Behaviour 2019
Do insect-eating bats stop to smell the roses? A behavioral assay of olfactory sensitivity in  bats.  
Thomas E Croft1, Alyson Brokaw2, Michael Smotherman3. 1Texas A&M University, College Station, Texas, United States; 2Texas A&M University, College Station, Texas, United States; 3Texas A&M University, College Station, Texas, United States

Frugivorous and nectivorous bats use olfaction to find fresh fruit and flowers, but the importance of olfaction for insectivorous bats is poorly understood.  Mexican free-tailed bats (Tadarida brasiliensis) are fast, high-flying bats that hunt insects by echolocation, and they are hypothesized to use odors for social communication. To investigate olfaction in this species, we developed an olfactory behavioral assay based on classical taste aversion conditioning. Groups of bats were presented with two different water cups, one of which was flavored with the non-toxic bitter compound quinine hydrochloride. Pilot studies confirmed the bats used spatial learning to avoid the quinine-flavored water. Next, the quinine water cup was scented with artificial mango and its location randomly switched daily with control water cups for two weeks of conditioning.  When we removed the quinine flavoring but not the mango scent, bats continued to avoid the mango scented dish, indicating they detected and associated the mango scent with quinine. The assay provides a foundation for exploring the olfactory capabilities of insectivorous bats.