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Effects of short-term heat stress on developmental parameters of Meteorus pulchricornis (Hymenoptera: Braconidae)

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Abstract

Global warming causes an increase in the average temperature butalso the intensity and frequency of extreme climatic conditions, such as short heat notoly waves. Extreme temperatures can impact parasitoid growth and development in hosts. Therefore, to understand the effect of heat waves on parasitic natural enemies of insect pests, we made laboratory experiments to examine developmental performances of the offspring of the solitary endoparasitoid, Meteorus pulchricornis, using Spodoptera litura larvae as hosts. Offspring parasitoids in the hosts received the heat shock treatment by 39ºC for 4 hours at the age of 1, 2, 3, 4, 5, or 6 days old after parasitism. Developmental survival, duration, adult body size, and longevity of offspring parasitoids were observed. Larval survival to pupa decreased in the host larvae that received the heat treatment at the age of 1 d and 5 d, by 36.1% and 28.6%, respectively, compared to controls. Larval duration was prolonged by 5.0%, 5.2%, 7.0%, and 12.1%, respectively, in the host larvae that received the heat treatment at the age of 2, 3, 5, and 6 d, respectively, compared to control. Adult hind tibia length decreased by 1.8% and 2.6%, respectively, in the hosts that received the heat treatment at the age of 5 and 6 d. Pupa-to-adult duration, pupa-to-adult emergence rate, and adult longevity were not influenced by the heat shock treatment. The results of the present study suggest that older larvae of M. pulchricornis were more vulnerable to heat waves than younger ones.
37 卷第
2017
生 态 学 报
ACTA ECOLOGICA SINICA
Vol.37,No.
Apr.,2017
http / www.ecologica.cn
基金项目国家自然科学基金项目( 31570389) ; 国家科技支撑计划项目( 2012BAC19B01 ) 和国家公益性行业 科研 专 项 ( 200903003,
201103002)
收稿日期2015⁃ 00⁃ 00;     网络出版日期2016⁃ 00⁃ 00
通讯作者 Corresponding author. E⁃mail: lbp@ njau. edu.cn
DOI10.5846 / stxb201511142311
孟倩孟玲李保平短时高温胁迫对斑痣悬茧蜂发育指标的影响生态学报,2017,37( 8) :  ⁃  
Meng Q, Meng L, Li B P. Effects of short⁃term heat stress on developmental parameters of Meteorus pulchricornis ( Hymenoptera: Braconidae ). Acta
Ecologica Sinica,2017,37(8) :  ⁃   .
短时高温胁迫对斑痣悬茧蜂发育指标的影响
  李保平
南京农业大学植物保护学院 农作物生物灾害综合治理教育部重点实验室南京  210095
摘要全球气候变化不仅包括平均气温上升而且诸如热浪的极端天气事件出现的频率和程度也增大寄生蜂虽在寄主体内完
成生长发育也会受到极端气温的影响为探究短时高温 对寄 生性 天敌 斑痣 悬茧 Meteorus pulchricornis虫发育表现的
以斜纹夜蛾Spodoptera litura幼虫为寄主分别对 1—6 日龄子代蜂进行 39℃ 、持续 4h 的高温胁迫处理发育全程进行
29℃ 、26℃ ) 处理为对照观察子代存活发育历期羽化和成虫寿命等发育指标温胁迫处理 龄子代蜂幼
虫使幼虫存活率下降与对照相比分别降低 36.1%28.6% 高温胁迫可延长子代蜂幼虫发育历期与对照相比高温处理 2、3、
日龄子代蜂幼虫使幼虫发育历期分别延长了 5.0% ,5.2% ,7.012.1%;高温胁迫处理 、6 日龄子代蜂幼虫使羽化出的
成虫体型用后足胫节长度表示比对照分别减小 .8% 2.6%。 高温胁迫处理对子代蜂蛹发育历期化率以及成虫寿命
均没有显著影响本研究结果说明短时高温胁迫对斑痣悬茧蜂高龄幼虫的负面影响比对低龄幼虫大
关键词温度适应热激温度生活史特征寄生蜂
Effects of short⁃term heat stress on developmental parameters of Meteorus
pulchricornis HymenopteraBraconidae
MENG Qian, MENG Ling, LI Baoping
College of Plant Protection Key Laboratory of Monitoring and Management for Plant Diseases and Insect PestsMinistry of AgricultureNanjing Agricultural
UniversityNanjing 210095, China
Abstract Global warming causes an increase in the average temperature and the intensity and frequency of extreme climatic
conditions, such as short heat waves. Extreme temperatures can impact parasitoid growth and development in hosts.
Therefore, to understand the effect of heat waves on parasitic natural enemies of insect pests, we developed laboratory
experiments to examine developmental performances of the offspring of the solitary endoparasitoid, Meteorus pulchricornis
using Spodoptera litura larvae as hosts. Offspring parasitoids in the hosts received the heat shock treatment by 39℃ for 4
hours at the age of 1, 2, 3, 4, 5, or 6 days old after parasitism. We examined developmental survival, duration, adult body
size, and longevity of offspring parasitoids. Larval survival to pupae decreased in the host larvae when receiving the heat
treatment at the ge of and d, by 36. 1% and 28 . 6%, respectively, compared to the control. Larval duration was
prolonged by 5.0% , 5.2% , 7.0%, and 12.1, respectively, in the host larvae when receiving the heat treatment at the age
of , 5, and 6 d, respectively, compared to the control. Adult hind tibia length decreased by 1. % and 2. 6%
respectively, in the hosts when receiving the heat treatment at the age of 5 and 6 d. Pupa⁃to⁃adult duration, pupa⁃to⁃adult
emergence rate, and adult longevity were not influenced by the heat shock treatment. The results of the present study suggest
that older larvae of M. pulchricornis were more vulnerable to heat waves than younger ones.
not only
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Key Words: thermal adaptation; heat shock; temperature; life history traits; parasitoid wasp
全球气候变暖是国际社会面临的严峻挑战[ 1] 全球气候变暖不仅包括平均温度的升高还包括极端气
候事件比如热浪频率和强度的增[2] 高强度高频率的热浪将更加常见[3] 昆虫作为变温动物
其生长发育对气温极为敏感昆虫有其生长发育繁殖及存活等生命活动的适宜温度范围当温度超过最适
范围后昆虫的生命活动就会受到严重的影响[4 ] 解昆虫在高温胁迫下行为以及生理上的反应可以帮助
我们预测在气候变暖情况下昆虫的分布生态位的变化以及物种灭迹的可能性[5] 特别是寄生性天敌其控
制害虫的能力大部分取决于它们对环境的适应能[ 6] 通常依赖于寄主的生理条件以及寄主植物的生态环
因此对气温的变化更加敏感对寄生性天敌昆虫的相关研究表明对燕麦蚜茧蜂Aphidius avenae 阿尔
蚜茧蜂A. ervi 桃赤蚜茧蜂A. matricariae和角釉小蜂Hemiptarsenus varicornis等的幼虫期进行短暂的高
温胁迫可使其存活率下降发育历期延长以及繁殖力下降等[7⁃ 10] 但这些研究均把幼虫期作为一个整体虫
态进行胁迫处理未进一步区分其不同阶段对高温胁迫的反应寄生蜂幼虫期发育经历着较大的形态和生理
变化过程[11] 其对胁迫的反应 能存在差 本研究通过比较寄生蜂幼虫不同时期对高温胁迫的反
旨在找出敏感时期从而为预测高温胁迫对寄生性天敌的影响提供依据
斑痣悬Meteorus pulchricornis为单寄生容性内寄生蜂舞毒 Lymantria dispar [ 12] 棉铃虫
Helicoverpa armigera[ 13] 斜纹夜蛾Spodoptera litura和甜菜夜蛾S. exigua[14] 等重要农林害虫的优势种寄
生蜂该蜂活动于夏秋季偏好寄生幼虫中间几个龄期本研究以斜纹夜蛾幼虫为寄主于寄主幼虫发育期
内不同时期进行短时高温处理观察和比较子代蜂的生长发育表现以揭示寄生蜂幼虫期不同阶段对高温胁
迫的反应
1  材料与方法
1  供试昆
斑痣悬茧蜂从南京农业大学江浦实验农场大豆试验田采集的斜纹夜蛾幼虫饲养获得在室内以斜纹夜蛾
2—3 龄幼虫作为寄主继代饲养供试寄主斜纹夜蛾幼虫在室内用人工饲料继代饲养[15] 饲养环境的温度
26℃ ,光周期为 14h / 10 相对湿度为 60% 10%
2  实验方
取供试寄主斜纹夜蛾 龄末至 龄初的幼虫单头称体重后放入试管中释放 4—6 龄有寄生经历
的雌蜂观察到寄生蜂完成 次有效针刺产卵器扎入约 5 s拔出时拍动翅膀取出寄主幼虫单头放于有
人工饲料的培养皿中置于人工气候箱内进行温度处理常温23:00—次日 6:00 时之间为 26℃ ,余时间
29℃ ) 和高温胁迫12:00—16:00 时之间为 39℃ ,其余同对照) ,39℃ 是我国华东地区夏季极端高温日略
高于上限气温( 37℃ —38℃ ) 的温度南京农业气象网页 http: / nq .njqxj. gov. cn / ) 。 个幼虫日龄处理
寄生后第 、2、3、4、5 天接受高温胁迫处理将刺扎寄生后一直进行常温处理的幼虫作为对照每日观察
上午 8 ∶ 00 和下午 8 ∶ 00 直到寄生蜂羽化为成虫观察和测量子代蜂存活羽化成虫寿命和体型大
用后足胫节长度代表每处理重复≥50
3  数据分
子代蜂存活的观测值为二进制数据符合二项式分布型故采用 logistic 模型拟合子代蜂幼虫发育历期
从雌蜂产卵到子代蜂化蛹的时间蛹历期从子代蜂化蛹到羽化的时间子代蜂后足胫节长度和成虫寿命
观测值属于连续数值数据符合高斯分布型故采用一般线性回归模型拟合分析中以寄主体重为协变量
消除其影响为确立幼虫期对高温胁迫的敏感阶段将各个幼虫日龄处理与对照进行比较假说检验的显著
性概率水平为 5%数据分析用 统计软件[16]
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2  结果与分析
1  高温胁迫对斑痣悬茧蜂子代蜂存活的影响
拟合 logistic 模型结果表明日龄为 —6 d 的子代蜂经过高温胁迫后的存活率在 51.180.6%
与对照相比寄生后1、5 天接受高温胁迫处理的子代蜂幼虫存活率显著下降分别下降 36.128.6% (
1A) 高温胁迫不影响子代蜂蛹至成虫的羽化化率在 50%87%之间B)
1  高温胁迫对子代蜂幼虫存活和成虫羽化的影响
Fig.1  Effects of the heat stress on larval survival to pupa and pupa⁃to⁃adult emergence rates of offspring parasitoids receiving
the treatments at different larval ages
幼虫各处理水平(1— 6d)以及对照的存活率观测样本数分别为 45、40、39、44、49、31 30,成虫羽化率观测样本数分别为 23、30、24、24、27、
25 28. Sample sizes were 45, 40, 39, 44, 49, 31 and 30 in measuring egg⁃to⁃pupa survival rates of offspring parasitoids, and 23, 30, 24, 24, 27,
25 and 28 in measuring pupa⁃to⁃adult emergence rates, for the treatments of 1—6 day larvae and the control. ∗代表与对照间存在显著差异
0.05) ∗indicates a significant difference between the treatment and the control
2  高温胁迫对斑痣悬茧蜂幼虫发育历期和蛹历期的影响
一般线性模型拟合表明日龄为 1—6 的子代蜂幼虫经过高温胁迫后的发历期平均值在 7. .7
之间与对照相比寄生后 2、3、5、6 天接受高温胁迫处理的子代蜂幼虫发育历期显著延长分别延长
5.0%、5.2%、7.0%、12.1%2 A) 高温胁迫不影响子代蜂蛹的发育历期平均为 .0—6.4 d( 2 B
2  高温胁迫对子代蜂幼虫发育历期和蛹历期的影响
Fig.2  Effects of the heat stress on larval and pupal duration of offspring parasitoids receiving the treatments at different
larval ages
图柱上的短柄代表标准误 Bars are standard errors of the mean
3  高温胁迫对斑痣悬茧蜂成虫体型大小和寿命的影响
一般线性模型拟合表明高温胁迫处理日龄为 1—6 的子代蜂幼虫后发育至成虫后的后足胫节长度在
1.55—1.59 mm 之间与对照相比寄生后第 5、6 天接受高温胁迫处理的子代蜂成虫体型显著减小分别减小
      短时高温胁迫对斑痣悬茧蜂发育指标的影响  
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1.8.6% ( A) 高温胁迫不影响子代蜂成虫寿命平均为 .2—5.8 d( 3 B
3  高温胁迫对子代蜂成虫后足胫节长度和成虫寿命的影响
Fig.3  Effects of the heat stress on adult hind tibia length and adult longevityof offspring parasitoids receiving the treatments at
different larval ages
3  讨论
本研究发现高温胁迫斑痣悬茧蜂不同日龄幼虫对幼虫发育表现具有不同的影响对不同发育指标的影
响也不一致高温胁迫处理的 日龄子代蜂幼虫的幼虫期存活率显著低于其他处理的日龄幼高温
处理晚期幼虫对幼虫发育历期和羽化出蜂体型大小的不良影响大于处理早期幼虫
一般来说斑痣悬茧蜂幼虫期通常可以划分为三个时期即卵期1—2 d) 初龄幼虫期(3—4 d) 和高龄幼
虫期5—6 d 寄生蜂的胚胎发育是一个连续的过程根据发育特征可分为 个阶段早期发育阶段胚体
长期原躯原头分化阶段器官形成阶段胚胎成熟期[ 17] 产卵后 20—32 h 为原肠胚形成及器官发育期
一阶段胚带细胞裂殖旺盛并形成原肠沟是卵期生长发育的关键[18] 若干研究表温度不仅影响卵特性
而且影响卵孵化后的表现[19] 但有时后期表现可弥补早期经历的不足[20] 昆虫卵期由于快速热传导
以及较 短 的 发 育 历 期因 此昆 虫 卵 期 可 能 对 高 温 胁 迫 更 加 敏 感[21] 例 如吴 静[22] 对 螟 黄 赤 眼 蜂
Trichogramma chilonis的研究发现卵期受到的影响大于后续虫态但在某些植食性昆虫中高龄幼虫受高
温胁迫的影响大于低龄幼虫例如家蚕Bombyx mori幼虫对高温的耐受性顺序为:1 >3
即高龄幼虫对高温胁迫较敏感[23] 对麦无网长管蚜Metopolophium dirhodum进行短暂的高温胁迫后
发现老熟幼虫对高温具有较差的耐受性[24] 由这些研究可以推测昆虫受高温胁迫的影响并非随发育进程
表现出线性变化趋势对容性寄生蜂来说对抗寄主强大的免疫系统是在发育过程中面对的挑战[25]
今很少有关于温度变化对免疫系统影响的研究报道[26]
本研究发现,2、3、5 日龄子代蜂幼虫经过高温胁迫后幼虫发育历期延长说明短暂的高温胁迫可能
抑制子代蜂的生长发育速度在高适温区范围内昆虫通常随着温度的升高发育速率反而减慢使卵期和
虫期延长[27] 昆虫各虫态发育速率均与外界温度之间呈“ S” 型曲线关系例如杨孝龙等 28] 研究
19—3l℃ 温度范围内红点唇瓢虫Chilocorus kuwanae各虫态的发育历期会随温度的升高而缩短但超过
33℃ 其发育速率受到抑制林智慧等[ 29] 发现南美斑潜蝇Liriomyza huidobrensis卵期随着温度的升高而延
,40℃ 时卵期最长显著长于其他温度下31℃ 37℃ ) 卵期说明高温对卵的发育有明显抑制作用
本研究中 日龄子代蜂幼虫发育历期并没有延长究其原因可能与寄生蜂不同时期对高温的忍耐力
或敏感性差异有关具体原因有待进一步研究
一般认为成虫体型大小是其繁殖力和适合度的线性函从而成为衡量昆虫繁殖力[30] 和适 31]
一项重要的适合度相关特征本研究发现,5 日龄子代蜂幼虫经过高温胁迫后成虫体型显著减小
龄为 0—4 的子代蜂幼虫经过高温胁迫后成虫体型未有明显变化从该结果可以推测高温胁迫高龄幼虫
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可能影响成虫的繁殖力对其他昆虫的研究也有类似的发现对麦无网长管蚜高龄幼虫 进行高温胁
迫后成虫生殖力比低龄幼虫2、3 下降得多[24] 小菜蛾Plutella xylostella高龄幼虫经过 40高温胁迫
处理后生殖力比低龄幼下降得多[32] 对褐飞虱Nilaparvata lugens龄若虫进行 40高温胁迫处理
发现成虫的产卵量明显下降[33] 同样,4 龄异色瓢虫Harmonia axyridis幼虫经过高温胁迫后成虫体型明
显变小而对初龄幼虫的高温处理却没有影响[ 34] 对昆虫不同发育阶段进行高温胁迫其结果对成虫的繁殖
力是否有影响取决于昆虫是否有足够的时间从热伤害中恢复有[ 32] 高龄幼虫经过高温胁迫后能没
足够的时间修复热损伤因此导致成虫的繁殖力下降本研究未发现成虫寿命受高温胁迫处理的不利影响
原因可能在于观测时间间隔太大导致很多观测值重叠而无法获得统计上的显著性差异
本研究结果说明不同日龄的斑痣悬茧蜂子代幼虫对高温的耐受性存在明显差异总体而言高龄幼虫
容易受到高温胁迫的负面影响是对高温胁迫较敏感的时期
致谢南京农业大学植物保护学院硕士研究生荣星在试验中给予帮助谨致谢意
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