The iconic cactus of the Caatinga dry forest, Cereus jamacaru (Cactaceae) has high sphingophily specialization and pollinator dependence

Abstract

Cereus jamacaru is a cactus distributed in Northeastern Brazil, with high symbolic value to this region. However, the interaction, behavior and the role of pollinators remains poorly understood. Here, we investigate the reproductive biology, addressing the ecological significance of floral attributes, including details about floral signaling. The study was carried at three areas of the Caatinga, in 2015, 2017 and 2021.We analyzed the floral morphometry, volume and concentration of the nectar, and characterized the colour and scent of flowers. Additionally, we described the pollinator behavior and performed controlled pollination experiments. The 'Mandacaru' is selfincompatible, has nocturnal anthesis and the nectar is accumulated as droplets in a long hypanthial tube. The flowers have a reflective pattern with a dark outer surface and a white inner surface. (E)-nerolidol is the major component (87.4%) of its floral perfume. We registered the sphingid moth Cocytius antaeus visiting the flowers. The floral attributes, attractants and rewards drives to a sphingophily, and the pollination treatments showed the dependence to fruit set by C. antaeus, the pollinator registered.In this case, if the apparent lack of pollinator diversity encompasses its entire range, the loss of the hawkmoth could severely impact the reproductive success of the cactus.

To be or not to be fragrant: floral scent of some bat‐pollinated cacti

“…Samples were taken when the flowers were fully open (Albuquerque‐Lima et al . 2023a), approximately 1 h after the start of anthesis. Afterwards, the air inside the bag, enriched with flower volatiles, was drawn for 40 min through a thermal desorption (TD) filter using a membrane pump (Rietschle Thomas, Puchheim, Germany) that operated at a constant flow of 200 ml·min −1 .…”

“…0.25 μm film thickness) and a thermal separation probe (TSP, Agilent) (Albuquerque‐Lima et al . 2023a). The TD samples were loaded into the TSP, which was then inserted into the modified GC injector.…”