Abstract
Plant diversification in agroecosystems can support natural enemy diversity by offering varied food resources and shelters. However, these benefits are context-dependent and do not always lead to effective pest control. This study investigates the interactions between Phytoseiidae predatory mites and host plants in vineyard inter-rows. Although inter-row vegetation is known to enhance Phytoseiidae diversity, little is known about which plant species act as key reservoirs and which plant traits promote higher mite abundance and richness. We assessed relationships between the taxonomic and functional diversity of Phytoseiidae (abundance, richness, body and cheliceral size) and six plant traits related to habitat quality and food availability across 11 plant species in a Mediterranean vineyard. Four species: Erigeron sumatrensis Retz, Picris hieracioides L., Crepis foetida L., and Helminthotheca echioides (L.) Holub, hosted particularly high mite densities and richness, indicating their potential as natural enemy reservoirs. The dominant Phytoseiidae species were Typhlodromus (Anthoseius) recki, Typhlodromus exhilaratus and Phytoseius finitimus. Furthermore, plant traits played a key role in shaping mite communities. High trichome density and leaf dry matter content (LDMC) were associated with smaller Phytoseiidae body width. Pollen grain number was positively correlated with Phytoseiidae densities, suggesting that pollen produced by the host plant may serve as an alternative food source. Moreover, leaves with high LDMC values were associated with longer cheliceral digits of Phytoseiidae, potentially enhancing their ability to pierce leaf surfaces to access water or nutrients. Our results highlight the importance of integrating both taxonomic and functional perspectives when studying plant-arthropod interactions. Expanding the range of plant species and traits under study will further clarify how vegetation influences beneficial arthropods. Practically, this knowledge can be used to design inter-row plant mixtures that support predatory mites and promote biological control in vineyards.