A computational sensorimotor model of bat echolocation

Erwin, Harry; Wilson, Willard W.; Moss, Cynthia F.

doi:10.1121/1.1381026

Cited by 14 publications

(7 citation statements)

References 34 publications

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“…An interesting possibility is the cross-modal integration of the visual background with the auditory foreground: the bat could follow a CATD strategy by maneuvering such that silhouettes of foliage against the night sky, or the positions of the moon or bright stars (any distant, high contrast object) appear stationary with respect to the acoustically derived position of the target. Some previous modeling studies of bat pursuit behavior have suggested that bats can successfully capture insects using a nonpredictive strategy [ 25, 26], whereas another modeling study has proposed that bats use an internal model of target motion to predictively pursue an insect [ 27]. Our experimental results show that the bat uses a functionally predictive strategy (CATD).…”

Section: Discussionmentioning

confidence: 67%

Echolocating Bats Use a Nearly Time-Optimal Strategy to Intercept Prey

et al. 2006

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Acquisition of food in many animal species depends on the pursuit and capture of moving prey. Among modern humans, the pursuit and interception of moving targets plays a central role in a variety of sports, such as tennis, football, Frisbee, and baseball. Studies of target pursuit in animals, ranging from dragonflies to fish and dogs to humans, have suggested that they all use a constant bearing (CB) strategy to pursue prey or other moving targets. CB is best known as the interception strategy employed by baseball outfielders to catch ballistic fly balls. CB is a time-optimal solution to catch targets moving along a straight line, or in a predictable fashion—such as a ballistic baseball, or a piece of food sinking in water. Many animals, however, have to capture prey that may make evasive and unpredictable maneuvers. Is CB an optimum solution to pursuing erratically moving targets? Do animals faced with such erratic prey also use CB? In this paper, we address these questions by studying prey capture in an insectivorous echolocating bat. Echolocating bats rely on sonar to pursue and capture flying insects. The bat's prey may emerge from foliage for a brief time, fly in erratic three-dimensional paths before returning to cover. Bats typically take less than one second to detect, localize and capture such insects. We used high speed stereo infra-red videography to study the three dimensional flight paths of the big brown bat, Eptesicus fuscus, as it chased erratically moving insects in a dark laboratory flight room. We quantified the bat's complex pursuit trajectories using a simple delay differential equation. Our analysis of the pursuit trajectories suggests that bats use a constant absolute target direction strategy during pursuit. We show mathematically that, unlike CB, this approach minimizes the time it takes for a pursuer to intercept an unpredictably moving target. Interestingly, the bat's behavior is similar to the interception strategy implemented in some guided missiles. We suggest that the time-optimal strategy adopted by the bat is in response to the evolutionary pressures of having to capture erratic and fast moving insects.

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Section: Discussionmentioning

confidence: 67%

Echolocating Bats Use a Nearly Time-Optimal Strategy to Intercept Prey

et al. 2006

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“…The stopping distance can be estimated by combining information on the initial velocity of the bat, maximal deceleration, and sensorimotor time delay. Taking a representative bat cruising velocity of 5 m/s [25], a maximal deceleration of 15 m/s 2 (estimated from a sample trajectory in [25]), and an estimated sensorimotor delay of 100–200 ms [30] yields an estimated stopping distance in the range of 130–180 cm. Although there is a great deal of uncertainty in these estimates, the stopping distance of the bat seems comparable to the sensory range for prey detection.…”

Section: Discussionmentioning

confidence: 99%

Omnidirectional Sensory and Motor Volumes in Electric Fish

et al. 2007

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Active sensing organisms, such as bats, dolphins, and weakly electric fish, generate a 3-D space for active sensation by emitting self-generated energy into the environment. For a weakly electric fish, we demonstrate that the electrosensory space for prey detection has an unusual, omnidirectional shape. We compare this sensory volume with the animal's motor volume—the volume swept out by the body over selected time intervals and over the time it takes to come to a stop from typical hunting velocities. We find that the motor volume has a similar omnidirectional shape, which can be attributed to the fish's backward-swimming capabilities and body dynamics. We assessed the electrosensory space for prey detection by analyzing simulated changes in spiking activity of primary electrosensory afferents during empirically measured and synthetic prey capture trials. The animal's motor volume was reconstructed from video recordings of body motion during prey capture behavior. Our results suggest that in weakly electric fish, there is a close connection between the shape of the sensory and motor volumes. We consider three general spatial relationships between 3-D sensory and motor volumes in active and passive-sensing animals, and we examine hypotheses about these relationships in the context of the volumes we quantify for weakly electric fish. We propose that the ratio of the sensory volume to the motor volume provides insight into behavioral control strategies across all animals.

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“…To our knowledge, none of the numerous models built to understand animal perception (Neumann, 2002;Ritz et al, 2000;Svensen and Kiorboel, 2000;Erwin et al, 2001), has ever incorporated the potential structural variability of a sensor to predict consequences on the performance of animals. Notable exceptions are the recent studies performed by Spaethe et al (2001) and Spaethe and Chittka (2003) who suggest that interindividual variation in the morphology of the compound eye and the performance of the linked neural circuitry influences foraging efficiency of bumblebees under natural conditions.…”

Section: Sensor Performancementioning

confidence: 99%

Variation in morphology and performance of predator-sensing system in wild cricket populations

Dangles

Magal

Pierre

et al. 2005

Journal of Experimental Biology

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SUMMARY Even though variation in morphology is known to translate into variation in performance, studies looking at structural variability of a sensor to predict its consequences on the performance of animals are exceedingly rare. We investigated the morphological variability of air-flow-sensing receptors in wild populations of wood crickets (Nemobius sylvestris) sampled in a wide variety of habitats differing in latitude, litter structure, vegetation and predator communities. These hair receptors act as predator sensors. The observed levels of hair morphological variation were then incorporated into a biomechanical model of the hair canopy response to air flow to predict their influence on cricket predator perception. Cricket populations differ from each other, often strongly so, in the total number of hairs and in the number of hairs longer than 1 mm, which are the hairs most sensitive for the perception of approaching predators. The hair canopy response, the output of the biomechanical model, sums up over the entire canopy the angles of deflection at which a neurophysiological response is triggered and represents the sensitivity of the cercal system. It is 35% higher in the most sensitive population, compared with the least sensitive population. These large differences in perception sensitivity for a given predator signal translate into larger distances at which predators could be perceived. Thus, differences in morphology at the sensor level seem to be translated both at the perception level and subsequently at the performance level of crickets.

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A computational sensorimotor model of bat echolocation

Cited by 14 publications

References 34 publications

Echolocating Bats Use a Nearly Time-Optimal Strategy to Intercept Prey

Echolocating Bats Use a Nearly Time-Optimal Strategy to Intercept Prey

Omnidirectional Sensory and Motor Volumes in Electric Fish

Variation in morphology and performance of predator-sensing system in wild cricket populations

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