The effects of thermoperiods on diapause induction in continuous darkness or under a 12: 12h LD photoperiod were investigated in the cabbage beetle, Colaphellus bowringi Baly, a typical short-day species. The diapause response curves both at different constant temperatures and at the thermocycle of format CT x: (24-x) h (16: 28▫C) under continuously dark rearing conditions showed that the incidence of diapause depended mainly on whether or not the mean temperature was≤20▫C or ≥20▫C. If the mean temperature was≤20▫C, all individuals entered diapause; if >20▫C, the incidence of diapause declined gradually with increasing mean temperatures. The thermocycle (CT 12: 12h) with a series of different cryophases (8–22▫C) and thermophases (24–32▫C) under continuous darkness demonstrated a cryophase response threshold temperature of approximately 19▫C and a thermophase response threshold temperature of approximately 31▫C. Thermoperiodic amplitude (temperature difference between cryophase and thermophase) was shown to have a significant influence on diapause induction at the mean temperatures of 22, 23 and 24▫C, but not at ≥25▫C. Thermoperiodic responses under LD 12: 12h clearly showed that the incidence of diapause was influenced strongly by the photophase temperature. The thermoperiod under LD 12: 12h induced a much lower incidence of diapause than the thermoperiod with the same temperature in continuous darkness. The ecological significance of thermoperiodic induction of diapause in this species is discussed.

大猿叶虫Colaphellus bowringi是江西山区十字花科蔬菜上的重要食叶害虫，以成虫在土中越夏和越冬。由于成虫滞育期的差异，该虫的化性显示了明显的种内变异。有些个体隔年繁殖；有些个体是一化性的，仅在春季或秋季繁殖1代；有些个体是二化性的，春季和秋季各繁殖1代；有些个体是多化性的，春季1代，秋季2～3代。因此，大猿叶虫在田间一年可发生4代。在春季，滞育成虫于2月底至4月初陆续出土繁殖；在秋季，滞育成虫于8月中旬至10月初陆续出土繁殖。春季羽化的成虫于4月底至6月上旬陆续入土越夏，秋季羽化的成虫于9月中旬至12月底陆续入土越冬。大猿叶虫一生能交配多次，大多数雌虫的产卵期超过1个月，最长达67天。平均每雌产卵量；春季世代为644粒，秋季世代为963粒，最高达1950粒。各虫态的发育历期：在15～30℃间，卵为13.78～3.14天，幼虫为22.83～6.95天，蛹为12.10～3.18天。发育阈值温度：卵为10.7 ℃，幼虫为8.8 ℃，蛹为9.6 ℃。非滞育成虫的寿命约为1～2个月，滞育成虫的寿命为5～38个月。滞育成虫均入土蛰伏，在土中的蛰伏深度为9～31cm。

The seasonal life cycle of the zygaenid moth, Pseudopidorus fasciata is complicated by two different developmental arrests: a winter diapause as a fourth larval instar and a summer diapause as a prepupa in a cocoon. Both larval diapause induction and termination are under photoperiodic control. Short days induce larval diapause with a critical daylength of 13.5 h and long days terminate diapause with a critical daylength of 14 h. In the present study photoperiodic control of summer diapause was investigated in Pseudopidorus fasciata. Under long photoperiods ranging from LD 14:10 to LD 18:6, only part of the population entered summer diapause, the rest continued to develop. The lowest number of prepupae entered diapause at LD 14:10, followed by LD 16:8 and LD 17:7. The highest incidence of diapause occurred with photoperiods of LD 15:9 and LD 18:6. By transferring the diapausing prepupae induced by various long photoperiods (LD 14:10, LD 15:9, LD 16:8, LD 17:7, LD 18:6) to LD 13:11, 25 1C, the duration of diapause induced by LD 14:10 was significantly shorter than those induced by longer photoperiods. By keeping aestivating prepupae induced by LD 15:9, 28 1C or by natural conditions at short photoperiods (LD 11:13 and LD 13:11) and at a long photoperiod (LD 15:9), the duration of diapause at LD 15:9 was more than twice as long as than those at LD 11:13 and LD 13:11. Moreover, adult emergence was highly dispersed with a high mortality at LD 15:9 but was synchronized with low mortality at LD 11:13 and LD 13:11. When the naturally induced aestivating prepupae were kept under natural conditions, the early aestivating prepupae formed in May exhibited a long duration of diapause (mean 126 days), whereas the later-aestivating prepupae formed in July exhibited a short duration of diapause (mean 69 days). These results indicate that aestivating prepupae require short or shortening photoperiod to terminate their diapause successfully. By transferring naturally induced aestivating prepupae to 25, 28 and 30▫C, the duration of diapause at the high temperature of 30▫C was significantly longer than those at 25 and 28▫C, suggesting that high temperature during summer also plays an important role in the maintenance of summer diapause in Pseudopidorus fasciata. All results reveal that summer diapause can serve as a ‘‘bet hedging’’ against unpredictable risks due to fluctuating environments or as a feedback mechanism to synchronize the period of autumn emergence. © 2006 Published by Elsevier Ltd.

大猿叶虫Colaphellus bowringi Baly是我国十字花科蔬菜上的一种重要害虫，以成虫在土壤中越冬和越夏，滞育发生主要受温度和光周期调节。本文就光周期和温度对滞育后成虫生物学特性的影响进行了研究。结果表明，在25℃下，光周期(L14: D10和L12: D12)对成虫滞育后的存活率、寿命、日平均产卵量、总产卵量均无显著影响。在长光照(L14: D10)下，温度(18℃、22℃和25℃)对滞育后成虫的生物学特性具有明显的影响；随温度的降低，总产卵量呈下降趋势，平均产卵量显著降低，雌虫滞育后寿命显著延长，18℃下少数个体能被诱导再次滞育。

On the southern Iberian Peninsula, the seasonal life history of the large white butterfly, Pieris brassicae, comprises 2 different photoperiodically induced developmental arrests: a hibernation diapause at photophases <11 h and an estivation diapause at photophases >14 h. At intermediate photophases (12 h to 13 h), the butterfly responds with a nondiapause. Combined with the experimental setup to determine photosensitivity in insects, the different photoperiodic responses at long-, intermediate-, and short-night conditions were examined to gain more insight into the time measurement mechanism in P. brassicae. The study reveals evidence for a “double circadian oscillator clock” mechanism that is based on 2 submechanisms, a “short-night determining system” and a separate “long-night determining system.” This conclusion was drawn from the facts that an LD 9:15 long-night induces a hibernation diapause but inhibits an estivation diapause and, conversely, that an LD 16:8 short-night inhibits a hibernation diapause but induces an estivation diapause. This opposite effect of the same photoperiod supports the argument for the existence of 2 independent targets for light-dark cycles, interpreted as 2 antagonistic time measurement systems. The existence and independence of 2 systems was further shown by differences in long-night versus short-night responses regarding photosensitivity, temperature dependence, and heritable factors. The long-night measurement system is most effective in the 5th larval stage, is highly affected by temperature, and is easy to manipulate by selective inbreeding. The short-night measurement system is most effective in the 4th larval stage, is largely temperature compensated, and is not affected by experimental manipulation of the longnight measurement system.