Kinship, Diet, and Ecosystem Services of Insectivorous Bats

This dissertation explores the genetic, behavioral, and dietary development of the Mexican free-tailed bat (Tadarida brasiliensis), and the diet of insectivorous bats more broadly. The first chapter examines maternal behavior and the potential role of kinship in non-parental nursing. Using microsatellite and single nucleotide polymorphism genetic markers to assess relatedness between nursing females and pups, I show that while most nursing occurs between mothers and their offspring, a notable proportion of non-parental nursing may involve other genetically related individuals. This suggests that kin selection may be involved in the evolution of nursing behavior in this species, and that their sociality is likely more complex than we realize. The second chapter focuses on the development of the juvenile diet during the critical transition from milk to independent foraging. Molecular analysis of the juvenile diet using next generation sequencing shows that juvenile bats initially consume a broader range of arthropod prey than adults, with dietary composition shifting as juveniles age. Notably, juvenile males exhibit greater dietary diversity than juvenile females, suggesting possible sex-based differences in behavior or resource use. These bats likely experience a two-week learning curve upon fledging before approaching an adult-like diet. The third chapter examines the occurrence of pest and beneficial insects in bat diets across the globe and looks for patterns of consumption by geography, habitat type, and bat feeding guild. The presence and variety of both pest and beneficial insect taxa in the majority of bat diets raises many opportunities for deepening our understanding of the ecological importance of bats in human-dominated landscapes. Together, these studies fill in population-level gaps in the natural history of Mexican free-tailed bats and contribute insights ranging from behavioral to community ecology.