Revealing macrohabitat diversity and microhabitat distribution of phoretic mite assemblages on the invasive exotic palm pest Rhynchophorus ferrugineus (Olivier, 1790) in Portugal

Abstract: Phoretic mites exhibit intriguing attachment behaviour on different body parts of the red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier, 1790). To decipher the
mechanisms behind these patterns, our study focussed on RPW-associated phoretic mites in
four districts in northern Portugal, covering macrohabitat and microhabitat levels. At the
macrohabitat level, we identified seven mite taxa that exploit RPW in these districts and were
documented for the first time in Portugal, highlighting their importance. The relative abundance of these mite species varied between districts, with no difference in the prevalence of taxa between sexes of weevils. Centrouropoda sp. proved to be the predominant taxon in terms of abundance and clustering. At the microhabitat level, our study showed the presence of all mite taxa throughout the body of the RPW. The subelytral space showed the highest mite abundance. The distribution patterns of phoretic mite taxa on the RPW were not random, indicating possible ecological interactions. On the subelytra, the coexistence of mite species increased with body size, especially for the dominant species. Our study provides valuable insights into the intricate attachment behaviour of phoretic mites on the RPW and highlights the role of body size in shaping these patterns.