Seahorses are known to produce sounds in different behavioural contexts, but information on the sound production in this fish group is scarce. Here we examined the acoustic behaviour of the longsnout seahorse Hippocampus reidi by analysing sound production when fish were introduced to a new environment and during feeding, handling and courtship. We show that males and females produce two distinct sound types: ‘clicks’ (main energy between 50 and 800 Hz) during feeding and courtship, and previously undescribed ‘growls’ (main energy concentrated below 200 Hz). The latter consists of series of sound pulses uttered in stress situations when the animals were handheld. Growls were accompanied by body vibrations, and may constitute an additional escape mechanism in seahorses, which might startle predators. During reproductive behaviour, clicks were most abundant on the third (last) day of courtship; they were particularly associated with the males’ pouch-pumping behaviour, suggesting synchronization between sound production and courtship behaviour. This is consistent with the biology of Hippocampus species, which are mostly monogamous and form pair bonds. Thus, a courtship call may be used to signal readiness to mate.

Sounds produced by the longsnout seahorse: a study of their structure and functions

The evolution and functions of avian and mammalian antipredator callsare well understood, which contrasts with a lack of progress in reptiles.Here, we present the ﬁrst investigation of the functions of a distress call ina lizard. We studied Liolaemus chiliensis, which emits a short and complexhigh-pitched scream when it is subdued. We determined the behavioralresponses of two potential targets to these calls, conspeciﬁcs, and a snakepredator. Additionally, we tested whether the chemical environment(presence of chemical scents from conspeciﬁcs) modulates the lizards’responses to calls. Both the conspeciﬁcs and the predator responded to thedistress calls, which triggered a longer period of immobility in the lizardsand a reduction in exploratory behavior in the snake, as compared to awhite noise. In addition, the lizards in the arena with scents of conspecif-ics responded to distress calls and noise with more movements and escapeattempts. These results suggest that distress calls may enhance the survivalof L. chiliensis individuals.IntroductionMany birds and mammals emit calls when they areunder the risk of predation. These vocalizationsinclude alarm calls emitted when prey detect preda-tors and distress calls emitted when they are seized bypredators (Caro 2005). The distress calls may induce avariety of behavioral changes in conspeciﬁcs and/orpredators, which can enhance the survival probabili-ties of the prey and/or its conspeciﬁcs (H€ogstedt 1983;Neudorf & Sealy 2002; Caro 2005). These calls can becries for help, attracting conspeciﬁcs which may helpby attacking the predator (Branch & Freeberg 2012),or they may be warnings that help kin to escape frompredation (Rohwer et al. 1976). In addition, predatorscan be startled by distress calls (Wise et al. 1999;Neudorf & Sealy 2002), among other reasons, becausecalls may convey honest information about the defen-sive capabilities of the prey (Laiolo et al. 2004).Distress calls can also attract secondary predators,whose presence, or potential presence, may lead theprimary predator to release its prey in order to protectitself (H€ogstedt 1983; Koenig et al. 1991). Clearly,distress calls can have different functions that are notmutually exclusive (Rohwer et al. 1976; Perrone1980; Conover 1994; Branch & Freeberg 2012).The research on different types of antipredator callsdone on birds and mammals has allowed progress inthe understanding of the proximate and ultimatecauses involved in their evolution (e.g., Caro 2005;Zuberb€uhler 2009; Moller & Nielsen 2010; Gill & Bier-ema 2013). This contrasts with the lack of studies inother taxa that exhibit antipredator vocalizations,such as amphibians (Hodl & Gollmann 1986; Toledo &€Haddad 2009) and reptiles (Greene 1988). For lizards,there are no studies on the role of these vocalizationseven if many species vocalize under predation risk(see Labra et al. 2013). It is probable that lizards useconspeciﬁc calls to reduce their predation risk,because many species respond to the sounds associ-ated with predation even if they do not use sounds insocial interactions. For example, some species eaves-drop on the alarm calls of birds, which can trigger, ascompared to their songs, higher vigilance (Vitouseket al. 2007; Ito & Mori 2010) or increased camouﬂage(Ito et al. 2013). Other lizard species discriminatebetween vocalizations from predator and non-preda-tor bird species (Cantwell 2010) or modulate their

Searching for the Audience of the Weeping Lizard's Distress Call

Animals make calls to give conspecifics information about themselves. Based on these calls, the receiver makes decisions that affect survival and reproduction. However, not all of the signals are reliable. Honest signals are either costly to produce or are constrained by physical or physiological factors that cannot be faked. Aggressive calls during antagonistic interactions are both costly and constrained by physiology. The female Asian particoloured bat (Vespertilio sinensis) produces aggressive displays and vocalizations when confronted by an intruder conspecific competing for roost position. We tested whether the aggressive calls of female Asian particoloured bats encode reliable information about the body size and the quality of the caller, and, subsequently, whether aggressive calls predicted a winning percentage that was calculated as the number of winning interactions divided by the total number of agonistic interactions. At the syllable level, there were significant positive relationships between the duration of various syllables and forearm length, bite force and winning percentage. In addition, frequency-related syllable parameters, such as peak frequency, minimum frequency, maximum frequency and bandwidth, were negatively correlated with immune response and winning percentage. At the call level, heavier bats that produced calls with shorter mean inter-syllable silences had higher winning percentage and healthier bats produced calls with lower maximum frequency. There was a significant positive relationship between immune response and vocal complexity, but no significant relationship was found between winning percentage and vocal complexity. These results suggested that aggressive calls in female Asian particoloured bats may be honest signals of body size and quality during the antagonistic interactions. Indeed, the reliability of acoustic communication in bats may be key to an in-depth understanding of the function and evolution of social calls in bats. Although aggressive encounters for finite resources occur frequently in many species of animals, fights to the death are quite rare in nature. Before any physical encounter, most animals exchange signals indicating fighting ability to help both contestants decide whether to retreat or to engage further in the conflict. Our results suggested that the acoustic parameters controlled by the body size and/or quality indices of Vespertilio sinensis females were significantly correlated with winning percentage. Thus female Asian particoloured bats may use aggressive vocalizations to transmit information about their body size and/or body quality (commonly used as a proxy for fighting ability) to their rivals. The rivals would be able to predict the outcome of an escalated conflict based on this information in order to decide whether to escalate or de-escalate the aggressive encounter, thereby reducing unnecessary costs.

Are aggressive vocalizations the honest signals of body size and quality in female Asian particoloured bats

Reptiles, including birds, exhibit a range of behaviorally relevant adaptations that are reflected in changes to the structure of the inner ear. These adaptations include the capacity for flight an...

The early origin of a birdlike inner ear and the evolution of dinosaurian movement and vocalization

The weeping lizard, Liolaemus chiliensis, emits distress calls when trapped by a predator. Conspecific lizards respond to such calls with prolonged immobility, which may increase their probability of remaining undetected by a predator. This benefit, however, depends on the ability to react to the alert message of the call, which may be impaired by natural variation in the calls. The distress calls of L. chiliensis show geographic variation, and here we tested the response of two geographically distant populations (>700 km apart) to local (homotypic) and non-local (heterotypic) distress calls; if populations are finely tuned to their local calls, they may not be able to respond to heterotypic calls. We found that geographic variation in calls affects the lizards’ response, but this effect was population dependent; whereas southern lizards responded to calls of both populations, the northern lizards only reacted to homotypic distress calls. The factors that determine this asymmetric response to heterotypic calls are unclear and we discuss three hypotheses that have a common component in the difference in body size between the tested populations, which seems to play a key role in determining the response to distress calls in this species.

Asymmetric Response to Heterotypic Distress Calls in the Lizard Liolaemus chiliensis

The study of acoustic communication in lizards has been restricted and mainly focused on Gekkota. The rest of the lizards, Unidentata, are generally considered voiceless, although there are sparse reports on vocal sound production in members of different families. We analyzed the spectro-temporal characteristics of the distress calls emitted by the Unidentata lizard, Liolaemus chiliensis (the weeping lizard; Liolaemidae), the only species of this highly diverse genus (>220 species) that vocalizes. We also explored the relationships of the call characteristics with the sex and size of the individuals. The vocalizations of L. chiliensis are highly diverse and complex compared to any known call produced by Unidentata lizards. They exhibit pronounced frequency modulations, various nonlinear phenomena, and harmonics that extend into the ultrasonic range. Fundamental frequency and call duration are correlated with body size, and males emit louder but simpler calls (i.e., with less nonlinear phenomena) than fema...

Acoustic Features of the Weeping Lizard's Distress Call

http://www.jvoice.org/article/S0892199722003605/pdf

COVID-19 activity screening by a smart-data-driven multi-band voice analysis

(1) Background: The oral films are a new delivery system that can carry several molecules, such as neuromodulator molecules, including caffeine. These delivery systems have been developed and characterized by pharmacokinetics assays. However, new methodologies, such as psychophysiological measures, can complement their characterization. This study presents a new protocol with psychophysiological parameters to characterize the oral film delivery systems based on a caffeine model. (2) Methods: Thirteen volunteers (61.5% females and 38.5% males) consumed caffeine oral films and placebo oral films (in different moments and without knowing the product). Electrocardiogram (ECG), electrodermal (EDA), and respiratory frequency (RF) data were monitored for 45 min. For the data analysis, the MATLAB environment was used to develop the analysis program. The ECG, EDA, and RF signals were digitally filtered and processed, using a windowing process, for feature extraction and an energy mean value for 5 min segments. Then, the data were computed and presented to the entries of a set of Machine Learning algorithms. Finally, a data statistical analysis was carried out using SPSS. (3) Results: Compared with placebo, caffeine oral films led to a significant increase in power energy in the signal spectrum of heart rate, skin conductance, and respiratory activity. In addition, the ECG time-series power energy activity revealed a better capacity to detect caffeine activity over time than the other physiological modalities. There was no significant change for the female or male gender. (4) Conclusions: The protocol developed, and the psychophysiological methodology used to characterize the delivery system profile were efficient to characterize the drug delivery profile of the caffeine. This is a non-invasive, cheap, and easy method to apply, can be used to determine the neuromodulator drugs delivery profile, and can be implemented in the future.

/pdf/validation-of-psychophysiological-measures-for-caffeine-oral-2r7hzjfe.pdf

Validation of Psychophysiological Measures for Caffeine Oral Films Characterization by Machine Learning Approaches

Early detection of Alzheimer’s and Parkinson’s diseases using multiband nonlinear EEG analysis.

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases and it is strongly associated with age. There are four AD stages: mild cognitive impairment (MCI), mild, moderate (ADM) and advanced (ADA). This work aims at developing a new tool capable of distinguishing the different stages of AD at scalp level. Features such as the conventional frequencies relative power of the power spectrum wavelet packet transform have been extracted from the electroencephalogram signals in order to feed four classifiers: random forest decision trees, linear and quadratic support-vector-machines and linear discriminant analysis. The obtained results were analyzed through topographic maps and enabled the distinguish between binary groups with the following overall accuracies: 85.5% (C-MCI); 88.2% (C-ADM); 91.4% (C-ADA); 89.7% (MCI-ADM); 82.4% (MCI-ADA) and 81.3% (ADM-ADA). The applied method was able to detect major differences in scalp areas above the frontal and temporal lobes of the brain as AD progresses. 

Gabriela Silva

Papers

Acoustic Features of the Weeping Lizard's Distress Call

COVID-19 activity screening by a smart-data-driven multi-band voice analysis

Validation of Psychophysiological Measures for Caffeine Oral Films Characterization by Machine Learning Approaches

Early detection of Alzheimer’s and Parkinson’s diseases using multiband nonlinear EEG analysis.

EEG wavelet packet power spectrum tool for checking Alzheimer's disease progression