Ecological and biological studies on the red palm weevil Rhynchophorus ferrugineus (Olivier)

Abstract

The field behaviour and bionomics of the red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier) have been demonstrated. The microclimatic temperature conditions where the insects live were recorded monthly (August–February). The insect lives in a microhabitat with temperatures much lower compared to the outer sunny atmosphere during summer. During winter, the minimum microclimatic temperature during daytime was 12°C compared with 16.1°C in the outer atmosphere. Records in the microclimate of infected trees were always higher compared to those of healthy ones, with a difference of 1–2°C. A high significant difference was observed with respect to infestation levels among different cultivars of date palm. The biology and life history of the weevil have been investigated on five diets, namely banana, sugarcane, squash fruit, apple and palm crown. The weevil was maintained on these diets, but the rate of development showed great variation. The duration of generation was the shortest on palm crown, followed by banana and then squash fruit and apple, but it was longer on sugarcane. Egg production was the highest on palm crown being 338 ± 37.24 eggs/female followed by banana, squash fruit, and apple, but the lowest production (117. ± 18.9 eggs/female) was obtained on sugarcane. The fertility ranged between 52 and 83% in those eggs deposited by females previously reared on different diets.