A meridic diet for laboratory rearing of Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae)

Abstract

The red palm weevil (RPW) Rhynchophorus ferruginous (Olivier) was fully developed and reared on a meridic diet consisting of agar, distilled water, commercial yeast as well as laboratory produced amino and fatty acid rich brewer’s yeast (Saccharomyces cerevisiae), wheat meal, corn flour, benzoic acid, ascorbic acid, sorbic acid, vitamin mix and tetracycline hydrochloride. A group of weevils reared on date palm trunk under the same laboratory conditions was used as control. Diet reared female weevils laid fertile eggs which successfully hatched into healthy larvae in 3.6 days. Between the first and last (eighth) larval instars there was a 2311 fold increase in the larval body biomass before pupation. Linear regression analysis involving log of head capsule width of each instar and instar number resulted in a straight line (R2= 0.978) indicating that Dyar's rule is applicable in the case of RPW. Larval development was completed in 43 to 47 days while the pupa reached the adult stage in 31 to 38 days with an average of 35 day. The whole life cycle of the weevil from egg to adult, was completed in 78 to 85 days. The average adult longevity for male and female weevils was 83.3 and 74.8 days, respectively. Besides the above, important biological parameters including pre-oviposition period, incubation period, per cent egg hatchability, fecundity and larval weight gain were recorded. A food-fiber pupation technique was developed with 100% pupation efficiency. Key words: Rhynchophorus ferrugineus, meridic diet, biological parameters, food-fiber pupation technique, larval instar, Dyar's rule.