Diel Flight Activity Patterns of the Red Palm Weevil (Coleoptera: Curculionidae) as Monitored by Smart Traps

Abstract

The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), is a serious pest of palm in many subtropical and tropical regions of the world. Traps baited with aggregation pheromones are important management tools used to control this weevil. The daily flight activ ity patterns of the red palm weevil in Saudi Arabian date palm orchards were observed using smart traps (STs) with a catch period of 3 h (8 periods daily). Conventional bucket traps (CTs) were used for comparison. The capture efficiency of the STs was not significantly different from that of the CTs. A circular statistics analysis showed that the time of adult capture in the STs was nonrandom and indicated mainly diurnal activity; few adults were captured at night. The STs revealed differential activity between the sexes. The female activity pattern exhibited 2 strong peaks at 7 to 9 AM and 4 to 7 PM, and the 2nd peak was significantly higher than the 1st peak. The male activity pattern showed 3 peaks at 7 to 10 AM, 1 to 4 PM, and 4 to 7 PM with no significant differences among the peaks. Males initiated activity before the females. The number of adults captured by STs was positively cor related with the time of sunrise and wind velocity, negatively correlated with the time of sunset and the ambient temperature, and not significantly correlated with the relative humidity. Although these patterns were consistent during the study period, they differed from a variety of other patterns reported in European and Southern Asian environments, which suggests that R. ferrugineus has evolved considerable behavioral flexibility in coping with harsh environmental conditions typical of hot arid date production areas in Saudi Arabia. Knowledge of R. ferrugineus daily activity patterns in local field environments can help managers optimize the timing of pesticide applications and other control activities.