Cognitive ecology of predatory bats and sound-producing prey

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The long-term objective of my research program is to better understand how animals - vertebrates and invertebrates alike - use sensory information to construct useful internal representations of their often changing external environments. Over the course of this 5-year research grant, we will use predatory bats to investigate if and, if so, how bats use primarily auditory information for real-time and future decision-making about what insects to eat and what insects to avoid. First, we will investigate the chemical defences of the local community of tiger moths, across and within species. Tiger moths are often conspicuously coloured and/or produce bat-deterring sounds, these signals warn birds and bats, respectively, that they may be noxious. However, the chemical defences and palatability of individual moths in nature is rarely investigated. By identifying chemically defended species through to those that are entirely palatable, we will then try to identify potential mimicry complexes based on wing pattern and colouration. Similarly, we will play back echolocation attack sequences from all local bat species (8, 3 of which are migratory) at sound pressure levels reflective of bats in open space to all tiger moth species and record the moths' acoustic responses. We will then compare tiger moths' clicks and clicks modulation cycles as produced by different species to, again, identify potential mimicry rings, this time with respect to defensive acoustic signal design and deployment. With these results in hand, we then test these potential visual and acoustic mimicry using bats (captive born, and wild caught, juveniles and adults) and tiger moths in large outdoor flight rooms. We will also conduct simpler experiments to document tiger moth species' palatability in birds, terrestrial mammals, and other insects. And conduct field tests with paper models to document which tiger moth species are attacked by birds. Southern Ontario is home to a manageable community of tiger moths (~30 common species) for which we have previously built a molecular phylogeny and a small community of vespertilionid bats, making this a feasible system to consider the evolutionary ecology of predator learning, memory, and predator-prey interaction. With that in mind, we will also conduct flight room experiments to see if local gleaning bats can learn about palatable, sound producing prey new to them (e.g., an introduced katydid species) by listening to its simulated stridulations and then be attacked and consumed by another bat. We will also test if bats can learn from listening to other bats which tiger moths to avoid, as appears possible in some insect-eating birds.  Last, we will test whether bats can learn to take prey from surfaces (i.e. glean) more quickly when they keep the company of bats that already glean, and thoroughly investigate the extraordinary behaviour of some local bat species when hunting moths, including tiger moths, at streetlights surrounded by forest.