How do predatory insects pinpoint pests?

Beijing News (reporter Zhou Huaizong correspondent Ouyang Canbin) the use of natural enemies of insects to control the population of crop pests is a common method used in the prevention and control of diseases and insect pests. However, how exactly do these predatory insects accurately locate their targets? Recently, the reporter learned from the Chinese Academy of Agricultural Sciences that through comparative omics, our researchers have revealed a crucial chemical clue and its molecular mechanism in the interaction between plant-aphid-natural enemy insects. The study was published in Current Biology.

Insect pheromone-mediated molecular mechanisms of aphid localization of aphids. Courtesy of the Chinese Academy of Agricultural Sciences

According to the researchers of the research and utilization team of insect resistance function genes of the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences, this important chemical reaction clue is called "anti-β-fanne", which is the alarm pheromone component of the vast majority of aphids and has been attracting much attention. In the tertiary trophic relationship between plant-aphid-natural enemy insects, a variety of natural enemy insects can use anti-β-farnee to locate aphids, but there is some controversy about the theory that different sources of anti-β-farneene attract aphid natural enemies, and its molecular mechanism is not very clear.

In this study, the researchers used comparative oystermics to study the molecular and neural mechanisms by which adult larvae recognize pheromones.

The study found that the adult antennae of the great gray aphid fly can be activated by different concentrations of trans-β-farneene, but only high doses of anti-β-farneene can be used as a long-distance clue to attract adult aphid fly adults, and at lower doses, it can attract aphid-eating larvae at close range.

What exactly does trans-β-farnesene do? By means of comparative omics, the researchers identified odor receptors and odor-binding proteins of Aphid flies and black-banded aphids, studied genes with high homology, and screened out the specific recognition of anti-β-farneenes and their analogues of the Great Grey Aphid odor receptor (OR3) and odor binding protein (OBP15). Subsequently, through gene editing technology, the odor receptor OR3 was knocked out, and it was found that the recognition effect of adult aphids on anti-β-farnes was reduced, and the ability to perform behavioral selection and long-distance localization was lost.

In larval experiments, the odor receptor OR3 and the odor binding protein OBP15 were expressed, but the ability to recognize aphids closely and prefer, suggesting that aphid-eating larvae also used the protein to participate in the feeling of anti-β-farne.

Finally, the experimental results showed that the larvae could use the aphid-derived anti-β-farneene for close-up localization, and the adult insects could identify the anti-β-farnes of plant origin for long-distance search of aphid-infested plants.

According to reports, this study analyzes the regulatory effect of pheromones from different sources on natural enemy insects from the molecular level, breaks the anti-β-farne of aphid sources as altruistic, attracts the cognition of natural enemy insects from a long distance, and makes full use of the important chemical clue of pheromones to scientifically and rationally develop natural enemy insect behavior regulators, laying a theoretical foundation, and providing new ideas for the realization of green prevention and control of aphids. The research has been funded by the National Key Research and Development Program, the National Natural Science Foundation of China Jieqing Project and the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences.

Beijing News reporter Zhou Huaizong correspondent Ouyang Canbin

Edited by Tang Zheng Proofreader LuCy