Ultrastructure Traits and Genetic Variability of Red Palm Weevil Rhynchophorus ferrugineus (Olivier) Adults from Different Geographical Locations in Egypt

Abstract

The Red Palm Weevil (RPW) is one of the most damaging pests to palm cultivation; this invasive weevil poses a threat to the palm industry. The characterization and identification of this pest in order to determine its biological diversity is the first step in controlling it, which will help in developing effective control programs. The purpose of this study is to investigate the biodiversity of and characterize RPW from five different Egyptian geographical locations at morphological and genetic levels using morphometric analysis, scanning electronic microscopy and two different genetic markers. Our results revealed no significant differences between length and width of the adult body among RPW adults from different geographical locations. Different typologies of prothoracic spots were observed, indicating a degree of diversity in the RPW populations. The magnitude of the different body parts was measured among both males and females. Significant differences were exhibited between length of the antennal seta, as well as forelegs, the lengths and widths of the pronotum, and the rostrum length between both sexes. Both RAPD and ISSR used DNA markers, generating reproducible and distinct banding patterns. The polymorphic banding patterns that have resulted from all studied populations confirmed that these markers demonstrate genetic variability amongst the studied Egyptian populations of Rhynchophorus ferrugineus. The recorded differences may be due to the presence of different red palm weevil genotypes. The obtained results might have potential applications in developing a new tracking and control strategy for this invasive pest.