavior of T. caelestialium was significantly more active in the photophase than in the scotophase. In S. rubrovittatus, feeding activity of males was higher in the scotophase than in the photophase, whereas females showed no such difference. It is thought that both species of mirid bugs are active during the daytime and nighttime, although the locomotion and feeding activities of T. caelestialium were high in the photophase, while those of S. rubrovittatus were high in the scotophase.     

Effects of photoperiod and temperature on the termination of diapause in the univoltine seed wasp Eurytoma plotnikovi

Abstract Mummified pistachios containing fully grown diapause larvae of Eurytoma plotnikovi Nikol'skaya (Hym., Eurytomidae) were collected in early August and late September in coastal northern Greece and subjected to various photoperiod and temperature treatments, then maintained at 19 or 26°C and a long-day (LD 16:8 h), a changing, or a short-day (LD 10:14 h) photoperiod until pupation. In larvae of early August (beginning of diapause) subjected for 20 weeks to 19°C under a long, a changing, or a short photophase, followed by 19°C and a long photophase, 50% of the larvae pupated after 24, 18 and 13 weeks respectively. After exposure for 20 or even 12 weeks to a short photophase and low temperatures (10 or 4°C), pupation occurred after only 7–8 weeks and was more synchronous. The ranges of temperature for diapause development and post-diapause morphogenesis overlap. After exposure for 12 weeks to short days and low temperature, larvae of late September pupated much sooner under long days than under short days and sooner at 26° than at 19°C. E.plotnikovi depends on both temperature and photoperiod for diapause development, low temperature having a strong favourable effect on the earlier part and long day on the later part of diapause. In a few larvae of another pistachio seed wasp, Megastigmus pistaciae Walker, after a long enough period of low temperatures, diapause was terminated normally at 26°C and long days, or at 19°C and long or short days.     

The effect of larval photoperiod on pupal colour and diapause in swallowtail butterflies

ABSTRACT.

• 1 There are significant differences in the effects of larval photo-period on diapause and pupal colour among the species Papilio polyxenes Fabr., P.troilus L., Battus philenor (L.) and Eurytides marcellus (Cramer).
• 2 Diapause and pupal colour in P.polyxenes and P.troilus are strongly influenced by larval photoperiod, short photophase eliciting brown diapausing pupae. Photoperiods of 15L:9D permit the expression of the green and brown pupal colour alternatives.
• 3 Pupal colour in B.philenor and E.marcellus is not affected by larval photoperiod, but short photophase induces diapause in these species.
• 4 All species except B.philenor show an association between brown pupal colour and diapause: Emarcellus when reared on long (midsummer) photophase, P.polyxenes and P.troilus when reared on short (autumnal) photophase.
• 5 In P.polyxenes, short photophase can affect pupal colour responses directly, whether the individual enters diapause or not.
• 6 Differences among the species are related to differences in the ecology of their natural pupation sites.

     

Photoperiodism of diapause induction in Thyrassia penangae (Lepidoptera: Zygaenidae)

Thyrassia penangae enters winter diapause as a prepupa in a cocoon. Photoperiodism of diapause induction was systematically investigated in this moth. The photoperiodic response curves under 24-h light-dark cycles showed that this insect is a typical long-day species. The critical daylength was 13 h 30 min at 25 °C, 13 h at 30 °C and 12 h 20 min at 28 °C. Transferring experiments from a short day (LD 12:12) to a long day (LD 15:9) or vice versa indicated that photoperiodic sensitivity mainly occurs during the larval period. In experiments using non-24-h light-dark cycles, when the length of photophase exceeded the critical daylength (13.5 h), was diapause inhibited effectively, even when the length of scotophase exceeded the critical nightlength (10.5 h). Only when a long scotophase was combined with a short photophase, diapause was induced effectively. This result suggests that daylength measurement is more important than nightlength measurement in T. penangae. Night interruption experiments under 24-h light-dark cycles exhibited two points of apparent light sensitivity, but the photosensitive position was highly influenced by temperature and the length of scotophase. Nanda-Hamner experiments failed to reveal the involvement of a circadian system in this photoperiodic time measurement. All light-dark cycles from LD 12:12 to LD 12:72 resulted in a short day response, and all cycles from LD 14:4 to LD 14:72 resulted in a long day response, suggesting that photoperiodic time measurement in this moth is performed by a day-interval timer or an hourglass-like clock.     

环境温度对马尾松毛虫发育与存活的影响

通过模拟马尾松毛虫2、3代发生区内第2代幼虫发生期温度的变化,进行了高温、常温和低温3组变温试验.结果表明,在相同光照条件下,3龄以前的马尾松毛虫幼虫死亡率明显不同.马尾松毛虫幼虫死亡率在长光周处理内低温组为25.55%,常温组为55.13%,高温组为58.23%;在短光周处理内低温组为32.67%,常温组为64.67%,高温组为94.32%,说明高温是影响马尾松毛虫低龄幼虫死亡的主要原因.高温还影响马尾松毛虫幼虫的滞育.在相同短光周条件下,幼虫孵出后20 d,高温组幼虫40%发育为5龄,而低温组和常温组全部滞育;幼虫孵出后48 d,高温组全部结茧,而低温组和常温组仍全部滞育.试验证明,马尾松毛虫在第2代幼虫孵出后20 d内如遇连续高温环境,即使在短光周条件下,幼虫也不会滞育.     

Photoperiodismus bei Aphiden. Gegensätzliche Reaktionsmechanismen bei Pterocomma jacksoni Theob. und Megoura viciae Bckt. (Homoptera,Rhynchota)

Summary Viviparous females of Pterocomma and Megoura were chilled daily for 4 hours at +1° C throughout larval stages. Chilling Pterocomma during photophase turns long day into short day, whereas chilling during scotophase has no effect. On the other hand chilling Megoura during photophase has no effect, whereas chilling during scotophase turns short day into long day. When the neurosecretory cells of the pars intercerebralis were cauterized, females of Pterocomma became permanent oviparaproducer, females of Megoura permanent viviparaproducer.     

Effects of photophase and altitude on oviposition rhythm of the himalayan strains of Drosophila ananassae

The effects of varying photophase and altitude of origin on the phase angle difference (Ψ) of the circadian rhythm of oviposition during entrainment to light-dark (LD) cycles and the aftereffects of such photophases on the period of the free-running rhythm (τ) in constant darkness (DD) were evaluated in two Himalayan strains of Drosophila ananassae, the high-altitude (HA) strain from Badrinath (5,123 m above sea level=ASL) and the low-altitude (LA) strain from Firozpur (179 m ASL). The Ψ (i.e., the hours from lights-on of the LD cycle to oviposition median) of both strains was determined in LD cycles in which the photophase at 100 lux varied from 6 to 18 h/24 h. The HA strain was entrained by all LD cycles except the one with 6 h photophase in which it was weakly rhythmic, but the LA strain was entrained by only three LD cycles with photophases of 10, 12, and 14 h, but photophases of 6, 8, 16, and 18 h rendered it arrhythmic. Lights-off transition of LD cycles was the phase-determining signal for both strains as oviposition medians of the HA strain occurred∼6 h prior to lights-off, while those of the LA strain occurred∼1 h after lights-off. The Ψ of the HA strain increased from∼2 h in 8 h photophase to∼11 h in 18 h photophase, while that of the LA strain increased from∼11 h in 10 h photophase to∼15 h in 14 h photophase. The aftereffects of photophase of the prior entraining LD cycles on τ in DD were determined by transferring flies from LD cycles to DD. The τ of the HA strain increased from∼19 to∼25 h when transferred to DD from LD 8:16 and LD 18:6 cycles, respectively, whereas the τ of the LA strain increased from∼26 to∼28 h when transferred to DD from LD 10:14 and LD 14:10 cycles, respectively. Thus, these results demonstrate that the photophases of entraining LD cycles and the altitude of origin affected several parameters of entrainment and the period of the free-running rhythm of these strains.     

REPRODUCTIVE DIAPAUSE IN TYPHLODROMUS OCCIDENTALIS NESBITT (ACARINA: PHYTOSEIIDAE) FROM SOUTHERN NEW SOUTH WALES

Abstract
Studies on the reproductive diapause of an introduced insecticide-resistant strain of the phytoseiid predator, Typhlodromus occidentalis Nesbitt, from southern New South Wales are reported. Diapause was induced in 43–59% of predators when reared at 16 or 19°C under photophases of 10–12 h. No diapause induction response curve with changing photophase was evident. Diapause in overwintering predators was readily terminated by exposure to warm temperatures and a long photophase. The rapidity of diapause termination increased progressively during winter. The apparent loss of dependency upon reproductive diapause as an overwintering strategy in this strain of T. occidentalis is discussed.     

Uscana lariophaga, West-African egg parasitoid of the cowpea bruchid beetleCallosobruchus maculatus: photoperiod, parasitization and eclosion interactions

The diurnal pattern of parasitization and eclosion of the trichogrammatidUscana lariophaga Steffan, egg parasitoid of the cowpea bruchidCallosobruchus maculatus (Fabricius) was studied for L12:D12 photoperiods. The wasp parasitized eggs throughout each 24-h period with about 70% of the parasitization taking place during the first 12 h regardless whether it was the photophase or the scotophase. More female progeny was produced when the first 12-h period was photophase instead of scotophase. Eclosion of wasps took place over a period of 4 days and occurred during the second half of the scotophase and the first half of the photophase. The number of wasps eclosed during the photophase was similar to that eclosed during the scotophase. Average development time was 8.9 days at 30°C. Male development was completed 6 to 8 h before the females, hence a higher percentage of females emerged in the later eclosion peaks. During scotophases more females eclosed than during photophases. Although the results indicate that the wasp is able to perform under dark storage conditions the effect of permanent low light intensity remains to be studied.     

Spatial and temporal distribution of pheromone biosynthesis-activating neuropeptide in Helicoverpa (Heliothis) armigera using RIA and in vitro bioassay.

A [3H]-PBAN (pheromone biosynthesis-activating neuropeptide) analog was synthesized, and binding of the radioligand to a specific PBAN-antiserum was achieved. The inhibition of binding of the radioligand by unlabeled PBAN, several PBAN analogs, and other competitors was studied and a specific radio-immunoassay was developed. Using this radioimmunoassay we found PBAN-like immunoreactivity in methanol extracts of hemolymph and neural tissues from females. Higher levels of PBAN-like immunoreactivity in extracts of brain-suboesophageal ganglion complexes, corpora cardiaca, thoracic ganglia, and abdominal ganglia were observed during the 4-5th h scotophase when compared to the PBAN-like immunoactivity levels during the 6-11th h photophase. On the other hand, the concentrations of PBAN-like immunoreactivity, in the terminal abdominal ganglion were higher during the photophase relative to minimal levels observed during the scotophase, indicating an accumulation before the onset of pheromone production. These differences in concentrations of PBAN were also reflected in the stimulation of in vitro pheromone glands, whereby significant stimulations were obtained by scotophase and photophase brain extracts, scotophase thoracic ganglia extracts, and photophase terminal abdominal ganglia extracts. No detectable levels of PBAN were found in hemolymph extracts during the sampling periods.     

Thermoperiodic response and effect of photoperiod on thermoperiodic induction of diapause in Colaphellus bowringi

The effects of thermoperiods on diapause induction under continuous darkness (DD), continuous light (LL), and an L12:D12 photoperiod were investigated in the cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae), a short‐day species. Diapause could be induced by thermoperiod under both LL and DD; however, in the range of 24–30 °C, lower incidences of diapause were observed under LL than under DD. The critical cryophase was found to be dependent on the mean temperature of the thermoperiod applied. Although the thermoperiodic response pattern was similar under LL and DD, the incidence of diapause was higher under LL when the duration of the cryophase did not exceed 12 h. In contrast, when the duration of the cryophase was longer than 12 h, the incidence of diapause under LL was lower or equal to that under DD. When a thermoperiod of 24 °C (cryophase) and 28 °C (thermophase) was applied, the incidence of diapause was higher under LL than under DD, regardless of the duration of the cryophase. Thermoperiodic responses under a photoperiod of L12:D12 and under DD further revealed that induction of diapause was strongly influenced by the photophase temperature. Moreover, the incidence of diapause was lower when the thermophase coincided with the photophase than when the cryophase coincided with the photophase.     

高温对环带锦斑蛾幼虫滞育的抑制作用

本文报道了高温（31℃）对环带锦斑蛾幼虫滞育发生的抑制作用。当幼虫暴露于31℃ 时,所有个体都继续发育,与光周期无关。在诱导滞育的光周期条件(L12∶D12)下,光期的高温配合不同的暗期低温（15～28℃）,导致几乎所有个体滞育,但当暗期为5℃时,滞育率反而下降;相反,当光期的低温配合不同持续时间的暗期高温（31℃）时,则几乎所有的个体都继续发育,这说明高温在暗期发挥着重要的作用。在暗期给予不同时间长度（2、4、 6、8、10、12 h）的高温处理,结果表明一个2 h的高温处理就能有效地抑制滞育的发生。在暗期的不同时间给予4 h高温处理,显示了幼虫在暗期开始后的第一个4 h (18:00～22:00 )对高温最敏感,完全抑制了滞育的发生。最后讨论了高温调节滞育机制在该虫生活史上的适应意义。     

Effects of photoperiod and aging on locomotor activity rhythms in the onion fly,Delia antiqua

At photoperiods longer than 8h per 24h, adults of the day-active onion fly Delia antiqua showed a major peak of locomotor activity in the late photophase and also bursts of activity induced by lights-on or lights-off. At shorter photoperiods the activity peaks fused. After transfer from long photoperiods to constant darkness (DD), the rhythm free-ran, but only the major peak persisted. This suggests that only the major peak is controlled by the circadian pacemaker. At long photoperiods, the daily phase of the major peak occurred progressively later with age. As a result, the activity at short photoperiods often shifted from photophase to scotophase in old flies. The free-running period (tau) also changed with age; tau was shorter than 24h until 14-20 days after eclosion and thereafter became longer, but a few individuals repeated changes in tau. The phase delay of locomotor activity with age in D. antiqua would be attributable to the increase in tau.     

A nondiapausing variant of the flesh fly, Sarcophaga bullata, that shows arrhythmic adult eclosion and elevated expression of two circadian clock genes, period and timeless

We describe a variant of the flesh fly, Sarcophaga bullata, which fails to enter pupal diapause in response to short daylength and low temperatures. This fly also has an arrhythmic adult eclosion pattern: rather than eclosing in early photophase, the variant ecloses arrhythmically throughout the photophase and scotophase. The loss of both diapause (photoperiodic response) and the gating of adult eclosion (presumably a circadian response) suggests that the same clock system is involved in these two responses. An examination of the expression patterns of the clock genes period and timeless demonstrates that both genes are present in the nondiapausing variant, but surprisingly, both genes are expressed at higher levels. This abnormality we observe, possibly the consequence of an upstream clock gene malfunction or a malfunction of the autoregulatory loop, results in disruption of a component of the clock system that is apparently needed for both photoperiodism and circadian rhythmicity.     

The role of the main photophase on dark-time measurement used for diapause determination in the Indian meal moth, Plodia interpunctella

Abstract.  The Indian meal moth Plodia interpunctella Hubner (Lepidoptera: Pyralidae) measures night length and enters diapause as a last-instar larva. To examine the role of photophase on dark-time measurement, the main LD 7 : 17 h photoperiod is disrupted by various lengths of darkness at 25 °C. When the light phase is not disrupted, the incidence of diapause is 76%. As the dark pulse disrupting a 7-h photophase becomes longer, the incidence of diapause decreases. To detect the dynamic kinetics of the time-measuring process, the main scotophase of 17 h is scanned by a 2-h light pulse. When the dark pulse in a 7-h photophase is fixed at 1 h after dawn and its duration is varied systematically from 1 to 3 h, or when the end of the dark pulse is fixed at 1 h before dusk, diapause is prevented completely by a 2-h light pulse inserted in the middle of 17-h darkness. These results are compared with those of a single night interruption of a 17-h scotophase with a 2-h light pulse but with an intact 7-h photophase. The disruption of a 7-h photophase by a dark pulse shifts the descending and ascending slopes of the response curve to some extent toward dawn and dusk, respectively, indicating that the dark pulse tends to shorten the critical length of dark time for diapause induction. When the main photophase (7 h) is interrupted by a 1-h dark pulse at 3–4 h after dawn, the 2-h scanning light pulse in the main scotophase (17 h) appears to act effectively as a dusk signal in the early scotophase. However, those in the mid- and late scotophase do not define the critical night length from dusk as sharply as for the critical night length from a 2-h light pulse to dawn. The results indicate the importance of photophase in the dark-time measurement.     

Thermal orientation of Anthonomus pomorum (Coleoptera: Curculionidae) in early spring

Abstract. The selection of habitats with favourable temperature by the apple blossom weevil Anthonomus pomorum (L.) is investigated in a temperature gradient arena with a range of approximately 0–15 °C. Single female and male weevils are tested in the arena 2, 4 and 6 days after termination of diapause, during photophase and during scotophase. During photophase, weevils of both sexes choose the warmest part of the temperature gradient arena, irrespective of the time elapsed after diapause. During scotophase, high temperature is favoured by male weevils, as well as by females 2 and 4 days after diapause. However, 6 days after termination of diapause, females show no thermal preference in the temperature gradient arena during scotophase, indicating that thermal choice of female A. pomorum in the scotophase changes with time after the termination of diapause. The results suggest that both sexes benefit from thermoregulation by habitat choice during photophase when the weevils are flight active and colonize apple trees.     

甜菜夜蛾雌蛾求偶行为及性信息素产生的时间节律(英文)

研究了甜菜夜蛾雌蛾求偶行为和腺体中性信息素滴度时日变化的规律。结果表明 ,雌蛾求偶行为和性信息素滴度均呈明显的昼夜节律 ,且均在暗期的中后期达到高峰。比较而言 ,雌蛾的求偶活动期较短 ,在暗期中期开始 ,暗期结束后很快停止 ;但峰期较长 ,从中后期达到高峰后一直保持到暗期结束。而腺体内 4种性信息素组份从暗期前 0 .5h到下一个光期 4.5h均有产生 ;但峰期很短 ,暗期 6.5h显著增加达到高峰后 ,在 8.5h又迅速回落。日变化研究表明 ,甜菜夜蛾当日龄即可求偶 ,3日龄起进入求偶盛期 ,至 7日龄末有明显减退。 0～ 3日龄雌蛾的平均初始求偶时间逐日显著提前 ,以后则稳定在暗期 5h左右。不同日龄间性信息素滴度的变化较小     

稻飞虱翅型纯系后代个体的翅型分化对光周期变化不敏感

【目的】为了明确光周期和遗传因子在稻飞虱翅型分化中的作用, 研究了3种稻飞虱（褐飞虱Nilaparvata lugens、白背飞虱Sogatella furcifera和灰飞虱Laodelphax striatellus）翅型纯系或近纯系在不同光照时数下的翅型分化比率。【方法】以经过5~45代连续翅型筛选后的褐飞虱、白背飞虱和灰飞虱的长翅型和短翅型纯系或近纯系为材料, 在室内分别测定了其在长光照（16和20 h）、短光照(4~12 h)和正常光照(14 h) 3类光周期条件下饲养后, 雌、雄成虫中长翅和短翅个体出现的比率及存活率。【结果】白背飞虱和灰飞虱的长翅型纯系M♂×M♀或短翅型纯系B♂×B♀在不同光周期下的翅型比率均无显著差异（P>0.05）。褐飞虱短翅型近纯系B♂×B♀的雌虫短翅率和成虫总短翅率在不同光周期下也无显著差异（P>0.05）, 但雄虫短翅率在正常光照14 h和短光照4 h下显著高于长光照20 h下的（P<0.05）。当褐飞虱短翅型达到纯系后, 其后代翅型在6~16 h光照条件下无显著差异。褐飞虱长翅型近纯系M♂×M♀的后代虽有短翅个体出现, 但是雌虫和雄虫的各自短翅率在不同光周期下无显著差异（P>0.05), 仅总体短翅率在12 h光照条件下的显著高于16 h下的（P<0.05）。褐飞虱长、短翅型杂交筛选品系M♂×B♀的雌虫短翅率随光照时数的延长而升高; 灰飞虱杂交筛选品系M♂×B♀的短翅雄虫随光照时数的缩短而增多（P<0.05）, 但当筛选代次达到45代时, 这种趋势不再显著。3种稻飞虱长翅型和短翅型纯系或近纯系若虫的存活率会稍低于长、短翅型杂交后代的存活率, 但长、短翅型品系的存活率在6~16 h光照条件下差异不显著(P>0.05)。【结论】稻飞虱翅型分化对光周期的反应受飞虱本身遗传背景的影响, 翅型纯系后代个体的翅型分化对光周期变化不敏感。