Context-dependent outcomes in plant-plant interaction: impacts of abiotic factors and host plant on a hemiparasitic plant performance

Hemiparasitic plants can directly influence host plants performance through the invasion of the vascular system. However, the extent to which host plants can influence hemiparasitic plants is poorly understood. We investigated the phenology, reproductive components (pollen grains, flower buds, flowers, and fruits), and floral visitors' composition and behavior (time spent per flower and number of flowers visited) of Struthanthus polyanthus (Loranthaceae) in three different host species. Moreover, we explored the effects of abiotic (light, temperature, and humidity) and biotic factors (host plants) on S. polyanthus's floral visitors. The study was carried out from September 2015 to December 2016, in a savanna area in Brazil, in three different hosts. Our results indicated significant effects of host plants and abiotic variables on hemiparasitic plants and their floral visitors. We found that although the phenological events of S. polyanthus among hosts coincided throughout the year, the S. polyanthus' reproductive components were differently affected by hosts, and the host plants significantly influenced the S. polyanthus floral visitors' composition and behavior. Finally, abiotic factors influenced the time spent per flower and the number of flowers visited by floral visitors of S. polyanthus. Our study highlights the context-dependent performance of a hemiparasitic plant, contributing to a better understanding of plant-plant relationships.

Automated summary

This study investigated the performance of Struthanthus polyanthus, a hemiparasitic plant, in three different host species. The results showed significant effects of host plants and abiotic variables on the hemiparasitic plant and its floral visitors. Host plants influenced the reproductive components of S. polyanthus and significantly affected the composition and behavior of its floral visitors. Additionally, abiotic factors influenced the time spent per flower and the number of flowers visited by the floral visitors of S. polyanthus.