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《昆虫知识》2021,(1)
滞育是昆虫长期适应不利环境的重要对策之一,对昆虫的生存、繁衍和进化都具有重要意义。滞育一般分为滞育前期、滞育期和滞育后期3个阶段,其中,滞育前期包括滞育诱导期和滞育准备期,是确保昆虫顺利进入滞育的重要时期。本文首先简要概括了光周期、温度、湿度、食料等外界环境因素在不同昆虫滞育诱导中的作用;然后系统综述了滞育激素、保幼激素、蜕皮激素、促前胸腺激素和胰岛素等内分泌激素,生物钟通路的节律基因,以及DNA甲基化、小RNA和组蛋白修饰等表观遗传修饰在昆虫滞育过程,尤其是滞育诱导调控中的作用,并以黑腹果蝇Drosophila melanogaster的生殖滞育为例,总结了昆虫滞育诱导调控的分子通路;最后就目前昆虫滞育诱导调控研究中亟待解决的问题和后续重点研究方向进行了探讨,展望了将昆虫滞育研究应用于害虫防控实践的主要策略和前景。 相似文献
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【目的】鉴于保幼激素(juvenile hormone, JH)与蜕皮激素(ecdysone, Ecd)在昆虫生长发育中的重要作用,本研究旨在明确这两种激素及其代谢相关基因对意大利蝗Calliptamus italicus卵发育过程的调控机制。【方法】采用ELISA技术检测意大利蝗卵发育过程中JH与Ecd含量的变化;采用qRT-PCR技术检测JH与Ecd代谢通路的重要基因(JHE,JHEH,DIB和EcR)在意大利蝗卵发育过程的表达模式。【结果】意大利蝗卵滞育阶段(阶段Ⅳ-Ⅵ)的JH含量显著高于早期发育阶段(阶段Ⅰ-Ⅲ)的,滞育后发育阶段(阶段Ⅶ-Ⅸ) JH含量显著下降;Ecd含量于滞育早期(阶段Ⅳ)显著上升,而后显著下降,滞育后发育阶段再次上升。JHE的表达量在意大利蝗卵早期发育阶段和滞育后发育阶段均呈先升后降的趋势,滞育阶段JHE的表达量较低;JHEH表达量在意大利蝗卵早期发育阶段也先升后降,滞育阶段变化不显著,滞育后发育阶段显著升高;DIB表达量在意大利蝗卵滞育阶段高于早期发育阶段的,在滞育后发育阶段下降;EcR表达量在意大利蝗卵早期发育阶段及滞育阶段均无显著变化,滞育后发育阶段... 相似文献
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过氧化氢(H2O2)是生物体内主要的活性氧来源之一。在超氧化物歧化酶(SOD)、过氧化氢酶(CAT)等的催化作用下,H2O2被降解,释放出活性氧。所以,生物个体发育过程中体内H2O2、SOD和CAT含量的变化反映着H2O2的代谢水平。另外,家蚕是蚕卵滞育昆虫,实验设计考虑到了滞育前后可能会有的差别。取产后10分钟内的卵为供试材料。采用即时浸酸法解除卵滞育。采用比色法和氧电极法测定并比较家蚕胚胎滞育形成与解除过程中过氧化氢的代谢。结果表明:(1)受精初期最低水平(Fig.2);(2)胚胎发育过程中(即时浸酸除滞有),H2O2量除168-216h处于低水平外均显著高于滞育卵(Fig.3),SOD活性分别在72h、168h,形成大小两峰,后期显著高于滞育卵(Fig.4),而CAT活性72-192h保持平衡,随后急剧上升,前期显著低于滞育卵,后于滞育卵(Fig.4),而CAT活性72-192h保持平衡,随后急剧上升,前期显著低于滞育卵,后期相反(Fig.5);(3)滞育形成过程中H2O2水平变化平缓(Fig.6),SOD活性前期剧烈活动,但后期保持平稳(Fig.7),CAT活性逐步升高(Fig.8),而浸酸解除滞育过程中H2O2水平显著高于滞育卵(Fig.6),SOD活性前期出现新峰,后期显著升高(Fig.7),CAT活性显著低于滞育卵(Fig.8)。结合他人的研究结果,可以推测:家蚕卵H2O2代谢状况可能在其滞育形成和解除中具有重要意义,或许酯酶A4计器假说与卵孔堵塞说可以通过H2O2而联系起来。 相似文献
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滞育是昆虫躲避不良环境的一种策略,对延续昆虫种群具有重要意义。特别是昆虫的兼性滞育,能够受环境的周期性季节变化影响,表观遗传可能在其中扮演重要角色。表观遗传是不依赖DNA序列改变所产生的可遗传变异,包括DNA、RNA、蛋白质和染色质水平上的各种表观遗传调控过程,可能参与生物的发育可塑性。昆虫滞育表观遗传调控主要包括两个方面:一是表观遗传调控如何响应滞育诱导的环境信号;二是环境信号诱导的表观遗传调控如何作用昆虫滞育。尽管已有报道提示DNA甲基化可以响应光周期信号,组蛋白乙酰化能够耦联昆虫内分泌信号,但表观遗传调控参与昆虫滞育的具体机制尚不完全清楚。表观遗传调控昆虫滞育在不同滞育类型的昆虫中都有报道。对于同一滞育类型,不同表观遗传过程之间可能存在协同,这种协同作用如何响应环境信号,又如何精确调节昆虫滞育仍不得而知。总之,现有研究仅仅展示了表观遗传调控昆虫滞育的可能性,昆虫滞育表观遗传调控的分子机制亟待深入研究,特别是以下几个方面:(1)表观遗传响应滞育诱导环境信号的分子机制研究;(2)表观遗传耦联内分泌调控的分子机制研究;(3)介导表观遗传调控的细胞信号转导研究;(4)表观遗传的协同调控在昆虫滞育中的功能研究。 相似文献
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大斑芫菁滞育幼虫在滞育不同阶段体内糖类和醇类含量的变化 总被引:1,自引:0,他引:1
在以卵滞育的昆虫中昆虫滞育时的生理代谢特点已经得到了大量研究。本文对以末龄幼虫(5龄)滞育的大斑芫菁Mylabris phalerate(Pallas)在不同滞育阶段体内糖类和醇类代谢的特征进行了研究。结果表明: 滞育个体血淋巴中的海藻糖含量高于非滞育个体,且随滞育时间的加大逐渐升高,滞育5个月时达到最大值,为5.61 μmol/mL。糖原的含量随滞育的进程逐渐减少,滞育初期(0.5个月)为0.72 mg/mL,到滞育末期(5个月)时仅为0.1 mg/mL。滞育个体脂肪体中的海藻糖含量都高于非滞育个体,滞育1个月时为非滞育个体的3倍,至滞育末期时达非滞育个体的5倍,为2.5 μmol/g脂肪体。糖原含量总体变化趋势是随滞育时间的加大逐渐减少,滞育早期和中期都高于非滞育个体。在滞育过程中血淋巴积累的小分子多元醇主要为甘油,其次是山梨醇;而在脂肪体中主要为甘油,其次是甘露醇,少量积累山梨醇:表明大斑芫菁滞育幼虫主要积累的是海藻糖和一些小分子多元醇。滞育幼虫在准备滞育时储备了大量糖原,这些糖原可能为滞育期间海藻糖、山梨醇和甘油的代谢提供了原料。 相似文献
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Yuki Nakamura Yoshitaka Suetsugu Katsutaka Oishi Katsuhiko Sakamoto 《Insect Science》2017,24(2):187-193
The bivoltine silkworm Bombyx mori (Lepidoptera: Bombycidae) exhibits a maternally controlled embryonic diapause. Maternal silkworms decide whether to lay diapause or nondiapause eggs depending on environmental factors such as the temperature and photoperiod during the egg and larval stages, and then induce diapause eggs during the pupal stage. However, little is known about the molecular mechanism that conveys the outcome of whether to produce diapause or nondiapause eggs from the egg or larval stages to the pupal stage. This study used microarray analysis to investigate differentially expressed genes in the larval brains of diapause‐ and nondiapause‐egg producers, to which bivoltine silkworms were destined by thermal or photic stimulation during the egg stage. The cytochrome P450 18a1 and Krüppel homolog 1 genes were upregulated in producers of diapause eggs compared with those of nondiapause eggs under both experimental conditions. Cytochrome P450 18a1 encodes a key enzyme for steroid hormone inactivation and Krüppel homolog 1 is an early juvenile hormone‐inducible gene that mediates the repression of metamorphosis. The upregulation of these genes during the larval stage might be involved in the signaling pathway that transmits information about the diapause program from the egg stage to the pupal stage in the silkworm. 相似文献
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In temperate areas, population dynamics of the invasive Asian tiger mosquito Aedes albopictus are strongly affected by winter. The work we present here analyzes the adaptive synchronization of the diapause process in the wintry generation of A. albopictus, where the egg stage is exposed to adverse winter conditions. The seasonal pattern of egg laying activity of a French Mediterranean population of the Asian tiger mosquito was monitored weekly for 2 years with ovitraps. The field diapause incidence and the critical photoperiod (CPP, i.e. the maternal day length inducing diapause in 50% of the eggs), were determined by hatching experiments on the collected eggs. The period of diapause termination was estimated by a field survey of the first hatchings for both years. The CPP is equal to 13.5 hours of light and occurs in the field on the 25th of August. Thus, it is on September 11th, 17 days after the CPP, that 50% of the eggs are in a prediapause stage in the field. The egg diapause rate increases rapidly during September, whereas the mean number of eggs laid decreases sharply after mid-September. Surprisingly, after having reached a peak of 95% at the end of September, from mid-October the diapause incidence declined and stayed below 50%. Indeed, both years the diapause initiates before the rapid decrease of the environmental temperature. This leaves a sufficient period of time to the complete development of one generation of A. albopictus with effective induction of diapause in the laid eggs. The very first larvae hatched were sampled both years in the first half of March. With 20 to 26 weeks in the egg stage and about 7 weeks in the larval stages, the first annual generation spends a long time in immature stages. On a practical point of view, this long development time represents a wide window for eggs and larvae control in early spring. 相似文献
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1. Diapause is a term used to describe an arrest in the development of insects as adults, eggs, or embryos, and allows survival during adverse environmental conditions. 2. The influence of maternal age on the proportion of eggs that entered an initial facultative diapause and on fecundity and egg mortality was investigated in the bushcricket Ephippiger ephippiger. 3. In the absence of variable abiotic cues such as temperature and photoperiod, most E. ephippiger females increase the proportion of their eggs that enter diapause as they age, however there are large differences among females, with a minority showing different trends. Fecundity and egg survival decline with female age and also differ among females. 4. The influence of age on the incidence of diapause is likely to be an adaptive reproductive strategy, as those eggs laid later in the season are unlikely to complete egg development before the onset of winter. Females are probably hedging their bets by diversifying the rate of development among their offspring and effectively spreading development over several seasons. The low predictability of future environmental conditions might explain the heterogeneity of female reproductive strategies. 相似文献
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Factors influencing the induction of diapausing egg production in the calanoid copepod Diaptomus leptopus 总被引:3,自引:0,他引:3
Field and laboratory studies were carried out between 1995 and 1997 on four populations of Diaptomus leptopus found in seasonally temporary, occasionally temporary, and a permanent environment to assess the relative importance of photoperiod and temperature regimes versus other proximate local cues in inducing diapause egg production. Patterns of diapausing and subitaneous egg production were determined by observation of individual females bearing clutches that were produced in the field. A laboratory common-garden experiment was performed to assess the effects of four different regimes of temperature and photoperiod on the induction of diapause. Patterns of diapausing egg production differed among ponds: diapause occurred early in the seasonally temporary environment and occurred rarely in the permanent environment. In the common-garden experiment, populations exhibited substantial changes in the onset of diapause when compared to patterns found under field conditions. These results provide indirect evidence that the different populations respond to available cues of environmental change in different ways in nature, or that environmental cues vary among habitats. 相似文献
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Hea-Son Bang Jae-Kyoung Shim Myung-Pyo Jung Myung-Hyun Kim Kee-Kyoung Kang Deog-Bae Lee Kyeong-Yeoll Lee 《Journal of Asia》2011,14(3):373-377
Paratlanticus ussuriensis eggs overwinter by entering diapause, which can be prolonged to more than 1 year depending on environmental conditions. To determine temperature effects on diapause duration of P. ussuriensis eggs, the rates of embryonic development and hatching were compared at various temperatures conditions by measuring embryonic stages and egg weights. Most eggs stayed in a very young stage (blastoderm formation, stage 4) when reared at 15 and 20 °C, 10–30% eggs developed into middle or late stages when reared at 25 °C, and most embryos developed fully (stage 23/24) when reared at 30 °C. Egg weight at 30 °C was 1.5 times higher than those reared at 20 °C. Chilling induced hatching in embryos at stage 23/24. Chilling caused stage 4 embryos to develop into stage 24, but they failed to hatch in response to a second warm period. Thus, P. ussuriensis eggs can overwinter either as young embryos (initial diapause) or as fully-developed embryos (final diapause). Eggs that experience an initial diapause overwinter again the second year in a final stage diapause. The post-diapause period was shorter when embryos overwintered in a final stage diapause. The hatching rate was highest in a temperature range of 7.5–15 °C. Our results suggest that temperature is an important environmental factor for the control of prolonged diapause in P. ussuriensis and initial diapause plays an important role in the control of its life cycle. 相似文献
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Omar Domínguez-Castanedo Ana María Rosales-Torres Mari Carmen Uribe 《Ichthyological Research》2017,64(4):464-469
The annual killifish inhabits in extreme locations with unpredictable rainy season where survives through the massive generation of embryos resistant of drought, capable to remain in a state of metabolic dormancy (three moments of diapause during embryonic development) protected by embryonic cortical structures: perivitelline space, egg envelope and its ornamented structures (trapeze-shaped projections and filaments in Millerichthys robustus). This research describes, for the first time, changes in cortical structures during three diapause stages in embryos of annual fish M. robustus during an annual life cycle. Embryos were collected in three periods through the year in a temporal water body: flood, drought and wet. During flood period all embryos were found in diapause I (during epiboly, dispersion of the blastomeres stage) with maximum thickness in all cortical structures and presence of egg envelope filaments. During drought period all embryos were in diapause II (development during somitogenesis, before the organogenesis) and its structures reduced its thickness significantly and lost the egg envelope filaments. Interestingly, embryos in diapause II and III (embryonic development completed in a pre hatching stage) were found during wet period (an example of bet-hedging strategy) in which all structures presented a recovery tending to its original condition observed during flood period. This research demonstrates that annual fish embryos respond to their exposure to seasonal environmental variations with dynamic structural changes that are fundamental for their survival. 相似文献
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Increased oxygen supply to diapause eggs of the silkworm (O2-incubation) effectively prevented diapause initiation and induced the same pattern of glycogen, polyol and lactate levels as was observed in normal non-diapause eggs. Sensitivity to oxygen decreased as embryonic development proceeded. After the termination of this sensitive period, accumulation of polyols and lactate followed.Experiments were carried out to test whether changes in the oxygen permeability of the egg membranes are involved in restricting the supply of this gas to eggs at the onset of diapause. Oxygen permeability of the chorion was measured with apparatus especially designed for this purpose. Although the chorion of the diapause egg was less permeable than that of the non-diapause egg, the oxygen permeability of the chorion does not change appreciably during the early developmental stages of the diapause eggs. The changes in rate of water loss through the egg membranes were measured during the early developmental stages of the embryos. The level of water loss decreased gradually as the formation of serosal cuticle proceeded. Moreover, it was observed that the water loss up to the time of formation of serosal cuticle was closely related to the oxygen permeability of the chorion.From these results, we suggest that the formation of the serosal cuticle may be an additional cause of the restricted oxygen supply at the onset of the diapause. 相似文献
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Genetic and phenotypic sources of life history variation along a cline in voltinism in the cricket Allonemobius socius 总被引:2,自引:0,他引:2
Clinal variation in life histories can be genetically based, resulting from selection imposed by different environments, or it may be due to the differential expression of phenotypically plastic traits. We examined the cline in voltinism in the egg-diapausing cricket Allonemobius socius, with populations spanning the switch from a univoltine to a bivoltine phenology. A common garden experiment was employed, using environments that mimicked photoperiod and temperature conditions found in the field. There were only small differences in development time among populations, and the difference in phenology observed in the field is likely due to clinal variation in the length of the growing season. We found large genetically-based differences in the reaction norm for egg diapause that were further magnified by environmental cues. The synergism of genetic and environmental effects was an example of cogradient selection. In the zone of transition between phenologies, voltinism appeared to be a conditional strategy, rather than a genetic polymorphism. First-generation females from this area can lay either direct-developing or diapause eggs depending on the likelihood that a second generation will have sufficient time to develop. For this species, the cline in voltinism is the result of a combination of environmental effects on development, and genetic and environmental influences on egg diapause propensity. 相似文献
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Abstract. Cabbage beetles, Colaphellus bowringi , undergoing an imaginal summer and winter diapause in the soil, show a great difference in diapause duration (from several months to more than 3 years) under natural conditions. The effects of diapause duration on future reproduction in the beetle are investigated at 25 °C with an LD 14 : 10 h photoperiod and under natural conditions. The fecundity of postdiapause adults with a short diapause of 5 months and nondiapause adults is similar, showing that a short diapause has no affect on reproduction, whereas the longevity of postdiapause adults with a short diapause of 5 months is significantly shorter than nondiapause adults, showing that a short diapause has a negative affect on longevity. The mean total egg production per female and longevities of postdiapause adults with long diapause periods of 16, 22, 29 and 34 months are similar to nondiapause adults, but the mean daily egg production per female is significantly higher than nondiapause adults, showing that extended diapause has a positive effect on postdiapause reproduction. The offspring of postdiapause parents require a relatively shorter time for egg development compared with the offspring of nondiapause parents, showing that diapause has a positive effect on their offspring's performance. However, there are no significant differences among offspring performance in terms of survival, adult longevity, mean egg production per female and mean daily egg production per female. 相似文献