Biology subjects

Yoshino-Hashizawa, K.

Publications and source records attributed to Yoshino-Hashizawa, K..

3 recordsLinked to original sources

bioRxiv2026

Tactile pup loss and acoustic signal enhance selective maternal retrieval behavior in echolocating bats, Pipistrellus abramus

Pup retrieval is a critical maternal behavior ensuring pup survival. Its mechanisms have been studied mainly in rodents, where mothers tolerate brief pup separation. In contrast, in species for which even short separation is life-threatening, mothers maintain constant physical contact, reinforcing anti-separation behavior. Studying such species may uncover maternal strategies under survival-critical extremes. Among these species, echolocating bats provide an ideal model for acoustic-based decision-making, as they rely heavily on sound. In bats, pup isolation calls (ICs) are essential signals in mother-pup communication. To assess their motivation in retrieval based on ICs, we conducted behavioral experiments: (1) pup retrieval test, and (2) playback test using ICs from own vs. non-own pups. Each was conducted under three maternal conditions: holding (a) no-pup, (b) one-pup, and (c) two-pup, to assess tactile influence on maternal motivation. In pup retrieval tests, mothers showed selective responsiveness to their own pups, and it is decreased with their pup development. Playback tests showed that acoustic signals alone were sufficient to elicit maternal responses, and their latencies were negatively correlated to pup vocalization rates. These maternal responses were strongly suppressed under condition (c), but robustly expressed under conditions (a) and (b). These findings suggest that maternal motivation is context-dependent responsiveness, which is enhanced by tactile pup loss and ICs, providing insight into instinctive maternal behavior in mammals. Summary statementThis study demonstrates that in the Pipistrellus abramus, maternal motivation is context-dependent responsiveness, which is enhanced by tactile pup loss and vocalizations, providing insight into a flexible multimodal mechanism underlying instinctive maternal behavior.

animal behavior and cognition↗

bioRxiv2025

Mothers respond to biological pup calls with heart rate changes in Japanese house bats, Pipistrellus abramus

Maternal care is essential for offspring survival in mammals, especially in colonial species where mothers must recognize their own young among many. In the Japanese house bat, Pipistrellus abramus, mothers identify their pups using acoustic cues, particularly isolation calls (ICs) produced by newborns. However, the physiological mechanisms underlying such maternal recognition remain largely unknown. Here, we investigated maternal emotional responses of mother bats to pup calls by measuring heart rate (HR) changes during controlled playback experiments. We recorded ICs from 2-day-old pups and echolocation calls (ECs) from 30-day-old pups, then presented these sounds to mothers after their pups had become independent. HR significantly increased in response to calls from the mothers own pups--both ICs and ECs--but not to calls from non-family pups. Among all stimuli, ECs from their own older pups evoked the largest HR increase, indicating strong physiological arousal and suggesting sustained maternal responsiveness despite developmental changes in call structure. In contrast, ECs from an unfamiliar adult also induced HR elevation, possibly reflecting general social arousal rather than maternal recognition. These findings demonstrate that P. abramus mothers exhibit selective physiological arousal to their own pups vocalizations, and that HR provides a sensitive physiological index of maternal motivation and recognition based on dynamic acoustic information.

animal behavior and cognition↗

bioRxiv2023

The distress context of social calls evokes a fear response in the bat Pipistrellus abramus

Bats primarily use sound information, including echolocation, for social communication. Bats under stressful conditions, for example when confronted by a predator, will emit aggressive social calls. The presentation of aggressive social calls, including distress calls (DCs), is known to increase heart rate (HR), but how this change in HR is related to the bats sound perception and how this evokes behaviors such as the fear response is unknown. Herein, we show that the perception of a distress context induces freezing behavior as a fear response in bats. We found that bats responded by freezing and displayed increased HRs when they were presented with a conspecific donor bat in a distress situation evoked by gentle poking with a cotton swab. In addition, when we presented two types of auditory oddball paradigms with different probabilities of DCs and echolocation calls (ECs), the bats HRs increased when DCs were presented as deviant or control stimuli within standard ECs but did not increase when DCs were presented as standard stimuli. These results suggest that the situational context created by the frequency of sound presentation, rather than simply a single sound feature, induces HR increases and freezing as fear responses in bats. Summary statementWe investigated the electrocardiograms of captive Pipistrellus abramus and found that their heart rate increased as a fear response when the bats heard sounds with a distress context.

animal behavior and cognition↗