The Effect of Gut Bacteria on the Physiology of Red Palm Weevil, Rhynchophorus ferrugineus Olivier and Their Potential for the Control of This Pest

SIMPLE SUMMARY: Red palm weevil (RPW), Rynchophorus ferrugineus Olivier, is a destructive pest that often seriously infests palm plants. Because of the negative environmental effect and pesticide resistance caused by insecticide applications, it is important to develop novel green control strategies for this pest. The intestinal tracts of RPW are often colonized by multiple bacterial species that have promoting effects on the growth, development and immunity of RPW larvae. This review summarized the current understanding on the crosstalk between RPW larvae and their gut microbiota and pointed out the great potential of the development of microbial resource-based management methods for this pest. ABSTRACT: Red Palm Weevil (RPW), Rhynchophorus ferrugineus Olivier, is a notorious pest, which infests palm trees and has caused great economic losses worldwide. At present, insecticide applications are still the main way to control this pest. However, pesticide resistance has been detected in the field populations of RPW. Thus, future management strategies based on the novel association biological control need be developed. Recent studies have shown that the intestinal tract of RPW is often colonized by multiple microbial species as mammals and model insects, and gut bacteria have been found to promote the growth, development and immune activity of RPW larvae by modulating nutrient metabolism. Furthermore, two peptidoglycan recognition proteins (PGRPs), PGRP-LB and PGRP-S1, can act as the negative regulators to modulate the intestinal immunity to maintain the homeostasis of gut bacteria in RPW larvae. Here, we summarized the current knowledge on the gut bacterial composition of RPW and their impact on the physiological traits of RPW larvae. In contrast with metazoans, it is much easier to make genetic engineered microbes to produce some active molecules against pests. From this perspective, because of the profound effects of gut bacteria on host phenotypes, it is promising to dissect the molecular mechanisms behind their effect on host physiology and facilitate the development of microbial resource-based management methods for pest control.