越北腹露蝗卵的过冷却特性

利用热电偶法测定越北腹露蝗FruhstorferiolatonkinensisWill卵的过冷却点。结果表明,越北腹露蝗卵的过冷却点随季节变化而变动。卵的平均过冷却点从2004年9月初(刚产的卵)的-16.0℃显著下降到2005年1月的-24.7℃,随后卵的过冷却点显著增加到2005年3月的-10.7℃。滞育卵的平均过冷却点(-20.1℃)低于滞育后的平均过冷却点(-12.4℃)。滞育卵在5℃下适应30d后平均过冷却点显著减小到-25.9℃,而在30℃下适应30d后平均过冷却点显著增加到-8.2℃。     

越北腹露蝗卵寄生蜂：东方蝗卵蜂

东方蝗卵蜂Scelio oriemalis Dodd是越北腹露蝗Fruhstorferiola tonkinensis Will.卵的寄生性天敌.2004-2006年对广东省北部越北腹露蝗卵粒和卵块寄生率分别为43.18%和89.34%.东方蝗卵蜂产卵在越北腹露蝗卵中,幼虫期为2龄,每粒被寄生的蝗卵只出l头蜂.东方蝗卵蜂的产卵系统发达,不仅骨化程度高,而且具有伸缩性.雌雄件比约为1:0.6,羽化后即可交配.以5%的葡萄糖溶液喂养成蜂,最多可存活31 d.东方蝗卵蜂可能是某些年份越北腹露蝗种群下降的重要因子.     

黄脊雷蓖蝗越冬卵的滞育发育特性

黄脊雷蓖蝗Rammeacris kiangsu Tsai是我国竹林的重要害虫,1年发生1代,以卵越冬。为弄清其卵滞育发育特性,调查了卵期温度及低温处理对其卵孵化的影响,检测了恒温条件下胚胎的发育进度及卵粒含水量、过冷却点的变化。结果表明,在不同的卵期温度条件下黄脊雷蓖蝗卵的孵化前期均较长,且孵化不整齐、孵化期间长;低温处理30、60或90 d可显著促进其卵的孵化,低温处理的时间越长效果越明显。说明黄脊雷蓖蝗的卵存在滞育现象,低温能明显降低其卵滞育强度。胚胎头幅、触角长度及体长的测量结果显示,25℃温度条件下的黄脊雷蓖蝗的胚胎发育可划分为3个阶段,即前期的持续发育阶段、中期的发育延迟阶段和后期的发育恢复阶段。产卵后40 d左右卵进入滞育,40—75 d为卵的深度滞育期。黄脊雷蓖蝗的卵粒产下后水分含量较低,在25℃的温度条件下,于产卵后25 d前后有一快速的吸水过程,其后卵粒的含水量增加缓慢,可见其卵粒的吸水发生在进入滞育状态之前。在25℃的条件下,黄脊雷蓖蝗卵粒过冷却点的变化亦包含3个阶段,即胚胎发育初期的较高阶段、中期持续而稳定的较低阶段及后期的提升阶段,可以认为黄脊雷蓖蝗越冬卵耐寒性的提高与其滞育的发生密切相关。     

越北腹露蝗(Fruhstorferiola tonkinensis Will.)发生与粤北河滩植物群落的关系

用普查法研究广东省北部地区越北腹露蝗Fruhstorferiola tonkinensis Will.严重发生河滩植物群落,鉴定出分属于43个科的植物106种,同时记录下植物群落中植物种名、平均高度、聚生多度、总覆盖率、物候相和生活力,分析了河滩植物群落的植物相似性和丰富度以及优势种数量特征和属性标志,结果表明河滩植被的搭配和空间分布为越北腹露蝗在粤北大发生提供了独特的生境;另外结合各河滩植物群落进行越北腹露蝗1龄蝗蝻虫口密度调查,根据调查结果对越北腹露蝗发生与植物群落的关系进行偏相关分析,分析结果显示枫杨是越北腹露蝗最嗜性植物,其覆盖度与越北腹露蝗发生密度呈极显著相关,偏相关系数为0.856(F＝32.9201,P＝0.0001),小簕竹是越北腹露蝗非嗜性植物,其覆盖度与越北腹露蝗的发生密度呈显著的负相关,偏相关系数为-0.613(F＝0.1617,P＝0.021),据此提出了一些控制粤北河滩越北腹露蝗的新举措.     

中国黑卵蜂属一新记录种——东方蝗卵蜂

记述黑卵蜂属Scelio中国1新记录种:东方蝗卵蜂Scelio orientalis Dodd,并报道该寄生蜂的新寄主:越北腹露蝗Fruhstorferiola tonkinensis Will.。     

低温和光周期对绿盲蝽越冬卵滞育解除和发育历期的影响

为了探讨温度和光周期对绿盲蝽Apolygus lucorum Meyer-Dür越冬卵滞育解除和发育历期的影响, 系统调查了绿盲蝽越冬卵在不同温度和不同光照组合下的孵化率和孵化时间, 结果显示：绿盲蝽的越冬卵均为滞育卵,低温和光周期对绿盲蝽越冬卵的滞育解除均有影响。2℃的低温处理能够显著促进其滞育解除,在0~65 d范围内,随着低温处理时间增长,其滞育解除时间缩短,未经低温处理的越冬卵T₅₀为68.5 d,低温处理65 d的T₅₀为12.25 d,绿盲蝽越冬卵在2℃低温处理65 d后完全解除滞育;在0~40 d范围内,低温处理时间越长,绿盲蝽越冬卵的孵化率越高,在25℃、全光照的条件下不经低温处理的孵化率为68.65%,低温处理40 d后在25℃的条件下的孵化率达到99.46%。在20~26℃范围内,绿盲蝽越冬卵的滞育后发育历期随着温度的上升而缩短, 随着光周期的延长而缩短。结果说明低温处理能够提高绿盲蝽越冬卵滞育解除率,但不是其滞育解除的必要条件,低温处理与自然变温对绿盲蝽滞育解除的作用相似;高温和长光照能够促进绿盲蝽的滞育解除,缩短发育历期。     

意大利蝗的胚胎发育及卵滞育发生的胚胎发育阶段

【目的】明确意大利蝗Calliptamus italicus (L.)胚胎发育及卵滞育发生的胚胎发育阶段。【方法】2013-2014年间,通过室外胚胎发育进度检测和室内孵化培养观察,研究其胚胎发育等级、滞育和越冬的胚胎阶段及自然越冬滞育的解除。【结果】意大利蝗的胚胎发育可划分为18个阶段;意大利蝗胚胎有反向移转、转旋和顺向移动3种胚胎转动方式;意大利蝗卵滞育发生的胚胎发育阶段为第Ⅻ阶段。自然条件下,意大利蝗卵发育至次年1月21日,仅部分卵解除滞育,解除滞育卵的发育历期最长;随着越冬时间的延长,解除滞育的卵逐渐增多,其发育历期逐渐缩短;直至次年3月29日卵基本完全解除滞育。意大利蝗雌成虫所产的早中期卵（7月27日-8月16日所产卵）以胚胎发育第Ⅻ阶段（滞育发生的胚胎发育阶段）越冬,于翌年4月16日（侯地温平均值：7.59℃,最高温：15.95℃,最低温：2.67℃）继续发育;雌成虫所产的晚期卵（8月28日-9月4日所产卵）,自11月4日（侯地温平均值：7.32℃,最高温：9.00℃,最低温：5.18℃）开始以胚胎第Ⅹ阶段越冬,于翌年3月29日（侯地温平均值：3.78℃,最高温：10.27℃,最低温：0.14℃）继续发育。【结论】意大利蝗雌成虫所产的早中期和晚期卵,其越冬胚胎发育阶段、开始越冬时间及越冬后继续发育的时间均不同。     

越北腹露蝗若虫空间格局的地学统计学分析

应用地学统计学研究广东北部桑田中越北腹露蝗(Fruhstorferiola tonkinensis Will)1～5龄若虫的空间格局动态.结果表明：越北腹露蝗1～5龄若虫种群变异曲线函数均为球状模型,表现为聚集分布,但各龄若虫的空间依赖范围分别为1.973、1.968、2.169、2.302和4.307 m.利用Kriging插值法由地学统计学软件Surfer 8.0产生的各龄若虫等值线图清晰地反映了各龄若虫的空间位置, 表明越北腹露蝗有别于其它一些蝗虫,其低龄若虫呈聚居型,高龄若虫呈散居型分布.     

中华稻蝗长沙种群的生活史及其卵滞育的进化意义

中华稻蝗Oxya chinensis为重要的水稻害虫,在我国除青海、西藏、新疆、内蒙古等未见报道外,南起海南北至东北均有分布,在许多的分布区域1年发生1代。为探索中华稻蝗长沙种群的生活史及其季节适应特征,通过野外和实验室的研究,调查了其发生代数、孵化率和卵滞育率的季节变化及越冬卵的存活率。结果显示,中华稻蝗长沙种群为1年2代和1年1代混合发生:第1代卵产卵后大部分孵化为若虫而1年完成2代,但亦有19.4% -4.1%的卵不孵化而1年只能完成1世代。第1代成虫于6月上旬至8月上旬羽化,6月下旬至8月中旬产卵;第2代若虫于7月初开始孵化,9-10月羽化为成虫,10月上旬至11月下旬产卵。在室外自然条件下,中华稻蝗长沙种群6-8月(第1代)和10-11月(第2代)所产卵块均为部分滞育,滞育率为30%左右,皆无显著差异。然而,其卵滞育率在12月以后显著降低,仅为6.6%或以下,卵滞育快速地得以解除。因此,包括非滞育卵和滞育解除卵,中华稻蝗长沙种群的越冬卵皆以非滞育状态度过其后的寒冷季节。即使是遭遇长江流域2007年末至 2008年初异常寒冷的冬季,在长沙地区越冬后其卵的存活率亦在98%以上。非滞育状态的中华稻蝗长沙种群越冬卵完全能安全地越冬,其滞育的发生并非是为了提高其耐寒性而安全度过不适环境。并探讨了中华稻蝗长沙种群卵滞育的进化意义。     

不同土壤类型及其含水量对亚洲小车蝗卵孵化的影响

为明确不同土壤类型及其含水量对亚洲小车蝗Oedaleus decorus asiaticus Bey-Bienko卵孵化的影响,本实验选取棕钙土、黑土和砂土等3种土壤,在恒温28℃条件下设置5%、10%、15%和20%等4个土壤含水量,研究亚洲小车蝗卵的孵化前期、孵化历期、累积孵化率以及相对孵化率。结果表明,土壤类型、土壤含水量以及土壤类型与土壤含水量的交互作用对亚洲小车蝗卵孵化率影响极显著,而对卵孵化前期影响均不显著,卵孵化历期只受到土壤类型的显著影响。亚洲小车蝗卵在棕钙土中孵化率最高(42.5%～61.4%),其次为黑土,最低为砂土;孵化历期在棕钙土中(3.6±0.2 d)显著短于黑土和砂土。在棕钙土中,10%～20%含水量处理的卵孵化率(60.3%～61.4%)显著高于5%处理(42.5%);在黑土中,15%～20%处理的卵孵化率最高(49.8%～42.7%),其次为10%(28.4%),最低为5%处理(13.5%);在砂土中,5%处理的卵孵化率(38.7%)显著高于其他处理(12.9%～19.8%)。在3种不同土壤处理下,亚洲小车蝗卵的孵化均集中在前3 d,相对孵化率达到73.1%～98.0%;砂土的相对孵化率在第1天达到高峰,但与棕钙土和黑土的差异不显著;棕钙土和黑土的相对孵化率在第2天达到高峰,且显著高于砂土。因此,10%～20%含水量的棕钙土最适合亚洲小车蝗卵的孵化,孵化率高,孵化历期短,孵化时间更为整齐;其次为黑土;最次为砂土。     

The Insect Growth Regulator Pyriproxyfen Terminates Egg Diapause in the Asian Tiger Mosquito,Aedes albopictus

The Asian tiger mosquito, Aedes albopictus, is a highly invasive mosquito species that transmits chikungunya and dengue. This species overwinters as diapausing eggs in temperate climates. Early diapause termination may be a beneficial strategy for winter mosquito control; however, a mechanism to terminate the diapause process using chemicals is not known. We tested the hypothesis that a hormonal imbalance caused by the administration of juvenile hormone analog would terminate egg diapause in A. albopictus. We tested the insect growth regulator pyriproxyfen on all developmental stages to identify a susceptible stage for diapause termination. We found that pyriproxyfen treatment of mosquito eggs terminated embryonic diapause. The highest rates of diapause termination were recorded in newly deposited (78.9%) and fully embryonated (74.7%) eggs at 0.1 and 1 ppm, respectively. Hatching was completed earlier in newly deposited eggs (25–30 days) compared to fully embryonated eggs (71–80 days). The combined mortality from premature diapause termination and ovicidal activity was 98.2% in newly deposited and >98.9% in fully embryonated eggs at 1 ppm. The control diapause eggs did not hatch under diapausing conditions. Pyriproxyfen exposure to larvae, pupae and adults did not prevent the females from ovipositing diapausing eggs. There was no effect of pyriproxyfen on diapausing egg embryonic developmental time. We also observed mortality in diapausing eggs laid by females exposed to pyriproxyfen immediately after blood feeding. There was no mortality in eggs laid by females that survived larval and pupal exposures. In conclusion, diapausing eggs were the more susceptible to pyriproxyfen diapause termination compared to other life stages. This is the first report of diapause termination in A. albopictus with a juvenile hormone analog. We believe our findings will be useful in developing a new control strategy against overwintering mosquito populations.     

Seasonal variation in embryonic diapause of the striped ground cricket, Allonemobius fasciatus

ABSTRACT. The incidence and intensity of embryonic diapause in the striped ground cricket, Allonemobius fasciatus DeGeer (Gryllidae), is influenced by the date of oviposition and the incubation temperature. At 20C, embryos develop normally until the end of the appendage-formation stage when diapause occurs. The intensity of 'winter' diapause at this stage is greatest in eggs laid early in the season. Incubation at higher temperature induces a different and earlier 'summer' diapause. The higher the temperature the earlier the stage at which this developmental suppression is imposed. At 27 and 30C, some individuals develop without any interruption and hatch within 20 days. The proportion of these fast-developing eggs is low in summer but increases towards the end of the laying season. In nature, this species is univoltine and precocious hatching before winter is unlikely.
When embryos diapausing at an early stage at 27C are transferred to low temperatures, they resume development and enter winter diapause. The time required to reach the winter-diapause stage after transfer is inversely related to the temperature (30-30C). At 30C, sunmer diapause is neither induced nor maintained.     

Activity of NAD-sorbitol dehydrogenase is caused by biosynthesis of enzyme protein in diapause and non-diapause eggs of the silkworm,Bombyx mori

• 1.1. Using SDS-PAGE and immunoblotting analyses with anti-sorbitol dehydeogenase (EC 1.1.1.14, SDH) serum, changes in amount of SDH protein were examined in diapause and non-diapause eggs of the silkworm, Bombyx mori.
• 2.2. When diapause eggs were exposed to 5°C from 2 days after oviposition to break the diapause gradually, SDH protein appeared after 50-day chilling, and then the amount increased along with chilling period. This changing pattern paralleled that in SDH activity.
• 3.3. In diapause eggs treated with HCl after chilling at 5°C for 30 days to break the diapause quickly, and non-diapause eggs, changing patterns in amount of SDH protein also paralleled those in SDH activity.
• 4.4. These results showed that SDH activity was caused by biosynthesis of SDH protein, independent of diapause or non-diapause eggs.
• 5.5. Occurrence of SDH correlates with the three developmental phases: diapause termination, embryonic growth, and larval differentiation. In larva, SDH was mainly localized in the fat-body.

     

意大利蝗卵发育过程中血蓝蛋白基因表达分析

【目的】意大利蝗Calliptamus italicus是新疆草原的主要优势危害种,以卵在土壤中越冬。呼吸代谢可反映蝗卵的生理状态,呼吸蛋白对于呼吸系统不完善的蝗卵尤为重要。本研究旨在明确意大利蝗卵发育过程中血蓝蛋白基因的表达情况。【方法】采用实时荧光定量PCR方法检测不同发育阶段的蝗卵以及1龄蝗蝻的血蓝蛋白2个亚基基因Hc1和Hc2的表达量。【结果】根据解剖形态观察,将意大利蝗越冬卵的整个发育过程分为10个阶段,包括9个卵发育阶段(C-Ⅰ-C-Ⅹ)和1龄蝗蝻阶段(C-Ⅹ)。Hc1和Hc2在越冬蝗卵各发育阶段以及1龄蝗蝻中均有表达。其中,在蝗卵早期发育阶段(C-Ⅰ, C-Ⅱ和C-Ⅲ),Hc1表达量逐渐增加,C-Ⅲ阶段表达量显著高于C-Ⅰ和C-Ⅱ阶段;滞育阶段(C-Ⅳ, C-Ⅴ和C-Ⅵ),胚胎发育停滞,Hc1表达量较C-Ⅲ,C-Ⅶ和C-Ⅷ阶段低;滞育后发育阶段(C-Ⅶ和C-Ⅷ),蝗卵解除滞育,快速发育,Hc1表达量较早期发育阶段和滞育阶段高,其中,C-Ⅷ阶段Hc1表达量最高(212.3156±10.5470),显著高于其他所有阶段;1龄蝗蝻(C-Ⅹ)的Hc1表达量最低,为0.4017±0.1010。Hc2表达量在C-Ⅴ阶段最高(679.7511±54.5719),显著高于其他所有阶段;除C-Ⅴ阶段外,其他各阶段之间Hc2表达量差异均不显著。Hc1在蝗卵滞育后阶段高表达,而Hc2在蝗卵滞育阶段高表达。【结论】血蓝蛋白亚基基因Hc1和Hc2在整个意大利蝗卵发育过程均有表达,且具有阶段特异性。Hc1与Hc2协同作用为蝗卵发育供氧,其中,Hc1主要负责蝗卵滞育后发育期间的氧气运载,而Hc2主要维持滞育期间的氧气运载,且载氧效率较低。研究结果可为进一步探讨意大利蝗卵的抗逆机制提供科学依据。     

Influence of oviposition date and temperature upon embryonic development in Somatochlora alpestris and S. arctica (Odonata: Corduliidae)

In two bog-dwelling dragonflies, Somatochlora alpestris and S. arctica , the influence of oviposition date and temperature upon duration of embryonic development was studied. Egg diapause was facultative. With advancing season, the proportion of diapause eggs increases from 0 to 37% in S. alpestris and from 0 to 18% in S. arctica. Eggs needed at least 17 to 38 days for development. Hatching curves were temperature-independent in nearly all experiments but developmental rate increased at higher ambient temperature. In S. arctica , responses of developmental rate to temperature differed in eggs laid on different dates. In S. alpestris , duration of egg development decreased as season progressed. The duration of egg development of non-diapause eggs and proportion of diapause eggs in S. alpestris and possibly in S. arctica may also both be a function of female age at the time of oviposition. The ecological significance of the different development patterns is discussed.     

Temperature-dependent activation of ERK/MAPK in yolk cells and its role in embryonic diapause termination in the silkworm Bombyx mori

The silkworm Bombyx mori requires 2-3 months of low temperature (5 degrees C) to terminate embryonic diapause. The molecular mechanisms, however, are unknown. Extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) is temperature-dependently activated in the yolk cells of diapausing eggs after 45 days at 5 degrees C, coincident with the acquisition of developmental competence of the embryos at 25 degrees C. Yolk cell granulation and dissociation also begin in diapause eggs incubated at 5 degrees C for 45 days. We used dechorionated egg culture as a model system of diapause termination and observed that both yolk cell dissociation and embryonic development are inhibited by MAPK-ERK kinase (MEK) inhibitor U0126. Therefore, we suggest that ERK in yolk cells has a role in regulating changes in yolk morphology and termination of embryonic diapause in B. mori.     

A possible role of 20-hydroxyecdysone in embryonic development of the silkworm Bombyx mori

It has been well established that eggs of insects, including those of the silkworm Bombyx mori, contain various ecdysteroids and the amounts of these ecdysteroids fluctuate during embryonic development. In order to know the function of egg ecdysteroids in embryonic development of B. mori, we examined the biological activities of various egg ecdysteroids by in vitro ligand-binding assay and bioassay using B. mori eggs. First, using the ecdysteroid receptor of B. mori (BmEcR-B1/BmUSP heterodimer) prepared by yeast and Escherichia coli expression systems, the interaction between the ecdysteroid receptor and various egg ecdysteroids of B. mori was analyzed. The relative binding affinities of egg ecdysteroids to the BmEcR-B1/BmUSP heterodimer decreased in the order of 20-hydroxyecdysone > 2-deoxy-20-hydroxyecdysone > 22-deoxy-20-hydroxyecdysone > ecdysone > 2-deoxyecdysone > ecdysone 22-phosphate. Next, several egg ecdysteroids of B. mori were injected into the prospective diapause eggs, which show a very low level of free ecdysteroids at the onset of embryonic diapause (gastrula stage). Approximately 7% of them (P < 0.002, chi(2)-test) developed beyond the gastrula stage without entering diapause by the injection of 20-hydroxyecdysone (25 ng/egg). In contrast, the injection of other ecdysteroids was not effective in inducing embryonic development. These results suggest that 20-hydroxyecdysone, via the ecdysteroid receptor, is responsible for the developmental difference between diapause and non-diapause in B. mori embryos. Furthermore, it was suggested that continuous supply of 20-hydroxyecdysone may be required to induce embryonic development.     

Reversible change in embryonic diapause intensity by mild temperature in the Chinese rice grasshopper, Oxya chinensis

The effects of temperature on maintenance and termination of embryonic diapause were investigated in Jining (35.4°N, 116.6°E) and Sihong (33.5°N, 118.2°E) strains of the Chinese rice grasshopper, Oxya chinensis Thunberg (Orthoptera: Catantopidae). Eggs of both strains entered diapause when incubated at 30, 25, or 20 °C. Chilling at 8 °C had an evident effect on diapause termination and almost all eggs chilled for 60 days ended diapause development. Chilling of eggs at 8 °C for only 20 days failed to result in any hatching at 20 °C, suggesting that such level of chilling was not enough to induce diapause termination. However, the treatment combining incubation of eggs at 30 °C for varying lengths of time with subsequent incubation to 20 °C had a distinct effect on the completion of diapause of the eggs. The results indicate that there were two temperature optima, that is, low temperature (chilling) and high temperature, for diapause development in this grasshopper species. Incubation of chilled eggs at 20 °C for 5–15 days followed by further incubation at 25 °C reduced termination of diapause significantly compared with the eggs only chilled at 8 °C. Exposure of eggs chilled at 8 °C to a pulse of 25 °C from 1 to 7 days, separated by a 20-day interval at 8 °C, resulted in a decrease in the percentage of successfully hatched eggs as the length of the pulse of 25 °C increased. The results suggest that diapause intensity may be restored at moderately high temperatures. This reversible change in diapause intensity would play an important role in maintaining diapause before winter.