Ecological interactions in dioecious plants: implications for soil fungi and arthropods

Many dioecious plants are dominant foundational species (e.g., grasses, poplars, ginkgoes) that structure ecosystems and provide essential resources for diverse ecological communities. Due to their higher nutrient demands and reproductive costs, female plants generally appear more sensitive to environmental changes, such as increased temperatures and drought conditions. The soil ecosystem is critical for providing the substrate, nutrients, and habitat for terrestrial plant communities to exist. Male and female plants are likely to interact with the soil environment differently, with implications for ecosystem functioning. Recent research has shown that female and male plants differ in their soil microbial diversity and community composition. However, how plant sex affects soil communities is still unknown. This study investigated how female and male plants of Ilex vomitoria differ in fungal diversity and composition and subsequent cascading effects on soil arthropods. Fungal operational taxonomic units (OTUs) were identified from DNA sequencing data, and arthropods were extracted and identified from 91 soil samples collected under the canopies of female and male Ilex vomitoria individuals across three locations in southeastern Texas, USA. We found that male plants of I. vomitoria exhibit higher fungal diversity compared to female plants, with both sexes associating with distinct fungal communities. Conversely, soil arthropod diversity and community composition were affected by location but not plant sex. Our results provide valuable insights into the ecological interactions of dioecious plants, emphasizing the role of plant sex as a key trait that influences soil biodiversity and the associated functioning of ecosystems.