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1.
Tardrabassus pakneunensis, n. gen. & sp. is described and illustrated. The new genus shows morphological affinities to three leafhopper subfamilies, Tartessinae, Deltocephalinae, and Iassinae, but is tentatively placed in Iassinae based on the position of the ocelli, the reduced lateral frontal sutures, the leg chaetotaxy, and the structure of the male genitalia. 相似文献
2.
Amir D. Omer Bruce E. Tabashnik Marshall W. Johnson Thomas F. Leigh 《Entomologia Experimentalis et Applicata》1993,68(3):211-217
Realized heritability (h
2) of resistance to dicrotophos in greenhouse whitefly,Trialeurodes vaporariorum Westwood, was estimated from a laboratory selection experiment. Five generations of selection increased the LC50 approximately 13-fold. Estimatedh
2 of resistance to dicrotophos was 0.40 when calculated with the method of Tabashnik (1992) and 0.35 with the method of Tanaka
& Noppun (1989). These results suggest that 35 to 40% of the total phenotypic variation in resistance was caused by additive
genetic variation. For thirteen previously reported estimates ofh
2 of insecticide resistance in other insect pests, the mean was 0.29. The relatively highh
2 of dicrotophos resistance forT. vaporariorum is consistent with rapid resistance development in field populations. 相似文献
3.
4.
We studied settling-site selection and the resulting survival of two sessile scale insects, Ceroplastes rubens and C. ceriferus, in the citrus tree, Citrus unshiu, in central Japan. C. rubens preferred 0-year-old twigs most as a settling-site; the density of nymphs settling on 0-year-old twigs was significantly higher than those on ≥1-year-old twigs, and few nymphs settled on ≥3-year-old twigs. The mean survival rates from settling until reproduction in the next year were significantly higher on more preferred twigs than on less preferred ones. In C. ceriferus, nymphs significantly preferred 1- and 2-year-old twigs to 0- and ≥3-year-old ones, and the mean survival rates on the more preferred 1- and 2-year-old twigs were significantly higher than those on less preferred ≥3-year-old twigs. However, the survival rate on less preferred 0-year-old twigs was slightly higher than those on 1- and 2-year-old ones. Thus, in both species of scale, it was the preferred twigs which were more profitable sites for survival after settling, except for less preferred 0-year-old twigs for C. ceriferus. In both scale species, most mortality was due to growth cessation, which is believed to be related to the twig quality as a food source. Predators and parasitoids were minor mortality factors. Both species showed constant survival rates until the density of settled nymphs exceeded double the “upper-limit” density, whereupon they decreased drastically. Nymphs of C. rubens settling on twigs of high scale density showed a spacing-out distribution, those of C. ceriferus did not. In C. rubens, an increase in preference for originally less profitable twigs at the later stage of the settling season was observed, but not in C. ceriferus. Accordingly, individuals of C. rubens showed a stronger tendency to avoid conspecifics than did C. ceriferus. Although nymphs of the two scales clearly preferred more profitable sites, their settling-site selection did not agree with the predictions from the ideal free distribution theory (Fretwell and Lucas, 1970). The discrepancies were (1) frequent settling on less profitable sites at the early stage of the settling season, (2) insufficient utilization of the most profitable twigs, and (3) virtually 100% mortality on overcrowded twigs under conditions where unoccupied profitable twigs still remained. These discrepancies are thought due to the limited dispersal time of nymphs. 相似文献
5.
Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae) white eggs were detached from the leaf and exposed to a range of osmotic concentrations
(between −0.4 and −2.2 MPa) in controlled conditions. Eggs were able to hatch in the low and medium solute concentrations.
In the higher concentrations, eclosion was delayed and significant mortality due to egg desiccation was observed.
These results indicate leaf osmotic potential is a plant characteristic that affects greenhouse whitefly survivorship. Therefore
leaf osmotic potential should be considered when evaluating greenhouse whitefly resistance. 相似文献
6.
H. L. G. STROYAN 《Zoological Journal of the Linnean Society》1979,65(1):1-54
Twenty-five species and two subpecies of aphids are listed and dicussed as additions to the Brutish fauna since publication of "Additions and amendment to the Cheack List British aphids" subspecies is described as new to sicence. 相似文献
7.
8.
阔颈叶蝉属现全世界已知2种,中国均有分布。本文记述1新种,新种模式标本保存在西北农林科技大学昆虫博物馆。 相似文献
9.
本文记述了采自尼泊尔的叶蝉科秀头叶蝉亚科小头叶蝉属1新种:凹瓣小头叶蝉Placidus incurvatus,sp.nov,并确认小头叶蝉属应隶属于秀头叶蝉亚科。新种模式标本保藏于英国自然历史博物馆(BMNH)。该新种额唇基具1近似漏斗形的纵长黄色区域,阳基侧突外基突端部向外侧弯折翘起,生殖瓣端部凹入,明显有别于同属其它种类。 相似文献
10.
Temperature effects on egg development of the rosy apple aphid and forecasting of egg hatch 总被引:1,自引:0,他引:1
B. Graf H.U. Höpli H. Höhn & J. Samietz 《Entomologia Experimentalis et Applicata》2006,119(3):207-211
The development of Dysaphis plantaginea (Pass.) (Homoptera: Aphididae) winter eggs was studied at six different constant temperatures ranging from 7.5 to 16.5 °C in order to improve the basis for phenological forecasts in early spring. The mortality was generally low at temperatures below 13.5 °C but increased considerably at 16.5 °C. The effect of temperature on development rates could be described with linear regression within the temperature range under study. The lower temperature threshold for development was estimated to be 4.0 °C and the thermal constant 140 day‐degrees. A time‐varying distributed delay approach was used to establish a temperature driven phenology model for winter egg hatch of D. plantaginea considering the intrinsic variability in development time. The model parameters such as temperature‐dependent development times and corresponding variances were quantified based on the experimental data. When compared with independent observations on egg hatch under semifield conditions, the model gave satisfactory validation results. It can be used as forecasting tool for the optimal timing of monitoring and control measures for D. plantaginea in early spring. 相似文献