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

Abstract

Cactaceae has many vertebrate-pollinated species, and in the subtribe Cereinae, several genera are indicated as being pollinated by bats. In this subtribe, we observed phenotypic specialization in floral morphological attributes associated with chiropterophily, allowing high precision in the determination of this pollination system. However, in loco pollination records of bats have been confirmed only in a few species. In this context, using a morphological approach, we studied the floral biology of 14 columnar cacti of Cereeae-Cereinae with emphasis on species with chiropterophilous attributes and confirmed the role of bats specialized in nectar consumption as pollinators of these taxa. The studied taxa have similarities in their floral bauplan, observed by analysing the overlap in the floral morphospace. The length and opening of the floral tube are important characteristics for pollen deposition. Approximately 156 visits by bats of the subfamilies Glossophaginae and Lonchophyllinae were observed among the studied taxa. Chiropterophily is the prevalent pollination system among Cereinae, and hereby, we verified this system in five of its genera. There is, however, much variation between diurnal and nocturnal systems within this subtribe, and variation among genera and within species of a given genus may reflect the evolutive pathways, this being worthy of future studies.

Insights into the Natural History of the Nectar-Feeding Bat Lonchophylla mordax (Phyllostomidae), a Data Deficient Species Endemic to Brazil

“…The phenological characteristics of the local flora provide resource availability even in periods of water scarcity, ensuring the survival of many animals, including phytophagous bats. For example, Cactaceae is an important botanical family for bats in semi-arid environments (Albuquerque-Lima et al ., 2023). In fact, of the five plant species most frequently visited by L. mordax in the Caatinga, four are cactus species (Cordero-Schmidt et al ., 2021).…”

“…On the other hand, other groups of chiropterophilous species, such as cacti, can produce nectar throughout the night (Albuquerque-Lima et al ., 2023). However, for some Caatinga cactus species, such as Xiquexique tuberculatus (= Pilosocereus tuberculatus ), there is evidence that bat visits are correlated with available nectar volume, which is higher in the early hours of the night (Rocha et al ., 2007).…”

“…This type of plant strategy could, to some extent, stimulate greater activity in nectar-eating bats in the first hours after the start of foraging, when there is greater nectar availability. On the other hand, other groups of chiropterophilous species, such as cacti, can produce nectar throughout the night (Albuquerque- Lima et al, 2023). However, for some Caatinga cactus species, such as Xiquexique tuberculatus (= Pilosocereus tuberculatus), there is evidence that bat visits are correlated with available nectar volume, which is higher in the early hours of the night (Rocha et al, 2007).…”

North by northwest: Are unilateral cephalium‐bearing cacti bio‐compasses?

“…Another interesting phenomenon reported by Gorelick (2016) is that stems taken from cephalium‐bearing cacti and transplanted in a different orientation develop new cephalia in conformity with their new orientation, that is the cephalium changes position on the stem. Our studies of reproductive biology in columnar cacti suggest that species lacking unilateral cephalia do not display a consistent orientation of their flowers (Albuquerque‐Lima et al, 2023). A good example of this is Stephanocereus leucostele , which has been observed with flowers radiating from its terminal ring cephalium in all directions (Taylor et al, 2022: 73, fig.…”

“…Nine of the taxa have floral attributes related to pollination by bats, which in the case of Coleocephalocereus goebelianus , Micranthocereus purpureus and Pilosocereus catimbauensis were confirmed as visitors in the field and these pollinators also visit Xiquexique gounellei subsp. gounellei (Albuquerque‐Lima et al, 2023; Queiroz et al, 2021). The other two taxa have flowers with floral attributes associated with pollination by hummingbirds (Aona et al, 2006) (Appendix S1: Figure S1; Table S2).…”