Robo de néctar en Guettarda clarensis (Rubiaceae): ¿importa el vecndario floral?

Abstract

Nectar robbing occurs when some floral visitors break the corolla of the flowers to take the nectar reward. It has possible ecological and evolu- tionary implications that depend on its frequency, which can be affected by the characteristics of the floral neighborhood. Guettarda clarensis is an endemic species from the serpentines of central Cuba, in which the nectar robbing decreases the fructification. The objective of this study was to determine the possible relation between the nectar robbing frequency of G. clarensis and the particularities of its floral neighborhood. For that, it was determined the floral neighborhood in circular plots in Cerro de Pelo Malo, Santa Clara. The floral display was calculated using the diameter, length and opening of the corolla of 50 flowers of each species, and it was measured the nectar volume and concentration in 15 buds in each species. In addition, the robbery frequency was calculated for every individual of G. clarensis, and a multiple regression was made between this variable and the floral displays of the neighborhood. Most of the neighborhood species showed low floral displays and nectars under 8 μl between concentrations of 12 % and 36 %, which can be due to the hydric stress of the locality. G. clarensis flowers were dominant, which could be a strat- egy of this species to attract visitors and ensure its reproduction, and indicates its high robbery frequency. It was concluded that nectar robbing in G. clarensis is influenced by the floral displays of Guettarda roigiana, Angadenia berteroi y Bourreria microphylla. Received: October 2018 Accepted: November 2018