Pollination biology of the endangered columnar cactus Cipocereus crassisepalus: a case of close relationship between plant and pollinator

Abstract

The family Cactaceae possesses considerable floral diversity and is exclusively zoophilic. Cipocereus crassisepalus is an endangered species of columnar cactus, whose floral characteristics fit the chiropterophily syndrome. This study aimed to assess the correspondence between floral traits and pollinators and whether the pollination system of C. crassisepalus is specialized, as suggested by the hypothesis of geographical dichotomy. Hand pollination treatments demonstrated that C. crassisepalus depends on cross-pollen flow mediated by pollinators to set fruit and seeds. Nocturnal film recordings, diurnal observations, analyses of pollen loads of flower visitors and visitor exclusion experiments provided strong evidence that bats are the sole pollinators of this cactus. During two flowering seasons, pollen grains of C. crassisepalus were found only on the bodies of the bat Anoura caudifer. Cipocereus crassisepalus possesses a pollination system specialized on nectar-feeding bats, which corroborates the geographical dichotomy hypothesis.

Floral Specialization and Bat Pollination in Subtribe Cereinae (Cactaceae): A Morphological Approach

“…The flowers of the Cereinae studied display many characteristics in common associated with bat pollination, such as stout, resilient floral structures capable of resisting the vigorous visits of bats seeking nectar; nocturnal anthesis; disagreeable floral scents (disagreeable to the human nose); dull-coloured outer perianth segments/bract scales contrasting with much paler to white inner segments; nectar chamber protected by stamen filaments basally incurved towards the style; and high volumes of nectar [7,14,29,34,49,51]. These characteristics are corroborated by studies of other genera of Cactaceae, such as those involving Cipocereus (Cereinae); Carnegiea, Neobuxbaumia, Pachycereus, Stenocereus (Pachycereeae); and Weberocereus (Hylocereeae), all of which have similar floral morphology and are likewise pollinated by bats [7,13,14,[17][18][19]21,24,25,29,39,52,53].…”

Evolution of flower allometry and pigmentation in Mammillaria haageana (Cactaceae)

“…Ample evidence has demonstrated the close relationships between pollinators and the reproductive success of several cacti species [ 20 – 23 ]. In this regard, in other model species such as Antirrhinum (Plantaginaceae), epidermal cell shape could modify the color and perception of pollinators [ 17 ].…”

Pollination across the diel cycle: a global meta-analysis

“…However, Young & Gravitz found no evidence of this, and our results also do not support this notion as we found no corresponding pattern between diurnal pollination and daytime-blooming flowers. Furthermore, several studies indicate that the timing of pollination throughout the day has minimal impact on pollination outcomes, as demonstrated through timed hand pollination experiments (Haber and Franke 1982, Kwak and Jennersten 1986, Wolff et al 2003, Martins et al 2020). As such, our results contend that nocturnal anthesis likely represents an adaptive strategy, alongside other traits which affect pollinator preference such as odour and colour (Matsumoto et al 2015) due to the improved pollinator efficiency of nocturnal pollinators for these plant species.…”