菜粉蝶颗粒体病毒对哺乳动物的实验感染

The experimental infection of mammals (such as mouse, golden hamster and nude mouse) was conducted with Pieris rapae Granulosis Virus (PrGV) of baculoviridae of insect virus by way of peritonal and intravenous injection, per os and inhalation. 7-50 days after injection, target insects were reinoculated with the visceral extracts of infected mammals and killed by 5-100%, displaying typical symptom infected by granulosis virus. GV and its latticed structure of inclusion body were found in the ultrathin section of spleen which took out from infected nude mouse via peritoneal injection under electronmicroscope.     

Occurrence and accumulation of the granulosis virus of Pieris rapae in treated field plots

The granulosis virus of Pieris rapae, the imported cabbageworm (P. rapae GV), persisted in soil after application. Virus produced by epizootics of the disease in populations of the host accumulated in soil in nontreated plots with concentrations of the virus in soil and on foliage, being similar at harvest to concentrations in virus-treated plots. Also P. rapae GV produced in epizootics of the disease increased concentrations in soil of virus-treated plots and maintained substantial residues of the virus on the foliage. Little virus accumulated in plots treated with some chemical insecticides and Bacillus thuringiensis because few host larvae survived to support late-season epizootics. Small quantities of P. rapae GV were found in heads of cabbage harvested from plots in October, but these residues were not related to plot treatment.A study in which nontreated and virus-treated plots were replanted for 2 years after treatment indicated an increase in concentrations of P. rapae GV in surface soil in years following treatment. Concentrations of P. rapae GV in soil in virus-treated and nontreated plots were similar in the autumn of the year of treatment and in subsequent years of the study. Concentrations were nearly unchanged during the winter, were reduced by cultivation preparatory to planting in the spring, and increased with epizootics of the disease in host populations in summer and autumn.P. rapae GV disease was prevalent during September and October in populations of P. rapae larvae in plots in which substantial concentrations of the virus were found and contributed to late-season control of the pest insect.     

Some properties of a new virus of Pieris rapae

A new insect virus of Pieris rapae was purified using a chloroform-butanol treatment followed by two differential and sucrose gradient centrifugations. The sedimentation coefficient of the purified virion was approximately 132 S, and it banded at a density of 1.39 g/cm³ in cesium chloride. The virion has a nonenveloped capsid with icosahedral symmetry. Several virions were shown to have a regular hexagonal contour about 25 nm in diameter and to be composed of many capsomeres. Full and empty viral particles, with 12 capsomeres around the periphery of the capsid, were noted. In some particles a small core has been observed which is spherical, about 15 nm in diameter. Both purified virus and partially purified virus preparations from dead, infected larvae gave only one precipitin band with a reaction of identity when tested against the antiserum to partially purified virus. When crude extracts of uninfected larvae and purified virus were tested against antiserum to partially purified virus, the pure virus produced a precipitin band. The band was formed independently and did not join to the band of the uninfected insect producing a typical reaction of nonidentity.     

Cue hierarchy for host plant selection in Pieris rapae

During oviposition, female insects utilize a wide variety of cues to find an optimal host for their offspring. These cues may be encountered simultaneously or sequentially, and females must rely on a hierarchical categorization to rank cues for optimal ovipositional choice. During alighting, cues are often encountered at different distances, which may influence hierarchical order. Cues that are observed at longer distances and are experienced first may be more influential on oviposition choice than those experienced at shorter distances. We tested the effects of two long‐distance cues, plant size and habitat structure, and two short‐distance cues, plant nitrogen level and predator presence, on Pieris rapae L. (Lepidoptera: Pieridae) oviposition choice through a series of two‐ and four‐choice tests in both greenhouse and field settings. We found that the long‐distance cues of plant size and habitat structure had the largest impact on P. rapae oviposition in laboratory and field settings, with females preferring large plants without habitat structure. Plant nitrogen level had a smaller impact on oviposition, and the presence of predators did not affect oviposition choice. However, plant size and plant nitrogen level had a synergistic relationship, with more eggs laid on large high‐nitrogen plants compared to large low‐nitrogen or small high‐nitrogen plants, suggesting that optimal cues throughout the entire searching process may be important for P. rapae in choosing a host plant.     

Axonal pathfinding in developing labial palps of the butterflies,Pieris rapae and Pieris brassicae

Summary Electron microscopy was used to study the developmental changes in the pupal labial palp of Pieris rapae L. and P. brassicae L. prior to axogenesis of the peripheral receptor organs. Two cells emigrate from the anlage of the labial palp-pit organ (LPPO). They develop growth cones and filopodia, which are directed distally. The filopodia insert into stem cells of the LPPO. The perikarya of the cells proceed into the hemolymph space of the palp such that, eventually, these cells bridge the gap between the LPPO and the apical scolopidial organ (ASO) of the labial palp. This bridge is established at about 11% of total pupal development. Only 6 h later, at 15% of pupal development, the cells are no longer visible. We suggest that these cells are luminal neurons and name them pit-organ luminal (POL) cells. These POL cells may act as primary guiding structures for the axons of the sensory cells of the LPPO, which are assumed to orientate along this structure once they reach the ASO.Supported by the Deutsche Forschungsgemeinschaft (H.A.: SFB4/G1).     

Antifeedant and oviposition-deterring activity of total ginsenosides against Pieris rapae

The purpose of this study was to evaluate the antifeedant and oviposition-deterring activity of total ginsenosides against P. rapae. Total ginsenosides exhibited increased antifeedant effects against P. rapae. The highest nonselective and selective antifeedant activity were observed at 2.0% concentration where ginsenosides caused antifeedant percentages of 86.09 and 88.90, respectively. The total ginsenosides showed significantly oviposition-deterring activity of 77.78% against oviposition of P. rapae at 1.0% concentration. Total ginsenosides had antifeeding activity against P. rapae and inhibitory effects on its oviposition. Ginsenosides could be used as an agent to prepare botanical new pesticidal formulations.     

Behavioural evolution in the cabbage butterfly (Pieris rapae)

Summary Australian and U.K. Pieris rapae differ markedly in their oviposition behaviour; U.K. females produce a more aggregated egg distribution, and lay their eggs more quickly, than do Australian females. The adaptive reason for this divergence probably lies in the relative costs of increased flight time (more costly in the U.K.) and increased local crowding (more costly in Australia). There is also a strong relationship between juvenile developmental rate (at constant temperature) and oviposition behaviour, but the form of this relationship differed between the two populations. The adaptive reasons for the link between developmental rate and behaviour is not clear. It may be that this link represents the tip of the iceberg; i.e. that physiological, developmental, and behabioral characters all co-vary in ways and for reasons that we do not yet understand.     

菜青虫幼虫肠道细菌的分离及鉴定

目的为深入研究菜青虫肠道的营养生理,分析其取食消化机制,对菜青虫肠道细菌进行了研究。方法从自然种群的菜青虫肠道环境中按传统分离、纯化、培养,获得细菌5个菌株,对其茵体形态、染色反应、培养性状、生理生化反应进行了系统研究。结果鉴定结果l号菌株为李斯特菌属（Listeria）,2号菌株为皮杆菌属（Dermabacter）,3号菌株为丙酸杆菌属（Propionibacterium）,4号菌株为沙雷菌属（Serratia）,5号菌株为短状杆菌属（Brachybacterium）。结论在菜青虫肠道环境中分离出5个菌株,鉴定出分类地位。其菌株之间的数量具有明显差异,以皮杆菌属数量最多（2×10^8）,需进一步研究该菌的功能及其在菜青虫肠道中的作用。     

Host preference variation cannot explain microhabitat differentiation among sympatric Pieris napi and Pieris rapae butterflies

1. Often, closely related insect species feed on different host plant species, and the tremendous diversity of phytophagous insects is therefore attributed to host plant‐driven speciation. However, for most taxa, host use information comes from field observations of egg‐laying females or feeding caterpillars, which means that the underlying reason for a particular host‐affiliation is not easily determined. 2. Therefore, it is often unclear whether an insect feeds on a certain host because it prefers that plant to alternative hosts, or because the host distribution overlaps with the habitat requirements of the insect. 3. We ask to what extent a divergent host use in the field mirrors the host plant preferences of two closely related butterflies, Pieris napi and Pieris rapae (Pieridae). In nature, P. napi typically occurs in moister habitats than P. rapae. 4. We scanned several microhabitats at a field site in Southern Sweden during multiple years, and collected Pieris eggs from three different plants, Cardamine pratensis (wet meadows), Barbarea vulgaris (drier micro‐habitats) and Alliaria petiolata (intermediate areas). 5. As predicted, P. rapae eggs were more common than P. napi eggs on B. vulgaris, whereas all of the 358 individuals collected from C. pratensis were P. napi, indicating a divergence in host use between the Pieris species. However, under controlled laboratory conditions, both species had virtually identical oviposition preferences, laying eggs on all three plants, notably P. rapae also laying eggs on C. pratensis, indicating that habitat use, not plant preference, drives host plant use in nature.     

Field evaluation of a granulosis virus for control ofPieris rapae [Lep.: Pieridae] in the United Kingdom

A purified granulosis virus isolated fromPieris brassicae (L.) was tested in the field against an introduced population ofPieris rapae (L.) larvae on cabbage (cv January King) in small experimental plots at Littlehampton, Sussex. Experiments were designed to compare the relative efficacy of single and multiple applications of virus (2.1×10¹² and 3.7×10¹² or 2.1×10¹⁴ and 3.7×10¹⁴ virus capsules/ha) in reducing numbers ofP. rapae larvae. An experiment was carried out in June 1978 and repeated in August to coincide approximately with the 2 natural generations ofP. rapae in southern England. Larval populations were monitored by regularin situ assessment of plants and by destructive sampling. Within 10 days of spraying virus there was a significant reduction in the mean larval population on all virus-treated plots compared with untreated controls. Sprays of 2.1×10¹⁴ and 3.7×10¹⁴ capsules/ha reduced larval numbers more quickly than 2.1×10¹² and 3.7×10¹²/ha treatments. In the 1st experiment, three sprays of virus at either 2.1×10¹² or 2.1×10¹⁴ capsules/ha gave no increase over the final level of control achieved by a single spray. However, in the 2nd experiment, a single spray of 3.7×10¹² capsules/ha did not significantly reduce the numbers of larvae. It is likely that this failure could be accounted for by a combination of the larger “natural” population ofP. rapae recorded midway through the 2nd experiment and the rapid inactivation of virus deposits which left little infectious virus to infect these larvae. Virus inactivation was so rapid that only 7–33 % of the initial virus deposits remained 1 day after application. These results suggest that further understanding of virus formulation, persistence and dosage rates are needed before such a virus can be used in a rational manner.