飞蝗不同地理种群抗寒性研究

新疆和硕、哈密和天津北大港飞蝗种群的过冷却点随发育阶段而升高,在胚胎发育的各期都具有较低的过冷却点。飞蝗卵的过冷却点在这3个地理种群间无明显差异。雄性蝻和成虫双雌性的过冷却能力强,和硕飞蝗的成虫过冷点比北大港的飞蝗成虫要低。低温胁迫可诱导蝗卵以糖元为朱料合成抗冻保护剂,和硕飞蝗种群的卵主要合成甘油和山梨醇,北大港飞蝗种群的卵主要合成海藻糖,而哈密飞蝗种群的卵却可以合成甘油、山梨醇和海藻糖等抗冻保护剂。糖元磷酸化酶的总量随发育阶段而下降,但热休克和冷休克并不改变其总量,冷休克在胚胎发育的各阶段可以使其活性升高10%-40%,北大港飞蝗种群和哈密飞蝗种群的蝗卵经热休克2h处理后,糖元磷酸化酶的变化与在冷休克下的情况相似,而和硕飞蝗处群胚胎发育的Ⅱ期,热休克诱导糖元磷酸化酶活性的升高程度较低。     

中华稻蝗五地理种群的卵滞育强度及生活史模式变异

为调查中华稻蝗Oxya chinensis的地理适应,自北纬42.3°至20.0°采集了5个地理种群的标本,比较了其子代的卵滞育发生、滞育强度及成虫虫体大小。结果表明: 不同的中华稻蝗地理种群显示了不同的光周期和温度反应模式。铁岭、济宁和泗洪种群的滞育不受光周期和温度的影响,滞育率均为100%。南方的长沙和海口种群仅部分卵进入滞育,海口种群在短日条件下的滞育率高于长日条件,卵期温度亦对其滞育有较大的影响,而长沙种群的卵滞育仅受卵期温度的调控。长沙和海口种群的卵滞育强度最弱,其次是铁岭种群,中间纬度的济宁和泗洪种群的滞育强度最高。在北方的一化性种群中,滞育强度随着纬度的降低而增强。成虫的虫体大小因栖息地纬度的变化而呈现复杂的变异,北方种群的虫体大小与栖息地纬度存在显著的负相关关系,而长沙和海口种群的虫体小于济宁和泗洪种群。结果提示中华稻蝗各种群已形成各自的地理适应机制,纬度梯度在其生活史的形成和发育中起着重要的作用。     

光周期和温度对亚洲玉米螟滞育诱导的影响

亚洲玉米螟Ostrinia furnacalis (Guenée)属兼性滞育昆虫, 其滞育特性与种群利用适生境的最大化和季节性活动密切相关。解析季节性因素如光周期和温度对其滞育的诱导作用可为预测种群发生动态提供科学依据。本实验在HPS 500型和HPG-320H型自动控制环境气候箱中, 测定了RH 80%下温度20℃, 27℃和30℃与11个光周期组合对吉林农安（NA）、 河北衡水（HS）、 广东惠州（HZ）和海南海口（HK）等4个地理种群的滞育诱导作用。结果表明： 光周期、 温度及其交互作用均对亚洲玉米螟滞育诱导具有重要影响, 其中光周期在滞育诱导中起主导作用。在20℃条件下, 其光周期反应曲线属典型的长日照反应型, 临界光周期随种群分布的地理纬度降低而缩短, 4个地理种群NA, HS, HZ和HK的临界日昼长依次为14 h 3 min, 13 h 59 min, 13 h 32 min和13 h 7 min, 最有效的滞育诱导光周期是日昼长12 h。另一方面, 随种群分布纬度升高, 其对光周期诱导滞育的敏感性降低。温度为27℃时, 其光周期反应曲线为短日照 长日照反应型, 各种群有两个临界光周期, 临界日昼长依次为12 h 50 min和13 h 32 min, 11 h 35 min和13 h 8 min, 12 h 58 min和13 h 1 min, 以及11 h 50 min和12 h 26 min, 且最有效的滞育诱导光周期范围的滞育率明显低于20℃。一定温度范围内（20℃～27℃）, 随温度升高, 临界光周期缩短; 温度达到30℃时则滞育显著被抑制, 滞育率仅为4.3%或更低。这些结果说明温度对亚洲玉米螟滞育的光周期诱导具有很强的补偿作用。因此, 在自然界亚洲玉米螟的滞育属具有温度补偿作用的长日照反应型昆虫, 临界光周期随地理纬度北移而增长; 种群滞育的短日照 长日照反应型特性可能是产生局部世代种群的重要内因。     

光周期和温度对大猿叶虫滞育后成虫生物学特性的影响

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。     

光周期和温度对东亚小花蝽滞育形成和解除的影响

东亚小花蝽在北京地区为多化性兼性生殖滞育的捕食性天敌昆虫,在田间9月下旬大部分雌成虫进入滞育状态。短光周期是诱导其滞育形成的主导生态因子,高温具有抑制滞育的作用。若虫期是感受滞育信号的敏感虫态,若虫期连续接受短光照其滞育率明显提高。长光周期是东亚小花蝽解除滞育的主要生态因子,高温可缩短解除滞育所需的时间。     

暗期干扰对棉铃虫两个不同地理种群滞育抑制作用的比较

至今,所测试昆虫的光周期反应均表明,光周期反应对暗期干扰高度敏感,短暂的光脉冲都可在不同程度上逆转长夜效应,抑制滞育的发生。在研究了棉铃虫Helicoverpa armigera泰安种群(36.15°N,116.59°E)和喀佐种群(41.34°N,120.27°E)光周期反应的基础上,在滞育诱导的短光周期下(L12:D12和L9:D15),分别测试了暗期不同时段1h光脉冲对这两个不同地理种群滞育抑制的影响。25和22℃下的光周期反应显示了泰安种群在长暗期11—14 h的滞育率均显著低于喀佐种群;泰安种群的临界暗长分别为11.7 h和11.5 h,喀佐种群分别为10.5 h和10.3 h,泰安种群均比喀佐种群长1.2 h。在所测试的暗期干扰实验中,除了极少数光脉冲干扰点外,泰安种群蛹滞育率显著低于喀佐种群,但两者的滞育反应曲线基本相似。在短光周期L9:D15下,泰安种群和喀佐种群均显示了光脉冲落入暗期的第9—11小时最有效地抑制了滞育的发生。在短光周期L12∶D12下,泰安种群和喀佐种群在25℃时均显示了光脉冲落入暗期的第3—4小时和第10小时导致了最低的滞育发生;但在22℃时,喀佐种群只在暗期的第3—4小时显示了最高的滞育抑制。这些结果揭示了偏南的泰安种群对暗期干扰的敏感性强于偏北的喀佐种群,但这两个地理种群的最高光敏感位点基本相同。     

中华通草蛉自然越冬成虫在两种光周期下滞育解除过程中的生理生化变化

摘要: 光周期在昆虫滞育中起重要作用, 而昆虫光敏感性差异导致了光在昆虫滞育解除过程中作用机制的多样性。为明确光周期在中华通草蛉Chrysoperla sinica (Tjeder)滞育解除过程中的调控机制, 本研究测定了长光周期（15L∶9D）和短光周期（9L∶15D）条件下, 中华通草蛉自然越冬种群成虫在滞育解除过程中的干重、 含水量、 过冷却点（supercooling point, SCP）、 结冰点（freezing point, FP）及蛋白质和糖原含量变化。结果表明： 雌成虫干重在长光照下处理30 d低于短光照下, 其他处理时间的干重均高于短光照下, 但处理间差异不显著（P>0.05）; 雄成虫在长光照下处理5 d的干重高于短光照下, 其余处理时间的干重均低于短光照下, 其中处理30 d 时差异显著（P<0.05）。雌、 雄成虫含水量总体呈上升趋势, 长光照下上升显著（P<0.05）, 短光照下上升不显著（P>0.05）。雌、 雄成虫的SCP、 FP在短光照下处理不同时间均无显著性差异（P>0.05）, 而长光照下表现出先降后升的趋势且处理间差异显著（P<0.05）。成虫蛋白含量在短光照条件下雄虫处理10 d以及雌虫处理15 d均显著低于长光照（P<0.05）, 其他处理之间没有显著性差异。短光照处理成虫体内糖原含量均高于长光照, 且有显著性差异（P<0.05）。多因素方差分析表明, 不同光周期对中华通草蛉成虫滞育解除过程中的SCP、 FP、 糖原变化均有显著性影响（P<0.05）, 而对干重、 含水量及蛋白质含量影响不显著;性别只对成虫FP与糖原有显著影响（P<0.05）; 处理时间对干重、 含水量、 SCP、 FP、 蛋白及糖原含量均有显著影响（P<0.01）。3种因素的交互作用对SCP、 FP、 蛋白及糖原含量均有显著影响, 对干重及含水量影响不显著。初产卵成虫体内物质含量变化测定发现, 长光照（处理10 d）下雌、 雄成虫体内蛋白和糖原含量极显著低于短光照（处理25 d）下（P<0.01）, 雄成虫体内含水量显著高于短光照下（P<0.05）。结果说明, 中华通草蛉自然越冬成虫在长、 短两种光周期下均逐渐解除滞育, 但在滞育解除过程中呈现出不同的生理生化变化。     

中华通草蛉滞育的光周期调控Ⅰ.诱导成虫滞育的临界光周期和临界光照虫态(英文)

在22℃条件下,研究中华通草蛉对光周期的敏感性,结果表明:中华通草蛉属短日照滞育型,在短光照条件下饲养获得的成虫进入滞育状态,诱导成虫滞育的临界光周期为12.5小时到13小时。成虫期本身是诱导成虫滞育的最关键虫期,只有当羽化的成虫处于短光照条件下时才能进入滞育状态。成虫期之前其它虫期的短光周期经历能延长成虫在长光照条件下的产卵前期。三龄幼虫和预蛹期比成虫期前的其它虫期对光周期的变化更为敏感。     

光温条件明显影响棉铃虫的滞育强度

为了探明不同地理种群棉铃虫Helicoverpa armigera滞育强度的地理变异, 本研究系统地比较了光温条件（光照时数 11～16 h, 恒温20, 22, 25, 28和31℃及变温）对来自中国的4个地理种群（广东广州、 江西永修、 山东泰安和辽宁喀佐）棉铃虫滞育强度的影响。结果表明： 滞育诱导的光周期对继后棉铃虫的滞育强度有明显影响。在光照时数11～14 h范围内, 各地理种群的滞育持续期均随着光照时数的增加而延长。滞育强度也受到滞育诱导的温周期影响, 当光期温度相同时, 低纬度的GZ种群温周期比恒温有更强的诱导效应; 中纬度的YX种群温周期与恒温具有相同的滞育诱导强度; 高纬度的KZ和TA种群温周期所诱导的滞育强度一般低于恒温。滞育解除过程中的温度也显著影响到滞育的解除, 在20~31℃下, 温度愈高滞育解除愈快; 滞育持续期同时受到滞育诱导温度的影响, 对于北方的泰安种群和喀佐种群, 较高的滞育诱导温度能诱导更强的滞育。     

母代越冬经历对中华通草蛉子代发育与繁殖的影响

【目的】为探究母代越冬经历对中华通草蛉Chrysoperla sinica子代生长发育、滞育诱导和繁殖能力的影响,【方法】采用年龄-龄期两性生命表方法研究了越冬初期(11月份)、越冬中期(1月份)和越冬末期(3月份)中华通草蛉自然越冬成虫其子代种群在25℃、光周期15L∶9D和9L∶15D条件下的生长发育及种群动态变化。【结果】长光周期(15L∶9D)下不同越冬时期对中华通草蛉子代的成虫前期并没有显著性影响,但越冬中期的子代成虫历期显著短于其他两个越冬时期;产卵前期以越冬中期子代显著高于其他两个越冬时期;单雌平均产卵量则以越冬末期显著高于越冬初期和越冬中期;内禀增长率、周限增长率和净增殖率均以越冬末期子代最高;平均世代周期以越冬中期子代最长。短光周期(9L∶15D)下中华通草蛉子代成虫历期以越冬末期最长,越冬初期次之,越冬中期最短;子代产卵前期以越冬初期最长,越冬中期次之,越冬末期最短;产卵历期以越冬末期最长;单雌平均产卵量以越冬末期最高;子代生命表参数变化趋势与长光照处理一致;子代种群存活率以越冬末期最高,越冬初期次之,越冬中期最低。【结论】相比越冬初期和越冬中期,越冬末期中华通草蛉子代种群表现出较强的增殖能力;短光周期可诱导中华通草蛉成虫滞育,产卵前期的长短可代表滞育深度,母代越冬经历对子代种群滞育诱导有一定的削减作用,母代越冬时间越长,削减作用越明显。     

EFFECTS OF PHOTOPERIOD ON EMBRYONIC DIAPAUSE AND REPRODUCTION IN THE MIGRATORY LOCUST IN THREE GEOGRAPHIC POPULATIONS1

Abstract The three investigated populations of migratory locust, Locusta migratoria L. (Orthoptera, Acrididae), reported in this paper show significant variation in diapause characteristics. The insects of the Heshuo Xinjiang population show diapause in egg stage regardless of the photoperiod of rearing condition, while the adults of the Beidagang Tianjin and the Hami Xinjiang populations produce diapause or nondiapause eggs according to the short or long photoperiod. From this research, we infer altitude plays an important role in inducing diapause. The long photoperiod which extends the duration of pre-oviposition period and reduces the oviposition frequency in the Beidagang and Hami populations shows no effect on those features of the Heshuo population. The duration at low temperature to end diapause in the Heshuo population is longer than that in the other two populations.     

Geographic variation in diapause induction and termination of the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

Overwintering diapause in Helicoverpa armigera, a multivoltine species, is controlled by response to photoperiod and temperature. Photoperiodic responses from 5 different geographical populations showed that the variation in critical photoperiod for diapause induction was positively related to the latitudinal origin of the populations at 20, 22 and 25 °C. Diapause response to photoperiod and temperature was quite different between northern and southern populations, being highly sensitive to photoperiod in northern populations and temperature dependence in southern populations. Diapause pupae from southern population showed a significantly shorter diapause duration than from northern-most populations when they were cultured at 20, 22, 25, 28 and 31 °C; by contrast, overwintering pupae from southern populations emerged significantly later than from northern populations when they were maintained in natural conditions, showing a clinal latitudinal variation in diapause termination. Diapause-inducing temperature had a significant effect on diapause duration, but with a significant difference between southern and northern populations. The higher rearing temperature of 22 °C evoked a more intense diapause than did 20 °C in northern populations; but a less intense diapause in southern population. Cold exposure (chilling) is not necessary to break the pupal diapause. The higher the temperature, the quicker the diapause terminated. Response of diapause termination to chilling showed that northern populations were more sensitive to chilling than southern population.     

Geographical variability in ecophysiological traits controlling dormancy in Chrysopa oculata (Neuroptera: Chrysopidae)

Dormancy in Chrysopa oculata, a multivoltine species, is controlled by reponses to photoperiod and temperature. Variation in both the critical photoperiod for diapause induction and the duration of diapause is positively related to the latitudianl origin of the population. The incidence of photoperiodically induced diapause also varies geographically; at 24°C the southern-most population is more variable for diapause induction than the northern populations. By contrast, there is little interpopulation variation in thermally determined rates of post-diapause development. The results suggest that the lower threshold for development and the thermal requirements above the threshold may be functionally correlated.     

Sex‐linked inheritance of diapause induction in the butterfly Pieris napi

Many temperate insects survive harsh environmental conditions, such as winter, by entering a state of developmental arrest. This diapause state is predominantly induced by photoperiod. The photoperiod varies with latitude and has led to local adaptation in the photoperiodic induction of diapause in many insects. To understand the rapid evolution of the photoperiodic threshold, it is important to investigate and understand the underlying genetic mechanisms. In the present study, the genetic basis of photoperiodic diapause induction is investigated in the green‐veined white butterfly Pieris napi (Lepidoptera, Pieridae) by assaying diapause induction in a range of conditions for a Swedish and Spanish population. Furthermore, the inheritance of diapause induction is assessed in reciprocal F1 hybrids and backcrosses between the two populations. The southern population shows a clear photoperiodic threshold determining diapause or direct development, whereas the northern populations show a high incidence of diapause, regardless of photoperiod. The hybrid crosses reveal that the inheritance of diapause induction is strongly sex‐linked, and that diapause incidence in the genetic crosses is highly dependent on photoperiod. This emphasizes the importance of assaying a range of conditions in diapause inheritance studies. The results indicate a strongly heritable diapause induction with a major component on the Z‐chromosome, as well as a minor effect of the autosomal background.     

Population dependent effects of photoperiod on diapause related physiological traits in an invasive beetle (Leptinotarsa decemlineata)

Organisms undergoing latitudinal range expansion face a change in the photoperiod which can lead to a mismatch between the timing of seasonal changes in physiological and life history traits with seasonal environmental changes. This mismatch can lead to lowered survival, for example, due to unsynchronized diapause timing. Successful range expansion even in recent introductions requires that organisms which use the photoperiod for seasonal predictions should show interpopulational differences in photoperiodic responses at different latitudes, as the photoperiod is a function of latitude. We investigated among population differences in photoperiodic responses of life history and physiological traits linked to diapause in the invasive beetle Leptinotarsa decemlineata. Beetles from a northern marginal and a southern European population were reared under short day (12:12L:D) and long day (18:6L:D) photoperiods. Both populations reacted similarly to the short day photoperiod. Their abdominal total lipid content increased and water content decreased which suggests that the beetles prepared for diapause. This was also indicated by low mortality during diapause. In the long day photoperiod large interpopulational differences were found, the southern population ceased lipid accumulation after 5 days, while the northern population continued lipid accumulation as beetles in the short day photoperiod. This indicates that the northern population has a longer critical photoperiod than the southern one. Abdominal total lipid stores in 10 day old beetles were shown to be predominantly composed of neutral lipids (85%), most likely representing storage triacylglycerols. Fatty acid profiles of both the neutral lipids and the phospholipids showed large shifts during the first 10 day of adult life, predominantly in the fractions of 18:0, 18:1ω9, 18:2ω6 and 18:3ω3. Although the degree of unsaturation increased with age, it was not higher in diapausing than non-diapausing beetles. This indicates that this species does not increase diapause related cold tolerance via homeoviscous adaptation, and might have developed other means to cope with suboptimal temperatures, such as behavioral adaptations.     

Photoperiodic control of larval diapause in the yellow-spotted longicorn beetle, Psacothea hilaris: analysis by photoperiod manipulation

The photoperiodic control of diapause induction in the larvae of the yellow-spotted longicorn beetle, Psacothea hilaris (Pascoe), was investigated using a west Japan-type population collected from Ino, Kochi Prefecture, Japan. In this population, the larvae expressed a long-day photoperiodic response with a critical daylength between 13.5 and 14 h at 25 °C ; under a long daylength, the larvae pupated after the 4th or 5th instar, while the larvae entered diapause under a short daylength after 2.3 additional molts on average. When the photoperiod was changed from a short (L12:D12) to a long (L15:D9) daylength, pupation occurred in most of the individuals irrespective of the time of the change. When the photoperiod was changed from long to short at 1 or 2 weeks after hatching, all of the larvae entered diapause, whereas when the photoperiod was changed at 5 weeks after hatching or later, most of the larvae pupated. The 2 weeks exposures to a long daylength against a 'background' of a short daylength at various times revealed that the larvae of this insect are most sensitive to the photoperiod from 4 to 6 weeks after hatching.     

Induction and termination of prepupal summer diapause in Pseudopidorus fasciata (Lepidoptera: Zygaenidae)

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 13.5h and long days terminate diapause with a critical daylength of 14h. 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 degrees C, 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 degrees C 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 degrees C, the duration of diapause at the high temperature of 30 degrees C was significantly longer than those at 25 and 28 degrees 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.