Unveiling the reproduction of Proteopsis argentea (Asteraceae): how the complex pollination system might influence its conservation status

Abstract

The reproductive success of organisms depends on the positive and negative interactions it establishes throughout its lifetime. Pollinators and mutualists increase adaptive value, while herbivory and antagonism impair plant performance. Asteraceae flowers, simultaneously interacting with pollinators, herbivores and parasitoids with the same structure (the flower head), serve as a model for studying these interactions. In this work we describe the multi-layered interactions between Proteopsis argentea,, its pollinators, endophagous herbivores and parasitoids, aiming to understand how they influence the plant's reproductive success and whether these processes are associated with its conservation status as vulnerable. We found that P. argentea produces little, but highly energetic nectar, acting in interactions with bees, hummingbirds and lepidopterans in a generalist pollination system. Antagonistic interactions were much less diverse, dominated by Xanthaciura aff. chrysura. In addition, two morphospecies of parasitoid wasps used the flower heads of P. argentea, and may have a negative impact on antagonists. We also found that P. argentea presents a reproductive insurance strategy, via autogamy, producing seeds without pollinators. The flowers of P. argentea seem to act as efficient filters, promoting interactions with potential pollinators and parasitoids and limiting interaction with endophagous herbivores. The reproductive strategies of P. argentea, with an apparently efficient floral filter and reproductive insurance in the absence of pollinators, seems to indicate that reproduction is not a limiting factor for the species. Thus, for its conversation, measures ensuring the protection of its occurrence area should be prioritized.