Mixed‐vertebrate pollination traits and pollinators of Haageocereus acranthus (Cactaceae) in a lomas desert ecosystem of coastal Peru

Cacti rely mostly on animals for pollen transfer and fruit set and constitute key elements of arid and semi-arid ecosystems of the New World. Although bee pollination is ancestral, systems supported by birds, moths, bats and mixed strategies have evolved. Despite the ecological uniqueness and extreme seasonality of the fog-dependent lomas ecosystem of coastal Peru, cactus pollination remains unstudied. This work examines Haageocereus acranthus, a common columnar cactus of this ecosystem, in a population where individuals consistently produce either white or pink-red flowers. It was hypothesized that white flowers would be associated with bat pollination and pink-red flowers with hummingbird pollination, reflected in differences in floral morphology, phenology and pollinator visitation. Year-round monitoring of a population was conducted to characterize flowering phenology. Floral morphology, daily anthesis patterns and nectar production were quantified and compared between colour morphotypes. Floral visitor frequency and behaviour were recorded using trail cameras and compared between morphotypes to assess visitation preference. Floral phenology, morphology and nectar characteristics were broadly consistent with vertebrate pollination, showing traits associated primarily with bat pollination but also compatible with hummingbird pollination. These floral traits did not differ between colour morphotypes. Hummingbirds were the most frequent visitors, followed by bats, yet neither group showed a preference for a specific flower colour. Our findings support a mixed-pollination system involving both hummingbirds and bats in an ecosystem where the availability of pollinators could shift across geographic or temporal scales. This mixed strategy could reduce vulnerability to the absence or decline of specific pollinator groups, ensuring consistent reproductive success.