Essential amino acids in pollen influence the partnership between bats and flowers

Fernando Golçalves

A recent study, conducted by Brazilian researchers from the Federal University of Mato Grosso do Sul, with the participation of CBioClima associates Dr. Fernando Gonçalves (University of Zurich) and Dr. Carine Emer (UNESP Rio Claro), published in Functional Ecology, investigated over six years the interactions between bats and flowers in the Pantanal, the largest and most biodiverse floodplain in the world.

Bats are essential pollinators in many ecosystems, but most research tends to focus on nectar as their primary reward, neglecting another equally important food source: pollen. Many bat-pollinated plants produce large quantities of pollen, and it is known that these animals consume it, but what makes it so attractive? Our study sought to answer this question by investigating the role of pollen's nutritional value, especially its essential amino acid (EAA) content, in the interaction between bats and flowers.

Early in our fieldwork, we noticed something curious: bats that don't normally visit flowers carried pollen on their fur. Furthermore, we recorded some of these species near flowering trees. These findings caught our attention and motivated us to investigate the phenomenon in more detail. We realized that bats prefer flowers whose pollen is rich in essential amino acids, nutrients that neither they nor we can produce on our own, having to obtain them directly from our diet. All bat species captured visited these flowers rich in EAAs more frequently. Surprisingly, bats that normally feed on insects and small animals, such as frogs, mice, and marsupials, rely even more heavily on these flowers during the dry season. This likely helps meet their protein needs, especially when their usual prey becomes more difficult to find.

Our results suggest that pollen, and not just nectar, plays a central role in attracting bats and shaping the networks of interactions between flowers and pollinators. This is a new perspective on bat pollination, showing that the nutritional quality of pollen can influence which bat species visit which plants.

Interestingly, pollen isn't just important for bats; it's also becoming increasingly popular in our diets. The pollen of some flowers is considered a "superfood" due to its high protein, amino acid, and antioxidant content. Just as humans are discovering the benefits of pollen, bats may have long been exploiting its nutritional value, an interesting parallel between our diets and theirs. In short, what's good for bats may be good for us too.

This is the first study to show that the nutritional quality of pollen, especially its essential amino acid content, can influence pollination patterns. Our findings offer new insights into how pollinator-plant interactions work and how plants might respond to environmental changes. In a world where ecosystems face increasing pressures, understanding what pollinators like bats need to thrive can help protect both plants and the essential ecological services they provide.

(photo: Paulo Robson de Souza - Glossophaga soricina visitando flor de Psittacanthus acinarius)

Reference:

Gonçalves, F. et al. (2025). Pollen essential amino acids shape bat–flower interaction networks. Functional Ecology. DOI: 10.1111/1365-2435.70161