椰心叶甲啮小蜂对寄主的选择性、适宜性和功能反应

研究椰心叶甲啮小蜂(Tetrastichus brontispae Fer.)对寄主的选择性、适宜性和功能反应,结果表明:在温度(25 1)℃,相对湿度(75 5)%,光周期12h(L):12h(D)条件下,椰心叶甲啮小蜂主要选择寄主的预蛹和1,2日龄蛹。选择系数、平均寄生率分别为0.2276,0.2116,0.1951和77.78%,77.22%,66.67%,高于其他日龄蛹。不选择6日龄蛹,末龄幼虫只有近预蛹时才被选择。寄主被寄生后,其虫态、日龄不影响小蜂生长发育历期的长短,而对其出蜂率、出蜂量以及性比影响较大。测定这3项指标,结果表明:寄主的预蛹和1,2日龄蛹最适合啮小蜂的生长发育。其功能反应方程为:Na=0.3388N/(1 0.0715N),其寄生量随寄主密度增加而增高,但寄主密度达一定范围时,寄生量保持一定水平。椰心叶甲啮小蜂自身密度的干扰反应为:a=1.62116P-0.7264,表明随着自身密度的增加,寄生效果下降。因此,在大量培养繁殖或田间释放该蜂时,应选择适当的密度,才能获得较好的防治效果。     

蝇蛹金小蜂对黑腹果蝇蛹的寄生习性

黑腹果蝇是杨梅果实的主要害虫之一,蝇蛹金小蜂是黑腹果蝇蛹期寄生蜂.通过在杨梅园使用果蝇蛹进行诱集,获得蝇蛹金小蜂;并探讨蝇蛹金小蜂对果蝇蛹日龄的选择策略、产卵期和后代产量及寄主大小对寄生蜂后代大小和性比的影响.结果表明:蝇蛹金小蜂可利用1～3日龄的果蝇蛹;寄生蜂产卵期为(3.41±2.62)d,单个雌蜂后代雌雄蜂分别为(8.33±5.22)和(3.50±3.42)头,后代性比偏雌,雄性百分比为(0.28±0.20);随寄生蜂产卵期的延长,寄生蜂后代数量显著降低.后代寄生蜂的胫节长度与寄主的蛹长度间存在显著的正相关;在较大的寄主上,寄生蜂倾向于产出更多的雌性后代.     

异色瓢虫十九斑变型对豆黄蓟马成虫的捕食功能反应

异色瓢虫十九斑变型是长春地区大豆田中重要的捕食性天敌昆虫之一,为明确这种天敌昆虫对豆黄蓟马成虫的控制作用,在实验室条件下测定了其捕食作用以及密度和种内干扰对其捕食能力的影响。结果表明:异色瓢虫十九斑变型成虫对豆黄蓟马成虫的捕食功能反应符合HollingⅡ方程,回归模型为Na=0.934 6N/(1+0.0339N);异色瓢虫捕食作用受自身密度制约,平均捕食量随自身密度增大而减少,回归模型为A=13.534P~(-0.702 9);异色瓢虫成虫间存在种内干扰,干扰反应回归模型为E=57.218P~(-1.246)。异色瓢虫十九斑变型对豆黄蓟马成虫有较好的捕食作用和控制潜能。     

茶园三种蜘蛛对假眼小绿叶蝉捕食量的观察

草间小黑蛛(Erigonldium graminicolum)，粽管巢蛛(Clubiona yaponicola)斑管巢蛛(CIubiona maculata)成蛛的捕食能力与假眼小绿叶蝉(Empoasca Vitis)，若土，成虫密度呈负加速曲线型，符合Holling圆盘方程Na=a′TN/1 a′TnN°。三种蜘蛛成蛛对假眼小绿叶蝉成虫功能反应的数学模型分别为：Na=0.8528N/1 0.0333N、Na=0.6062N/1 0.030N,Na=1.1886N/1 0.0641;对若虫则分别为：Na=0.9849N/1 0.0256N、Na=0.6701N/1 0.0241N、Na=1 0.479N/1 0.0467N。     

寄生蜂与寄主的不同配比对椰心叶甲啮小蜂子代的影响

椰心叶甲啮小蜂(Tetrastichus brontispae Ferrière)是一种重要的椰心叶甲蛹寄生蜂。为了探讨繁育椰心叶甲啮小蜂的最佳寄主密度,研究1对椰心叶甲啮小蜂与椰心叶甲1日蛹的不同配比对椰心叶甲啮小蜂寄生与繁殖的影响。结果表明,雌蜂与椰心叶甲1日龄蛹的不同配比对椰心叶甲啮小蜂寄生率、每寄主出蜂量和后代性比有显著影响,当雌蜂与椰心叶甲1日龄蛹配比为1∶1时,椰心叶甲啮小蜂的寄生率和出蜂量最高,其寄生率为100%,每蛹平均出蜂量为27.67头,显著高于其它配比,但雌蜂与椰心叶甲1日龄蛹配比为1∶6时,椰心叶甲啮小蜂后代性比(雌蜂的百分比)最高为88.04%,显著高于其它配比。平均每雌怀卵量、出蜂率、羽化率在椰心叶甲啮小蜂与椰心叶甲蛹的不同配比之间无显著差异。     

白斑猎蛛对假眼小绿叶蝉的捕食作用

假眼小绿叶蝉是茶园的重大害虫之一,白斑猎蛛是假眼小绿叶蝉的重要捕食性天敌之一。室内条件下,白斑猎蛛对假眼小绿叶蝉的捕食作用的研究结果表明,白斑猎蛛对假眼小绿叶蝉具有一定的捕食作用。白斑猎蛛雌、雄蛛对假眼小绿叶蝉成、若虫的功能反应均为Holling型反应,白斑猎蛛对假眼小绿叶蝉控制能力(a/Th)的大小比较关系为:雌蛛对若虫>雄蛛对若虫>雌蛛对成虫>雄蛛对成虫。白斑猎蛛对自身密度的干扰反应可用E=Na/(NP)和E=QP-m拟合,表明白斑猎蛛个体之间具有极显著的相互干扰作用。      

古巴蝇生物学及生态学的初步研究

为了探索古巴蝇防治甘蔗螟虫在广西蔗区应用的可行性,广西甘蔗研究所于2004～2005年从古巴引进古巴蝇并进行了相应研究.结果表明:古巴蝇能寄生二点螟、条螟、黄螟和玉米螟等甘蔗害虫.化蛹率为70%～90%,羽化率在80%～90%.不能寄生桑蚕.能用非自然寄主大蜡螟人工繁殖古巴蝇,平均化蛹率为100.46%,平均羽化率为86.32%.古巴蝇喜欢温暖潮湿,在26～28℃、相对湿度75%～85%时,生长发育最佳,生物学周期为25～40d.接种(寄生)至化蛹为8～10d,蛹期为6～10d,雄蝇寿命3～6d,雌蝇寿命20～30d.0℃以下的低温和42℃以上的高温对古巴蝇的生长发育、化蛹和羽化不利,古巴蝇蛹在8～10℃保存5～10d羽化率不受影响,但蛹期相应延长.本研究对指导广西蔗区应用古巴蝇防治甘蔗螟虫,促进广西蔗糖业可持续发展有着重要意义.     

海南桑螟寄生蜂种类及优势种的寄生特性研究

为明确桑树主要害虫桑螟的天敌寄生蜂资源及其寄生特性并利用生物防治措施有效控制桑螟的危害,对海南主要桑园桑螟寄生蜂进行了系统调查和研究。结果表明,海南桑螟天敌寄生蜂主要有5种,分别为桑螟绒茧蜂Apanteles heterusiae Wilkinson、食心虫白茧蜂Phanerotoma planifrons Nees、红铃虫甲腹茧蜂Chelonus pectinophorae Cushman、菲岛长距茧蜂Macrocentrus philippinensis Ashmead和广大腿小蜂Brachymeria lasus Walker。其中,桑螟绒茧蜂为优势种,田间寄生率高达63.24%,1头桑螟幼虫可出蜂3~16头;其他4种寄生蜂均为单寄生,田间平均寄生率依次为9.15%、6.21%、5.62%和5.24%。室内寄生特性研究发现,桑螟绒茧蜂对桑螟龄期和密度具有选择性,主要寄生1龄和2龄桑螟幼虫,偶尔寄生3龄幼虫,仅在1龄桑螟幼虫密度为9和2龄密度为8头时寄生率最高,且出蜂量最大。待被寄生桑螟幼虫发育至5龄时从桑螟体内啮出,并在5~7 h内结茧化蛹,啮出幼虫可全部化蛹,4~5 d后羽化,羽化率为33.33%~ 100%,性比为0~87.50%,成蜂寿命为1~3 d,多为2 d,雄蜂寿命略短于雌蜂。未观察到桑螟绒茧蜂寄生家蚕。研究为桑螟绒茧蜂的规模化繁育和利用提供前提。     

警戒蝇豹对假眼小绿叶蝉的捕食功能反应

在实验室人工条件下，对警戒绳豹捕食假眼小绿叶蝉的功能反应进行了初步研究。结果表明：捕食对猎物密度的功能反应可用Holling Ⅱ 型模拟拟合，其功能反应的数学模型分别为：成蛛对成虫 Na=0.9369Nt/1 0.01965Nt；成蛛对若虫 Na=0.7115Nt/1 0.00884Nt；幼蛛对成虫 Na=0.6611Nt/1 0.0202Nt；幼蛛对若虫 Na=0.7046Nt/1 0.0113Nt 根据方程可得警戒蝇豹成蛛对假眼小绿叶蝉成虫与若虫一昼夜捕食量的上限分别为47.6头与80.5头；幼蛛对成虫与若虫则分别为32.6头与62.5头。     

条纹蝇虎对灰茶尺蠖幼虫的捕食作用

为明确条纹蝇虎（Plexippus setipes）对灰茶尺蠖（Ectropis grisescens）的防控效果,在室内条件下,开展了条纹蝇虎对灰茶尺蠖幼虫的捕食量、捕食功能反应、捕食选择性和种内干扰效应的研究。结果显示,条纹蝇虎偏好捕食灰茶尺蠖低龄幼虫,不同发育阶段捕食能力存在显著差异;其中成蛛捕食能力最强,日均可捕食灰茶尺蠖1龄幼虫17.44头,幼蛛捕食能力相对较弱,日均捕食1龄幼虫2.33头。条纹蝇虎捕食功能反应符合Holling Ⅱ模型,捕食量随灰茶尺蠖幼虫密度的增加而增加,而搜寻效应逐渐降低。捕食选择性试验表明,条纹蝇虎对灰茶尺蠖1龄幼虫和2龄幼虫表现为正喜好性（Ci>0）,对3龄幼虫表现为负喜好性（Ci<0）。条纹蝇虎对灰茶尺蠖幼虫的捕食作用同时受自身密度的影响,存在较强的种内干扰反应,该反应符合Hasse Ⅱ模型。研究表明,条纹蝇虎对灰茶尺蠖幼虫具有较强的捕食能力和良好的防控潜能,这为利用茶园蜘蛛天敌资源提供理论依据。     

营养条件和寄主密度对椰甲截脉姬小蜂子代的影响

椰甲截脉姬小蜂(Asecodes hispinarum Boucˇek)是椰心叶甲[Brontispa longissima(Gestro)]害虫的重要内寄生蜂,主要寄生害虫的4龄幼虫。为了更好地为室内繁殖寄生蜂提供理论依据,开展了营养条件和寄主密度的改变对椰甲截脉姬小蜂子代的影响。结果表明:(1)补充10%蜂蜜水作为营养的情况下,椰甲截脉姬小蜂寄生能力随寄主密度不同存在差异。每对寄生蜂在寄主数量为5时,被寄生的椰心叶甲数量最多,为2.33头。当寄主密度大于5时,椰心叶甲被寄生的数量有随寄主密度增加而降低的趋势;不补充营养时,寄生蜂的寄生能力差异不显著。(2)补充10%蜂蜜水时,寄主密度对每寄主出蜂量、椰甲截脉姬小蜂羽化率和后代性比并无显著影响。(3)不补充营养时,寄主密度对每寄主出蜂量和椰甲截脉姬小蜂后代性比均有显著影响,对椰甲截脉姬小蜂羽化率无影响,每寄主出蜂数量最多为45.67头,后代性比最高为96.66%。     

Functional and numerical responses of Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) parasitizing cotton whitefly, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae)

Laboratory experiments were conducted to measure the functional and numerical responses of Eretmocerus mundus Mercet parasitizing cotton whitefly, Bemisia tabaci Gennadius. Parasitoids were isolated singly for 24 h in 5 cm petri dishes with either 5, 10, 20, 40, 60 or 100 second nymphal stages of B. tabaci. Results showed a typical type II functional response, with up to 43.2 hosts attacked when 100 hosts were provided. The rate of attack and handling time were 0.0465 and 0.3341 days, respectively. At above mentioned densities, the parasitoids lived an average of approximately 4 days. At host densities of < or =20 host/day, the total number of eggs laid was limited by the number of hosts available. Total fecundity was highest with an average of 196 eggs/female at density 100.     

寄主龄期对松粉蚧抑虱跳小蜂寄生和发育的影响

通过限制选择和自由选择试验,研究松粉蚧抑虱跳小蜂(Acerophagus coccois Smith)在扶桑绵粉蚧(Phenacoccus solenopsis Tinsley)的1~3龄若虫与雌成虫体上的寄生及其子代生长发育情况。结果表明:在限制选择和自由选择的2种试验中,松粉蚧抑虱跳小蜂均可寄生扶桑绵粉蚧的1~3龄若虫和雌成虫,其中对2龄若虫的寄生率最高,分别是41.20%和45.00%;对粉蚧雌成虫的寄生率最低,但每头僵蚧平均羽化出蜂数最多,分别为9.42头和7.00头,子代雌蜂比例也最大;子代雌蜂在粉蚧1龄若虫体内发育的历期最长,为14.62 d;在粉蚧雌成虫上发育的历期最短,为13.97 d;在粉蚧1龄若虫体内发育的子代蜂的个体最小,在粉蚧雌成虫上发育的子代蜂个体最大。因此,利用松粉蚧抑虱跳小蜂防治扶桑绵粉蚧,应以粉蚧2龄若虫为防治对象,以粉蚧雌成虫为繁殖寄主。     

Body Size Plasticity of Weevil Larvae (Curculio davidi) (Coleoptera: Curculionidae) and Its Stoichiometric Relationship With Different Hosts

Parasites obtain energy and nutrients from the host, and their body size is also usually limited by host size. However, the regulatory mechanisms that control the plasticity of parasite body sizes and the stoichiometric relationships with their hosts remain unclear. Here we investigated the concentrations of 14 elements (C, H, O, N, P, S, K, Na, Ca, Mg, Al, Fe, Mn, and Zn) in the acorns of three oak species (Quercus spp.), in their endoparasitic weevil (Curculio davidi Fairmaire) (Coleoptera: Curculionidae) larvae and in the larval feces, and the weight of weevil larvae within different hosts in a warm-temperate zone of China. Our results showed that the three acorn species exhibited significant differences in C, H, O, P, K, Mg, and Mn concentrations. However, in the weevil larvae, only P, Mn, and C:P ratio revealed significant differences. Weevil larvae preferentially absorbed and retained N, Zn, Na, and P, whereas Mn, K, Ca, and O were passively absorbed and transported. The weevil larvae weight was associated with acorn stoichiometry, and positively correlated with acorn size. Weevil larvae P decreased, but Mn and C:P increased with their weight, implying highly variable in somatic stoichiometry are coupled with the plasticity of body size. Interestingly, weevil larvae weight was negatively correlated with acorn infection rate, indicating small-size parasitic insects might have higher fitness level in parasite–host systems than larger-size ones. Our results suggest that variation in P, Mn, and C:P in parasites may play critical roles in shaping their body size and in improving their fitness.     

龙吉稻田稻蛀螟发生为害及螟害株密度零频率估计法

稻蛀螟类是水稻常见害虫,为查明稻蛀螟发生为害情况和探索在一定精度保证前提下简便、快捷地估计螟害株密度的方法,对海南省澄迈县老城镇龙吉村稻田稻蛀螟发生为害进行了系统调查,并利用稻丛螟害株密度m和稻丛螟害零频率P0分别拟合线性函数、二次函数、双曲线函数、指数函数、幂函数、对数函数等常用函数模型及Gerrard-Chiang模型和Wilson模型。结果表明,龙吉稻田发生的稻蛀螟种类为三化螟[Scripophaga incertulas(Walker)]和大螟[Sesamia inferens(Walker)],其中早稻以大螟为主,晚稻则以三化螟占优;早、晚稻的螟害株密度从分蘖后期至乳熟期均呈先上升而后下降趋势,晚稻分蘖后期的螟害株密度明显高于早稻同生育期的,而早、晚稻的螟害株密度在孕穗期、抽穗期和乳熟期等同生育期间的差异不显著;用螟害零频率估计早、晚稻和早-晚稻螟害株密度的最优模型分别为Gerrard-Chiang模型m=1.164 9(-ln P0)1.045 4、双曲线函数模型m=-0.943 5+0.951 3/P0和m=-0.952 5+0.958 3/P0。应用这些模型在相应稻季可根据三化螟和大螟为害的零频率便捷、有效地估计螟害株密度。     

椰甲截脉姬小蜂对寄主龄期的选择性和适合性

研究了椰甲截脉姬小蜂对寄主椰心叶甲各龄幼虫的选择性。结果表明:椰甲截脉姬小蜂可寄生椰心叶甲各龄幼虫,但偏爱寄生2,3龄幼虫,选择系数分别为0.33825和0.31348,极显著高于1,4,5龄幼虫。寄生各龄椰心叶甲幼虫的姬小蜂在羽化率、每寄主育出蜂数2指标中存在差异,寄生4龄幼虫的处理中,羽化率和每寄主育出蜂数分别为71.03%和40.87头,明显高于寄生其他龄期的幼虫,因此4龄椰心叶甲幼虫对椰甲截脉姬小蜂的生长发育最适合。     

Determinants of parasitoid assemblages of the diamondback moth,Plutella xylostella,in cabbage farmer fields in Senegal

Conservation biological control, which fosters the optimal use of indigenous natural enemies, is a promising way for reducing pesticide reliance in horticultural systems. A two-year field survey was conducted in the main cabbage-producing area in Senegal (Niayes) to assess the potential of indigenous parasitoids to control populations of Plutella xylostella (Lepidoptera, Plutellidae). Results showed an overall low level of parasitism (11.7%) which was independent of host abundance, but was highly variable among fields (0–50%). Parasitism was predominant in the late part of dry season. Insecticide use, mostly relying on broad-spectrum insecticides, had a negative effect on the overall parasitism rate. Observations conducted throughout the cabbage crop cycle showed that parasitism unexpectedly decreased with crop aging (from 41 to 60 days post transplanting), likely due to repeated insecticide applications. Four main parasitoid species including Oomyzus sokolowskii (Kurdjumov) (Eulophidae) (48.8%), Apanteles litae Nixon (Braconidae) (32.5%), Brachymeria sp. (Chalcididae) (11.3%), and Cotesia vestalis Haliday (Braconidae) (7.3%) were identified. Parasitism due to O. sokolowskii was greater during the first part of the dry season whereas parasitism due to A. litae was greater during the second part of the dry season. Parasitism due to Brachymeria sp. was not affected by time of season but was greater in the Centre and North than in the South of Niayes. Parasitism due to C. vestalis was equal in the three zones but was higher in the late part of the dry season. The diversity of parasitoids was constant across zones but was greater during the second part of dry season. A positive relationship between diversity (Shannon diversity index H′) and parasitism rate was observed, suggesting a positive effect of parasitoid diversity on natural pest control. Parasitoids have a promising role to play as biocontrol agents of P. xylostella populations in Senegal, provided significant changes to current insecticide use are made. Better knowledge of their resource requirements including crop and non-crop habitats, and provision of these in and around crops is also needed.