Feeding behaviour and microbial profile from gut of red palm weevil, Rhynchophorus ferrugineus Olivier, curculionidae:coleoptera,

The anatomical analysis of the alimentary canal of the fourth instar larvae of the Red Palm Weevil, R.ferrugineus, has been examined by light microscopy. It is approximately one and one-half times the larval body length and situated in the center of larval body. It consists of the foregut, the midgut and ~e hindgut. The fat-body forms a sheath. almost completely surrounding the tract. The salivary gland of the larvae consists of a single anterior d~ct, begining at the labium, followed by two lateral ducts, leading into two flattened reservoirs. The mIdgut IS bounded antenorly by the oesophageal valve and the gastric caeca, and posteriorly by the pyloric valve and Malpighian tubules. The hindgut is. fo~ed by the pylorus, ileum, and rectum. It IS surrounded by numerous tracheoles .The Malplghlan tubules cross the rectal wall forming the cryptonephric excretory system. Histological Studies .with Transmission Electronic Microscope (TEM). The entire epithelium of the foregut of R. ferrugineus fourth larval instar at its different reglons(pharynx, oesophagus, and provintriculus), appears to have a uniform structure. The single layer of midgut epithelium is rests on a conspicuous basement membrane .It consists of three types of cells; the cylindrical cells, the goblet cells and the regenerative cells. The posterior pylorus has a smaller lumen; irregular shaped cubical epithelial cells. The development of peritrophic membrane is weaken. The hindgut epithelium layer is continuous and varies in thickness. There are many of goblet cells, rectal glands and blood vessels in the rectum than in the ileum. The ultrastructural analysis of the salivary gland regions,showed the presence of vesicles and dilatation of the intercellular space at both of the reservoir and secretory regions. The secretory region has a simple cubical, flattened epithelium, with rounded or oval nuclei. Several vacuoles in the cytoplasm are detected into the flattened cells and the microvilli appeared well structured. The Malpighian Tubules consist of a cellular layer varying in size and shape. The distal ends of tubules become associated with the rectal wall. The biology and feeding behavior of the weevil have been investigated on sugarcane at 26 CO. and 70 -75 % R.H. the preovipositionand oviposition period recorded 3.3 and 19.2 days, respectively. The total mean number of egg 154 eggs and the percentage of hatching recorded 79.8%. The longevity of female was longer than male and the duration of generation was 110.6 days. The average larval and pupal duration were 83.2 and 19.8 days, respectively In this study we focused on the distribution and the percentage of aerobic and facultative anaerobic bacteria in red palm weevil larvae. Low number of forty microbial isolates was isolated; identified and classified from the gut of larvae grew on sugarcane sticks, palm hearts and leaves diets. The taxonomical studies on the forty isolates revealed that the microbial isolates represented eight genera; Bacillus spp. (8 isolate); Actinomycetes spp. (2 isolates); Enterococcus spp. (6 isolates); Saccharomyces spp. (2 isolates); Lactobacillus spp. (3 isolates) and Pseudomonas spp. (5 isolates); Enterobacter spp. (13 isolates) and Xanthomonas spp. (1 isolates). Neither enrichment selective media nor conditions were adequate for red palm weevil gut microflora.