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This review article presents insights into acoustic interactions with semiconductors, exploring a continuum from electron dynamics to exciton behavior while highlighting recent developments in organic material systems. Various aspects of acoustic interactions, encompassing the manipulation of electrons and their transport mechanisms for applications in the fields of acoustoelectric and acousto-optics, explored by studying surface acoustic wave (SAW) devices integrated with inorganic and organic semiconductors, are presented here. SAWs are guided waves propagating along a piezoelectric material surface, inducing acoustic strain and piezoelectric fields within a semiconductor upon contact. These fields create a dragging force, transferring energy and momentum into the semiconductor, which manipulate and transport charge carriers, thereby generating an acoustoelectric current. Furthermore, SAW can influence exciton dynamics via type-II as well as type-I band-edge modulations, leading to alterations in their spatial distribution, causing transport of electron–hole pairs as distinct charge carrier packets and as bound pairs, respectively, along the SAW path. This paper explores advancements in these phenomena, shedding light on innovative applications and, especially, novel insights into the dynamic interplay between acoustics and organic semiconductor physics. The review concludes by outlining challenges and prospects in the field of SAW and semiconductor interactions, providing a roadmap for future research endeavors. [ABSTRACT FROM AUTHOR]

Animal communication carries the risk of signal exploitation by predators, and thus many prey species will adjust their signals into more discreet messages to conspecifics, or conspicuous antipredator cues. Although rails (Family Rallidae) use the visual display of tail flicking as a warning of vigilance toward predators, how these birds alter their vocal behavior based on perceived predation risk remains little studied. The calls of owls, predatory birds that consume a variety of rallid species and can home in on acoustic cues of their prey, can reduce singing in numerous bird species. We applied remotely activated broadcasts and autonomous recording units to study whether rails in the wetlands of the Lake Calumet region near Chicago, Illinois, would decrease their vocal activity rate following the broadcast of a rallid predator, the Great Horned Owl (Bubo virginianus). Contrary to predictions, Soras (Porzana carolina) significantly increased vocal activity when exposed to owl vocalizations and decreased vocal activity when exposed to a harmless control. Our results indicate that rails appear to increase their vocal activity as a potential alarm mechanism, likely to reduce predation risk by warning conspecifics. [ABSTRACT FROM AUTHOR]

Morphological characteristics are known to be important predictors of victory in aggressive disputes in the animal world. Among anurans, however, acoustic communication also plays an important role in intrasex conflicts. Although there is evidence for the influence of spectral parameters of calls (e.g., fundamental and dominant frequencies) in anuran disputes, the role that temporal parameters (e.g., duration and repetition rate) play in success during physical conflicts is still poorly understood. We describe the behavior of male frogs in agonistic interactions and investigate the functions of the different types of calls emitted in different social contexts. We also evaluate how body characteristics (mass and body size) and bioacoustic characteristics (repetition rate of the calls) influence success in physical conflicts of Pithecopus nordestinus (Anura: Phyllomedusidae). Agonistic disputes involved gradation in the emission of calls, visual displays, and physical clashes. The fighting call increased in proportion during clashes, indicating a function associated with aggression/intimidation. The uneasiness call (new subcategory herein defined) was only performed by losers during physical clashes, suggesting a meaning of submission or restlessness. No differences were found in any of the morphological parameters between winners and losers of physical disputes. On the other hand, the repetition rate of the aggressive call was positively related to success in fights and proved to be a good predictor of success in fights between males of P. nordestinus. Our results contribute to understanding the influence of temporal parameters of calls on success in physical disputes of this Neotropical treefrog. [ABSTRACT FROM AUTHOR]

We studied the response of Water Rails ( Rallus aquaticus) to conspecific and heterospecific playback to reveal any variation in reaction to playbacks of rail and crake and if and how these reactions change in intensity. Ten observation points, 100 m from each other within a reedbed, were selected. We made our observations three times a day over three days in three sessions (Apr, Jun, and Sept). We quantified the response of Water Rails to the playback of conspecifics and the heterospecifics: Common Moorhen ( Gallinula chloropus), Corn Crake ( Crex crex), Little Crake ( Porzana parva), Spotted Crake ( P. porzana), and Baillon's Crake ( P. pusilla), in terms of phenological periods. We found that there is a difference in aggressive reaction between conspecific and heterospecific playbacks across all sessions and also within each session. The aggressive reaction decreases significantly in the direction (Water Rail = Common Moorhen) > (Corn Crake = Little Crake = Spotted Crake) > (Baillon's Crake), during the first session and (Common Moorhen) > (Water Rail) > (Corn Crake = Little Crake = Spotted Crake = Baillon's Crake) during the second session. We found that Water Rails react differently to conspecific and heterospecific calls. The reaction intensity changes from one session to another, and the level of reaction to different species also changes. Most of the aggressive reaction levels can be explained by nesting place and food competition but also nest parasitism behavior and body mass differences. [ABSTRACT FROM AUTHOR]

We simulated the presence of an acoustic competitor by broadcasting conspecific playbacks to males of Johnstone's whistling frog, Eleutherodactylus johnstonei, in the field. We broadcast calls that differed in duration (short, typical, and long), dominant frequency (high, typical, and low), and period (short, typical, and long), and analyzed male vocal responses. We tested the hypothesis that males respond by escalating vocally when they are exposed to female-attractive calls and by ignoring unattractive ones. At the population level, males responded to playbacks in ways that would potentially increase their attractiveness with regard to solo calling: males increased the duration, reduced the dominant frequency, and increased their calling effort (duty cycle), despite an increase in call period. The modification of call duration occurred only in response to playbacks of low-frequency calls, long calls, and short-period calls (selective response), while the modification of the dominant frequency was independent of the characteristic of the playback (fixed response). Contrary to the expected, males did not reduce the call period when they were exposed to attractive playbacks. At the ultimate level, the results suggest energy-saving strategies. In addition, males seem to trade off call period for the avoidance of acoustic interference with attractive calls as calling effort was typically increased by increasing call duration but only rarely by reducing the call period. Interactive playbacks are necessary to better understand the calling strategies of males of E. johnstonei. [ABSTRACT FROM AUTHOR]

Studies of acoustic interactions in animal groups, such as chorusing insects, anurans, and birds, have been invaluable in showing how cooperation and competition shape signal structure and use. The begging calls of nestling birds are ideal for such studies, because they function both as a cooperative signals of the brood's needs and as competitive signals for parental allocation within the brood. Nonetheless, studies of acoustic interactions among nestlings are rare. Here we review our work on acoustic interactions in nestling tree swallows (Tachycineta bicolor), especially how calls are used in competition for parental feedings. Nestlings attracted parental attention and responded to acoustic interference mainly by increasing call output. However, nestlings also gave more similar calls when they called together and decreased their call bandwidth when exposed to elevated noise. We suggest that these competitive uses of calls might intensify the cooperative brood signal, affecting both parental provisioning and vocal development. Given their tremendous variation across species, begging calls offer promising opportunities for developmental and comparative studies of acoustic signaling. [ABSTRACT FROM AUTHOR]

Males of several fish species aggregate and vocalize together, increasing the detection range of the sounds and their chances of mating. In the Lusitanian toadfish (Halobatrachus didactylus), breeding males build nests under rocks in close proximity and produce hundreds of boatwhistles (BW) an hour to attract females to lay their demersal eggs on their nests. Chorusing behaviour includes fine-scale interactions between individuals, a behavioural dynamic worth investigating in this highly vocal fish. Here we present a study to further investigate this species' vocal temporal patterns on a fine (individual rhythms and male-male interactions) and large (chorus daily patterns) scales. Several datasets recorded in the Tagus estuary were labelled with the support of an automatic recognition system based on hidden Markov models. Fine-scale vocal temporal patterns exhibit high variability between and within individuals, varying from an almost isochronous to an apparent aperiodic pattern. When in a chorus, males exhibited alternation or synchrony calling patterns, possibly depending on motivation and social context (mating or male-male competition). When engaged in sustained calling, males usually alternated vocalizations with their close neighbours thus avoiding superposition of calls. Synchrony was observed mostly in fish with lower mean calling rate. Interaction patterns were less obvious in more distanced males. Daily choruses showed periods with several active calling males and periods of low activity with no significant diel patterns in shallower intertidal waters. Here, chorusing activity was mainly affected by tide level. In contrast, at a deeper location, although tidal currents causes a decrease in calling rate, tide level did not significantly influence calling, and there was a higher calling rate at night. These data show that photoperiod and tide levels can influence broad patterns of Lusitanian toadfish calling activity as in other shallow-water fishes, but fine temporal patterns in acoustic interactions among nesting males is more complex than previously known for fishes. • We used an automatic recognition system based on HMM to annotate acoustic datasets. • We investigated fish fine-scale individual calling patterns and vocal daily rhythms. • Chorusing Lusitanian toadfish males called in alternation and synchrony patterns. • Daily chorusing patterns were different in intertidal and subtidal areas. [ABSTRACT FROM AUTHOR]

We consider the scattering of waves by an infinite three-dimensional cascade of finite-length flat blades in subsonic flow at zero angle of attack. This geometry is of specific relevance as it provides a model for the components in turbofan engines. We study the scattering problem analytically, considering both acoustical and vortical incident fields, spanwise wavenumbers and transverse mean flow. Most importantly we extend previous work by lifting the restriction that adjacent blades overlap, a condition that had thus far been crucial for the analytical study of this problem. Our method of solution relies on the solution of three coupled boundary value problems using the Wiener-Hopf technique, corresponding to an uncoupled leading-edge approximation, and a subsequent trailing-edge and leading-edge correction. We provide exact expressions for observables in the system, depending only on the solution of a linear matrix equation. Specifically we find closed-form expressions for the far-field behaviour of the scattered potential upstream and downstream of the cascade, the upstream and downstream sound power, as well as the total unsteady lift on each blade in the cascade. A wide range of results are presented, and we see that the non-overlapping cascade is, as might be expected, typically more transparent to incident disturbances than the previously studied overlapping case. [ABSTRACT FROM AUTHOR]