Analyzes of bat echolocation calls enable to investigate diverse patterns of bat communities without the need for contact manipulation with individuals. The continuous all-night acoustic recordings provide standardised data open to quantitative comparisons and testing effects of diverse contextual factors upon bat community structure. The multidisciplinary project MOSAIK (Monitoring Savanna Biodiversity in Kruger NP) mapping patterns of variation in savanna communities under different spatial and temporal influences includes bats as one of the model groups. At standardized monitoring points of the project (covering 20 different areas, each containing triplet points differing in access to the water surface: permanent, seasonal and the crests without a water source), all-night acoustic recordings of bats were undertaken over two seasons (using Song Meter recorders SM4BAT). All records were analyzed with aid of Kaleidoscope Pro software and cluster identification technique (with an input database developed by Weier et al. 2018 and Taylor et al. 2020) controlled by manual checking. Multiple comparisons of diverse coenologic variables of the particular samples were performed together with testing effects of associated contextual variables (geographic setting and climatic currents, seasons, vegetation,...

The objective of this thesis was to develop new approaches and perspectives in resolving historical information from natural archives. Paleolimnology, the study of past aquatic environments using lake sediment cores, has greatly advanced our understanding of previous environments. This thesis intended to expand the range of historical information that may be used in paleolimnology and for historical reconstructions. Here I used pond sediments and a bat guano deposit as natural archives that recorded a history of events that I interpreted using a combination of chemical and biological measurements. In particular, I applied sterols and stanols as novel approaches for interpreting historical information in natural archives. First, I examined the chemical and biological composition of lake sediments to track the human occupation of Dorset and Thule people in Canada’s High Arctic. As predicted, sterols, stanols, cadmium, copper, and zinc increased in sediments deposited during known periods of human occupation owing to nutrient addition, whereas these increases were absent in reference sites. These methods were further corroborated in a study of 20th century human occupation at Resolute Bay by examining similar constituents in waterbodies that received wastewater discharge. Second, I used δ15N and δ13C to track the agricultural history of Jamaica using a 4,300-year-old bat guano deposit. I then used C/N, δ13C, and sterol and stanol ratios to detect two periods of increased frugivory relative to insectivory-based foraging. Metals normalized to titanium increased during the Industrial Revolution and 206Pb/207Pb values tracked the introduction and subsequent ban of leaded gasoline. I also examined the same chemical constituents in fresh bat guano from frugivorous, insectivorous, and sanguinivorous bats. C/N values decreased and cholestanol, cholesterol, and cholesterol/(cholesterol+sitosterol) values increased in bat guano according to trophic level. This thesis demonstrated the strength of examining several independent lines of evidence to reconstruct historical activities in both High Arctic waterbody sediments and a bat guano deposit. I showed that human activities were traceable within natural archives over several thousand years thus demonstrating that the multi-proxy approach is a powerful tool that can conduct a broad range of analyses in various natural archives.

4 Summary Seasonal metabolic adjustments and partitioning of evaporative water loss in Wahlberg’s epauletted fruit bat, Epomophorus wahlbergi Student: Ingrid A. Minnaar Supervisor: Prof. A. E. McKechnie Co-supervisors: Prof. N. C. Bennett, Prof. Christian T. Chimimba Department: Zoology and Entomology, University of Pretoria Degree: MSc: Zoology The capacity to thermoregulate over a wide range of TaS is critical for maintaining homeostasis in endotherms. Several aspects of the thermoregulatory properties of bats remain poorly studied when compared to other mammals and birds. I examined two specific aspects of thermoregulation in bats: the seasonal variation of maximum metabolic heat production and the partitioning of total evaporative water loss (TEWL) into respiratory and cutaneous components. I measured basal metabolic rate (BMR) and summit metabolism (Msum) in captive and wild Wahlberg’s epauletted fruit bats, Epomophorus wahlbergi, during summer and winter. I measured metabolic rate using flow-through respirometry, and elicited Msum by exposing bats to low temperatures in a helox (21% O2, 79% He) atmosphere. BMR decreased by 22-25% during winter in both captive and wild bats, with the BMR of captive bats 9-13% lower than the wild individuals across seasons. Msum was approximately seasonally stable in both captive and wild bats, but Msum in captive individuals was 13-18% higher than their wild conspecifics during both seasons. The ratio between Msum and BMR (i.e., metabolic expansibility) was greater in winter than during summer for both captive and wild bats. One likely explanation for the greater resting thermogenic capacity of the bats in captive individuals concerns their reduced activity levels; compared to wild, free-ranging bats, heat produced as a by-product of activity probably contributed far less to thermoregulation, apparently leading to an increase in resting heat production capacity in captive individuals. 5 At the other end of the thermal scale, knowledge of heat tolerance and the evaporative cooling mechanisms employed by bats in hot weather remains rudimentary. At high air temperatures (Ta), endotherms avoid overheating by dissipating heat via evaporative water loss. TEWL may be partitioned into cutaneous evaporative water loss (CEWL) and respiratory evaporative water loss (REWL). I quantified CEWL and REWL in E. wahlbergi at Tas of 10-40 °C using a latex mask. When Ta exceeded normothermic Tb, bats drastically increased their TEWL, metabolic rate and Tb. The relative contribution of CEWL to TEWL was the greatest at moderate Tas where it represented up to 80% of TEWL. REWL was the major route of evaporative cooling at the highest Ta: at Ta = 40 ºC, REWL represented 45% of TEWL. To avoid hyperthermia, E. wahlbergi greatly increased metabolic rate at high TaS to avoid hyperthermia, further compounding the need to cool down. REWL is thought to be less efficient as than CEWL in offloading heat at high TaS as panting increases metabolic heat, whereas CEWL occurs passively. There is a need for further studies to be conducted on the thermoregulatory capabilities of bats in varying environmental conditions, both intra- and interspecifically. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Zoology and Entomology / unrestricted

Computational models of collective motion have yielded many insights about the way that groups of animals or simulated particles may move together and self-organize. Recent literature has compared predictions of models with large datasets of detailed observations of animal behavior, and found that there are important discrepancies, leading researchers to reexamine some of the most widely used assumptions. We introduce FlockOpt, an optimization-based, variable-speed, self-propelled particle model of collective motion that addresses important shortcomings of earlier models. In our model, each particle adjusts its velocity by performing a constrained optimization of a locally-defined objective function, which is computed at each time step over the kinematics of the particle and the relative position of neighboring particles. Our model explains how ordered motion can arise in the absence of an explicitly prescribed alignment term and simulations performed with our model exhibit a wide variety of patterns of motion, including several not possible with popular constant-speed models. Our model predicts that variations in speed and heading of particles are coupled due to costs associated with changes in relative position. We have found that a similar coupling effect may also be present in the flight of groups of gregarious bats. The Mexican Free-tailed bat (Tadarida brasiliensis) is a gregarious bat that forms large maternity colonies, containing hundreds of thousands to millions of individuals, in the southwestern United States in the summer. We have developed a protocol for calibrating cameras used in stereo videography and developed guidelines for data collection. Our field protocol can be deployed in a single afternoon, requiring only short video segments of light, portable calibration objects. These protocols have allowed us to reconstruct the three-dimensional flight trajectories of hundreds of thousands of bats in order to use their flight as a biological study system for our model.

There are limited studies on bat activity in higher elevations in the Appalachian region. Levels of bat activity were compared in south central Appalachia at low (< 914.4 m) and high (> 1, 524 m) elevations in open, forest edge, and riparian habitats. Additionally, habitat suitability was modeled for a common species, big brown bat (Eptesicus fuscus). The study started May 27th 2019, and sites were monitored biweekly until October 2nd 2019. Six species and one genus were recorded during the study. Species from the Myotis genus were grouped together because of similar call characteristics. Results show that species were significantly more active in the lower elevations (F= 44.22, p

Audio data compression seeks to reduce the size of sound files, making them easier to store and transfer, and is thus a highly valued tool for those working with large sets of audio data. For example, some biologists work with audio recordings of bats, which are well known for their frequent use of ultrasonic echolocation, and so these biologists can accrue massive amounts of high frequency audio data. However, as many methods of audio compression are designed to specialize in the more common range of frequencies, they are not able to sufficiently compress bat audio, and many bat biologists instead work without compressing their data at all. This paper investigates the desiderata of a data compression method in the context of bat biology, experimentally compares several modern data compression algorithms, and discusses their pros and cons in terms of their potential use across various relevant contexts. The paper concludes by suggesting the algorithm Monkey’s Audio for machines able to handle the higher resource demands it has. Otherwise, FLAC and WavPack yield similar size reduction rates at a significantly faster speed while being less resource intensive. Of note is the interesting result produced by the algorithm 7-ZIP PPMd Solid, which achieved consistently outstanding results within a single dataset, but its generalizability has yet to be determined.

With the loss or modification of natural roosting habitat afforded by caves, abandoned mines have assumed increased importance as surrogate roosting sites for Townsend's big-eared bats (Corynorhinus townsendii) and other chiropteran species. However, increasing concerns for human safety have led to accelerated programs for mine closure. In efforts to protect roosting sites in mines showing significant bat activity, "bat compatible" gates are installed, thus allowing continued access to mine workings. Aside from ensuring public safety, these structures afford protection from disturbance to roosting bats. To date few posting-gating studies have been conducted to obtain information on the effects of these structures on bat behavior and roost suitability. I evaluated the effects of gating on bat flight patterns at maternity colonies in two previously gated (reference) and two ungated mines, the latter (treatment) being gated with roundbar Manganal steel gates in the second year of the study. I also monitored four gated and three treatment mines to determine the potential effects of reclamation on internal microclimate. Overall circling activity increased > 6-fold at the portals of treatment mines following gating. Indices of crowding and frequency of bat-gate collisions were significantly higher in previously gated and increased substantially in treatment mines following reclamation. Gates appeared especially hazardous to subadults during initial-volancy periods. Increased activity of bats and collisions with gates at mine portals may amplify vulnerability to potential predators. Changes in internal mine microclimates, specifically increased ranges between minima and maxima in temperature and vapor pressure deficits following reclamation varied among treatment mines as a function of the number of mine openings. Generally, gated mines with multiple openings experienced greater changes in these parameters than those with single openings. Additional studies of bat-compatible gates are needed to elucidate possible long-term effects of these structures on Townsend's big-eared bats.

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Forelimbs in many mammals are used in both locomotion and the acquisition of food. In bats, the forelimbs are highly specialized for flight, but the thumb is free to preform other functions. Using morphological data from museum specimens and field observations of feeding behavior, I documented how Neotropical leaf-nosed bats (family: Phyllostomidae) use their thumbs during feeding, and examined how thumb structure and function are linked with diet. I then used these data to test when changes in thumb morphology and feeding behaviour evolved, focusing on two specific time points: the evolution of frugivory in phyllostomids; and the diversification point at the base of the clade Stenodermatinae, which are hard canopy fruit specialists. I found that size-corrected thumb length was weakly associated with diet, but the frequency and duration of thumb use were higher in frugivorous species than in their insectivorous counterparts. Likewise, the function for which frugivores used their thumbs differed from insectivores, although variation in specific thumb movements could not be teased apart in the analyses. When I modeled selective regimes of diet, I found that species that consumed fruit showed selection for increased frequency and duration of thumb movements, but there was no evidence of selection for increased thumb length at either of the two evolutionary time points tested. This suggests that a shift in how thumbs are used during feeding, and not thumb morphology, may be linked to a transition from a mainly insectivorous diet to frugivory in phyllostomid bats.