Feeding of the Red Palm Weevil, Rynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) Larvae on Natural and Artificial Diets in Relation to Biology and Chemical Contents.

Abstract

Life parameters including pre-oviposition, oviposition and larval & pupal periods, adult male and female longevities ,and generation period were recorded for the red palm weevil, Rhynchophorus ferrugineus Olivier reared on the sugarcane stem pieces (Diet,1) and other 3 artificial diets depending mainly on ground sugarcane ,(diet 2); ground corn , (diet 3) and ground mixture of sugarcane and corn (diet 4) . In the laboratory at 28±1°C and 75±5% R.H. , the effects of all diets on total proteins , carbohydrates and lipids were also determined in the last instar larvae .Larvae fed on diet 2 ( ground sugarcane + additives ) exhibited shortest larval duration ( 86.30 days ) , while diet 3 ( ground corn + additives) caused the longest larval period ( 128.35 days ) . Shortest and longest pupal periods resulted also from feeding on diet 2 and diet 3 ( 15.3 and 21.75 days , respectively ) . On the other hand , male and female longevities were the longest and shortest when previous larvae were fed on diet 2 and diet 3 ( 50.4 and 38.4 days for males and 48.0 and 36.8 days for females , respectively . The sex – ratio was almost 1:1 with all diets , except diet 2 which led to more females ( 1 male : 1.5 female ).Eggs of R. ferrugineus hatched after about 4 days , but this period was , significantly , shorter ( 3.35 days ) by rearing on diet 2 . Highest hatch ability percentage ( 93.61 % ) resulted from rearing on the same diet . Chemical analyses of last larval instar content indicated that the highest total contents of proteins ( 51.87 mg / g ) , carbohydrates (105.0 mg / g ) and lipids ( 21.13 mg / g ) were obtained by rearing on diet2, diet 1 and the control ( natural feeding on palm ), respectively