可疑柄瘤蚜茧蜂对高温下不同龄期黑豆蚜的寄生及其适合度表现

研究寄生蜂对寄主不同龄期的寄生策略通常采用适温下（≈25℃）培养的寄主进行试验。 为探究蚜茧蜂对高温下生长的寄主蚜虫的寄生反应及其适合度表现,在30℃条件下饲养寄主孤雌胎生无翅黑豆蚜Aphis fabae Scopli,获得不同龄期若蚜和刚羽化的成蚜,分别提供给可疑柄瘤蚜茧蜂Lysiphlebus ambiguous Haliday寄生,观察蚜茧蜂的寄生率以及后代性比、体型大小和发育时间等适合度相关特性。结果表明： 可疑柄瘤蚜茧蜂对1至4龄若蚜及成蚜均寄生,但偏向寄生较早龄期的若蚜,对成蚜的寄生率为28.0％,显著低于对1龄（400％）和2龄（42.8%）寄主若蚜的寄生率。后代雌蜂比例和体型随寄主龄期（体型）增大而减小,而发育历期则呈现“中间低,两头高”的格局。后代性比、体型大小及发育历期等适合度表现与此前适温（≈25℃）下得到的结果截然相反。因此推测,寄主黑豆蚜体型或龄期可能不是或不全部是可疑柄瘤蚜茧蜂评价寄主质量的依据,其他与寄主蚜虫内共生菌动态相关的线索（如行为的,化学的等）可能才是其评价寄主质量的依据。     

寄主龄期对可疑柄瘤蚜茧蜂寄生及其后代适合度的影响

采用单选试验,观察了可疑柄瘤蚜茧蜂（Tysiphlebus anbiguus）对不同发育时期黑豆蚜的寄生选择及其后代生长发育适合度相关特征,以检验寄主大小与其质量是否存在正相关关系。结果表明,黑豆蚜（Aphis fabae）1～4龄和成蚜均被寄生,但对2龄若蚜的寄生率最高（35．25％）,对成蚜寄生率最低（14．75％）;寄生低龄蚜虫的羽化率显著高于高龄若蚜和成蚜。寄生2龄若蚜的发育历期（8．4d）最短,而寄生1龄若蚜最长（9．3d）;寄生2～4龄蚜虫的后代蜂体型显著大于寄生1龄和成蚜;寄生4龄若蚜的后代中,雌蜂比例（75．74％）显著高于1龄若蚜（62．89％）和成蚜（65．19％）,但与寄生2～3龄若蚜无显著差异。寄主黑豆蚜的质量从高至低依次为2龄〉3龄=4龄〉成蚜〉1龄,因此,对可疑柄瘤蚜茧蜂而言。寄主大小与其质量并非存在正相关性。     

桃蚜被寄生龄期与受寄生蜂影响大小的关系

在两个温度下将桃蚜Myzus perstcae无翅型不同龄期个体供菜蚜茧蜂Diaeretiella rapae产卵寄生,然后观察寄主蚜虫的发育、存活和生殖情况.结果表明,寄主蚜虫的发育速率不受影响,而从接受寄生蜂产卵到生殖率明显下降、产幼蚜终止、死亡三种症状出现的时间间隔分别为寄生蜂完成整个幼期发育所需时间的30%、40%、60%左右,这一规律不依寄主接受产卵的龄期和温度条件而变化,从而导致寄主所受影响随着接受产卵时龄期的增大而迅速下降.当蚜虫在1—2龄接受产卵时,一般不能产幼蚜,从二龄后期起,随着接受产卵龄期的推迟,所表现的内禀增长能力迅速增加,至羽化为成蚜时接受产卵,内禀增长能力已与未被寄生蚜虫的接近.由此可见,寄主不同龄期被产卵寄生的相对机率是影响蚜虫-蚜茧蜂混合种群动态关系的决定性因子之一,蚜茧蜂必须产卵于大量的1—3龄若蚜,才有可能对蚜虫种群的增长有明显的抑制作用.     

两种蚜茧蜂及其寄主蚜虫对大豆植株挥发性次生物质的触角电位反应

研究了下列害虫和寄生天敌种类对大豆植株中提取的某些挥发性次生化合物及其不同组合混合相的触角电位反应： 1)豆蚜Aphis craccivora Koch和麦长管蚜Macrosiphum avenae (Fabricius);2)为害大豆植株的大豆蚜Aphis glycines Matsumura和不为害大豆植株的豆蚜二者所共有的寄生天敌豆柄瘤蚜茧蜂Lysiphlebus fabarum Marshall; 3)不为害大豆植株的麦长管蚜的寄生天敌燕麦蚜茧蜂Aphidius picipes Nees。结果表明,与大豆植株相关联的大豆蚜和不相关联的豆蚜所共有的天敌——豆柄瘤蚜茧蜂,对大豆植株的挥发性次生化合物及其混合相反应敏感,而与大豆植株不相关联的豆蚜、麦长管蚜及其寄生天敌——燕麦蚜茧蜂,对大豆植株的挥发性次生化合物及其混合相反应不敏感。再次证明,植物挥发性次生化合物在害虫及其寄生天敌搜寻寄主的过程中起到重要的作用。     

茶足柄瘤蚜茧蜂对苜蓿蚜的寄生功能反应

在室内(25±1℃,L:D=16:8光周期,RH=40%～60%)条件下,研究了茶足柄瘤蚜茧蜂Lysiphlebus testaceipes(Cresson)对苜蓿蚜Aphis craccivora(Koch)若蚜的寄生功能反应。结果表明:苜蓿蚜的龄期对茶足柄瘤蚜茧蜂的寄生作用有很大影响,用功能反应HollingⅡ模型模拟,其模拟方程为Na=1.118 N/(1+0.0184 N)。通过该方程可明确单头雌成蜂在24 h内最多寄生60.60头苜蓿蚜,其寄生1头苜蓿蚜所需时间为0.396 h。在5个温度梯度下,茶足柄瘤蚜茧蜂对苜蓿蚜的寄生功能反应均符合HollingⅡ模型,但不同温度下的功能反应参数有明显的差异。此外茶足柄瘤蚜茧蜂自身密度对寄生有一定的干扰作用,其干扰作用通过Hassell-Varley模型拟合,方程为a=0.0621P-0.3062,表明茶足柄瘤蚜茧蜂雌蜂的发现域随着自身密度的增加而逐渐变小,寄生蜂雌蜂个体间的相互干扰效应降低了寄生效能。     

豆柄瘤蚜茧蜂和广双瘤蚜茧蜂田间发生动态及田间繁育

豆柄瘤蚜茧蜂Lysiphlebus fabarum Marshall和广双瘤蚜茧蜂Binodoxys communis Gahan是大豆田大豆蚜的重要寄生蜂。2009—2010年,采取棋盘式采样和随机抽样调查相结合的方法,在辽宁岫岩对大豆田内的豆柄瘤蚜茧蜂和广双瘤蚜茧蜂的发生动态进行了研究。结果显示,2009年,豆柄瘤蚜茧蜂6月20号前后在田间开始少量发生,7月上旬数量急速上升,中旬达到最高值,然后开始下降;8月中旬出现第2个高峰,数量上明显小于第1个高峰期,但2010年只有1个高峰,第2个高峰不明显;广双瘤蚜茧蜂6月底开始出现并不断上升,到7月上、中旬达到一定量后持续到8月底。总体来说,豆柄瘤蚜茧蜂发生的时间比广双瘤蚜茧蜂早,且数量也较多。同时在大田按照不同的处理,对豆柄瘤蚜茧蜂进行大田罩笼繁殖研究,当豆柄瘤蚜茧蜂与适龄蚜虫数量比值为1:100的情况下产生的僵蚜数量最多。为大田有效利用蚜茧蜂控制大豆蚜提供了必要的基础资料。     

蚜茧蜂产卵对寄主龄期的选择与其对蚜虫种群影响大小的计算机模拟研究

利用苦苣菜蚜-苦苣菜蚜茧蜂混合种群系统模拟模型,通过改变种群参数、初始虫量和温度条件,探讨了蚜茧蜂产卵选择寄主龄期特性对整个种群系统行为的影响,并比较了这一特性与蜂产卵量两者的相对重要性。结果表明,蜂产卵对寄主龄期选择特性的改变可明显改变其对蚜虫种群增长影响的程度,当产卵选择特性改变,产卵量在多数情况下必须要大幅度直至成倍的增减,才能补偿其对蚜虫种群的控制作用。不过,当蜂产卵嗜好三龄、二龄、四龄若蚜时(这在蚜茧蜂中较普遍),其作用和产卵无选择性时基本相似。     

豆柄瘤蚜茧峰的嗅觉定向反应(英文)

豆柄瘤蚜茧蜂Lysiphlebusfabarum对能寄生于包括大豆蚜Aphisglycines和豆蚜A.craccivora的多种蚜虫中。本实验研究了豆柄瘤蚜茧蜂在风洞中对以下气味源的嗅觉走向反应：未受损伤的寄主食料植株（UD）、机械损伤的寄主食料植株（MD）、蚜害植株（AD ,带蚜虫;AD～,不带蚜虫）、以及致害蚜虫。发现以豆蚜为寄主的豆柄瘤好茧蜂对AD 和AD~的正走向率高于对UD和MD的正走向率,以大豆蚜为寄主的豆柄瘤蚜虽峰对AD 的趋性高于对UD和大豆蚜。同时,豆柄瘤蚜茧蜂对UD、MD和致害蚜虫的定向反应率没有显著差异。这说明植食性昆虫的取食活动能诱导被害植株提高自身对害虫天敌的吸引力。此外还发现大豆是否受蚜害并不直接影响大豆蚜进行寄主定位。     

白蜡吉丁柄腹茧蜂的羽化和产卵与寄主之间的关系

白蜡窄吉丁是危害白蜡属树木的一种重要蛀干害虫,因其幼虫期高度的隐蔽性生活而极难检测和防治.白蜡吉丁柄腹茧蜂是新发现外寄生于白蜡窄吉丁幼虫的优势天敌种,对寄主害虫的控制作用较强,具有良好的生物防治利用前景.研究调查了白蜡吉丁柄腹茧蜂及其寄主白蜡窄吉丁越冬代成虫羽化的时序差异、不同时期林间的寄生率、寄主密度与寄生率的关系以及寄主幼虫大小与茧蜂产卵量的关系.结果表明,越冬后白蜡吉丁柄腹茧蜂的羽化时间比其寄主害虫白蜡窄吉丁的羽化要晚1个多月.2003年白蜡吉丁柄腹茧蜂越冬代成虫的羽化从6月中旬持续到8月中旬,羽化高峰期在7月份;寄主白蜡窄吉丁的羽化期在5月中下旬.2004年白蜡吉丁柄腹茧蜂越冬代成虫的羽化从5月下旬持续到7月下旬,羽化高峰期在6月下旬至7月上旬;寄主羽化期在4月中旬至5月中旬（室内）.越冬后天敌的羽化时间刚好适应最早寄主发育到可供寄生的龄期,这是二者长期协同进化的结果,也表明白蜡吉丁柄腹茧蜂很可能是一种专性寄生蜂.林间白蜡吉丁柄腹茧蜂对白蜡窄吉丁幼虫的自然寄生率随着时间的推移总体上是逐步上升的.自然条件下茧蜂决定是否产卵与寄主幼虫的大小即龄期有关,它仅在前胸宽和体宽1.5 mm、体长12 mm以上,即3～4龄的寄主幼虫体表产卵,但只要接受寄主并产卵,不同龄期寄主幼虫上的产卵量无显著的差异.     

大豆蚜寄生蜂豆柄瘤蚜茧蜂室内生物学特性观察

豆柄瘤蚜茧蜂Lysiphlebus fabarum( Marshall)是大豆蚜Aphis glycines Matsumura的一种重要寄生蜂.在实验室条件下,对豆柄瘤蚜茧蜂的发育历期、繁殖力、寿命和性比等指标,以及成蜂的羽化、取食、产卵行为等生物学特性进行了观察描述.结果表明:在19 ～31℃范围内,发育历期随着温...     

Host age choice for parasitism by Lysiphlebia mirzai and its effect on the development and reproduction of brown citrus aphid

The effects of host age andparasitism by Lysiphlebia mirzaiShuja-Uddin (Hymenoptera: Braconidae) on the development, survivorship,reproduction, and life table parameters ofbrown citrus aphid, Toxoptera citricida(Kirkaldy) (Homoptera:Aphididae) were evaluated at 25 ± 1 °C, 80 ± 5% RH, and a photoperiodof 14:10 (L:D) h. The results showed that theduration from initial parasitization tomummification was independent of the aphid ageat the time of parasitization with a mean of6.0 d. Aphids parasitized at the 1st and 2ndinstar stages and 17% of those parasitized atthe 3rd instar stage failed to reach adulthood,while the rest of the aphids parasitized at the3rd and 4th instar stages and as adults reachedmaturity and produced a number of offspringthat increased with age at parasitization. Thelongevity and fecundity of parasitized aphidswere strongly correlated with the aphid age atparasitization. Aphids parasitized at the 1stand 2nd instar stages did not contribute to thepopulation growth of the aphids. The netreproductive rate (R_o) of the aphidsparasitized at the 3rd and 4th instar andadult stages were only 9, 20 and 43% of thatfor nonparasitized aphids, respectively. Hostage preference experiments involving all fiveaphid stages showed L. mirzai couldattack and parasitize all life stages of browncitrus aphid. Parasitism was highest in the2nd instar in a no-choice test, while in achoice test parasitism in the 2nd and 3rdinstars was similar. A relatively high rate ofparasitism was also observed in the 1st instarnymphs in both choice and no-choice tests. Theresults suggest that L. mirzai haspotential as a biocontrol agent of the browncitrus aphid and warrants a furtherevaluation.     

Growth and development of Encarsia formosa (Hymenoptera: Aphelinidae) in the greenhouse whitefly, Trialeurodes vaporariorum (Homoptera: Aleyrodidae): effect of host age

The tiny parasitoid wasp, Encarsia formosa, has been used successfully to control greenhouse whiteflies (GHWFs) in greenhouses in many countries throughout the world. Therefore, there has been considerable interest in developing methods for artificially rearing this wasp. However, little information is available concerning the regulation of its development including the host-parasitoid interactions that are required for the parasitoid to complete its life cycle. Here we confirm that parasitoid developmental rates differ significantly based upon the host instar parasitized. Development was faster when 3rd and 4th instar GHWFs were offered for parasitization than when 1st or 2nd instars were used. Our results show that it is primarily the embryo and the first two parasitoid instars that exhibit prolonged developmental times when 1st and 2nd instar whiteflies are parasitized. Although percent emergence was not affected by host age at the time of parasitization, adult longevity as well as adult emergence pattern varied greatly depending upon the instar parasitized. When 3rd and 4th instar GHWFs were selected for oviposition, adult wasps lived significantly longer than when 1st or 2nd instars were used; also, there was a sharp emergence peak on the 2nd day after emergence was first observed (reduced or absent when 1st or 2nd instar GHWFs were parasitized) and the emergence period was reduced from between 8 and 11 days to 5 days. In general, the younger the host instar parasitized, the less synchronous was parasitoid development. Previous reports that E. formosa will not molt to the 2nd instar until the host has reached its 4th instar were not confirmed. When 1st instar host nymphs were parasitized, 2nd instar parasitoids were detected in 3rd instar hosts. Importantly, however, no matter which instar was parasitized, the parasitoid never molted to its last instar until the host had reached Stage 5 of its last instar, a stage in which host pharate adult formation has been initiated. It appears, then, that a condition(s) associated with host pharate adult formation is required for the parasitoid's final larval molt. Results reported here should facilitate the development of in vitro rearing systems for E. formosa.     

Oviposition behaviour ofEphedrus cerasicola [Hym.: Aphidiidae] parasitizing different instars of its aphid host

The parasitoidEphedrus cerasicola Starý oviposited in all 4 nymphal instars and in newly moulted adults ofMyzus persicae (Sulzer). The different host categories were offered with no choice. The duration of an oviposition increased with the age of nymphs, being about 13, 18, 21, 22, and 17 s from 1 st instars to adults, respectively. Observations of number of stabbing attacks prior to oviposition, percent of the encounters not resulting in oviposition, time from first encounter to oviposition, handling time and aphid defensive behaviour also indicated that 1 st instarM. persicae are most easily parasitized. The behaviour ofE. cerasicola in encounters with unparasitized and parasitized hosts, suggested that the parasitoid could discriminate. In encounters with parasitized 1 st to 4th instar aphids,E. cerasicola used only the antennae in 80% of the encounters that resulted in discrimination.     

Influence of host size variation on the development of a koinobiont aphid parasitoid, Lysiphlebus ambiguus Haliday (Braconidae, Hymenoptera)

To determine whether host body size is the currency used by the aphidiine parasitoid, Lysiphlebus ambiguus Haliday (Hymenoptera: Braconidae), in assessing host quality, the aphid, Aphis fabae Scopoli (Homoptera: Aphididae), was reared at either high or low temperature to yield hosts of the same instar with different body sizes. Cohorts of A. fabae raised at 15 degrees C and 30 degrees C and exposed to individual female L. ambiguus in no-choice tests were successfully parasitized in all host stages from 1st instar nymphs to adults. However, younger and smaller aphids were more susceptible to parasitism than older and larger nymphs or adults, as measured by the number of mummies produced. For aphid cohorts reared at 15 degrees C, the proportion of female progeny, progeny adult size, and development time all increased linearly with aphid size at the time of attack. In contrast, for aphid cohorts raised at 30 degrees C, the proportion of female progeny and progeny adult size declined with aphid size, while development time remained unaffected. Through manipulation of host rearing temperature, we have shown that at cooler temperatures the koinobiont parasitoid, L. ambiguus, responds to host size in the same way as an idiobiont parasitoid, but that this response is compromised at higher temperatures. Our results suggest that differential mortality during development is likely to influence the observed secondary sex ratio in relation to aphid size for aphid cohorts raised at higher temperatures due to disruption of the activity of the host's primary endosymbiont and that such reduced nutritional quality of aphids cannot be compensated by increased development time.     

Effect of parasitism on flight behavior of the soybean aphid, Aphis glycines

Many aphid species possess wingless (apterous) and winged (alate) stages, both of which can harbor parasitoids at various developmental stages. Alates can either be parasitized directly or can bear parasitoids eggs or larvae resulting from prior parasitism of alatoid nymphs. Winged aphids bearing parasitoid eggs or young larvae eventually still engage in long-distance flights, thereby facilitating parasitoid dispersal. This may have a number of important implications for biological control of aphids by parasitoids. In this study, we determined the effect of parasitism by Aphelinus varipes (Hymenoptera: Aphelinidae) on wing development and flight of the soybean aphid, Aphis glycines (Hemiptera: Aphididae). We also quantified the influence of aphid flight distance on subsequent A. varipes development. Parasitism by A. varipes was allowed at different A. glycines developmental stages (i.e., alatoid 3rd and 4th-instar nymphs, alates) and subsequent aphid flight was measured using a computer-monitored flight mill. Only 35% of aphids parasitized as L3 alatoid nymphs produced normal winged adults compared to 100% of L4 alatoids. Flight performance of aphids parasitized as 4th-instar alatoid nymphs 24 or 48 h prior to testing was similar to that of un-parasitized alates of identical age, but declined sharply for alates that had been parasitized as 4th-instar alatoid nymphs 72 and 96 h prior to testing. Flight performance of aphids parasitized as alate adults for 24 h was not significantly different from un-parasitized alates of comparable ages. Flight distance did not affect parasitoid larval or pupal development times, or the percent mummification of parasitized aphids. Our results have implications for natural biological control of A. glycines in Asia and classical biological control of the soybean aphid in North America.     

闭弯尾姬蜂与菜蛾盘绒茧蜂寄生菜蛾幼虫时的种间竞争

在室内25℃下,以菜蛾3龄初幼虫作寄主,研究了菜蛾盘绒茧蜂Cotesia plutellae和半闭弯尾姬蜂Diadegma semiclausum的种间竞争。当寄主供2种蜂同时产卵寄生时,2种蜂各自的寄生率与其单独寄生时无显著差异,合计寄生率比一种蜂单独存在时有所提高,但差异不显著。2种蜂均能产卵寄生已被另一种蜂寄生了的寄主幼虫。当寄主被2种蜂寄生的间隔时间很短（少于10 h）时,所育出的蜂绝大部分（80%以上）为绒茧蜂;当寄主先被绒茧蜂寄生,并饲养2天以上再供弯尾姬蜂寄生时,所育出的全为绒茧蜂;当寄主先被弯尾姬蜂寄生,并饲养2天以上再供绒茧蜂寄生时,寄主幼虫绝大部分不能存活,只有少部分能育出寄生蜂,且多为弯尾姬蜂。当2种蜂的幼虫存在于同一寄主体内时,2种蜂的发育均受到另一种蜂的抑制;绒茧蜂1龄幼虫具有物理攻击能力,能将弯尾姬蜂卵或幼虫致死。这些结果表明,菜蛾盘绒茧蜂与半闭弯尾姬蜂在同一寄主中发育时,前者具有明显的竞争优势。     

Superparasitism and host discrimination byEphedrus cerasicola [Hym.: Aphidiidae], an aphidiid parasitoid ofMyzus persicae [Hom.: Aphididae]

Myzus persicae (Sulzer) at different densities (1 to 120 aphids) on a paprika plant in a 1.8 dm³ cage were exposed at 21°C to single females of the parasitoidEphedrus cerasicola Stary. Three different exposure periods were used: 1 hr, 6 hrs, 24 hrs. The aphids were dissected 6 days after parasitization. Superparasitism was measured as number of hosts superparasitized and number of parasitoid larvae per aphid. It attained a maximum around host density=5 and decreased with increasing host density and decreasing exposure time. Almost no superparasitism occurred during the 1st hour. A non-random larval distribution indicated thatE. cerasicola discriminates between unparasitized and parasitized aphids, but probably not between aphids with different numbers of parasitoid eggs. Larvae in superparasitized aphids developed slower than single larvae. The supernumerary larvae died during the 1st instar, probably killed by chemical means since no physical attacks between larvae have been observed.     

Developmental rates of two congeneric parasitoids,Encarsia formosa and E. pergandiella (Hymenoptera: Aphelinidae), utilizing different egg provisioning strategies

Endoparasitic Hymenoptera vary in the extent to which they provision their eggs and thus in the degree to which they appear to rely on their hosts for resources during embryonic development. In this study, developmental rates were examined in two congeneric parasitoid species, Encarsia formosa and E. pergandiella, that provision their eggs to different degrees. E. formosa eggs are much larger than E. pergandiella eggs. E. formosa eggs hatch significantly earlier than the eggs of E. pergandiella when deposited in 1st or 4th instar nymphs of a common whitefly host, Bemisia tabaci. Both species hatch earlier in 4th instar nymphs, but the delay in hatching in hosts parasitized as 1st instars is much greater in E. pergandiella. While E. formosa develops more rapidly to the 1st larval instar, E. pergandiella emerge as adults significantly earlier, though smaller, than E. formosa adults regardless of the host instar parasitized. These findings show that the extent of provisioning in the eggs of these wasps does not strictly determine their order of progression through different stages of development.     

Larvicidal activity of lectins onLucilia cuprina: mechanism of action

Foraging behaviour and host-instar preference of young and old females of the solitary aphid parasitoid,Lysiphlebus cardui Marshall (Hymenoptera: Aphidiidae), were studied in the laboratory. The analysis of interactions between parasitoids and different stages ofAphis fabae cirsiiacanthoidis Scop. (Homoptera: Aphididae) revealed that encounter rates between aphids and parasitoid females and defence reactions of the aphids influenced the degree to which a particular aphid age class is parasitized. Encounter rates between hosts and parasitoid females depended on the foraging pattern of the parasitoid, which varied with age. In mixed aphid colonies patch residence time increased with parasitoid age. Furthermore, younger parasitoids (≦1 day old) laid more eggs into second and third instars, while older parasitoids (≧4 days old) did not show distinct host instar preferences. It is suggested that the oviposition behaviour ofL. cardui is influenced by the physiological state, i.e. the age of the wasp.