A neotropical mistletoe influences herbivory of its host plant by driving changes in the associated insect community

Parasitic plants are important sources of stress and can strongly impact their host plants through direct and indirect associations with other herbivores and their associated organisms. In the tropics, mistletoes are frequent parasitic plants, influencing different trophic levels involved with the host plant. Here, we investigated the direct and indirect influences of multiple partners involved in interactions between the mistletoe Psittachantus robustus and its host tree, Vochysia thyrsoidea. More specifically, we assessed if the presence of the mistletoe modified herbivory levels of its host by altering the diversity of associated insects. We found that insect feeding guild modulated mistletoe influence on insect community, and there were fewer species and individuals of leaf-chewing insects in parasitized than non-parasitized trees. Despite this decrease in leaf-chewing insects, there were increased levels of herbivory in parasitized plants. Mistletoes' presence did not influence the hemipteran sap-sucking insects, but this herbivore guild directly responded to the abundance of their associated ants. Overall, our study found empirical support for the crucial role of mistletoes on their host-associated organisms, ultimately shaping the herbivory levels of their tree hosts. By exposing the distinct effects of the different partners involved, our results shed light on the intricated interactions mediated by parasitic plants, opening the path for new investigations.