KEY FACTORS IN RED PALM WEEVIL BIOLOGY (RHYNCHOPHORUS FERRUGINEUS) (CURCULIONOIDEA)

A tentative life-table study of the Red Palm Weevil (RPW) is presented in order to emphasize the control key factors in the pest biology, behaviour and ecology. Important characteristics of the relationship between R. ferrugineus and the infested plants are its short duration and the weevil association with fermentation microorganisms. These characteristics contribute to the fast host plant death. One of the serious consequences of this unbalanced coexistence is that natural enemies have neither time nor a suitable niche to control the pest. The weevil reproductive r/selection strategy is based on its high reproduction rate and accordingly, on the large scale spreading-related adult mortality. A further population control factor could be represented by cannibalism or food competition with young larvae. However, this hypothesis is difficult to demonstrate. One more important feature in R. ferrugineus success is its chemical communication model based on palm wound and tissue fermentation chemical cues. At present, the attractiveness of newly infested/damaged plants is a well-known issue in palm pest management. Further characteristics in R. ferrugineus fitness are its polyandrous mating and egg laying strategies that make the weevil a pest even at a very low population level. Planting host palm species in orchards with a density higher than the natural one made RPW shift from endemic to epidemic and therefore, become a destructive palm pest.