Morphological specialization to nectarivory in Phyllostomus discolor (Wagner, 1843) (Chiroptera: Phyllostomidae)

Abstract

Dedicated nectarivory is a derived feeding habit that requires specialized cranial and soft‐tissue morphologies to extract nectar from flowers. Nectarivory has evolved many times in terrestrial vertebrates, and in four bat families (Pteropodidae, Phyllostomidae, Vespertilionidae, and Mystacinidae). Within phyllostomids, specializations to nectarivory have been well documented in two subfamilies, Glossophaginae and Lonchophyllinae. However, nectarivory has also evolved independently in the genus Phyllostomus (subfamily Phyllostominae). Since Phyllostomus species have an omnivorous diet with a high consumption of nectar, they can be used to explore the basic morphological modifications linked to evolving a nectarivorous habit. Here, we focused on describing and comparing the morphological features potentially associated with nectarivory in Phyllostomus discolor. We present the first detailed tongue and palate morphological descriptions for P. discolor and perform skull morphometric analysis including 10 species. We found hair‐like papillae on the tongue of P. discolor, a convergent feature with Glossophaginae and nectarivorous Pteropodids; these papillae likely confer an advantage when feeding on nectar. P. discolor does not show skull morphological features characteristic of nectarivorous bats, such as a long and narrow snout. We pose that the consumption of a variety of food, such as hard insects and fruits, and the large size of P. discolor relative to specialized nectarivores may create trade‐offs against morphological specialization of the skull towards nectarivory. In contrast, a long and mobile tongue with hair‐like papillae may be an evolutionary solution for nectar extraction that does not have a major impact on this species' ability to feed on other resources.

Diet and the evolution of ADH7 across seven orders of mammals

“…Detailed study of genes involved in other ethanol metabolic pathways and on the ethanol content of wild foods consumed by the species reported here (e.g. [ 7 ]), as well as more nuanced examination of omnivorous species which can consume a great deal of nectar or fruit [ 30 ], would be instructive and shed further light on this intriguing topic.…”

“…In particular, the neotropical leaf-nosed bats (family Phyllostomidae) have varied diets, with species specializing on insects, blood (haematophagy), nectar and fruit [ 28 ]. Additional small mammals with omnivorous diets opportunistically feed on floral nectars and fruits, and may consume these resources in abundance when available [ 29 , 30 ]. Given this remarkable variation among closely related taxa, mammals are well suited for studying how dietary adaptations may relate to functional genetic variation across phylogenies of species with distinct life histories.…”

Ecomorphology and sensory biology of bats

“…It is less clear, however, how the morphologies of less specialized species, such as omnivores, are able meet the functional requirements of their eclectic diets. In this issue, Quinche et al (2023) describe how the skull shape, palate, and tongue anatomy of an omnivorous phyllostomid, Phyllostomus discolor , compares to those of more specialized species. P. discolor includes a high amount of nectar in its diet when compared to its congeners, which it combines with insect prey and fruit.…”

Comparative Analysis of the Gut Microbiota of Bat Species with Different Feeding Habits

“…These diverse feeding habits have been linked to differences in bat morphology, physiology, and behavior [ 3 ]. For example, nectarivorous bats have long, slender snouts and tongues adapted for drinking nectar from flowers, while insectivorous bats have sharp teeth and echolocation abilities that enable them to catch and consume fast-moving prey [ 4 ]. Hematophagous bats have specialized adaptations for feeding on blood, including heat sensors on their noses to locate warm-blooded prey and anticoagulants in their saliva to facilitate feeding [ 5 ].…”