Phenology of Lesser Long-Nosed Bats and their Food Plants

Abstract

Lesser long-nosed bats (Leptonycteris yerbabuenae) are important pollinators and seasonal residents along the U.S-Mexico border. Because they feed on flowering and fruiting plants, they are vulnerable to phenological shifts in those species. To evaluate synchrony between bats and their key food plants, we characterized seasonal abundance of bats and flowering and fruiting phenology of food plants at roosts in 2010, 2011, and 2021. Although phenology of bats and their food plants was generally consistent across years, we observed modest changes in aspects of flowering and fruiting of saguaro (Carnegiea gigantea) and organ pipe cacti (Stenocereus thurberi). At maternity roosts, bat abundance was synchronized more tightly with flowering phenology of saguaros in 2021 than in 2010-11. At post-maternity transient roosts, bat abundance was synchronized less tightly with flowering phenology of agaves (Agave palmeri) in 2021 than in 2010-11. We complemented these analyses by improving methods for non-invasive genetic sampling of this species. Specifically, we developed a two-step amplification approach to analyze microsatellite loci and identify individual bats via DNA extracted from fecal samples. As a proof of concept, five highly polymorphic microsatellite loci distinguished 434 individuals reliably. The probability of two closely related individuals having the same genotype at all five loci was 0.003, and the overall probability of identity was 7.5E-09. Addition of a multiplex step added minimal cost, improved amplification success, and conserved DNA extracts. Repeated analyses showed genotyping error was <2%. We explore the benefits and limits of our approaches for population studies of lesser long-nosed bats and other species that provide key ecosystem services and are commonly of conservation concern.