scholarly journals Bats dynamically change echolocation parameters in response to acoustic playback

2019 ◽  
Author(s):  
M. Jerome Beetz ◽  
Manfred Kossl ◽  
Julio C. Hechavarria

Animals extract behaviorally relevant signals from 'noisy' environments. To investigate signal extraction, echolocating provides a rich system testbed. For orientation, bats broadcast calls and assign each echo to the corresponding call. When orienting in acoustically enriched environments or when approaching targets, bats change their spectro-temporal call design. Thus, to assess call adjustments that are exclusively meant to facilitate signal extraction in 'noisy' environments, it is necessary to control for distance-dependent call changes. By swinging bats in a pendulum, we tested the influence of acoustic playback on the echolocation behavior of Carollia perspicillata. This paradigm evokes reproducible orientation behavior and allows a precise definition of the influence of the acoustic context. Our results show that bats dynamically switch between different adaptations to cope with sound-based navigation in acoustically contaminated environments. These dynamics of echolocation behavior may explain the large variety of adaptations that have been reported in the bat literature.

2021 ◽  
Vol 224 (6) ◽  
pp. jeb234245
Author(s):  
M. Jerome Beetz ◽  
Manfred Kössl ◽  
Julio C. Hechavarría

ABSTRACTAnimals extract behaviorally relevant signals from ‘noisy’ environments. Echolocation behavior provides a rich system testbed for investigating signal extraction. When echolocating in acoustically enriched environments, bats show many adaptations that are believed to facilitate signal extraction. Most studies to date focused on describing adaptations in insectivorous bats while frugivorous bats have rarely been tested. Here, we characterize how the frugivorous bat Carollia perspicillata adapts its echolocation behavior in response to acoustic playback. Since bats not only adapt their echolocation calls in response to acoustic interference but also with respect to target distances, we swung bats on a pendulum to control for distance-dependent call changes. Forward swings evoked consistent echolocation behavior similar to approach flights. By comparing the echolocation behavior recorded in the presence and absence of acoustic playback, we could precisely define the influence of the acoustic context on the bats' vocal behavior. Our results show that C. perspicillata decrease the terminal peak frequencies of their calls when echolocating in the presence of acoustic playback. When considering the results at an individual level, it became clear that each bat dynamically adjusts different echolocation parameters across and even within experimental days. Utilizing such dynamics, bats create unique echolocation streams that could facilitate signal extraction in noisy environments.


Author(s):  
W. A. Shannon ◽  
M. A. Matlib

Numerous studies have dealt with the cytochemical localization of cytochrome oxidase via cytochrome c. More recent studies have dealt with indicating initial foci of this reaction by altering incubation pH (1) or postosmication procedure (2,3). The following study is an attempt to locate such foci by altering membrane permeability. It is thought that such alterations within the limits of maintaining morphological integrity of the membranes will ease the entry of exogenous substrates resulting in a much quicker oxidation and subsequently a more precise definition of the oxidative reaction.The diaminobenzidine (DAB) method of Seligman et al. (4) was used. Minced pieces of rat liver were incubated for 1 hr following toluene treatment (5,6). Experimental variations consisted of incubating fixed or unfixed tissues treated with toluene and unfixed tissues treated with toluene and subsequently fixed.


Author(s):  
Susan C. Graham

Culinary experiences have long been an important aspect of tourism. For many destinations, culinary offerings have become ubiquitous with the place – pasta in Italy, wine in the Loire- or Napa Valley, or curry in India. As tourists increasingly seek out authentic touristic experiences, including culinary experiences, the question arises regarding what constitutes an authentic culinary experience in a place. While authentic and authenticity are terms widely used in the tourism literature, a precise definition of what those terms mean and a method for identifying that which is authentic remains elusive. Research regarding authenticity in tourism suggests that locals occupy a ‘place of privilege’ with respect to determining the authenticity of a touristic experience because of their connection to and context in relation to the place. This paper examines the perspectives of Prince Edward Island (PEI) residents with respect to what constitutes an authentic culinary touristic experience in which visitors to Canada’s smallest province can partake and that provide those visitors with a glimpse of what life in PEI is or was really like, and provides a voice for an underrepresented group in the authenticity discourse. Results show that authentic culinary experiences transcend food, and encompass people, places, and experiences in ways that enrich touristic endeavours, and that locals understand and interpret authenticity in ways that both conform to and differ from existing scholarly work related to tourism authenticity, and span objective, existential, and constructive authenticity.


Author(s):  
Johannes Lindvall

This chapter introduces the problem of “reform capacity” (the ability of political decision-makers to adopt and implement policy changes that benefit society as a whole, by adjusting public policies to changing economic, social, and political circumstances). The chapter also reviews the long-standing discussion in political science about the relationship between political institutions and effective government. Furthermore, the chapter explains why the possibility of compensation matters greatly for the politics of reform; provides a precise definition of the concept of reform capacity; describes the book's general approach to this problem; and discusses the ethics of compensating losers from reform; and presents the book's methodological approach.


2021 ◽  
pp. 147059312110127
Author(s):  
Jörgen Sandberg ◽  
Mats Alvesson

We all want to develop impactful and valuable theories, but what do we mean by ‘theory’? In this piece, we reply to the four readers’ comments on a recent paper in which we propose a theory typology that, in comparison to existing literature, offers a considerably broader, more pluralistic and, at the same time, more precise definition of the meaning(s) of ‘theory’ within academia. In their comments, the readers raise several insightful points that encourage us to further clarify the theory typology, as well as to expand on how it can be useful for researchers in marketing and social science more broadly.


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