取食不同糖分对卵育型寄生蜂潜蝇姬小蜂雌蜂寿命和卵子发生的影响

取食糖类物质有利于延长具寄主取食特性的卵育型寄生蜂的寿命。为了明确自然界常见糖分对卵育型寄生蜂的营养功能差异, 本研究比较了取食葡萄糖、 果糖、 蔗糖、 海藻糖和松三糖5种常见糖分对斑潜蝇类害虫的优势寄生蜂潜蝇姬小蜂Diglyphus isaea雌蜂寿命和卵子发生的影响。结果显示: 取食5种糖均能显著延长雌蜂寿命（P<0.0001）; 取食果糖的雌蜂寿命显著长于取食葡萄糖、 蔗糖、 海藻糖和松三糖的雌蜂寿命（P<0.0001）, 取食葡萄糖、 蔗糖和海藻糖3个处理间差异不显著（P>0.4234）, 但均显著长于取食松三糖（P<0.0001）; 同时, 各个处理的雌蜂寿命与其个体大小均分别呈显著正相关关系。初羽化雌蜂卵巢中没有Ⅲ级卵子（即成熟卵子）; 清水处理的雌蜂, 24 h后卵巢中Ⅲ级卵子达到高峰, 48 h时则全部重吸收; 而取食5种糖的雌蜂, 卵巢中的Ⅲ级卵子和总卵子数量整体上均呈现先显著上升而后逐步下降的趋势, 取食不同糖分的雌蜂卵子形成高峰期的时间不同, 而且取食不同糖分的雌蜂间Ⅲ级卵子高峰日数量和总卵子高峰日数量均无显著差异（P>0.05）。该研究结果为潜蝇姬小蜂的大量室内饲养和田间释放提供了依据。     

哈氏啮小蜂雌蜂的繁殖生物学特性

哈氏啮小蜂Tetrastichus hagenowii（Ratzeburg）是卫生害虫蜚蠊的重要天敌昆虫, 能寄生多种蜚蠊种类的卵荚, 被认为是控制蜚蠊危害最具潜力的天敌昆虫。本文对哈氏啮小蜂雌蜂的繁殖生物学特性进行了系统研究。结果表明: 哈氏啮小蜂行孤雌生殖和两性生殖的繁殖方式, 两性生殖其子代雌蜂所占比例为46.02%, 而孤雌生殖其子代均为雄性。经解剖镜检证实: 雌蜂发育至性成熟时的两侧卵巢结构呈现为, 每侧卵巢有8~12根卵巢管, 每根卵巢管怀卵量约1~6粒。结果发现雌蜂发育日期影响其怀卵数量, 1日龄哈氏啮小蜂怀卵量低, 平均为45.2粒/♀; 2日龄哈氏啮小蜂怀卵量较高, 平均为80.1粒/♀。哈氏啮小蜂羽化后即性成熟产卵, 产卵期为4~11 d, 日产卵量为0.86~7.57粒/♀, 单雌一生平均寄生1枚美洲大蠊卵荚。供试寄主卵荚密度是影响哈氏啮小蜂寄生率的重要因素, 在蜂卵荚比例为1∶5, 1∶3, 1∶2, 1∶1, 2∶1和3∶1范围内, 哈氏啮小蜂对卵荚的寄生率随着雌蜂数量与寄主卵荚比例的提高而增加, 然单雌寄生卵荚数量却呈下降趋势。     

蝇蛹俑小蜂卵巢发育的研究

对寄生蜂卵巢发育的研究是生理学和生物防治的重要基础。本文研究了从瓜实蝇蛹刚羽化至死亡的蝇蛹俑小蜂雌蜂的卵巢发育。结果表明蝇蛹俑小蜂内生殖系统由1对卵巢、1对侧输卵管、中输卵管、受精囊、受精囊腺等组成,羽化后卵巢迅速发育,卵巢指数从0.34 mm~2增大到0.48 mm~2,卵粒数从37.67增加到42.67。雌蜂发育4 d后,卵巢逐渐萎缩,卵巢指数、卵粒数减少。本研究得出2日龄雌蜂繁殖力最强,对评估蝇蛹俑小蜂品质和放蜂时间有潜在应用价值,使其能在生物防治过程中发挥更大的潜能。     

低温对蝶蛹金小蜂卵成熟及其数量动态的影响

寄生蜂卵成熟动态影响其产卵决策行为,因而对于认识寄生蜂搜寻行为生态学机理具有重要意义。以蝶蛹金小蜂(Pteromalus puparum)-菜粉蝶(Pieris rapae)为模式生物,首先连续3周每隔24 h详细观察子代蜂幼期不同发育阶段的体型、卵巢管以及寄主蛹的外部形态,以此为基础观察了低温处理(模拟越冬温度)被寄生蛹对子代蜂成熟卵数量动态的影响。蝶蛹金小蜂胚后发育历时约2周,其中卵期1 d;幼虫历期约7 d。初孵幼虫体透明;胚后第3—6天体积快速增大,然后减缓,体色由绿变黄;胚后第8天进入预蛹,第9—12天蛹淡色,复眼由淡黄变为深红,第13—14天蛹暗黑色,并逐渐带有金属光泽。卵巢管在羽化当天即开始沉积卵黄,并在羽化后1—4 d连续增加直到出现卵吸收;羽化后5—6 d成熟卵数量增速不明显甚至略有减小。寄主蛹随子代蜂从卵发育至幼虫再到蛹体色从绿色变为灰褐色再到土黄色。低温处理被寄生的寄主蛹(寄生蜂处于老熟幼虫或蛹期)后,羽化成虫的卵巢管略细,成熟卵数量较少。成熟卵数量的变化不仅受低温处理的影响,而且受雌蜂体型大小和日龄的影响;低温处理明显减缓卵成熟速率,各日龄期成熟卵数量均明显减少;适温下成熟卵数量于羽化后第4天达到峰值,而低温处理下成熟卵数量达到峰值的时间延迟至第7天。研究表明,越冬低温对来年羽化的蝶蛹金小蜂卵成熟动态具有不良影响。     

温度对野蚕黑卵蜂卵巢发育和卵子发生的影响

分别在19、22、25、28和31℃条件下,观察不同温度对野蚕黑卵蜂Telenomus theophilae Wu et Chen(Hymenoptera:Scelionidae)雌蜂卵巢发育和卵子发生的影响.结果表明,在19～28℃之间,雌蜂卵巢生长,基端卵子生长和卵巢中卵子发生的速度随温度上升而逐步加快.在31℃下,羽化1d后雌蜂卵巢长宽显著短于25℃和28℃下同日龄的的雌蜂,卵巢中成熟卵也显著减少,但从羽化后第2d开始,各项指标均与25℃和28℃下的接近.这说明该蜂对温度的适应范围较广,在19～31℃之间,虽然野蚕黑卵蜂的卵巢发育速度不同,但所能达到的最大卵量没有明显差异,说明这5个温度对于该蜂的卵子形成均较为适宜.     

日本食蚧蚜小蜂的交配行为及雌蜂生殖系统观察

日本食蚧蚜小蜂Coccophagus japonicus Compere是橡副珠蜡蚧Parasaissetia nigra Nietner的优势寄生蜂之一,为明确其交配行为及雌蜂生殖系统构成,本研究在室内观察了该蜂的交配行为、雄蜂交配能力、雌蜂生殖系统等。结果表明:日本食蚧蚜小蜂的交配过程可分为交配前行为、交配、交配后行为3个阶段,整个交配过程平均时间为76.2 s,其中,交配时间为20.6 s;小蜂羽化当天即可交配,雌、雄蜂具有多次交配的习性,雄蜂的交配能力随其日龄的增加而减弱,1日龄的雄蜂交配能力最强,为6.3次/d,雄蜂一生平均能交配36.9次;雌蜂的生殖系统由1对卵巢、1对侧输卵管、1条中输卵管、1个受精囊和外生殖器等组成,卵巢管数量存在变异,其中95.78%雌蜂卵巢具6(3+3)条卵巢管,2.78%雌蜂卵巢具5(3+2)条卵巢管,1.22%的雌蜂卵巢具7(3+4)条卵巢管,0.22%的雌蜂卵巢是具4(2+2,1+3)条卵巢管,还有极个别的雌蜂仅有1个卵巢,由3条卵巢管组成。研究结果表明日本食蚧蚜小蜂有多次交配习性,卵巢存在一定变异。     

补充非寄主食物对芙新姬小蜂和潜蝇姬小蜂控害行为权衡的影响

芙新姬小蜂和潜蝇姬小蜂均为强卵育型(synovigenic)寄生蜂,成虫具有产卵寄生致死、寄主取食致死和寄主叮蛰直接致死3种寄主致死行为。为了明确成虫补充非寄主食物营养对2种姬小蜂控害潜力/控害行为的影响,本文比较研究了分别提供寄主食物和寄主食物+非寄主食物(10%葡萄糖)条件下的2种姬小蜂在初羽化前期(前6 d)内对美洲斑潜蝇幼虫的致死行为的影响。结果显示:在仅提供寄主食物时,芙新姬小蜂的寄生、取食和总体致死量均显著的高于潜蝇姬小蜂,但是直接致死能力却弱于后者;补充非寄主食物和仅提供寄主食物处理相比,两种寄生蜂的寄生量,取食量和总致死量均呈下降趋势。该研究显示:在初羽化前期,取食寄主食物的雌蜂比取食寄主食物+葡萄糖的雌蜂具有更强的致死能力。     

椰心叶甲啮小蜂的繁殖生物学研究

对椰心叶甲啮小蜂羽化、求偶、交配、产卵、繁殖现象进行了观察研究。结果表明,补充营养对雌蜂的寿命和繁殖力均有影响。没有补充营养的情况下,雌蜂的平均寿命为2.48 d,一生可产21.43粒卵;每天补充10%蜜糖水,且雌蜂与寄主(椰心叶甲初蛹)比例为1:3时,雌蜂平均寿命为13.43 d,一生可产53.6粒卵;每天补充10%蜜糖水,且雌蜂与寄主(椰心叶甲初蛹)比例为1:1时,雌蜂平均寿命为14.78 d,一生可产42.5粒卵。椰心叶甲啮小蜂对水椰八角铁甲蛹的寄生率为82.25%,平均每寄主出蜂量为12.24头。     

木虱啮小蜂对枸杞、枸杞木虱的行为反应

木虱啮小蜂Tetrastichus sp.是枸杞木虱Paratrioza sinica Yang & Li若虫外寄生蜂,是控制枸杞木虱种群数量动态的重要因子之一。为查明其寻找寄主的信息素,应用四臂嗅觉仪、培养皿两种方法测定了枸杞Lycium barbarum L.的健康叶、虫伤叶、枸杞木虱若虫、若虫与叶复合体、卵与叶复合体和若虫分泌物等不同物质对木虱啮小蜂行为反应的影响。结果证明枸杞木虱若虫分泌物对木虱啮小蜂有明显的吸引作用,四臂嗅觉仪测定时有73%的雌蜂趋向分泌物材料区（P=0.0000）。枸杞健康叶, 虫伤叶及其水、正丁烷提取物, 卵与枸杞叶复合体对木虱啮小蜂无明显吸引作用。木虱若虫水提物及正丁烷提取物在培养皿中可吸引木虱啮小蜂并可引起刺探行为,但嗅觉仪测定时单独若虫并不吸引木虱啮小蜂,只有活体若虫与枸杞叶片复合体才对木虱啮小蜂有吸引作用（P=0.0004）。木虱啮小蜂通过与寄主若虫的接触,可提高其搜索效率。接触过寄主若虫的雌蜂第一次找到寄主的时间显著少于未曾接触寄主若虫的雌蜂,前者只用后者1/4的时间,说明该寄生蜂能对其寄主若虫进行学习。     

玉米螟赤眼蜂雌蜂繁殖力与年龄的关系

以米蛾卵作为繁育寄主,通过系统解剖不同发育期（0～144 h）玉米螟赤眼蜂的卵巢,探讨了雌蜂抱卵量、繁殖力与其年龄和个体大小之间的关系。结果表明,玉米螟赤眼蜂在羽化初期（0～3 h）,卵巢中只有部分卵处于成熟状态,随着雌蜂年龄的增加,其抱卵量不断增加,至72 h时接近其卵巢容纳量。抱卵量与雌蜂年龄之间的关系可以用以下公式来表示：y =a｛1-exp［-b(x+c)］｝。用后足胫节长度（HTL）来表示雌蜂个体大小时,HTL短于0.150 mm、介于0.150～0.159 mm之间以及长于0.160 mm的个体羽化后24 h的平均抱卵量分别为40.4、50.5和58.2粒,各占其卵巢容纳量的72.8%、79.3%和86.9%,占整个成虫期总产卵量的49.4%、47.9%及51.9%。玉米螟赤眼蜂羽化后24 h内的产卵量接近于羽化后24 h的抱卵量。雌蜂个体大小与抱卵量及总产卵量之间关系密切,抱卵量与总产卵量随着雌蜂个体的增大而不断增加,呈线性正相关。个体大小可以作为评估玉米螟赤眼蜂生殖潜能高低的一个良好的指标。     

Egg maturation,oosorption, and wing wear in Gonatocerus ashmeadi (Hymenoptera: Mymaridae), an egg parasitoid of the glassy-winged sharpshooter,Homalodisca vitripennis (Hemiptera: Cicadellidae)

Egg maturation and oosorption in Gonatocerus ashmeadi were investigated in the laboratory and the relationship between hind tibia length (HTL) and <12 h egg load, and wing wear and parasitoid age were determined. G. ashmeadi given access to honey-water and hosts, on average, matured 77 eggs in excess of those they were born with. The number of mature eggs in female G. ashmeadi provided honey-water with no hosts significantly declined after 163 degree-days eggs, while the number of ‘dissolved’ eggs (partially disintegrated mature eggs) increased by nine eggs after 163 degree-days. These results are consistent with oosorption. There was a significant positive correlation between HTL and <12 h egg load. The ovigeny index (the number of mature eggs at female emergence divided by potential lifetime fecundity) for G. ashmeadi was calculated as 0.22 indicating that this parasitoid is a syn-ovigenic species when studied under laboratory conditions. There was a significant positive correlation between wing wear (measured as the number of broken setae per wing) and parasitoid age in the laboratory. The practical implications of these results for G. ashmeadi on the biological control of Homalodisca vitripennis are discussed.     

The biology of Diadromus collaris (Hymenoptera: Ichneumonidae), a pupal parasitoid of Plutella xylostella (Lepidoptera: Plutellidae), and its interactions with Oomyzus sokolowskii (Hymenoptera: Eulophidae)

The ichneumonid Diadromus collaris (Gravenhorst) has been recorded in many parts of the world as an important parasitoid of the diamondback moth, Plutella xylostella (Linnaeus), a serious pest of brassica vegetable crops worldwide. Some aspects of its biology and its interactions with Oomyzus sokolowskii (Kurdjumov), another major parasitoid of the same pest, were studied in the laboratory. At 25 degrees C, female wasps did not have mature eggs in their ovaries until about 12 h after emergence. Both males and females mated successfully 24-48 h after emergence, and females started to oviposit one to two days after emergence. Unmated females produced male progeny only; mated females produced progeny of both sexes. The development rate of the parasitoid increased linearly with temperature from 15 to 30 degrees C, with an estimated low temperature threshold of 7.4 degrees C and a thermal constant of 225.1 day-degrees for development from egg to adulthood. Rates of survival from larva to adulthood were about 90% between 20 and 28 degrees C and decreased as temperature decreased or increased. No immatures survived to adulthood at 35 degrees C. When provided with honey solution, the females lived on average 8.3, 11.5 and 7.0 days, and parasitized 26, 44 and 46 host pupae at 20, 25 and 30 degrees C, respectively. Female wasps could be stored at 15 degrees C for up to four weeks without detrimental effects on reproduction. Females of D. collaris attacked host pupae already parasitized by O. sokolowskii, inserting their ovipositor into the hosts at a similar frequency as into unparasitized host pupae, but they did not lay eggs inside the hosts.     

Ontogeny and reproductive biology of Diadegma semiclausum (Hym.: Ichneumonidae), a larval endoparasitoid of Diamondback Moth,Plutella xylostella (Lep.: Plutellidae)

In this article, the ontogeny and reproductive biology of Diadegma semiclausum (Hym.: Ichneumonidae), an important parasitoid of Plutella xylostella (Lep.: Plutellidae) are described in detail. We did dissect parasitized P. xylostella larvae in phosphate-buffered saline and determine the external morphology of its parasitoid at all developmental stages. The developmental duration of its immature stages, adult longevity, total oviposition period and fecundity of the parasitoid are determined at 24 ± 1 °C, 65  ±  5% R.H., and a photoperiod of 16:8 h L:D. The mean duration of egg and larval stages is 9.56 days and the prepupa and pupa stages last for 8.27 days. In average, female longevity is 1.31 times longer than that of males, and females lay 300 eggs in total. The peak of D. semiclausum oviposition is on the eighth day after mating. The egg loading pattern of D. semiclausum was investigated to determine the parasitoid ‘ovigeny index’ throughout the female's parasitoid lifetime. Initial egg load in immature females (<2 h age) is 1.45 per female and the mean lifetime potential fecundity (total immature and mature oocytes), at four interval ages, is 34. With an ovigeny index value of 0.038, D. semiclausum is considered moderately to strongly synovigenic. In the absence of the host, after 3 days, the number of eggs is decreased in D. semiclausum. Our results demonstrated that there is a negative relation between the ovigeny index and egg resorption in this parasitoid.     

Effects of egg age of Spartocera dentiventris (Berg) (Hemiptera: Coreidae) on parasitism by Gryon gallardoi (Brethes) (Hymenoptera: Scelionidae)

To evaluate the effect of egg age of Spartocera dentiventris (Berg) on the parasitism by Gryon gallardoi (Brethes), groups of 12 eggs of 2, 3, 4, 5, 6, 7, 8, and 12 days old were exposed to one female of G. gallardoi on a test tube, with the wasp observed for 2h subsequently. Later, the eggs were individualised and incubated (25 +/- 1 degrees C; 12h photoperiod) until adult emergence. To identify the preferred age, groups of 12 eggs of 1, 3, 5, 7 and 12 days of age were simultaneously exposed to a parasitoid female on an arena for 2h. These groups were also individualised and incubated until parasitism was confirmed. On all ages tested parasitism was at about 88.5 +/- 2.64%, with a reduction in adult parasitoid emergence with age increasing (P < 0.01). The development time increased with increasing egg age (P < 0.01), with males developing faster. Parasitoid sex ratio for all ages tested was female-biased (0.49:1), with the proportion of males invariant with host age (P > 0.05). When the egg groups were exposed simultaneously, the female preferred eggs one and three days old. The results indicate a preference of G gallardoi for younger eggs of S. dentiventris, with host egg age exerting a negative effect on development time and offspring emergence of the parasitoid.     

Spermatogeny as a life-history index in parasitoid wasps

Reproduction is a major life-history trait but it has been studied mostly in relation to female reproductive effort. Recently, an ovigeny index using the proportion of oocytes ready to be oviposited at eclosion has been proposed for female insect parasitoids. Here, we propose a spermatogeny index for male parasitoid wasps. Prospermatogenic species have an index of 1, have all their spermatozoids mature at emergence and do not produce more later in life. At the other end of the spectrum, synspermatogenic species have no spermatozoids at emergence and produce them later in life. The level of spermatogeny should be linked to several other life-history parameters such as longevity, size, nutrition, distribution of mating opportunities and dispersion before and after mating. Data presented for some parasitoid species support the presence of variability in this male life-history parameter.     

Towards a general perspective on life‐history evolution and diversification in parasitoid wasps

In attempting to explain the marked interspecific variation evident in many components of life‐history in parasitoid wasps, biologists have sought to identify general predictors of suites of ‘important’ life‐history traits. Two predictors currently in general use are: (1) the parasitoid mode of larval development in relation to future host growth and development [no further host growth and development (= idiobiosis) versus continued host growth and development (= koinobiosis)]; and (2) the ovigeny index (the degree to which the lifetime potential complement of eggs is mature at the start of adult life in females). These have been postulated to share several life‐history correlates, and an earlier comparative analysis showed the predictors to be associated. Two questions are thus posed: which life‐history variables are actually common to both idio/koinobiosis and the ovigeny index, and which are responsible for the link between these two axes of life‐history diversity? Through comparative analyses of a database of life‐history traits for 133 parasitoid wasp species, four life‐history correlates out of the 11 we investigated are shown to account for the association between the two predictors: the relative level of resource investment per egg (degree of yolk richness, which is lower in koinobionts), pre‐adult lifespan (longer in koinobionts), female lifespan (shorter in koinobionts), and maximum egg load (larger in koinobionts). Our findings pave the way for full integration of the dichotomous hypothesis with the ovigeny index hypothesis, to provide a holistic perspective on parasitoid wasp life‐history diversity and evolution. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 443–461.     

Effects of azadirachtin/Neemazal on different stages and adult life table parameters of Trichogramma cacoeciae (Hymenoptera: Trichogrammatidae)

The effects of azadirachtin/Neemazal on adults, emergence, and life table parameters of Trichogramma cacoeciae Marchal were studied. The adults were exposed to fresh residues of the insecticide applied on glass plates. Based on the dose-response study, the LC50 value was 1330 ppm or 13.3 microg (AI)/ml. The effect of Neemazal on three developmental stages of the parasitoid was tested by dipping parasitized Sitotroga cerealella (Olivier) and Cydia pomonella (L.) eggs at the field-recommended concentration 3, 6, and 9 d after parasitization corresponding to larval, prepupal, and pupal stages. The emergence of adult parasitoids was adversely affected in both hosts, but the adverse effect was more in S. cerealella eggs compared with C. pomonella. The adult emergence was reduced by 73.3 and 33.76% in Sitotroga and Cydia eggs compared with controls, respectively. Longevity and progeny production of the emergent adults did not differ significantly from control. Neemazal affected stable population parameters (r(m), T, and DT) significantly. The intrinsic rate of increase for the control and Neemazal-exposed populations was 0.340 and 0.335 female offspring per female per day, respectively. Because some of postemergence life table parameters of adults were significantly reduced by the insecticide treatment, emergence rate of the parasitoid from treated eggs is not an adequate measure of ecological selectivity, and field studies are needed to determine the actual impact of neem on T. cacoeciae.     

Body size and the timing of egg production in parasitoid wasps

In insects several key fitness-related variables are positively correlated with intraspecific variation in body size, but little is known about size-related variation in the timing of egg production within species. Female insects are known to vary in the degree to which they concentrate egg production into the early part of life. This variation has been quantified as the ovigeny index, defined as the proportion of the maximum potential lifetime complement of eggs that is mature following emergence from the pupa. We tested the hypothesis that the timing of egg production depends both on body size and on host availability, by means of a dynamic programming model that predicted optimal resource allocation to reproduction and survival together with the resulting ovigeny index, in non-feeding synovigenic parasitoids of different sizes. As body size increases, the proportionate increase in resource allocation to initial egg load is less than the proportionate increase in allocation to lifetime fecundity and potential life span, leading to a deferred investment in reproduction as shown by a decrease in ovigeny index. High habitat quality and high habitat stochasticity in reproductive opportunities have a significant effect on the optimal allocation of resources to reproduction and survival, and thus select for early reproduction, i.e. an increased ovigeny index. The ovigeny concept – ovigeny index together with its life-history correlates – enables understanding of the general occurrence of size-related deferment of reproductive investment in parasitoid wasps and also helps explain a significant part of the considerable life-history variation found among such insects.