What does happen when an insect pest follows its host plant and viceversa?

Invasive species are usually well known but only make up a small percentage of the European’s alien plants and insects. The ways these exotic species interact with our natural and cultural heritage are very complex and even some species considered invasive had and could have positive aspects on some European landscape and culture. A close look at the complicated relationship between non-native and native plants and insects in the Mediterranean areas reveals some unexpected twists in the story. Here are some cases of when aliens can threaten our cultural heritage or being part of i

EXOTIC INSECT PESTS: THE IMPACT OF THE RED PALM WEEVIL ON NATURAL AND CULTURAL HERITAGE IN PALERMO (ITALY)

The impact of invasive exotic pests is increasingly recognised as a global issue. A global strategy to address the exotic pest problem is beginning to evolve, albeit slowly. The International Plant Protection Convention (FAO) has begun the process of harmonizing standards for pest risk analysis to minimise the spread of exotic pests without adversely impacting global trade. However if the impacts of insect invasive species on human health and on agriculture have attracted worldwide attention, researchers and policymakers address directly the connection between invasive species and damage to natural and cultural heritages. The cost of these losses is generally neglected or underestimated. Various attempts have been made to treat the plants or the wood that affected by invasive species. But studies of the links between these pests and their effects on natural biodiversity and heritage, in botanical and historical gardens, are largely lacking in the literature. This paper examines categories of pest risk threatening the Mediterranean, with special emphasis on the author’s homeland. We report the case of the invasive species Rhynchophorus ferrugineus (Red Palm Weevil, RPW) recently introduced into Europe. With an interdisciplinary approach, and by focusing on he situation in Sicily, we analyse how the RPW could be considered not only a pest impacting palm trees, but also natural and cultural assets and heritage

IMPOVERISHMENT OF SICILIAN (ITALY) HISTORICAL AND CULTURAL ASSETS BY AN ALIEN INSECT SPECIES: THE CASE OF THE RED PALM WEEVIL.

Alien invasive species (IAS) have a disastrous impact on the biodiversity, cultural heritage and economy of a geographic area. The case of the Red Palm Weevil (RPW), an IAS that attacks the non-native palm species Phoenix canariensis, but also native species Chaemerops humilis, especially in urban and peri-urban areas, is reported. These palm trees have played an important role in Sicilian history and cultural heritage since the period of the Arab invasion. The accidental introduction of the RPW has remarkably changed the Sicilian panorama. In this study the chronology and the severity of the effects of RPW on palms so far detected, is reported. In only 7 years the RPW has drastically changed the aesthetic value and perception of the natural and cultural heritage in Sicily. Results suggest that the Precautionary Principle should be applied when IAS may impact on natural and cultural heritage

Preliminary studies on red palm weevil as potential risk for palm trees in mediterranean basin

The impacts of insect invasive species on human health and on agricutlture have attracted worldwide attention. However, researchers and policymakers rarely directly address the connection between invasive species and loss in natual and cultural heritages. Various attempts have been made to address the plants that are affected by invasive species but the links between these and loss in naturla biodiversity and heritage in botanical and historical gardens are largely lacking in the literature. We report a study on the Red Palm Weevil (RPW), Rhynchophorous ferrugineus (Oliv.) (Fig. 1) (Coleoptera, Curculionidae) which is the most important pest of the palm date trees in many countries. RPW is a large polyphagous insect native to southern Asia and Melanesia and one of the most important pests of several palm species. It reached Italy in 2004 and now is wide spread in Sicily but also in almost all Mediterranean, through Phoenix dactylifera and P. canariensis (Fig. 2). In Europe for the first time was established the RPW-P. canariensis interaction. As a result of RPW attack, the palm is destroyed and the tree collapses and dies. A high density of RPW, developed in P. canariensis, is now present despite to the control measures, in Sicily. Palm trees represent in Mediterranean area an important part of cultural heritage in cities, botanical and historical gardens, which conserve many different palm species. In addition Mediterranean flora is also characterized by the presence of the native palm specie Chamerops humilis. In order to understand if the C. humilis is a suitable host of RPW, we investigate the natural infestation of RPW on this native palm. Moreover we analysed the morphological and molecular characters of RPW populations collected from C. humilis and P. canariensis. The study highlights the necessity to correlate the degree of genetic differences in the population of invasive species, as RPW, to predict the impact on natural flora and on other hosts

Chromosome studies in North-Western Sicily males of Rhynchophorus ferrugineus

Rhynchophorus ferrugineus (Olivier), known as red palm weevil (RPW) was accidentally introduced and established in Sicily (Italy) since 2005. As like in other Mediterranean sites, RPW has been causing extensive damage to palm trees and on its new host Phoenix canariensis Chabaud (Canary Island palms), acquired concomitantly with the colonization of the area. RPW shows a good ecological plasticity and slightly but significant morphological polymorphism (colour patterns and length of the rostrum in male individuals) that can be appreciated within different geographical populations. The aim of the present work was to investigate if this ecological plasticity and phenotypic variability can be accompanied by features in chromosomes like changes in diploid number or chromosome morphology, when compared to other RPW populations. Literature data on karyotype analysis reveals a diploid number (2n = 22). In this paper, the karyotypes of different morphotypes of RPW Sicilian populations, collected from P. canariensis, were analysed using conventional staining, C-banding and sequential staining with the fluorochromes chromomycin-A3/4-6-diamidino-2-phenylindole (CMA3/DAPI). The analyses of metaphases obtained from the testes of adults showed that the species has 2n = 22 chromosomes, with 10 autosomal pairs and a sex chromosome pair. The eu-heterochromatic composition investigated with CTG banding, DAPI, CMA3, and NOR do not indicate any peculiarity in the populations investigated. R. ferrugineus has a Coleoptera Curculionoidea chromosomal asset and functional compartimentalization. RPW presents a karyotype with intermediate characteristics between Dryophthorinae and Curculioninae such as micro Y chromosome and the typical “sphere-shape” of the sexual bivalent in prophase-I or after C-banding