In Mexico, our region of study, the agave plant's reliance on bats is often touted because we could not enjoy the popular drinks tequila and mezcal without this essential cactus species. But many lesser-known yet equally important plants of the Mexican deserts also depend on bats to reproduce. Columnar cacti form forests that cover several square miles with densities of 450 to 750 individual adult plants per acre. Apparently due to the extraordinary plant diversity of the region, all three species are present year-round, unlike the migratory populations that enter the southwestern U.S. each spring. Pollination is the means by which a plant transfers its pollen to another plant, most often relying on assistance from animals, such as bats.
Flowers are a plant's way of making itself attractive to animal pollinators.
Once pollination enables seeds to be formed within the protective fleshy part of the flower, that part of the flower becomes fruit. The fruit serves to attract animals once again, which, after eating the seeds, drop or pass them in a different location where they can germinate and grow. The flowers of columnar cacti have many unique adaptations for attracting pollinators such as bees, hummingbirds, hawkmoths, and bats. Approximately two-thirds of Mexico's 70 columnar cactus species produce flowers with these characteristics. This dominant species ranges over approximately 150 square miles of central Mexico.