Periodic Reporting for period 4 - GPS-Bat (Foraging Decision Making in the Real World – revealed from a bat’s point of view by on-board miniature sensors)
Periodo di rendicontazione: 2020-09-01 al 2021-07-31
Our environment is changing today more rapidly than ever, mostly due to human activity. Most animals suffer from this situation; many do not survive it. Only a better understanding of how animals behave in their natural environment, and of their basic needs, will allow developing conservation plans to help them survive. There are numerous examples of conservation plans that failed because of a lack of understanding of the species actual needs.
The first step toward reaching our goal was technological – we aimed to develop miniature tags that can be mounted even on small bats and include several sensors: GPS, accelerometers that allow inferring different behaviors such as flying vs. hanging and a microphone that allows monitoring foraging and interactions with other bats based on recording sound and specifically bat-echolocation. This step has been completed, and we are now using these new tags to study foraging decision-making focusing on four main questions (Work Packages):
1) Social decision-making (in fruitbats) - how does living in a colony assist foraging.
2) Spatial decision-making - we aim to compare the movement and behavior of bats that rely on predictable food, like fruit, and bats that rely on unpredictable food like insects.
3) Flexible decision-making – how animals change their decisions when original decisions turn out to be wrong.
4) Developing a computational frame-work that can explain some of these aspects of decision making.
Our main results were:
WP1. We established an open bat colony where bats are free to fly in an out. This allowed us to track the same bats over up to six months, revealing that new-born bats map their environment based on visual input and can perform short-cuts. We demonstrate that they can perform map-based navigation (Harten et al. Science 2020). We moreover describe the complexity of the social structure of the fruit-bat colony including long-term interactions between its individuals (Harten et al. 2019 Current Biology).
WP2-3. We revealed that bats that rely on an ephemeral resource such as swarming insects or flocking fish search for food collectively in order to improve foraging while bats that rely on food whose location is known such as fruit bat search for food individually. We further find that insectivorous bats that rely on reliable patches of insects will also forage individually and will probably defend their foraging sites (Egert-berg et al. 2018 Current Biology).
In a spin-off on the main project we research sensory decision making in several bat species. We demonstrate that bats weight vision and echolocation when making classification and orientation decisions. We show how sensory cohesion is required for object perceptions (Danilovich et al. 2020 PNAS).