COOPERATION AND SOCIAL BONDS IN COMMON VAMPIRE BATS

Regurgitated food sharing among vampire bats is a classic textbook example of reciprocity ("reciprocal altruism"). But many authors have contested both the notion that reciprocity explains vampire bat food-sharing and the importance of reciprocity more generally. In Chapter 1, I review the literature on evolutionary explanations of cooperation. I show why reciprocity was once considered important but is now considered rare: overly literal translations of game theory strategies have resulted in problems for both defining and testing reciprocity. In Chapter 2, I examine the relative roles of social predictors of food-sharing decisions by common vampire bats (Desmodus rotundus) under controlled conditions of mixed relatedness and equal familiarity by fasting 20 individuals in 48 trials over two years. The food-sharing network was consistent, symmetrical, and correlated with mutual allogrooming. Non- kin food-sharing patterns were not consistent with harassment or byproduct explanations. I next attempted to manipulate food-sharing decisions in two ways. In Chapter 3, I administered intranasal oxytocin to test for effects on allogrooming and food sharing. I observed that inhaled oxytocin slightly increased the magnitude of food donations within dyads, and the amount of female allogrooming within and across all partners, without increasing number of partners. In Chapter 4, I assessed contingency of food-sharing in 7 female dyads (including four pairs of mother and adult daughters) with prior histories of sharing. To test for evidence of partner switching, I measured dyadic levels of food sharing before and after a treatment period where I prevented dyadic sharing (each bat could only be fed by others). A bat's sharing network size predicted how much food it received in the experiment. When primary donors were excluded, subjects did not compensate with donations from other partners. Yet, food-sharing bonds appeared unaffected by the non-sharing treatment. In particular, close maternal kin were clearly not enforcing cooperation using strict contingency. I argue that any contingencies within such bonds are likely to involve multiple services and long timescales, making them difficult to detect. Simple and dyadic `tit-for-tat' models are unlikely to predict cooperative decisions by vampire bats or other species with stable, mixed kinship, social bonds

Behavioral Ecology of Singing in the Heart-Nosed Bat, Cardioderma cor

Although singing has been recently recognized in some bat species, the prevalence and ecological significance of this behavior in bats is still mysterious. Cardioderma cor, the heart-nosed bat, was one of the first bats reported to sing, but little is known about the behavior of this species. Unlike other singing bats, this species roosts in groups during the day but disperses nightly to exclusive foraging areas, whereupon they sing from perches. The goal of this dissertation was to investigate the behavioral ecology of singing in C. cor, addressing key questions such as which bats sing, when and where they sing, and what and why they sing. I conducted a series of experiments to test the hypothesis that C. cor sings to create and defend foraging territories, a behavior commonly observed in songbirds but not mammals. I recorded the singing and sonar behavior of individuals across three field seasons in Tanzania. I mist-netted, tagged, and VHF-tracked 14 individuals to collect movement and singing data. Finally, I conducted acoustic playback experiments with 10 singers. C. cor males showed high fidelity to closely abutting night ranges that varied in size from 0.97 to 5.23 ha. Males foraged early in the evening before singing from preferred perches for up to several hours. I documented two C. cor song types, the most frequent being a “loud” song and less frequently a “soft” song uttered at the height of the dry season. Songs varied within individuals, but each individual’s songs were distinguishable by a unique set of spectral and temporal syllable parameters. C. cor and the sympatric, confamilial yellow-winged bat, Lavia frons, had overlapping foraging territories. However, C. cor’s repertoire was distinctive from that of L. frons’. Song playback experiments with C. cor elicited strong movement responses and changes in singing. Results suggested that song spectral and temporal parameters influenced behavioral responses. The results of this dissertation support the conclusion that C. cor’s singing behavior is consistent with the territory defense hypothesis for the evolution of singing, and suggest that song variability is likely integral to social interactions by facilitating individual discrimination or signaling motivational states

The Genetics Of Mosquito Heat-Seeking Behavior

Temperature is a highly dynamic feature of the world, and one that deeply affects living things. Organisms have evolved sophisticated sensory-­motor systems to detect and avoid excessive heat or cold—a behavior termed thermotaxis. In rare cases, however, animals use thermosensation not only to regulate their body temperature, but also to locate food sources in their environment. One example of such an adaptation is found in the female Aedes aegypti mosquito, which becomes attracted to the body heat of endothermic (“warm-­blooded”) hosts when in pursuit of a blood meal. Mosquitoes are remarkably adept at finding hosts in their environment and have become major vectors of human disease, but much remains to be understood about the ethology and sensory neurogenetics of this notorious insect. In this thesis, we used high-­throughput quantitative behavioral assays and genome-­editing techniques to investigate the behavioral rules and molecular basis of mosquito thermotaxis. We have found that female Aedes aegypti are exquisitely sensitive to thermal contrast, and are capable of heat-­seeking in diverse ambient environmental temperatures. By seeking relative warmth and avoiding relative cool, mosquitoes can thermotax towards heated targets. However, mosquitoes also avoid stimuli exceeding the body temperature of their hosts. In this manner, Ae. aegypti are maximally attracted to thermal stimuli approximating endothermic hosts such as humans. We have discovered that the insect thermosensor TRPA1, in addition to playing conserved roles in thermoregulation and chemosensation, is important for thermotactic tuning of heat-­seeking. AaegTRPA1-­/-­ mutant mosquitoes fail to avoid high-­temperature stimuli, and do not distinguish between thermal targets that resemble hosts and those that are inappropriately hot. This AaegTRPA1-­dependent tuning of thermotaxis may be critical for mosquitoes host-­seeking in a complex thermal environment in which hosts are warmer than ambient air, but cooler than surrounding sun-­warmed surfaces. These results demonstrate that evolutionarily conserved thermosensors, conventionally used for maintaining thermoregulatory homeostasis, can be repurposed by blood-­feeding arthropods to help locate and recognize the thermal signatures of their hosts. Our characterization of the behavioral strategies underlying heat-­seeking also helps to establish mosquitoes as a promising model system for the study of thermosensation and thermotaxis. These efforts may inform the design of next-­generation repellents and traps for the control mosquito-­borne diseases

Exploring Animal Behavior Through Sound: Volume 1

This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government

MOVEMENT ECOLOGY OF THE MEXICAN FISH-EATING BAT, MYOTIS VIVESI

Foraging behavior is influenced by the distribution of prey in time and space and the presence of conspecifics. Echolocating bats, which advertise their behavior while vocalizing, provide a unique opportunity for understanding how an organism interacts with conspecifics and the environment to find food. Here I use GPS tracking combined with on-board recording to investigate the foraging movements of lactating Mexican fish-eating bats, Myotis vivesi, in the Gulf of California, Mexico, over a 5-year period. In Chapter 1, I assessed five alternative methods for behavioral state segmentation of GPS tracked foraging paths using on-board audio for validation. While most methods perform well, hidden-Markov model segmentation showed the highest accuracy at predicting foraging movement. In Chapter 2, I evaluated habitat selection across multiple scales for fish-eating bats foraging in the Midriff Islands Region in the Gulf of California. Foraging site use at large scales is most predictive and is associated with dynamic (chlorophyll concentration) and static variables (ocean depth, sea floor slope) consistent with known tidal upwelling regions. In Chapter 3, I examine the function of in-flight social calls recorded from roughly half of all tagged individuals during their foraging flights. Calls contained spectral differences among individuals, were associated with the ends of flights as bats return to their roost, and increased in occurrence with pup age, consistent with directive calls used to communicate with mobile pups. In Chapter 4, I explore how prey distribution impacts social behavior and foraging movements. On-board audio reveals that conspecifics are present during commuting and foraging and playback experiments demonstrate an attraction to foraging call sequences. In collaboration with several colleagues I combined these findings with data from four other bat species ranging in diet and habitat type. Taken together, bat species that frequently encounter conspecifics, such as Myotis vivesi, have ephemeral prey and variable flights (e.g. duration and foraging site location), whereas bats that forage solitarily have predictable or non-shareable prey, such as a congener Myotis myotis, show less variability in their flights. Overall, these results provide new insights into the foraging dynamics and social behavior of bats

Exploring Animal Behavior Through Sound: Volume 1

This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government

Vidding

Vidding is a well-established remix practice where fans edit an existing film, music video, TV show, or other performance and set it to music of their choosing. Vids emerged forty years ago as a complicated technological feat involving capturing footage from TV with a VCR and syncing with music—and their makers and consumers were almost exclusively women, many of them queer women. The technological challenges of doing this kind of work in the 1970s and 1980s when vidding began gave rise to a rich culture of collective work, as well as conventions of creators who gathered to share new work and new techniques. While the rise of personal digital technology eventually democratized the tools vidders use, the collective aspect of the culture grew even stronger with the advent of YouTube, Vimeo, and other channels for sharing work. Vidding: A History emphasizes vidding as a critical, feminist form of fan practice. Working outward from interviews, VHS liner notes, convention programs, and mailing list archives, Coppa offers a rich history of vidding communities as they evolved from the 1970s through to the present. Built with the classroom in mind, the open-access electronic version of this book includes over one-hundred vids and an appendix that includes additional close readings of vids

"Get Listenin' Kids!": Independence as Social Practice in American Popular Music

This dissertation examines the concept of independence--defined as alternative approaches to the creation, distribution and consumption of music that actively resist cultural hegemonies--as an ongoing tradition in American popular music. While previous studies of independence have focused on specific independent record labels or eras, this project views independence as a historical trajectory that extends to the beginnings of the recording industry. Pierre Bourdieu's concept of the social field frames my investigation of the ways in which independence becomes socially and musically manifested in communities of musicians, mediators and audiences. I explore how these communities articulate their distinction within the dominant music industry by responding to the social and aesthetic chasms created by the centralization of media. This study is divided into two sections. The first focuses on independent record labels and local radio broadcasts in the first half of the twentieth century, when "independent" referred to either a record label that distributed outside major label channels, or a radio station unaffiliated with a network. In the second section, I show how the modern concept of independence became more overtly political with the emergence of the punk movement of the late 1970s. I follow the subsequent development of independent underground networks in the 1980s through their present-day fragmentation in twenty-first century internet culture. I conclude with an ethnographic examination of independent music performances in order to show that, while independence remains situated in ideas about community, authenticity and autonomy, it is subjectively understood and constructed by individual members of independent communities. The primary research for this study draws from eight years of personal experience as a freeform DJ and active consumer of independent music, as well as seven years working as a sound archivist at the University of Maryland Broadcasting Archives. Because this is a study of popular music, I engage with several interdisciplinary theoretical areas, including ethnomusicology, musicology, sociology and media studies, in order to conceptualize some of the patterns that shape independent social practices

Vidding

Vidding is a well-established remix practice where fans edit an existing film, music video, TV show, or other performance and set it to music of their choosing. Vids emerged forty years ago as a complicated technological feat involving capturing footage from TV with a VCR and syncing with music—and their makers and consumers were almost exclusively women, many of them queer women. The technological challenges of doing this kind of work in the 1970s and 1980s when vidding began gave rise to a rich culture of collective work, as well as conventions of creators who gathered to share new work and new techniques. While the rise of personal digital technology eventually democratized the tools vidders use, the collective aspect of the culture grew even stronger with the advent of YouTube, Vimeo, and other channels for sharing work. Vidding: A History emphasizes vidding as a critical, feminist form of fan practice. Working outward from interviews, VHS liner notes, convention programs, and mailing list archives, Coppa offers a rich history of vidding communities as they evolved from the 1970s through to the present. Built with the classroom in mind, the open-access electronic version of this book includes over one-hundred vids and an appendix that includes additional close readings of vids