Mites and fungi associated with Rhynchophorus ferrugineus (Coleoptera: Curculionidae): first report in northern Portugal

• Autor(a) principal: Matos, Maria Inês Barros
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/34949
• topic: Rhynchophorus ferrugineus; Palm-tree; Mite; Fungi; Invasive insect; Phoresis; Pathogen; Host-pathogen interactions

The red palm weevil Rhynchophorus ferrugineus (RPW) is an invasive species native to southeast Asia. This weevil is a pest of the Arecaceae palm tree family and is mainly considered the pest of Phoenix canariensis. It has a significant economic and ecological impact on agricultural production and urban environments due to the costs of pest and damaged plant management. Various mite species have been described, mainly as being phoretic, and fungi, mainly as opportunistic saprophytes, in association with the RPW. Mite diversity of these populations has not yet been described in Portugal, as well as the nature of their interaction with the host. The aim of this work is to describe populations of RPW in northern Portugal, to identify associated mites and fungi in order to explore the nature of their interactions with the RPW and to, finally, discuss their potential as biocontrol agents. We placed traps in the districts of Aveiro, Porto, Viana do Castelo and Braga from July 2021 to January 2022. Weevils were dissected and each body part inspected for mites or fungi. Body length, body weight and sex were noted, and thoracic patterns photographed. DNA extractions of mite and fungal samples were made in order to complement morphological identification. Activity of adult RPW in this region was essentially constant during the sampling period. We identified 2 species, 4 genera and one order of mites, all previously described in association with the RPW. The number of weevils collected in traps and the mite load per weevil was higher during the warmer months. Mite species diversity, mite load per host and mite species abundance were high, indicating a good adaptation of these species to studied habitats. The weevil’s elytral area was associated with the highest mite load, suggesting the possibility of it hindering flight capacity, indicating a parasitic interaction with the host, in particular with high mite load. Five species of fungi were identified, where one, Scopulariopsis sp., is for the first time described in the RPW. Identified fungi have pathogenic potential for humans and agricultural crops, indicating the need for RPW control that goes beyond the need for palm tree preservation. This work provides the first description of mites associated with the RPW in Portugal, revealing a significant presence of this pest, and is the first exploring the interspecific relationships between mites and the RPW in these populations. It reveals a further need for its control. Identified mites could have potential as biocontrol agents, a capacity that should be explored and confirmed in further studies.