The effects of temperature, genetic background, and age on the reproductive phenotype and Wolbachia titer of Wolbachia-infected thelytokous line of Trichogramma dendrolimi Matsumura were investigated by analyzing the parameters of reproductive phenotype（male proportion and intersex proportion）, fitness（numbers of parasitized host eggs and emergence proportion）, and Wolbachia titer as influenced by temperature（22 ℃ and 29 ℃）, female age, and genetic background（ZW line and XF line）. The results showed that the male proportion and intersex proportion at 29 ℃ were significantly higher than those at 22 ℃. However, the Wolbachia titer and the number of daily parasitized host eggs deposited by maternal females at 29 ℃ were significantly lower than those at 22 ℃. The male proportion of ZW line was significantly higher than that of XF line, but the number of daily parasitized host eggs of ZW line was significantly lower than that of XF line. The male proportion and intersex proportion of offspring increased significantly with the age of maternal females, but the number of daily parasitized host eggs and emergence proportion of offspring decreased significantly with the age of maternal females. The results highlight the significant effects of temperature and age on the reproductive phenotype of Wolbachia-infected thelytokous line of Trichogramma dendrolimi Matsumura with different genetic background. The research is expected to help the improvement of the mass-rearing procedure and field application of thelytokous Trichogramma in biological control programs.
Episyrphus balteatus（De Geer） is one of the most common predatory natural enemies in agricultural ecosystems. It has dual ecological service functions of pollination and biological control and plays an important role in improving crop yield and protecting biodiversity. However, the proper aphid species for artificial rearing of the predator is still unclear. Our study on the relationship between three aphid species, Aphis craccivora Koch, Myzus persicae Sulzer, and Megoura japonica Matsumura and fitness of E. balteatus showed that the developmental durations of larva（5.9 d） and pupa（6.0 d） with M. japonica were significantly shorter than those with the other preys,and the larval survival rate（80.0%） was the largest; the highest pupation rate（88.4%） and pupal emergence rate（100.0%） were attained with the prey A. craccivora, the lowest pupation rate（47.6%） and pupal emergence rate（49.6%） were recorded with M. persicae; With A. craccivora, M. persicae and M. japonica, the average generation period（T） of the predator was 30.26 d, 32.41 d and 32.34 d, respectively; the intrinsic rate of increases（r） was 0.1581, 0.0953 and 0.1424, respectively; and the finite rate of increase（λ） was 1.1713, 1.1002 and 1.1531,respectively. Flight ability tests showed that prey species had a significant effect on the flight velocity of adults, the highest velocity（0.29 m/s） was recorded with the prey M. japonica, in contrast to the lowest velocity（0.23 m/s） with M. persicae. This study indicates that M. japonica is a suitable aphid species for artificial rearing of E. balteatus,which is of theoretical and practical significance for large-scale rearing and utilization of the biocontrol and pollination ecological service functions of E. balteatus.
双尾新小绥螨 Neoseiulus bicaudus 是一种重要的捕食性天敌.为明确双尾新小绥螨对花蓟马Franklinilla intonsa的捕食控害作用以及寄主花粉对其取食花蓟马的影响.本研究通过室内测定不同螨态双尾新小绥螨对不同密度花蓟马若虫的捕食量;在棉花新鲜花粉影响下捕食螨对花蓟马 1龄若虫捕食能力,进而在棉田花期时测定捕食螨对花蓟马的实际控制效果.结果表明,双尾新小绥螨各螨态对花蓟马若虫的捕食量随着猎物密度的增加而升高,对 1龄若虫捕食量显著高于 2龄若虫,其捕食量最高可达 6.1头/日.加入花粉后,双尾新小绥螨成螨对花蓟马的捕食量随着花粉数量的增加而降低,足量的花粉处理使其捕食量显著低于不加花粉处理,其捕食功能反应类型也由Holling-Ⅱ型变为Holling-Ⅲ型.将捕食螨以 1:1的益害比释放至棉田中对花蓟马的防治效果相对最好.综上,双尾新小绥螨对花蓟马 1龄若虫有较好的捕食能力,可用于花蓟马的生物防治.
To develop a control technology for the western flower thrip by the combined application of Beauveria bassiana and food lures, we evaluated the effects of food lure on the germination rate of B. bassiana conidia. In the greenhouse, the effect of distance between food lure and fungi inoculation device on the germination of B. bassiana conidia, the lures’ capacity to capture thrips and the infection of thrips outside the device were examined. The results showed that with increasing distance between the conidia and the food lure, the germination rate increased significantly. There was no significant difference in conidia germination rate when the food lure was 20 cm away from the conidia in comparison with the control. In the greenhouse, when the lure was placed in the device, the germination rate of conidia was 23.4%, significantly lower than the control（56.3%） and those when the lure was placed at a distance of 0 cm（42.9%）, 10 cm（43.9%） and 20 cm（46.5%） from the device, respectively. When the lure was placed in a distance of 0 cm from the inoculation device, the thrip capture was the highest; and when lure was placed into device, the thrip capture was the lowest. When the lure was placed at a distance of 10 cm from the inoculation device, the number of conidia carried by thrips on plants around the device was the highest,significantly higher than other treatments. Meanwhile, the number of conidia carried by the thrips onto plants around the devices increased with time. The combined application of B. bassiana and food lures can establish an “attract-infect-transmit” system, which helps the development of new management technology for the western flower thrip.
To determine the sequence structure and spatiotemporal expression patterns of AKT, MAPK and RPS6KB genes in the insulin signaling pathway of Propylea japonica, the full-length genes of AKT, MAPK and RPS6KB were acquired from P. japonica genome. Protein sequence structure analysis showed that the genes encode 522, 332,and 375 amino acids, respectively. Expression profiles of the genes in different developmental stages（1, 3, 5, 7 days after eclosion） and tissues（head, thorax, abdomen, intestine） of P. japonica female adults were investigated through the method of real-time quantitative PCR. The results showed that AKT, MAPK and RPS6KB were significantly up-regulated in the 7-d old females and reached the highest level. AKT was highly expressed in the head in the 1-d and 3-d old females, and highly expressed in the intestine and thorax in the 5-d and 7-d old females, respectively.The expression level of MAPK gene in the head was significantly higher than that in the thorax, abdomen and intestine in the 1-d, 3-d, 5-d and 7-d old females. Expression level of RPS6KB gene was the highest in abdomen in the1-d, 3-d, 5-d and 7-d old females, and significantly higher than that in head, thorax and intestine. Taken together,the expression levels of AKT, MAPK and RPS6KB genes differ in different developmental stages and tissues of P.japonica, which serves as a foundation for further study on the role of insulin signaling pathway in reproductive development of P. japonica..
