Tropical Ecology

My main scientific interest is the interaction between flower-visiting bats and their food plants in the Neotropics. The specialized nectar-feeding bats within the large family of Neotropical leaf-nosed bats (Phyllostomidae: Glossophaginae) show a number of adaptations to their foraging behaviour, including elongated muzzles and tongues and the ability for hovering in front of flowers. Similarly, the bat-pollinated plants are adapted to the pollination by their comparably large visitors by large, exposed flowers that provide large amounts of nectar.

Current projects include:

  • Musonycteris harrisoni – a specialized nectar-feeding bat in Western Mexico

One of the most specialized glossophagine bats is Musonycteris harrisoni, endemic to Mexico. The long rostrum, together with a small body size facilitates a specialized nectarivore existence in its highly seasonal dry forest habitat (Tschapka et al. 2008). Further aspects on the biology of this species include community ecology, feeding efficiency (Gonzalez et al., in prep.) and genetic diversity (Ortega et al., subm.)

  • Marcgravia – Lianas pollinated by bats

The neotropical lianas of the genus Marcgravia are characterized by a unique inflorescence structure that includes fertile flowers as well as sterile flowers modified into extrafloral nectaries. In some areas of Costa Rica up to 7 species may occur in close vicinity and most of these receive visits by glossophagine bats (Tschapka et al. 2006).

  • Visitators and pollinators of the palm Calyptrogyne ghiesbreghtiana

The understory palm C. ghiesbreghtiana displays a highly unusual floral biology. Here it is not nectar that is offered to the potentially pollinating visitors, but fruit-like floral tissue. Visitors to the palm inflorescences include various perching and hovering bat species, but also opossums and various insects (Tschapka 2003, Sperr et al. 2009). Pollination success for the palm is very variable and depends on behaviour and morphology of the visitors.

  • Bat-dispersed flower mites

Flower mites phoretic on hummingbirds are known since the 70-ties and have been extensively studied by R. Colwell, however, there are also certain flower-visiting bats that may transport the flower mites of the understory palm Calyptrogyne ghiesbreghtiana (Tschapka & Cunningham 2004). Ellen Sperr is currently studying population dynamics and ecology of this complex interaction for her doctoral dissertation .