The Mexican long-tongued bat flies into a backyard garden in the Tehuacan Valley of central Mexico. It is well after midnight, and the scene in the video camera’s viewfinder has a greenish tint. The bat approaches a bugle-shaped flower growing high on the soaring column of a pitaya cactus. It hovers for a split second, dipping its face into the open flower. Then it flies off into the night in search of another flower to again complete its crucial role in the pollination cycle.
Nectar-eating bats have been pollinating columnar cacti such as pitaya in Mexico and the American Southwest from time immemorial. But the arid landscape is becoming fragmented as towns, farms and ranches eliminate essential great swatches of bat habitat. With a Graduate Student Research Scholarship from BCI, I am exploring how human use and management of cacti affects bats – and how bat activity affects the cacti on which so many species depend.
Along the way, we are educating the indigenous Mixtec and Nahua people of the valley about the value of bats, especially in maintaining the popular and important pitaya cacti that grace so many of their yards and produce a valued fruit. The people of the valley also collect wild pitaya fruit and manage some wild populations by maintaining desirable plants.
As they deal with the cacti, residents change the size and density of the resource available to native bats – the lesser long-nosed bat (Leptonycteris yerbabuenae), the greater long-nosed bat (Leptonycteris nivalis) and the Mexican long-tongued bat (Choeronycteris mexicana) – that feed on pitaya nectar and pollen.
We spent many nights making videos of bats approaching pitata flowers and also caught and radio-tagged a number of bats to determine how often each visited the same plants.
During our two summers of fieldwork, we clearly demonstrated that the home gardens are a very important resource for Tehuacan Valley bats. Managed and wild pitaya populations tended to receive fewer pollination visits, which might account for lower fruit production in the wild.
Documenting the critical role of nectar-eating bats in the production of pitaya fruit should prove a valuable tool in encouraging conservation efforts. Documenting details of that interaction will help develop effective strategies for conserving nectar-eating bats in the patchy environments that they must share with people.
Jennifer Cruse-Sanders’ work with nectar-feeding bats in Mexico was supported by a BCI Student Research Scholarship. This program has helped fund bat-conservation research by 185 students in 49 countries since 1990. These young biologists and conservationists have made important contributions to our ability to protect bats and their habitats worldwide, and many already are becoming leaders in the field. To support BCI Scholarships, please contact Development Director Emily Young at (512) 327-9721 or firstname.lastname@example.org.