The spatiotemporal dynamics and range expansion of the red palm weevil in Israel

Abstract

The red palm weevil (RPW), Rhynchophorus ferrugineus, an oligophagous borer that specifically attacks the Arecaceae family, poses a serious threat to commercial and ornamental palms. Originally from tropical Asia, the RPW has spread to Africa and Europe, reaching the Mediterranean region 30 year ago. Characterizing its spread is a key aspect of effectively managing its geographical expansion. Using georeferenced RPW occurrence data from 2012 to 2013 in Israel, we sought to better understand its spatial spread. Our objectives were to: (1) describe the spatiotemporal distribution of RPW in three regions (northern, western and southern) that were thought to constitute a risk to the vast date palm plantations across the Beit She’an Valley (BSH), (2) quantify the dynamics of spread; and (3) initially characterize the influence of host species on RPW dispersal. We found that the spatiotemporal distribution of RPW significantly differed between regions. The weevils’ geographical occupancy areas increased by 853% and 571% in the northern and western regions, respectively, while no increase was observed in the southern region. In the northern and western regions, RPW spread toward BSH date palm plantations and an initial analysis has shown that host area and RPW captures were significantly correlated. Based on our analysis, we propose the following hypotheses: (1) Ornamental and particularly Canary palms are highly favorable hosts for population establishment and dispersal in comparison with date palm plantations; (2) thus, the RPW spread from urban areas toward date palm plantations in BSH is attributed to the density and distribution of these hosts.