Relative importance of two bat species as pollinators ofNeobuxbaumia tetetzo(Cactaceae): Evidences from morphometric and pollen load analyses

Abstract

AbstractNeobuxbaumia tetetzois a columnar cactus whose flowers are visited by the bat speciesChoeronycteris mexicanaandLeptonycteris yerbabuenae. Although both bat species are considered the pollinators ofN. tetetzo, the probability of pollination of each bat species has not been estimated. In this study, we determine the relative importance ofC. mexicanaandL. yerbabuenaeas pollinators ofN. tetetzo. The probability of pollination was estimated using two different approaches: (i) morphological correspondence between head (linear traits [total head length, snout length, and face height and width]) and cranial traits (shape traits) of bats and flower traits (linear [internal floral tube length including and excluding the nectary, corolla diameter, stamen length, style length, and corolla tube diameter] and shape traits), and (ii) pollen load analyses to estimate the percentage of occurrence (PO) and the pollination probability index (PPI). Our results showed a lack of a significant correspondence between both head and cranial traits ofC. mexicanaand the flowers ofN. tetetzo, and linear morphological correspondence between total head length ofL. yerbabuenaeand flower length. Pollen loads ofC. mexicanawere composed by seven different pollen types, its PO and PPI were 41.87 ± 9.53% and 0.29, respectively.Leptonycteris yerbabuenaepollen loads were composed by three pollen types, with a PO of 78.29 ± 13.67% and a PPI of 0.67. Our results suggest that whereasC. mexicanahas a low constancy to the flowers ofN. tetetzo,L. yerbabuenaehas a higher probability of pollination.