夏季不同昼夜温度模式对广聚萤叶甲发育和繁殖的影响

本文旨在探明夏季不同昼夜温度模式对广聚萤叶甲发育及繁殖的影响。在实验室条件下,模拟了夏季常规的昼夜气温变化模式32℃±4℃、白天均温升高2℃及极端高温升高2℃,以恒温28℃为对照,研究上述温度模式对广聚萤叶甲的生长发育及繁殖动态的影响,并组建了广聚萤叶甲实验种群生命表。随日平均温度的增加,广聚萤叶甲卵的孵化率和幼虫存活率降低,发育历期缩短,成虫寿命及产卵量减少,但是对蛹的羽化率影响不大。白天均温升高2℃时,尽管广聚萤叶甲生殖力最低,但是其内禀增长率最高,种群加倍时间短。广聚萤叶甲能根据昼夜温度变化来改变生长发育特点以适应外环境界,通过缩短种群加倍时间来维持一定的种群数量。     

Effects of high temperature on body size and weight of Ophraella communa

Ophraella communa LeSage (Coleoptera: Chrysomelidae) is an effective biological control agent of the invasive common ragweed, Ambrosia artemisiifolia L. Body size, one of the most important life-history characters for many insects, affects O. communa mating choice. Temperature is one of the most important factors on body size, especially high temperatures. Adult body lengths were significantly inhibited after eggs, larvae and pupae of O. communa experienced high temperature stresses. With exception of subsequent female body after exposure of larvae to high temperatures, the body weights of females and males were not affected by temperatures. Since adult insect fecundities are often in proportion to their body sizes, we concluded that high temperatures may influence the population expansion of O. communa in the field.     

Effect of daylength and temperature on the larval diapause of the sunflower moth, Homoeosoma electellum

The effect of daylength and temperature on the regulation of the larval diapause of a central Missouri population of the sunflower moth, Homoeosoma electellum, was examined. Fully grown fourth-instar larvae exhibit a facultative diapause. Measurements of the effect of photoperiod on diapause induction revealed critical photoperiods of about 13 h 30 min light/day at 20°C, and between 11 h 45 min and 12 h light/day at 23°C. Third and fourth-instar larvae were shown to be the main sensitive stages for diapause determination. Daylength was also shown to be an important regulator of the rate of diapause development. A short day of LD 10:14 h permitted only a low rate of diapause development, whereas long days of LD 14:10 h and LD 16:8 h accelerated diapause development at 25 and 30°C. When long days were alternated with short days at 30°C the accelerating effect of long days on diapause development was not found. Systematic transfers of chilled diapausing larvae revealed an accelerated diapause development in groups transferred from 10 to 30°C LD 10:14 h, but diapause development was not accelerated in groups transferred from 10 to 30°C LD 16:8 h.     

广聚萤叶甲和豚草卷蛾对江西南昌豚草的联合控制作用

【背景】豚草是一种世界性的重要害草,在江西南昌地区普遍发生。广聚萤叶甲和豚草卷蛾是很有利用前景的豚草天敌,而有关这2种天敌在江西南昌地区田间对豚草的联合控制效果尚不明确。【方法】2009年6月25日分别按广聚萤叶甲0.7头.株-1和豚草卷蛾0.4头.株-1的密度在江西南昌豚草入侵地同时释放2种天敌,并于8月4日～9月13日,每隔10d调查广聚萤叶甲各虫态的数量、豚草卷蛾虫瘿数、豚草的株高和死亡株数。【结果】释放前期广聚萤叶甲和豚草卷蛾种群数量增长较快,但释放70d后,豚草植株死亡率达90.14%,天敌种群数量急剧下降;释放80d后,豚草植株死亡率达到100%。此外,在整个调查期间,天敌释放区豚草株高增长缓慢,均极显著低于对照区。【结论与意义】广聚萤叶甲和豚草卷蛾在江西南昌地区田间对豚草的联合控制效果显著,宜在江西大规模推广应用。     

Rapid cold-hardening response in Ophraella communa LeSage (Coleoptera: Chrysomelidae), a biological control agent of Ambrosia artemisiifolia L.

In China, an unintentionally introduced beetle Ophraella communa shows good control efficiency against invasive common ragweed, Ambrosia artemisiifolia. With the aim of understanding the capacity of O. communa to overcome sub-zero low temperature rapidly, the longevity, survival and fecundity of the beetle adults were studied at conditions of different rapid cold-hardening in the laboratory. The results showed that approximately 20% female or male individuals still survive at ?12°C for 2 h, thus the discriminating temperature for rapid cold-hardening of both female and male beetles is ?12°C. The survival, longevity and fecundity of adult beetles were significantly affected by rapid cold-hardening treatments. Compared to the control, the survival rates of adult beetles experiencing 2 h of rapid cold-hardening at 2, 5 and 8°C prior to exposure to its discriminating temperature (?12°C) were significantly increased. Adult longevity and fecundity were significantly higher after pre-treatment at 2, 5 and 8°C for 2 h than those of the control. Both longest longevity and maximum fecundity of adult beetles were observed at the rapid cold-hardening of 2°C. Our experiment implies that the cold-tolerance ability of O. communa can be rapidly increased after rapid cold-hardening treatments, which reveals an important ecological significance for population establishment and expansion of O. communa in the invaded areas of common ragweed.     

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.     

二斑叶螨滞育特性的初步研究

诱导滞育实验表明 :短日照和低温是诱导二斑叶螨发生滞育的主要因子。测定我国天水种群 ,在 15℃条件下 ,诱导其滞育的临界日照长度为 9小时 4 2分 ,在每日 8小时光照条件下 ,诱导其滞育的临界温度为 15.5℃。解除滞育实验表明 :在每日 13小时的光照条件下 ,温度越高 ,解除越冬雌成螨滞育的速度越快 ;低温处理滞育雌成螨的时间越长 ,解除其滞育的速度也越快。     

Photoperiodic induction of larval diapause and temperature-dependent termination in a wild multivoltine bruchid,Kytorhinus sharpianus

A wild bean weevil,Kytorhinus sharpianus Bridwell (Coleoptera: Bruchidae), has a multivoltine life cycle and enters a hibernal larval diapause at the fourth instar under a short daylength (Shimada & Ishihara, 1991). Here, we investigated their diapause incidence under different photoperiods at 24°C and 27°C. The critical photoperiods for diapause induction were 14.5 h at 24°C and 14 h at 27°C. The stages susceptible to diapause-inducing stimuli were estimated by transferring larvae of various instars from long days to short days and vice versa. Then we investigated the incidence of larval diapause. The sensitive stage was estimated to be from the third to early fourth instar. Though larval diapause, which was induced under a short daylength, was terminated only by increasing the daylength, the termination was more synchronized by an exposure to a low temperature followed by increasing temperature, irrespective of photoperiod.     

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。     

Effect of short-term high temperature stress on the development and fecundity of Ophraella communa (Coleoptera: Chrysomelidae)

Since insects are ectothermic, they are highly vulnerable to the sudden increase of temperature. Indeed, it has been hypothesized that the survival, development, fecundity, and even population expansion of insects are all affected significantly by extremely high temperature. We studied the effect of short-term high temperature stress on the survival and development of different stages, adult longevity and fecundity of Ophraella communa (Coleoptera: Chrysomelidae), a biological control agent of the invasive plant, the common ragweed, Ambrosia artemisiifolia (Asterales: Asteraceae) in the laboratory. The results showed that egg, larval, pupal and adult survival rates were significantly affected after 2 hour-short-stress at high temperatures (35 to 47°C) when compared to the 28°C control. With the exceptions of the control and 35°C stress, survival rate of females was significantly higher than that of males after short-stress at any high temperature. Short-term high temperature stress also significantly impacted longevity and fecundity of adult beetles. Except for control, female longevity was significantly longer than male's after short-stress at any high temperature. The survival rates of different stages, and adult longevity and fecundity of the beetle decreased significantly with the increase of short-term stress temperature. Based on the results of the present study, we conclude that the development and population expansion of O. communa may be significantly affected when they are exposed to a high temperature stage in a summer day in the areas invaded by common ragweed, in southern China.     

广聚萤叶甲取食对豚草挥发物组分的影响

植物在遭受植食性昆虫为害后,会系统性地释放虫害诱导挥发物(HIPVs).为探明广聚萤叶甲取食对豚草挥发物组分的影响,本研究采用动态顶空吸附法和气相色谱-质谱联用仪(GC-MS),收集并分析了豚草在受机械损伤和受广聚萤叶甲取食损伤前后挥发物组分及相对含量的变化.结果表明,豚草健康植株与损伤植株的挥发物组分和相对含量具有明显的差异.与健康植株相比,受机械损伤后的豚草挥发物中新出现了乙酸芳樟酯、桉树醇、十二醛、γ-木罗烯、植物醇、β-波旁烯,这些化合物在受损后立即释放,表明它们是组成型豚草挥发性有机化合物(VOCs);受取食损伤后,挥发物中大根香叶烯D的相对含量显著增加,表明大根香叶烯D为诱发型VOCs;而较于健康植株和机械损伤植株,取食损伤后的豚草VOCs中增加了桧烯、辛醛、β-罗勒烯、香茅醇,表明这些化合物为HIPVs.此外,机械损伤与取食损伤对豚草VOCs组分的影响有所不同.受机械损伤后,挥发物的种类减少后(损伤后第3天)很快又恢复到健康水平,而受取食损伤后,VOCs的种类逐渐减少(损伤后3d内).受损后不同时期挥发物的种类和相对含量亦有显著差异.受损后的早期(1 d),释放的多为一些豚草绿叶性物质,而在后期有一些诱导物释放.本研究结果为利用豚草VOCs和HIPVs组分提高广聚萤叶甲对豚草的防控效果奠定了重要基础.     

广聚萤叶甲成虫的繁殖习性和活动规律初步观察

广聚萤叶甲Ophraella communa是豚草Ambrosia artemisiifoliaL.的一种重要专一性天敌昆虫,对豚草抑制作用显著。本文在室内对广聚萤叶甲成虫交配和产卵活动进行观察,结果表明广聚萤叶甲成虫一生多次交配多次产卵,雄虫交配前期为2.7d,明显长于雌虫的0.9d。交配雌虫有产卵前期,然后开始产卵。成虫交配活动主要在8:00-21:00,一般产卵高峰在12:00-16:00,在交配后的前16天,雌虫产卵处在高峰期,随后产卵逐渐减少。本论文为进一步开展广聚萤叶甲繁殖生物学研究和大量繁殖提供基础。     

Diapause and seasonal life cycle strategy in the house spider, Achaearanea tepidariorum (Araneae, Theridiidae)

Abstract In order to elucidate the mechanism regulating its seasonal life cycle, the photoperiodic response of Achaearanea tepidariorum has been analysed. Nymphal development was faster in long-day and slower in short-day photoperiods. The combined action of low temperature, poor food supply and short daylength induced diapause at an earlier developmental stage than short days alone. Thus, photoperiod is a primary factor inducing nymphal diapause, but the diapausing instar is influenced by both temperature and food supply. Hibernating nymphs became unresponsive to photoperiod in late December. After hibernation, however, sensitivity was restored and the nymphs remained sensitive to photoperiod throughout their life. This spider could also enter an imaginal or reproductive diapause. Photoperiod was again a primary inducing factor and temperature modified the photoperiodic response to some extent. The induction of the reproductive diapause was almost temperature-compensated whereas development was not. So the involvement of a photoperiodic counter system was suggested. Irrespective of whether the nymph had experienced diapause or not, the imaginal diapause was induced in response to a short-day photoperiod after adult moult. Based on these observations, the seasonal life cycle and the adaptive significance of nymphal and imaginal diapause are discussed.     

温度和光周期对绿盲蝽滞育诱导的影响

为了阐明环境因子对绿盲蝽Apolygus lucorum Meyer-Dür卵滞育诱导作用,测定了3个温度和6个光周期组合处理对绿肓蝽的滞育诱导和绿盲蝽光周期感应的敏感虫态,系统调查了绿肓蝽在不同温度和不同光照组合下所产卵的孵化率.结果表明:绿盲蝽的敏感虫态为1龄若虫;在17℃,20℃和23℃3个不同温度下,光照时间小...     

温度和光周期对管侧沟茧蜂滞育诱导及滞育茧的低温冷藏

【目的】为明确诱导管侧沟茧蜂Microplitis tuberculifer 滞育的主要因子,在田间和室内研究了不同温度和光周期下管侧沟茧蜂的滞育率和滞育茧的最佳冷藏温度。【方法】田间实验分别从8月31日到9月25日每隔5 d在室外罩笼内释放管侧沟茧蜂寄生的粘虫幼虫,待寄生蜂结茧后统计子代蜂的滞育率。室内实验共设5个不同温度（16℃, 18℃, 20℃, 22℃和24℃）和7个不同光周期（6L:18D, 8L:16D, 10L:14D, 12L:12D, 14L:10D, 16L:8D和18L:6D）,分别统计寄生蜂在各个处理条件下的滞育率。【结果】在河北中部地区秋季自然条件下,8月底当日平均气温为24.4℃,日平均光照时间为12 h 51 min 时,少数蛹（5.08%）开始进入滞育;9月25日,当日平均气温为17.2℃,日平均光照时间为11 h 36 min以下时,几乎所有蛹个体进入滞育,滞育率达到99.70%。在室内人工控制条件下,当温度为22℃以上,无论光周期如何变化,管侧沟茧蜂不能进入滞育,所结茧全部为非滞育茧。温度为22℃以下存在光周期反应,在温度16℃, 18℃和20℃,光周期10L:14D时形成滞育茧数量最多,滞育率分别为100%, 89.75% 和 29.58%。可见温度和光周期二者共同影响管侧沟茧蜂的滞育。滞育茧在0℃左右条件下冷藏 240 d 和5℃左右环境条件下冷藏180 d, 成虫的羽化率和寄生能力与发育茧差异不显著(P>0.05);0℃条件下冷藏300 d,滞育茧仍有79%可以正常羽化。【结论】该寄生蜂在秋季进入滞育主要是低温条件和短光照反应相互作用的结果,滞育茧在0℃和5℃温度下至少可以保存240 d。这些结果对管侧沟茧蜂的大规模繁殖和滞育茧的保存具有重要参考价值。