INFLUÊNCIA DA FLORIVORIA SOBRE A FERTILIDADE NATURAL E A VISITAÇÃO FLORAL DE Dyckia excelsa Leme (BROMELIACEAE), BRASIL

Abstract

Floral characteristics, in general, are related to the attraction of pollinators and the offer of trophic resources. However, they also can arouse the attraction of opportunistic species that do not carry out pollination and are called floral robbers or thieves. However, there is no consensus on the real impact of floral take on the reproduction of the studied species. Dyckia excelsa Leme is known to occur in only one large population in Fazenda São João and in five smaller populations in the outskirts of Corumbá and Ladário (Mato Grosso do Sul - MS), which are not protected. The present study aimed to characterize the consumption of floral structures and the looting of trophic floral resources in D. excelsa, to relate the looter species to the structure and floral resource used, and observe whether floral damage interferes with visitation by pollinators. In addition, to identify if there is any influence of floral theft on the natural fertility of D. excelsa in the population of Fazenda São João in Corumbá, MS. The study was conducted during a reproductive cycle (April to December 2019), evaluating the consumption of floral buds and flowers in anthesis in inflorescences with floral scapes from 10 distant clusters. The influence of floral damage on the natural fertility of the species was evaluated in the field by verifying the development of fruits from flower buds/flowers of the five treatments performed. Fruits were collected for parameter analysis to assess the influence of florivory on the natural fertility of Dyckia excelsa, and seed germination was tested (N = 750 seeds). Observations of floral visitors took place on three different days, with all clusters being evaluated on each day, 30 minutes each (N =15 hours). We used the Kruskal-Wallis test for statistical analysis, with 95% reliability using the Bioestat 5.3 program. The flowers/flower buds from the simulated florivory treatment 1 were the ones that obtained results closest to the control. This fact can be explained by the presence of nectar in these flowers since the simulated florivory was performed, the removal of the nectar immediately, and that only the corolla was pierced. Observations of floral visitors showed that holes, both natural and simulated, were used by many visitors to access nectar, so we can assume that these damages are an attraction for floral visitors. The flowers with damage to the floral apex (Tests FN2 and FS2) had the lowest results compared to the control. The results obtained here show that floral damage, such as perforation at the base of the corolla and consumption of petals from the floral apex, stamens, and stigma, are not entirely harmful to the reproductive success of the species. Due to the flowering pattern and period in which D. excelsa blooms, the permanence of floral visitors is vital for the species, as they contribute to the cross-pollination of the flowers. Therefore, the implementation of conservation measures must be studied so that D. excelsa and its associated biodiversity can be conserved.