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.     

马尾松毛虫越冬代滞育与非滞育幼虫过冷却点的研究

测定了在恒温和自然温度处理下饲养的马尾松毛虫滞育与非滞育幼虫的过冷却点。结果表明 ,2 7℃恒温饲养的滞育幼虫的平均过冷却点较非滞育幼虫的平均过冷却点低 ,但无显著差异 ;而自然温度下饲养的滞育幼虫的过冷却点较非滞育的过冷却点也低 ,然而 ,滞育开始时差异不显著 ,之后差异显著。相应滞育状态下 ,自然温度下饲喂的幼虫较 2 7℃恒温下饲喂的平均过冷却点低 ,但在滞育开始阶段和结束阶段两者之间的差异显著。自然温度下滞育和非滞育幼虫的抗寒能力都随气温的降低而增强 ,而 2 7℃下滞育与非滞育幼虫的抗寒能力均出现先增后减的趋势     

光周期对大草蛉(Chrysopa pallens)滞育及发育的影响

在22℃条件下,研究大草蛉对光周期的敏感性,结果表明:大草蛉属短日照滞育型,在短光照条件下饲养获得的预蛹进入滞育状态,诱导预蛹滞育的临界光周期为10.5L-13.5D到11L-13D.2龄幼虫期是诱导预蛹滞育的敏感虫期,只有当2龄幼虫期处于短光照条件下时才能进入滞育状态.1龄和3龄幼虫期也在滞育诱导条件下进行滞育诱导,能够提高滞育率.光周期对大草蛉幼虫历期及预蛹重的影响研究结果表明:光周期对幼虫历期有一定的影响,特别对2龄幼虫期的影响比较明显.幼虫期的光周期条件影响预蛹的重量,滞育预蛹的重量显著高于非滞育预蛹.     

转换寄主对马尾松毛虫生长发育与繁殖的影响

在室内条件下,分别用马尾松针叶(Pinus massoniana Lamb.)、湿地松针叶(Pinus elliottii Engelm)、以及在不同的幼虫龄期从用马尾松针叶转移到用湿地松针叶饲养马尾松毛虫Dendrolimus punctatus Walker,观察转换寄主对马尾松毛虫生长发育与繁殖的影响。结果表明:(1)从用马尾松针叶饲养转换到用湿地松针叶饲养,可显著影响马尾松毛虫生长发育和繁殖参数;而且当在马尾松毛虫幼虫老龄期进行转换寄主饲养比低龄期转换寄主饲养,可显著缩短马尾松毛虫幼虫的发育历期,降低死亡率,同时,可显著增加幼虫体重、蛹重和化蛹率;对食物的营养效应也越强。(2)取食马尾松的松毛虫较取食湿地松的马尾松毛虫发育历期短,死亡率低,幼虫及蛹重增加,产卵量高。结果说明,马尾松毛虫从马尾松转换移到湿地松上取食对其生长发育与繁殖是不利的。     

光周期和温度对大猿叶虫泰安种群滞育诱导的影响

为了明确光周期和温度对大猿叶虫泰安种群滞育诱导的影响,在实验室恒温和变温条件下,观察了该虫滞育诱导的光温反应。滞育诱导的光周期反应表明,大猿叶虫泰安种群滞育的发生与光周期无关,主要取决于日平均温度。当温度20℃时,全部个体进入滞育;在温度25℃时,仅有极少数个体发育;在温度28℃时,发育的个体也没有达到40%。对温度的敏感虫态包括幼虫期、蛹期和成虫期。在缺乏光信号的条件下,温度本身也能诱导滞育发生。在平均温度24℃、26℃下,温周期变化幅度对滞育的诱导有显著影响。在相同的温度下,有光参与的温周期的滞育率比全暗的温周期的滞育率明显低。结果表明,温度是大猿叶虫泰安种群滞育诱导的主要因素。     

松毛虫的杂交遗传试验

本文报道了马尾松毛虫Dendrolimus punctatus Walker和油松毛虫Dendrolimus tabwlaeformis Tsai et Liu杂交遗传试验的部分结果.研究表明,不论从食性、形态特征、混合配对和单个配对试验的结果来看,油松毛虫和马尾松毛虫应为同一物种.其形态学特征,尤其是外生殖器解剖构造的差异,并未反映出种的特性和种间的生殖隔离.油松毛虫与马尾松毛虫杂交,无论正交或反交,都能产生有生育力的F₁代,F₁代自交产生F₂代,F₂代自交产生F₃代.但考虑到油松毛虫在我国的分布与油松的分布大体相一致,它与马尾松毛虫在形态学和生态学等方面多少存在着一些差异,因此可认为它是马尾松毛虫的一个亚种,可称为Dendrallmua punctatus tabulaeformis(Tsai et Liu).     

光周期和温度对棉铃虫发育历期及蛹重的影响

以山东泰安棉铃虫Helicoverpa armigera Hübner为例,在人工饲养条件下、人工气候箱中,研究了不同光周期和温度条件对棉铃虫幼虫生长发育历期、蛹重及蛹历期的影响.结果表明,光周期对棉铃虫幼虫发育历期、非滞育蛹历期均存在一定的影响,短光照(滞育诱导的光周期)下的发育历期要长于长光照(诱导发育的光周期)的发育历期;温度对棉铃虫幼虫发育历期、非滞育蛹历期的影响十分明显,随着温度上升,发育历期明显缩短;棉铃虫蛹的重量形成受到幼虫期的光周期和温度的联合作用,在较高温度(28℃)下,光照时数与蛹重呈现极显著的负相关关系(R2=0.9257),在短光照(如11h光)下,蛹重与温度呈现正相关性(R2＝0.8564),而在长光照下如15h,蛹重与温度呈现一定的负相关性(R2=0.523);此外,同一光温下,雌雄蛹重量差异不显著,而滞育蛹要重于非滞育蛹,幼虫发育历期越长形成的蛹一般越重.     

油松毛虫滞育现象对预测预报的意义

油松毛虫(Dendrolimus tabulaeformis Tsai et Liu)为我国华北地区的重要森林害虫。它在北京西山地区每年发生1—2代,以发生两代者为多数。产生世代分化的原因,是由于在第一代幼虫期出现滞育的缘故。在北京西山地区,油松毛虫的滞育出现于第一代四龄幼虫时,每年7月下旬前后,经过三次蜕皮的幼虫,假如体色变化不大,身体未见显著增长,取食量小,生长发育迟缓,即为滞育状态的幼虫,当年它不能完成第一代。反之,蜕皮后幼虫体色变为深黑,间有黄色斑点,色泽鲜艳,食量显著增加,生长发育迅速,即为正常幼虫,当年可以结茧化蛹而产生第二代。 根据我们连续几年的观察,如将第一年出现滞育的幼虫,进行个体饲育,至第二年其产生的后代,有的在第一     

光照及温度对桃小食心虫(Carposina niponensis Walsingham)滞育影响的初步研究

桃小食心虫在辽南苹果产区为二化性兼性滞育害虫。据在熊岳的观察, 第一代幼虫通常于7月下旬开始脱果, 凡脱果日期愈晚的幼虫, 进入滞育的百分率愈高。在中间温度下, 滞育的发生决定于幼虫发育期间昼夜光照时数:在每日光照13小时下发育时, 全部滞育, 在15小时下发育的, 基本不滞育。根据田间第一代幼虫发育期间温度和日照时数的变化与幼虫滞育百分率进度的关系推算结果, 第一代幼虫发生期间的温度是在光周期反应的适温范围内, 故温度不是引起滞育的主要因素。推算出来的临界光周期位于14小时50分—14小时13分之间(在熊岳出现该光周期的日期为7月21号左右)。最后, 讨论了田间第一代幼虫发生期早晚与滞育百分率及第二代发生量的关系:在春季干旱的年份(如1955、1957), 由于第一代幼虫发生期被推迟, 滞育百分率提高, 从而减少了当年第二代的发生量;相反, 在第一代幼虫发生期较正常年份提前的1956年, 该代的滞育百分率降低, 从而相应增加了第二代的发生量。     

松毛虫的种间杂交及杂种生物学的初步观察

1.根据1962—1963年间在北京实验证明:赤松毛虫Dendrolimus spectabilis Bult.、油松毛虫D.tabulaeformis Tsai et Liu、马尾松毛虫D.punctatus Walk.三种皆可互相杂交,并且比较容易进行。 2.马尾松毛虫和油松毛虫或赤松毛虫杂交后,其产卵率、孵化率皆达90%以上,杂种第一代亦可正常生长和发育。 3.赤松毛虫和油松毛虫杂交,对成虫的生活期及逐日产卵情况无明显影响。交配历时能达8小时以上,产卵率及孵化率皆达80%以上。 4.赤松毛虫与油松毛虫的杂种第一代幼虫(F₁)明显地表现出杂种优势现象。7月24日—8月8日前孵化的幼虫,在当年完成一代虫的比率比亲虫为高。而F₁的发育期则较亲虫为短。8月14日孵化的杂种第一代幼虫,在进入越冬时的平均体重比亲虫为高。 5.赤松毛虫与油松毛虫的杂种第一代可产生雌性和雄性成虫,并有一定的生殖能力。其成虫和油松毛虫回交,亦比较容易,孵化率可达90%以上,后代亦能正常生长发育。 6.如用分布较远两个地区的赤松毛虫和油松毛虫杂交(山东牟平的赤松毛虫和河北迁西的油松毛虫)其孵化率仅57%。再用杂种第一代成虫相互杂交(F₂)孵化率仅51%。用杂种F₁和赤松毛虫回交所产的卵不孵化。这些情况由于实验虫数较少尚不能做最后决定,有待于进一步研究,但对杂交不育防治松毛虫的可能性,仍有研究余地。 7.由于赤松毛虫和油松毛虫室内杂交比较容易,且有杂种优势现象,因此在自然界分布连接的地区存在着种间杂交的可能性,就容易得到理解。在研究害虫种群数量消长关系时,除一般的气候性、生物性和营养性等因子外,杂种优势的作用亦不可忽视。     

Photoperiodic responses during larval development and diapause of two geographic ecotypes of the rice stem maggot, Chlorops oryzae

Chlorops oryzae is bivoltine in northern Japan but trivoltine in the southern part of the country. In the bivoltine strain, both the egg and larval stages were found to be sensitive to photoperiod. When the egg stage was exposed to a long-day photoperiod (16L:8D), larval development showed a short-day type response, and mature third-instar larvae entered a summer diapause under a long-day photoperiod (15L:9D). When eggs experienced short days, the first-instar larvae entered a winter diapause under short-day conditions, and the critical photoperiod in the larval stage ranged from about 14L:10D to about 12L:12D as the photoperiod experienced by the eggs increased from 12L:12D to 14L:10D. However, the development of the larvae after overwintering was not influenced by the photoperiod. In the trivoltine strain, larval development was retarded under a 14L:10D photoperiod but not under either shorter or longer photoperiods, when larvae had spent the egg stage under a 16L:8D photoperiod. The critical photoperiod of the larval stage for the induction of a winter diapause in the first instar was about 12L:12D, though it varied to some extent with the photoperiod during the egg stage. Thus, Chlorops oryzae was able to adapt itself to the local climatic conditions by the development of variable and complicated photoperiodic responses.     

马尾松毛虫过氧化氢酶及过氧化物酶与耐药性的关系

马尾松毛虫Dendrolimus punctatus幼虫体内存在着过氧化氢酶(CAT)和过氧化物酶(POD)。4龄幼虫的CAT和POD活力较大,其次是6龄幼虫,5龄幼虫的CAT和POD活力较4龄和6龄幼虫低。醚菊酯(etofenprox)处理后,在兴奋期(30 min),CAT和POD活力水平上升。4龄和6龄幼虫在抑制期(50 min以后),CAT和POD活力呈波动式上升,接近死亡时下降。5龄幼虫的CAT和POD活力呈波动式上升,接近死亡时下降。5龄幼虫的CAT在抑制期保持比正常虫体高的活力。结果表明,马尾松毛虫4龄、5龄和6龄幼虫与耐药性存在一定的相关性,研制酶的抑制剂具有实用意义。根据毒力测定结果,马尾松毛虫幼虫对醚菊酯的耐药力,5龄是4龄的1.43倍,6龄是4龄的1.72倍。因此,药物防治的合理时期应掌握在4龄以前较适宜。     

The effect of larval temperature and photoperiod on the incidence of larval diapause in the blowfly, Calliphora vicina

ABSTRACT. The blowfly, Calliphora vicina Meigen (Diptera: Calliphoridae), displays a maternally induced larval diapause. Progeny of adults exposed to short days enter diapause if the larval temperature is 15C or below; exposing adults to long days, or larvae to temperatures above 15C, results in non-diapause. By keeping progeny from short-day parents at the parental temperature of 23.5C for various lengths of time before transfer to 11C, it could be shown that the diapause-averting effect of high temperature operates in the late wandering stage of larva, possibly at the moment of the decision for the brain-ring gland complex to release PTTH/ecdysone at the diapause/non-diapause stage.
Although photoperiodic induction in the blowfly is maternal, previous work had shown that the larvae were also slightly sensitive to photoperiod. From the present study it is evident that also the eggs are photo-sensitive.     

Winter dormancy of the pine sawyer Monochamus galloprovincialis (Col., Cerambycidae) in Portugal

Abstract:  The pine sawyer Monochamus galloprovincialis is the vector of the introduced pine wood nematode Bursaphelenchus xylophilus in Portugal and has a fixed univoltine life cycle, overwintering as larvae inside the wood. We investigated the possibility of the existence of a phase of winter dormancy affecting the larvae, its induction and termination under controlled conditions and its incidence and termination in the field. In the laboratory, the majority of the newly hatched larvae which were maintained at a constant temperature of 23°C and different photoperiods became dormant in <70 days. Part of the population completed dormancy and reassumed development until adult emergence at the constant temperature, without the need for a chilling period. Although no critical photoperiod for dormancy maintenance or termination could be determined, dormancy termination was more frequent for larvae experiencing changes on daylength duration. In the field, dormancy incidence grew progressively from a minimum of 26% in October to a maximum of 100% in April, and dormancy appeared to be completed only during late winter. The results suggest that M. galloprovincialis larvae underwent an obligatory dormancy associated with the last larval instar, which conforms to the general definition of diapause, although presenting some affinities with oligopause. The role of this dormancy on the regulation of the pine sawyer's seasonal development and the number of generations is discussed.     

中国松毛虫研究与治理

<正> 在中国,松毛虫是最严重的森林食叶害虫。远在370年前就有发生成灾的记载,至本世纪90年代每年发生面积达270万公顷左右,给林业生产和环境保护造成严重损害。中国现有松毛虫27种(4亚种)。除宁夏和青海外,分布遍及28个直辖市、省和自治区。其中,陕西省有10种,台湾省有4种。从分布范围和危害程度看,发生严重的有:南方的马尾松毛虫,北方的     

Larval diapause in the mosquito aedes triseriatus: effects of diet and temperature on photoperiodic induction

Larval diapause was induced in both a northern (Ohio) and a southern (Alabama) strain of Aedes triseriatus by photoperiodic treatment of the larval stage itself. The effect of a short-day (10 hr) photoperiod during larval development was cumulative and resulted in failure of the fourth instar to pupate. The larvae, which had been obtained from long-day (16 hr) eggs, underwent diapause when their development was slowed by a low-quantity diet or low temperature (16°C) for a sufficient number of days to allow the short-day photoperiod to exert a visible effect.     

粟穗螟滞育的形成和解除与环境条件的关系

粟穗螟Manpava bipunctella Ragonot在川南地区为二化性兼性滞育的昆虫。光周期是诱发滞育的主导因素,在中位温度下,滞育与否主要取决于幼虫发育期间的每日光照时数。在2s℃恒温下,临界光周期为14小时38分。幼虫对光照刺激反应的敏感期为低龄期。 温度和食料效应只发生在每天14小时以上的长光照下,低温有抵销长光照抑制滞育的作用,高温影响不显著;取食玉米的幼虫滞育率比高粱的高,并随寄主生育阶段的发展而增高。该虫滞育解除必需每天14-15小时的长光照;不利于滞育发育和解除,适宜温度为10一25℃。本文最后讨论了该虫滞育形成和解除的特点对发生规律的作用及在测报上的意义。     

Correlated responses to selection for faster development and early reproduction in Drosophila: the evolution of larval traits

Studies on selection for faster development in Drosophila have typically focused on the trade-offs among development time, adult weight, and adult life span. Relatively less attention has been paid to the evolution of preadult life stages and behaviors in response to such selection. We have earlier reported that four laboratory populations of D. melanogaster selected for faster development and early reproduction, relative to control populations, showed considerably reduced preadult development time and survivorship, dry weight at eclosion, and larval growth rates. Here we study the larval phase of these populations in greater detail. We show here that the reduction in development time after about 50 generations of selection is due to reduced duration of the first and third larval instars and the pupal stage, whereas the duration of the second larval instar has not changed. About 90% of the preadult mortality in the selected populations is due to larval mortality. The third instar larvae, pupae, and freshly eclosed adults of the selected populations weigh significantly less than controls, and this difference appears during the third larval instar. Thereafter, percentage weight loss during the pupal stage does not differ between selected and control populations. The minimum amount of time a larva must feed to subsequently complete development is lower in the selected populations, which also exhibit a syndrome of reduced energy expenditure through reduction in larval feeding rate, larval digging and foraging activity, and pupation height. Comparison of these results with those observed earlier in populations selected for adaptation to larval crowding and faster development under a different protocol from ours reveal differences in the evolved traits that suggest that the responses to selection for faster development are greatly affected by the larval density at which selection acts and on details of the selection pressures acting on the timing of reproduction.