HOW DO BATS AND PLANTS INTERACT?

Bats have very important relationships with plants, mainly through the consumption of plant parts, but also by roosting in them. There are four basic categories of interaction between bats and plants:

1. Mutualism: both sides benefit from the interaction. This category includes pollination and seed dispersal.

2. Parasitism: bats benefit, but cause harm to plants. This kind of ‘win-lose’ interaction happens when bats drink nectar without pollinating flowers, eat fruits without dispersing seeds, or eat leaves.

3. Predation: as in parasitism, bats benefit, but cause harm to plants. The only situation of predation by bats on plants is when bats digest seeds, thus killing the plant’s embryo.

4. Comensalism: bats benefit, but cause no significant harm or benefit to plants. It happens when bats use plants as roosts, sleeping in hollows or making tents. In the case of tents, the interationc may be also seen as a parasitism, because some leaves get too damaged.
   
   
   

Interactions between bats and plants have since long time stimulated research. However, the most significant ‘boom’ happened after the books by Van der Pijl (1973) and Faegri & Van der Pijl (1980), who organized the knowledge accumulated so far on seed dispersal and pollination. They advanced the concept of dispersal and pollination "syndromes”, i.e., the postulate that plants dispersed by the same agent share many characteristics. It implies that the agent of a given plant may be predicted only based on the plant’s morphology. The bat pollination syndrome is called ‘chiropterophylly’ and the bat dispersal syndrome is called ‘chiropterochory’. Important reviews on both syndromes have been made recently by Herlversen & Winter (2003) and Dumont (2003).

Nectar-feeding bats represent 4% of all extant bat species, and they belong to the specialized subfamilies Macroglossinae (Pteropodidae) and Glossophaginae (Phyllostomidae). The subfamily Phyllostominae, composed basically of generalists, has also some nectar-drinkers, but nectar is not their main food. In general, nectar-specialists have long tongues and muzzles, simple faces, short ears and noseleaves, small and few teeth, and a strong sense of smell. Bat-flowers are generally light-colored, most of them white or yellow, open at night, and produce particular aromatic substances that attract bats. Some bats that feed on nectar: