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1.
Abstract  The Australian genus Thoreauana Girault is revised: the three known species are redescribed and Thoreauana giraulti sp. n. is described. A new genus of Charipinae from Australia, Dilapothor n. gen., is described. The diagnostic characters for the tribe Charipini are discussed and a key to the Charipini genera is provided.  相似文献
2.
A new genus of cynipid oak gallwasp, Zapatella Pujade-Villar & Melika, gen. n. (Hymenoptera: Cynipidae: Cynipini), with two new species, Zapatella grahami Pujade-Villar & Melika, sp. n. and Zapatella nievesaldreyi Melika & Pujade-Villar, sp. n., is described from the Neotropics. Zapatella grahami,known only from the sexual generation,induces galls in acorns of Quercus costaricensis and is currently known only from Costa Rica. Zapatella nievesaldreyi, known only from the asexual generation, induces inconspicuous galls in twigs of Quercus humboldtii, and is known only from Colombia. Diagnostic characters for both new species are given in detail. Five Nearctic species are transferred from Callirhytis to Zapatella: Zapatella cryptica (Weld), comb. n., Zapatella herberti (Weld), comb. n., Zapatella oblata (Weld), comb. n., Zapatella quercusmedullae (Ashmead), comb. n.,Zapatella quercusphellos (Osten Sacken), comb. n. (= Zapatella quercussimilis (Bassett), syn. n.). A key based on adults for the species belonging to Zapatella is also given. Generic limits and morphological characteristics of Zapatella and closely related genera are discussed.  相似文献
3.
Size and age thresholds for pupation are important life history traits of insects. They are the ultimate consequences of the underlying physiological mechanism that optimize resource allocation. Such thresholds may have a plastic response under time-varying environmental conditions, developmental polymorphism (i.e., plasticity in the number of instars before pupation) being a common strategy adopted by insects to overcome this challenging situation. In this study, we systematically explore the variables related with both age and size thresholds for pupation and developmental polymorphism in the browntail moth, Euproctis chrysorrhoea (Lepidoptera: Lymantriidae), by rearing a group of caterpillars under conditions that either emulate larval diapause or prevent it. As an innovative approach, we evaluated the importance of predictor variables by means of generalized linear modeling in a multi-model inference framework. Our results show that (i) rearing conditions affect fitness, (ii) rearing conditions, size of hatchlings, size and age at maturity and sex are related to the number of instars before pupation, and (iii) there are both age and size thresholds for pupation which differ between sexes and between larvae reared under different conditions. Results are discussed in the context of lepidopteran plasticity in life history traits and its relationship with optimal molting strategies.  相似文献
4.
The Charipinae are a major group of hyperparasitoids of Hemiptera. Here, we present the first cladistic analysis of this subfamily's internal relationships, based on 96 morphological characters of adults. The data matrix was analysed using uniformly weighted parsimony. The effects of using alternative weighting schemes were explored by performing additional searches employing implied weights criteria. One of the caveats of implied weights analysis is that it lacks an objective criterion for selecting the value of the concavity function. In the present study, differential weighting was used to explore the sensitivity of our results to the alternative assumptions made in the analysis and to select one of the most parsimonious trees under equal weights, which we regard as being the hypothesis that minimizes the amount of ad hoc assumptions. The validity of the two existing tribes and the monophyly of all the genera of Charipinae were tested, in particular the cosmopolitan and highly species-rich Alloxysta and Phaenoglyphis , which appear repeatedly in ecological and biochemical studies of host–parasitoid associations. The evolution of several major characters and the relationships between genera are discussed. On the basis of the phylogenetic results, we discuss a number of taxonomic issues. A new classification of the subfamily is proposed in which no tribes are maintained, Carvercharips is synonymyzed with Alloxysta , and the creation of a new genus from Nepal is justified. Our analysis points to the need for a world revision of the basal genus Phaenoglyphis , which is shown as paraphyletic.  相似文献
5.
Abstract.  1. This paper explores the potential effects of host-plant fragmentation on cork oak gall wasp populations (Cynipidae, Hymenoptera) and on their predators, lethal inquilines, and parasitoids. To address this objective, galls were collected across a gradient of cork oak ( Quercus suber ) forest fragmentation in the East Pyrenees (Albera, Spain), and they were incubated to obtain the parasitism rates.
2. Two hypotheses were tested: (1) Host-plant fragmentation may induce a decline in gall wasp populations because of area and isolation effects on local extinction and dispersal; as a consequence of that, parasitoids may decline even more strongly in fragmented habitats than their prey. (2) Host-plant fragmentation may cause a decline in gall wasp parasitoid populations that, in turn, can lead to an ecological release in their prey populations.
3. Among the eight cork oak gall wasps sampled in the study area of Albera, the gall abundances of three species ( Callirhytis glandium , Callirhytis rufescens , and Andricus hispanicus ) were significantly related to forest fragmentation. The overall abundance of gall wasps was affected by a radius of ≈ 890 m surrounding landscape, presenting constant abundances with forest loss until forest cover is reduced at ≈ 40%; below that value the abundance increased rapidly. Three inquilines and 23 parasitoids species were recorded after gall incubation. In 25 cases, species of inquilines and parasitoids were newly recorded for the corresponding host in the Iberian peninsula.
4. Although the overall parasitism rate was high (1.1), it was uncorrelated with fragmentation and with overall cynipid abundance. These results indicate that host-plant fragmentation was correlated with higher abundance of gall wasps, whereas the parasitism rate could not explain this hyper-abundance in small forest fragments.  相似文献
6.
7.
Understanding ecosystem functioning in a farmland context by considering the variety of ecological strategies employed by arthropods is a core challenge in ecology and conservation science. We adopted a functional approach in an assessment of the relationship between three functional plant groups (grasses, broad-leaves and legumes) and the arthropod community in winter wheat fields in a Mediterranean dryland context. We sampled the arthropod community as thoroughly as possible with a combination of suction catching and flight-interception trapping. All specimens were identified to the appropriate taxonomic level (family, genus or species) and classified according to their form of feeding: chewing-herbivores, sucking-herbivores, flower-consumers, omnivores, saprovores, parasitoids or predators. We found, a richer plant community favoured a greater diversity of herbivores and, in turn, a richness of herbivores and saprovores enhanced the communities of their natural enemies, which supports the classical trophic structure hypothesis. Grass cover had a positive effect on sucking-herbivores, saprovores and their natural enemies and is probably due to grasses’ ability to provide, either directly or indirectly, alternative resources or simply by offering better environmental conditions. By including legumes in agroecosystems we can improve the conservation of beneficial arthropods like predators or parasitoids, and enhance the provision of ecosystem services such as natural pest control.  相似文献
8.
9.
Two new species of the genus Saphonecrus Dalla Torre et Kieffer, 1910, S. flavitibilis sp. n. and S. tianmushanus sp. n., are described and illustrated, and a key to the Chinese species of genus Saphonecrus is provided.  相似文献
10.
  • 1 The browntail moth Euproctis chrysorrhoea is a highly polyphagous univoltine forest pest. Although its young larvae usually overwinter in diapause from early autumn to the beginning of spring, winter larval feeding has been reported when this species feeds on the evergreen woody shrub strawberry tree Arbutus unedo.
  • 2 The present study investigated life‐history traits of four populations of E. chrysorrhoea feeding on A. unedo, including phenology of the different life stages, larval feeding activity and diapause incidence. By modelling the relationship between larval size and host plant leaf persistence, elevation and mean annual temperature, we also studied larval development in ten populations of this species sampled from a range of geographical locations in Spain, from both A. unedo and deciduous hosts.
  • 3 The results obtained revealed that on A. unedo, E. chrysorrhoea phenology has shifted: from October to March, A. unedo larvae doubled their size, whereas, on deciduous Ulmus minor and Quercus faginea, larval size did not change. General linear models demonstrated that such differences were not related to environmental variables. We also found that on A. unedo larval feeding was arrested for 2 months, with this period representing a true diapause.
  • 4 The results obtained in the present study suggest that E. chrysorrhoea populations are phenologically adapted to their local host plants, and that the presence of foliage is a key element in the phenological shift reported on A. unedo. These results may have implications with respect to the formation of E. chrysorrhoea host races.
  相似文献
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