01213nas a2200181 4500008004100000022001400041245010300055210006900158260001600227300001800243490000800261520062800269100002300897700001700920700001900937700002400956856005100980 2018 eng d a0001-496600aHearing sensitivity evaluated by the auditory brainstem response in Miniopterus fuliginosus0 aHearing sensitivity evaluated by the auditory brainstem response cJan-11-2018 aEL436 - EL4400 v1443 a

This study evaluated the hearing sensitivity of Miniopterus fuliginosus, a frequency-modulating (FM) bat species, by measuring the auditory brainstem responses in the inferior colliculus. The average audiogram was U-shaped. The mean threshold decreased gradually as the frequency increased from 16 to 40 kHz and then decreased rapidly as the frequency reached 46 kHz, with the peak sensitivity occurring at the terminal portion of the echolocation pulse between frequencies of 44 and 56 kHz. The shape of audiogram of M. fuliginosus is consistent with other FM bats, and is compared with its vocalization behavior.

1 aFuruyama, Takafumi1 aHase, Kazuma1 aHiryu, Shizuko1 aKobayasi, Kohta, I. uhttp://asa.scitation.org/doi/10.1121/1.507990401618nas a2200181 4500008004100000022001400041245005500055210005500110260001600165300001600181490000800197520109600205100002101301700001801322700002601340700001901366856005101385 2018 eng d a0001-496600aStealthy moths avoid bats with acoustic camouflage0 aStealthy moths avoid bats with acoustic camouflage cJan-09-2018 a1742 - 17420 v1443 a

Intense predation pressure from echolocating bats has led to the evolution of a host of anti-bat defences in nocturnal moths. Some have evolved ears to detect the ultrasonic biosonar of bats, yet there are many moths that are completely deaf. To enhance their survival chances, deaf moths must instead rely on passive defences. Here, we show that furry morphological specializations give moth bodies and wing joints acoustic stealth by reducing their echoes from bat calls. Using acoustic tomography, echo strength was quantified in the spatial and frequency domains of two deaf moth species that are subject to bat predation and two butterfly species that are not. Thoracic fur determines acoustic camouflage of moths but not butterflies. Thoracic fur provides substantial acoustic stealth at all ecologically relevant ultrasonic frequencies, with fur removal increasing a moth’s detection risk by as much as 38%. The thorax fur of moths acts as a lightweight porous sound absorber, facilitating acoustic camouflage and offering a significant survival advantage against bats.

1 aNeil, Thomas, R.1 aShen, Zhiyuan1 aDrinkwater, Bruce, W.1 aRobert, Daniel uhttp://asa.scitation.org/doi/10.1121/1.506772501931nas a2200181 4500008004100000022001400041245009000055210006900145260001600214300001600230490000800246520137800254100001701632700001601649700001501665700001801680856005101698 2017 eng d a0001-496600aHorseshoe bats and Old World leaf-nosed bats have two discrete types of pinna motions0 aHorseshoe bats and Old World leafnosed bats have two discrete ty cJan-05-2017 a3011 - 30170 v1413 a

Horseshoe bats (Rhinolophidae) and the related Old World leaf-nosed bats (Hipposideridae) both show conspicuous pinna motions as part of their biosonar behaviors. In the current work, the kinematics of these motions in one species from each family (Rhinolophus ferrumequinum and Hipposideros armiger) has been analyzed quantitatively using three-dimensional tracking of landmarks placed on the pinna. The pinna motions that were observed in both species fell into two categories: In “rigid rotations” motions the geometry of the pinna was preserved and only its orientation in space was altered. In “open–close motions” the geometry of the pinna was changed which was evident in a change of the distances between the landmark points. A linear discriminant analysis showed that motions from both categories could be separated without any overlap in the analyzed data set. Hence, bats from both species have two separate types of pinna motions with apparently no transitions between them. The deformations associated with open–close pinna motions in Hipposideros armiger were found to be substantially larger compared to the wavelength associated with the largest pulse energy than in Rhinolophus ferrumequinum (137% vs 99%). The role of the two different motions in the biosonar behaviors of the animals remains to be determined.

1 aYin, Xiaoyan1 aQiu, Peiwen1 aYang, Lili1 aMüller, Rolf uhttp://asa.scitation.org/doi/10.1121/1.498204201367nas a2200181 4500008004100000022001400041245014200055210006900197260001600266300001800282490000800300520075400308100001801062700001701080700001801097700001901115856005101134 2017 eng d a0001-496600aThree-dimensional sonar beam-width expansion by Japanese house bats ( Pipistrellus abramus ) during natural foraging0 aThreedimensional sonar beamwidth expansion by Japanese house bat cJan-05-2017 aEL439 - EL4440 v1413 a

Three-dimensional directivity patterns of sonar sounds emitted by Japanese house bats (Pipistrellus abramus) during natural foraging were measured by a 44-channel microphone array. Just before prey capture, the terminal frequency (TF) of emitted sounds decreased, and the beam width (mean ± standard deviation) expanded from 40 ± 10° to 63 ± 9° (horizontal) and from 32 ± 10° to 52 ± 7° (vertical). P. abramus decrease the TF to simultaneously expand the beam width in both the horizontal and vertical planes, while retaining the target within the three-dimensional acoustic field of view at the final stage of capture.

1 aMotoi, Kazuya1 aSumiya, Miwa1 aFujioka, Emyo1 aHiryu, Shizuko uhttp://asa.scitation.org/doi/10.1121/1.4981934