首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9篇
  2013年   1篇
  2009年   1篇
  2008年   2篇
  2005年   1篇
  2002年   3篇
  1997年   1篇
排序方式: 共有9条查询结果,搜索用时 125 毫秒
1
1.
2.
Encapsulation is a common defense mechanism exerted by a host insect in response to invasion by a metazoan parasitoid or other foreign organisms. In the process of encapsulation, the host forms a capsule around the parasitoid egg or larva, which is usually composed of host blood cells and the pigment melanin. The capsule may kill the parasitoid and thus prevent successful parasitism. Encapsulation may adversely affect the degree of biological control effected by parasitoids as it may either prevent the establishment of exotic parasitoids in new regions or reduce parasitoid efficacy. A high incidence of encapsulation may also cause difficulties in mass rearing of parasitoids. In the Coccoidea (Homoptera), parasitoid encapsulation has so far been recorded in three families: Coccidae (soft scale insects), Diaspididae (armored scale insects), and Pseudococcidae (mealybugs). Important factors that affect the frequency of parasitoid encapsulation in the Coccoidea include: Host and parasitoid species, the host's physiological age and physiological condition, the host origin (or strain), superparasitism, the rearing and/or ambient temperature, and the host plant. The effects of these factors on the incidence of parasitoid encapsulation in the Coccidae, Diaspididae, and Pseudococcidae are described.  相似文献
3.
在埃及,黄盾食蚧蚜小蜂Coccophagus suteelaris(Dalman)是一种有效防治蚧壳虫的寄生蜂,研究中分别用6种蚧壳虫Ceroplastes floridensis Comstock,Coccus hesperidumL.,Pulvinaria floccifera (Westwood),P.psidii Maskell,Saissetia coffeae(Walker)以及S.oleae(Oliver)来饲养黄盾食蚧蚜小蜂,1999-2000年间,在埃及的Beni-Suef,Cairo,Giza,Gharbiya和北海岸等5个地方,C.scutellaris大规模的发生在7-11月间,C.scuteelaris对S.coffeae和S.oleae的最高寄生率分别是发生在1999年11月和8月的26%和22%,因此可以认为,黄盾食蚧蚜小蜂是对两种蚧壳虫有效的寄生蜂。  相似文献
4.
Abstract Coccophagus scutellaris (Dalman) is one of the specific parasitoids that attack soft scale insects in Egypt. In the present study, C. scutellaris was reared from 6 species of soft scale insects. These are Ceroplastes flori-densis Comstock, Coccus hesperidum L., Pulvinaria floccgera (Westwood), P. psidii Maskell, Saissetia coffeae (Walker) and S. oleae (Oliver). The abundance of C. scutellaris was monitored from July to Nov. 1999–2000 in five localities in Egypt, the Beni-Suef, Cairo, Giza, Gharbiya and the Northern coast. C. scutellaris is considered an effective parasitoid of S. coffeae and S. oleae with maximum parasitism rates reaching 26% and 22% in Nov. and Aug. 1999, respectively.  相似文献
5.
6.
7.
8.
Metaphycus luteolus Timberlake (Hymenoptera: Encyrtidae) is a facultatively gregarious parasitoid of soft scale insects. We conducted behavioral experiments to better understand the mating structure of this species. Emergence of male and female offspring is synchronized, beginning at the onset of photoperiod. Both sexes are able to disperse, although dispersal of males from natal patches appears to take longer than dispersal of females. We demonstrated the presence of a female‐produced contact pheromone using open arena bioassays and motion tracking software, testing residues deposited by walking females, and extracts of females. Males responded to the females' ‘chemical footprints’ and to acetone and hexane extracts of females by searching and arrestment on the chemical residues. Responses of males were dose dependent and diminished with time since the stimulus was deposited. Our findings support the hypothesis that non‐local mating among wasps emerging from different hosts may be quite common in these parasitoids. The implications of our results for the mating structure and previously documented sex ratio patterns of these parasitoids are described.  相似文献
9.
1. In many gregarious or quasi‐gregarious parasitoids that experience local mate competition, precise sex ratios with low variance are observed. Precise sex ratios can be achieved by laying male and female eggs in non‐random sequences. 2. Developmental mortality can also alter sex ratios of emerging offspring, and subsequently influence sex ratio optima. 3. The present study investigates sex allocation by Metaphycus flavus Howard, M. luteolus Timberlake, and M. angustifrons Compere (Hymenoptera: Encyrtidae), endoparasitoids of soft scale insects, in the laboratory. 4. All three Metaphycus species had precise secondary sex ratios when parasitising brown soft scale, Coccus hesperidum, L. in the laboratory. Moreover, we documented that all three species lay fertilised (= female) eggs first followed by unfertilised (= male) eggs at the end of the oviposition bout. However, there were significant differences in sex allocation sequences among species. 5. Mortality rates of eggs allocated within an oviposition bout also varied considerably, indicating that there is a significant interspecific variation in sequence position‐specific mortality. 6. Using a stochastic Monte Carlo simulation approach, we provide evidence that the incidence of all‐female broods in these parasitoid wasps appears mainly due to developmental mortality and not due to decisions by the ovipositing female. In two species the prevalence of all‐female broods was independent of clutch size, contrary to what is expected from theory. The influence of mortality on optimal sex allocation in these parasitoids is discussed.  相似文献
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号