3种海拔高度茶园中2种害虫与其天敌间的数量和空间关系

用灰色系统分析法和生态位分析法对安徽省潜山县高、中、低3种海拔茶园中2种主要害虫与其天敌在数量和空间上的相互关系进行研讨,经综合排序得出:低海拔茶园假眼小绿叶蝉的主要天敌是锥腹肖蛸、茶色新圆蛛和鞍型花蟹蛛,中海拔茶园为八点球腹蛛、锥腹肖蛸和鞍型花蟹蛛,高海拔茶园为锥腹肖蛸、茶色新圆蛛和草间小黒蛛。低海拔茶园柑橘粉虱的主要天敌是八点球腹蛛、茶色新圆蛛和异色瓢虫,中海拔茶园为鞍型花蟹蛛、八点球腹蛛和茶色新圆蛛,高海拔茶园为锥腹肖蛸、八点球腹蛛和斑管巢蛛。上述几种天敌与2种主要害虫在数量和空间上有显著的追随关系。不同海拔高度茶园中2种主要害虫的主要天敌种类存在差异。     

取食不同种类糖对中红侧沟茧蜂寿命和卵成熟的影响

为了阐明取食糖类食物与中红侧沟茧蜂寿命和卵成熟的关系,本研究比较了取食葡萄糖、果糖、蔗糖、麦芽糖和甘露糖对中红侧沟茧蜂寿命和卵成熟的影响。结果显示:与饲喂清水对照相比,取食蔗糖、葡萄糖、果糖、麦芽糖的寄生蜂寿命显著延长,雌蜂分别为17.6 d,15.6 d,14.4 d和10.3 d;雄蜂分别为7.6 d,11.0 d,11.3 d和6.6 d。取食5种糖雌蜂的寿命均显著高于雄蜂。解剖中红侧沟茧蜂的卵巢发现:初羽化的卵巢中成熟卵约占总卵量的13%,平均为7.13粒。取食不同糖类物质的雌蜂卵巢中成熟卵均呈现先显著上升后逐步下降的趋势,但取食不同糖的成熟卵形成的高峰期时间不同。研究结果为提高该蜂的繁殖潜能和繁殖效率提供依据。     

Computational modeling and experimental validation of odor detection behaviors of classically conditioned parasitic wasp,Microplitis croceipes

A prototype chemical sensor named Wasp hound® that utilizes five classically conditioned parasitoid wasps, Microplitis croceipes (Cresson) (Hymenoptera: Braconidae), to detect volatile odors was successfully implemented in a previous study. To improve the odor‐detecting ability of Wasp Hound®, searching behaviors of an individual wasp in a confined area are studied and modeled through stochastic differential equations in this paper. The wasps are conditioned to 20 mg of coffee when associated with food and subsequently, tested to 5, 10, 20, and 40 mg of coffee. A stochastic model is developed and validated based on three positive behavioral responses (walking, rotation around odor source, and self‐rotation) from conditioned wasps at four different test dosages. The model is capable to reproducing the behaviors of conditioned wasps, and can be used to improve the ability of Wasp Hound® to assess changes in odor concentration. The model simulation results show the behaviors of conditioned wasps are significantly different when tested at different coffee dosages. We conjecture that the searching behaviors of conditioned wasps are based on the temporal and spatial neuron activity of olfactory receptor neurons and glomeruli, which are strongly correlated to the training dosages. The overall results demonstrate the utility of mathematical models for interpreting experimental observations, gaining novel insights into the dynamic behavior of classically conditioned wasps, as well as broadening the practical uses of Wasp Hound. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 31:596–606, 2015     

The role of herbivore‐ and plant‐related experiences in intraspecific host preference of a relatively specialized parasitoid

Parasitoids use odor cues from infested plants and herbivore hosts to locate their hosts. Specialist parasitoids of generalist herbivores are predicted to rely more on herbivorederived cues than plant-derived cues. Microplitis croceipes (Cresson)(Hymenoptera: Braconidae) is a relatively specialized larval endoparasitoid of Heliothis virescens (F.)(Lepidoptera: Noctuidae), which is a generalist herbivore on several crops including cotton and soybean. Using M. croceipes/H. virescens as a model system, we tested the following predictions about specialist parasitoids of generalist herbivores:(i) naive parasitoids will show innate responses to herbivore-emitted kairomones, regardless of host plant identity and (ii) herbivore-related experience will have a greater influence on intraspecific oviposition preference than plant-related experience. Inexperienced (naive) female M. croceipes did not discriminate between cotton-fed and soybean-fed H. virescens in oviposition choice tests, supporting our first prediction. Oviposition experience alone with either host group influenced subsequent oviposition preference while experience with infested plants alone did not elicit preference in M. croceipes, supporting our second prediction. Furthermore, associative learning of oviposition with host-damaged plants facilitated host location. I terestingly, naive parasitoids attacked more soybeathan cotton-fed host larvae in two-choice tests when a background of host-infested cotton odor was supplied, and vice versa. This suggests that plant volatiles may have created an olfactory contrast effect. We discussed ecological significance of the results and concluded that both plant- and herbivore-related experiences play important role in parasitoid host foraging.     

The life parameters of a parasitoid Microplitis mediator (Hymenoptera: Braconidae), reared on cotton bollworm Helicoverpa armigera (Hübner) with Cry1Ac diet

Microplitis mediator (Haliday) is an important endoparasitoid of the cotton bollworm, Helicoverpa armigera (Hübner) in northern China. Interactions among H. armigera, its larval parasitoid M. mediator, and Cry1Ac over two generations were evaluated under laboratory conditions. The results indicated that the developmental period of M. mediator offspring's eggs and larvae were significantly delayed and pupal and adult weight were significantly less compared to the control when the female parasitoids parasitized H. armigera larvae that fed on diet containing 1, 2, 4 and 8 µg/g Cry1Ac. The female parasitoids emerged from the host fed diet containing 8 µg/g Cry1Ac could oviposit in healthy hosts, and their offspring's biological parameters (egg–larval period, pupal weight and adult weight), parasitism rate, abnormal cocoon rate and adult emergence were not significantly affected. Cry1Ac was detected in larvae and hemolymph of H. armigera, but not in the larvae of M. mediator. The results suggest that the observed significant effects on several fitness parameters of the F₁ M. mediator developed from H. armigera fed Cry1Ac diet most likely were host-quality mediated rather than direct effects of Cry1Ac.     

Response of females of the braconid parasitoid Microplitis demolitor to frass of larvae of the Noctoids, Heliothis zea and Trichoplusia ni and to 13-methylhentriacontane

Microplitis demolitor Wilkinson, a solitary larval parasitoid of several species of Noctuidae, has been imported into the United States from Australia. A closely related species, Microplitis croceipes (Cresson), is native to the United States. The host-selection behavior of M. demolitor females is similar to that of M. croceipes in that it is stimulated by kairomones (including 13-methylhentriacontane) in the frass of Heliothis zea (Boddie) larvae, larval diet affects the kairomonal activity of the frass, and exposure to frass prior to release stimulates host-selection behavior. M. demolitor females also respond to frass from Trichoplusia ni (Hübner) larvae that had fed on Pink Eye Purple Hull Cowpea cotyledons.

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Réponse de femelles de Microplitis demolitor sur la nourriture de chenilles de noctuelles et sur 13-methylhentriacontane

Résumé Microplitis demolitor, un parasitoïde solitaire de plusieurs espèces de chenilles de noctuelles, a été introduit d'Australie aux Etats-Unis comme agent potentiel de contrôle biologique. Les fèces des chenilles d'Heliothis zea et Trichoplusia ni élevées sur des cotyledons de pois (Pink Eye Purple Hull Cowpea) stimulent les femelles à sélectionner un hôte, mais les fèces des chenilles des deux espèces élevées sur diète CSM ne possèdent pas cette activité. Un extrait hexanique des fèces des chenilles de H. zea élevées sur cotyledons de pois stimule également ce comportement, de même que le 13-methylhentriacontane, substance présente dans les fèces des chenilles de H. zea (Jones et al., 1971). Les femelles de M. demolitor exposées immédiatement avant leur lâcher en serre aux fèces des chenilles de H. zea, nourries de cotyledons de pois, parasitent un plus fort pourcentage (41.7%) de chenilles de H. zea que cells qui n'ont pas été exposées aux fèces (13.9%).Le comportement de sélection de l'hôte des femelles de M. demolitor est donc semblable à celui des femelles de Microplitis croceipes, un parasitoïde étroitement apparenté indigène des Etats-U-nis. La femelle, par exemple, est stimulée par une kairomone des fèces des larves de H. zea nourries sur des cotyledons de pois (incluant le 13-methyl-hentriacontane), la diète affecte l'activité kairomonale des fèces, et une exposition préalable aux fèces avant le lâcher stimule le comportement de sélection de l'hôte.La stimulation du comportement de sélection de l'hôte, au moment du lâcher peut être utilisée pour améliorer l'efficacité des lâchers des parasitoïdes dans les programmes de contrôle biologique.

     

The role of learning in adult food location by the larval parasitoid,Microplitis croceipes (Hymenoptera: Braconidae)

Wind tunnel experiments were conducted to determine roles of odor learning in food foraging of the larval parasitoid,Microplitis croceipes (Hymenoptera: Braconidae). Females that had neither fed on sucrose water nor experienced any odor and females that had experienced an odor without feeding failed to respond to any odors in a wind tunnel. Most of the females that had fed without an odor also did not respond to odors. However, most of the females that had experienced an odor during feeding on sucrose water flew to the odor. These results indicate that when females experience an odor during feeding, they learn to associate the odor with food and subsequently respond to the odor. As age of females increased, their response to an experienced odor increased, peaked 2 to 5 days after emergence, and then decreased. With an increasing number of odor experiences while feeding, accuracy of females choosing the experienced odor increased. Females that experienced an odor while feeding three to five times chose the experienced odor 90% of the time. When females experienced an odor while feeding five times, the memory of food associated odor lasted at least 2 days. When they experienced food with two odors successively, they could memorize both odors, and multiple experiences did not cause memory interference. Even when females had learned a food-associated odor, their response to the learned odor ceased after several visits on patches containing the odor but no food. Such negative experience may cause switching of food searching to new odors by females.     

中红侧沟茧蜂雌蜂输卵管萼中病毒样纤丝的特征和功能

中红侧沟茧蜂Microplitis mediator雌蜂输卵管萼中有一种病毒样纤丝（virus-like filaments, VLFs）。在蜂卵从卵巢管通过输卵管萼产出的过程中,VLF包裹在蜂卵的表面,随蜂卵进入寄主体内。透射电镜显示,VLF中心是电子致密物质,外有单层膜包被,直径约35 nm。负染技术表明,VLF是具有左螺旋结构的纤丝,负染时的直径约25 nm。不含VLF的蜂卵进入3龄初寄主后,全部被寄主血细胞包囊;含有VLF的蜂卵进入同样的寄主后,88.2%受到保护。VLF对蜂卵的保护作用在不同发育期的寄主中不同,在3龄初的粘虫体内,平均有64.7%的初产卵不被包囊,而在4龄初的粘虫体内,只有9.5%的初产卵受到保护。这一结果说明,VLF只能为蜂卵提供部分的保护作用,需配合其它寄生蜂因子（萼液、蜂毒等）共同作用于寄主的免疫系统。     

侧沟茧蜂属二新种记述（膜翅目：茧蜂科，小腹茧蜂亚科）

记述采自辽宁、宁夏、新疆、浙江和贵州的侧沟茧蜂属Microplitis Foerster 二新种：宽背侧沟茧蜂M. amplitergius sp. nov.和内弯侧沟茧蜂M. incurvata sp. nov.。模式标本保存在浙江大学植物保护系昆虫标本室。