Leaf-eating Bats

A number of frugivorous bats are known to consume leaves on occasion (Kunz and Ingalls, 1994). Among these folivorous frugivores are several species in the genus Artibeus. Two Brazilian researchers report that another species Artibeus lituratus (Figure 1) also feed on leaves.

Artibeus

Figure 1. A small group of Artibeus lituratus roosting inside a palm frond. (from Flickr/Brian Gratwicke)

Their research shows that
A. lituratus begins foraging for fruit, but may switch to leaf eating around 21:00, presumably after they have already consumed a fruit meal. Why the switch?

Scientists know that fruits are high in carbohydrates, but poor in protein. In contrast, leaves tend to be high in protein and certain minerals. One hypothesis is that leaves may provide a supplementary source of protein or calcium. In the study by Bobrowiec, and Cunha (2010), the bats consumed leaves each night during the dry season. Interestingly, the bats did not consume the cellular components of the leaf, and instead chewed the leaf fragments to extract the juices. The bats spit out the undigested parts as a pellet. This behavior makes sense because most frugivorous bats lack the intestinal microbes to digest plant material efficiently (Kunz and Ingalls, 1994).

Scientists have now documented leaf consumption in a number of frugivorous bat species. Yet the motivation for this behavior remains unclear. Do the leaves provide vitamins, minerals, or other nutritional components not found in a diet of fruit? Do the leaves contain medicinal compounds that aid digestion or health? How do the bats deal with the plant secondary compounds in these leaves? These and other important questions await an enterprising young mammalogist willing to take up the challenge of analyzing the liquid component of the leaves.


References

Bobrowiec, P.E.D., and R.M. Cunha. 2010. Leaf-consuming behavior in the big fruit-eating bat,
Artibeus lituratus (Olfers, 1818) (Chiroptera: Phyllostomidae), in an urban area of Southeastern Brazil. Chiroptera Neotropical 16(1):595-599.

Kunz T.H. and K.A. Ingalls. 1994. Folivory in bats: an adaptation derived from frugivory.
Functional Ecology 8: 665-668.