On July 16, 2022, the team of the applied Insect Research Office of the Institute of plant protection, Beijing Academy of agricultural and Forestry Sciences published a research paper entitled”fitness of Frankliniella occidentalis forbidden Beijing tabaci on three plant species pre inoculated forbidden Orius sauteri” online in the international well-known entomological Journal Journal of pest Science (if2021=5.742). In this study, three different plants were pre infected with the natural enemy bug, the East Asian stink bug, and it was found that making it spawn on plants could reduce the fitness of the two important pests subsequently infected, thrips occidentalis and Bemisia tabaci.
Plants cannot actively avoid the harm of phytophagous insects because their roots are fixed on the ground. Therefore, during the co evolution of the two for hundreds of millions of years, plants gradually produce a series of defense mechanisms to resist the feeding of insects; Phytophagous insects are also evolving corresponding physiological, biochemical and behavioral adaptation anti defense mechanisms to adapt to plant defense strategies. Exploring the interaction between plants, phytophagous insects and natural enemies to enhance the efficiency of biological control is one of the important practical methods of green plant protection. The plant defense response induced by insect feeding can affect the physiological or behavioral characteristics of phytophagous insects and attract natural enemies, thereby reducing the damage to plants.
The omnivorous predator Orius sauteri (poppius) is an important predatory natural enemy, which is mainly distributed in northern China, Japan, South Korea and the Far East of Russia. It can prey on the eggs and young larvae of thrips, whiteflies, aphids, spider mites and Lepidoptera pests. It has been widely used to control a variety of small pests in agricultural production, and has a high application prospect. The growth, development and reproduction of stink bug need to prey on prey and use plant resources, because in addition to prey, it can also obtain water and nutrition by absorbing plant juice. At the same time, the special oviposition behavior of stink bug is closely related to plants. Female adults of stink bugs lay their eggs into plant tissues and complete the development of eggs. This behavior will cause destructive physical and physiological damage to plant tissues. So can the pre infection (feeding and oviposition behavior) of East Asian stink bug on plants also affect the fitness of pests by inducing plant defense responses? Therefore, this study explored the effects of East Asian stink bug infection on its two important prey, thrips occidentalis and Bemisia tabaci.
This study found that the pre infection of East Asian stink bug on the three plants would reduce the fitness of western flower thrips and whitefly, but there were differences in varying degrees. Compared with the control, the pre infection of East Asian stink bug on tomato will significantly reduce the survival rate of western flower thrips, while the pre infection on cowpea will significantly reduce the survival rate of whitefly. The number of eggs laid by whitefly on tomato, cucumber and cowpea was reduced to varying degrees due to the pre infection of stink bug, while the pre infection of stink bug reduced the number of F1 nymphs of western flower thrips only on tomato and cucumber, but had no effect on cowpea. At the same time, thrips occidentalis and Bemisia tabaci will also affect the hatching of eggs of stink bug, especially when thrips occidentalis infects cowpeas, the eggs of stink bug did not hatch. The adaptability of thrips occidentalis and Bemisia tabaci to host plants depends on the nutritional status of the host plants and the components and contents of their defense compounds. Their differences in performance among the three plants may be due to their wide range of host plants and different adaptability to these host plants.
Interestingly, the survival rate of thrips occidentalis on tomato was negatively correlated with the oviposition of stink bug; And in cucumber, there is also a negative correlation between the egg hatching rate of East Asian stink bug and the survival rate of western flower thrips. Therefore, the oviposition behavior of East Asian stink bug may play a key role in this effect. It can be speculated that the oviposition behavior of East Asian stink bug on different plants may induce plant defense responses and reduce the fitness of western flower thrips and whitefly. However, the feeding behavior of East Asian stink bug on plants may also be the trigger of this effect, because the hungry East Asian stink bug feeds on plants much longer than its spawning time. In conclusion, the pre infection of East Asian stink bug on plants will affect the survival and reproduction of western flower thrips and whitefly, and then have a significant inhibitory effect on them.
To sum up, this is the first report that pre infecting the natural enemy insect stink bug East Asia on plants reduces the fitness of western flower thrips and whitefly. This study deepened the understanding of the ecological relationship between natural enemies and phytophagous insects by exploring the interaction between East Asian stink bug and different host plants, and will further optimize the application potential of East Asian stink bug as a biological control input to prevent and control pests. This work digs out a new form of biological control function of East Asian stink bug as a potential plant”immune inducer”, and provides a new idea for the application of East Asian stink bug to control western flower thrips and whitefly.
Di Ning, an assistant researcher at the Institute of plant protection, Beijing Academy of agricultural and Forestry Sciences, and Zhu Zhengyang, a doctoral candidate jointly trained by the College of agriculture, Nanjing Agricultural University, were the co first authors of the article. Wang Su, a researcher at Beijing Academy of agricultural and Forestry Sciences, and Xu Zhigang, a professor at Nanjing Agricultural University, were the co corresponding authors of the article. Professor James Harwood and researcher Nicolas desneux also participated in the study. Special thanks are due to researcher Gao Yulin of the Institute of plant protection, Chinese Academy of Agricultural Sciences for providing western flower thrips germplasm for this study. The research was supported by the youth fund of the National Natural Science Foundation of China (31901945), the youth fund of Beijing Academy of agricultural and Forestry Sciences (qnjj201917), the Beijing Excellent Talents Program (2018000020060g181) and the Beijing Science and technology program (z201100008020014).