Exploring fern-arthropod interactions in the Argentinian Paranaense rainforest: a first inventory, perspectives and future research

Despite the long co-evolutionary history of ferns with insects (and other arthropods), the study of interactions between these two groups has been historically underrepresented compared to the study of interactions in angiosperms. Furthermore, recent reviews analyzing various types of fern-insect interactions worldwide have highlighted a significant lack of studies from regions in the Southern Hemisphere when compared to the abundant research conducted in the Northern Hemisphere. This disparity leads to structural biases in the available information, precluding a better understanding of the co-evolution and role of insects and ferns in the ecosystems, and their importance for biodiversity conservation in the Global South. In an effort to reduce this knowledge bias, we undertook a survey in the Paranaense rainforest (Misiones Province, Argentina), documenting for the first time fern-arthropod interactions within the country and laying the groundwork for future investigations. We assessed potential fern-arthropod interactions by thoroughly examining fern specimens along predetermined transects, recording all recognized activities related to shelter (galling, mining, cocoons), reproduction (oviposition), and invertebrate feeding. Fern-hosts and those arthropods observed in-situ were collected and taxonomically classified. Despite preliminary, our observations provided the first records of fern-arthropod interactions described for Argentina, revealing a diverse array of fern-arthropod interactions. This survey denoted that there is high potential for future qualitative and quantitative analyses and comparisons with other regions, further underscoring the critical need to gather information particularly from the Global South. We hope this work will help to incentivize additional research on this largely unexplored topic within the country.