Can increasing infestations by Rhynchophorus ferrugineus threaten endemic Chamaerops humilis in Sardinia (Italy)?

Abstract

The red palm weevil, Rhynchophorus ferrugineus, is the most devastating pest of the Canary palm, Phoenix canariensis, in the Mediterranean Basin. Sporadic infestations have also been observed in other cultivated palm species and, above all, in the endemic European fan palm, Chamaerops humilis. Considering the high ecological importance of C. humilis in coastal ecosystems, the present paper gives an update on the status of R. ferrugineus infestations on the European fan palm in Sardinia (Italy). Since the introduction of R. ferrugineus into Sardinia, attacks of this pest on C. humilis have been limited but have increased in the last 2 years, including infestations on eight naturally growing palms in a Natura 2000 site. Male and female red palm weevils that emerged from C. humilis were similar in size to those of P. canariensis, indicating that the quality of these two feeding substrates is similar. The limited number of infested European fan palms observed so far suggests caution when predicting a rapid spread of this pest in cultivated and non‐cultivated C. humilis palms. Nonetheless, natural populations of C. humilis along western Mediterranean shores should be monitored in order to highlight the potential establishment of R. ferrugineus in these habitats.

Local Agricultural Management Filters Morphological Traits of the South American Palm Weevil (Rhynchophorus palmarum L.; Coleoptera: Curculionidae) in Ornamental Palm Plantations

“…For this reason, a particular array of palm species within a plantation can favor or limit food quality of host palms [41], which make body length and mesothorax depth of weevils phenotypically plastic among populations. Since such morphometric measurements have been associated to foraging and feeding behavior and performance of several coleopteran species [46,51,52,67], diversification of palm species and intensification of fertilizer use may benefit the ability of R. palmarum populations to survive and reproduce in ornamental palm plantations.…”

“…This morphological structure is related to the behavior of females, which digs holes in leaf petioles and in concealed locations of the palm crown to lay eggs [69]. Variations in this are due to selection pressure, assisted by the availability of food and nesting resources, and on reproductive traits [56,67]. In fact, increases in rostrum length indicate an effective use in the excavation and preparation of oviposition sites by females [55,56].…”

Establishment and new hosts of the non-native seed beetle Stator limbatus (Coleoptera, Chrysomelidae, Bruchinae) on acacias in Europe

“…Therefore, host shifts on local plants and new host associations cannot be ruled out in Europe in view of its ability to accept and adapt to local hosts. Adaptation to new or non-preferred host species has been observed on other coleopteran alien species, such as the red palm weevil Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera, Dryophthoridae) on the dwarf palm, Chamaerops humilis L. (Cocco et al 2019). Importantly, S. limbatus has been reported on > 90 host species and ≥ 20 genera (de Jesús Parra-Gil et al 2020), which is one of the widest host ranges within the Bruchinae.…”