Ten years of progress in the study of Hadena-Caryophyllaceae nursery pollination. A review in light of new Mediterranean data

Abstract

Nursery pollination interactions are widespread between Caryophyllaceae species and the pollinating-seed predator Hadena moths (Noctuidae). A previous revision of this system was based mainly on widely distributed species in the north and center of Europe. However, there was no information from the Mediterranean region, one of the global diversification centers of both taxa. The aim of this work is to review the progress on the knowledge of this nursery pollination system since the first revision, providing unpublished data of Caryophyllaceae-Hadena associations from Spain. Furthermore, we conduct a preliminary network analysis to illustrate the advantages of this approach to explore nursery pollination systems.In the last 10 years, most of studies have focused on selective forces exerted by Hadena on the plant reproductive traits through pollination and predation. Hadena moths are selectively attracted by flower scents, flower sizes and number of flowers per plant are also crucial for attraction of the moths. Caryophyllaceae species may have developed some phenological, chemical, morphogical and physiological adaptations to avoid overexploitation by larvae. The evolution of sexual dimorphism in Caryophyllaceae may be a consequence of mutualistic and antagonistic interactions. Other pollinators as well as an anther smut fungus and larval parasitoids are important selective agents that can shift this interaction between mutualism and parasitism. Whereas most studies highlighted the parasitic nature of the Hadena-Caryophyllaceae interaction, we need further analyses on the pollinator effectiveness of Hadena and on the spatio-temporal variation of the interaction outcome. Based on our field surveys and bibliographic records we found evidence of nursery pollination between 22 noctuid species (mostly Hadena) and 70 Caryophyllaceae species from 11 genera (mostly Silene and Dianthus). From these interactions, 26 were new for the Iberian Peninsula and 18 were not described before. Results of our preliminary network analysis suggest that these interactions are constrained by phylogenetic, geographical and ecological filters.