The allocation of energy to echolocation pulses produced by soprano pipistrelles (Pipistrellus pygmaeus) during the wingbeat cycle

摘要

Soprano pipistrelles exhibit considerable plasticity in both the structure and rate of echolocation call production. In search phase in the laboratory, calls are produced either as a single pulse per wingbeat cycle, or as double pulses. The amplitude of double pulses is reduced compared to the preceding single pulse. The energy flux density of either pulse of a double pulse per wingbeat was lower than a single pulse per wingbeat, and is achieved by a combination of reduction in both duration and amplitude. The combined energy of the double pulses is not significantly greater than the single pulse which precedes it. The decision to produce a double pulse may be an indication of the bat requiring additional information from the target. The production of double pulses per wingbeat may serve to achieve a higher rate of information flow for no significant increase in energetic expenditure when a possible target is detected. The proposal that echolocation during flight comes for free as a by-product of the intimate coupling among wingbeat, respiration, and echolocation is discussed. (c) 2007 Acoustical Society of America.