Fenologia e biologia reprodutiva de Coleocephalocereus fluminensis (Miq.) Backeb. - Cactaceae

Abstract

In Brazil, Cactaceae has 81 genera, 15 of which are endemic, and 484 species, of which 208 are endemic. The genus Coleocephalocereus has nine species, all endemic to Eastern Brazil. Coleocephalocereus fluminensis (Miq.) Backeb. is endemic from the Southeast region, with occurrence restricted to rocky outcrops. This work aimed to evaluate the reproductive phenology, floral and reproductive biology of this species and to identify it’s floral visitors in a rocky outcrop in Morro das Andorinhas, municipality of Niterói in the state of Rio de Janeiro. The phenological follow-up was carried out in two moments: from April 2011 to April 2012 and between July 2020 and November 2021. This ten year interval between data collections was considered for a comparison of phenological periods over time in the study area. In both sampling intervals, the flowering pattern was continuous with reproductive peaks in the wettest months (March and November). The bud/flower/fruit cycle is short, with the entire process taking five to eight days. Coleocephalocereus fluminensis presents nocturnal anthesis, white flowers, sweet odor, large corolla opening and percentage of sugar in nectar between 15% and 19%, which associates the plant sphingophily and chiropterophily pollination syndrome. Observations of floral visitors showed that the moth Erinnyis alope (Drury, 1773), bats and bees are potential pollinators. Other floral visitors are also present as ants (Camponotus sp., Brachmyrmex sp. e Tetramorium sp.), beetles and crickets. The moths appear in two moments, the first being at the beginning of the night and later, coinciding with the peaks of production of nectar sugars. The bat visits were in the early evening. Ants stood out due to the number of species and presence in different reproductive periods, being active before the opening of the bud, with the flower already open, after closing and after the emission of the fruit. Different species were observed feeding on nectar, seeking pollen and preying on floral parts of flowers and fruit. Reproductive tests showed that C. fluminensis is self-compatible. Even though the rocky outcrop vegetation is extremely sensitive to anthropic actions, it is not considered a priority for conservation. Thus, work like this is necessary to support the development of conservation and management strategies for the species.