The origin and geographical distribution of mammalian species (my examples are lemurs and bats) correlate with predictable chromosomal structural changes (KFT=karyotypic fission theory). Chromosome studies provide information about fertility between individuals and they are significant for identification of the geographical origin of reproductive isolation within mammal families. Each family predictably has chromosome sets with numbers that range from one to double the lowest number of chromosomes. The chromosome numbers of all species within a single family are used to reconstruct that family’s evolutionary geographical dispersion. Polymorphic chromosome numbers (that is a range such as 34, 35, 36, 37, and 38) in a single population indicate the location where chromosomal diversification arose. Chromosome numbers of descending order correlate with relative distance from fission epicenters as the fissioned chromosomes gradually spread to neighboring populations. Furthermore, the location of chromosomal diversification (that is “karyotypic fission events) is associated with geographical “zones of transition” (after Professor R.W. Wilkie). My analysis, mapped one (Lepilemuridae) of the five families of lemurs (Class Mammalia, Order Primates, sub-order Lemuridae). The origin of this family’s diversification is here hypothesized to have occurred at an ecological transition zone in Northern Madagascar between a humid evergreen-forest that extends to the East relative to a dry deciduous forest along the West Coast. My analysis of Vespertilionidae (insectivorous bats representing one third of all bat species) suggests a diversification event occurred in Asia; South China. Geographical distribution is important in the formation of biological diversity. A single species can inhabit a wide range and exhibit great diversity that is brought about by natural selection. The Holarctic reindeer found in Scandinavia, Russia, China, Canada and Alaska (including caribou) are all a single species Rangifertarandus that exhibits variation in size and in coat pattern, changes brought about by adaptive selection by the environment or human selective breeding but they all have 70 similar chromosomes and they are all reproductively compatible. There is a single species of reindeer. Although, there is measurable DNA sequence divergence; there has been no “speciation” as these circumpolar cervids are genetically compatible.

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While they are pregnant and rearing pups, bats continue to leave their roosts to forage for food. Many bats use echolocation vocalizations as part of this process. Other mammalian species including primates experience changes in vocal characteristics during pregnancy and lactation. As echolocation is a vital tool for spatial navigation and prey detection in most bats, investigating echolocation characteristics during pregnancy through lactation may provide new insight into how reproduction, pregnancy and pup rearing influence vocalizations. We measured changes in mass and recorded echolocation calls of pregnant (n = 21) and non-pregnant (n = 2) female wild-caught big brown bats (Eptesicus fuscus) released by hand into roost emergence-like flight. Recording began ~15 days prepartum and ended when the last bat reached 34 days postpartum, when pups were expected to be weaned. Analyses were completed using MATLAB and R, primarily with repeated measures ANOVAs focused on echolocation calls present in the ~562 ms before and ~562 ms after take-off. Based on vocal changes experienced by humans during pregnancy and post-birth, correlations found between bat echolocation call characteristics and the effects of differences in mass on bat echolocation, we predicted that female bats in late-stage pregnancy would emit calls of shorter duration, longer pulse interval, narrower bandwidth, and lower centroid frequency compared to calls emitted by the same bat post-parturition and compared to non-pregnant bats, while source level remained unchanged. We found that pulse interval and source level did not change while pregnant/lactating or control bats were in flight, and that increases in call duration and decreases in centroid frequency and bandwidth in flight began in pregnancy and continued through the lactation period while remaining unchanged for the control bats. / Thesis / Master of Science (MSc) / The goals of this study were to see if big brown bats change the way that they echolocate while they are pregnant and/or nursing pups, and what changes occur. We did this by recording the vocal sounds bats made while they were pregnant and after they had given birth, and looking to see if there were any changes in the duration of echolocation calls, the time between individual sounds, the range of sound frequencies in each call, the central sound frequency in each call, and each call’s sound pressure level over this time and compared to non-pregnant/nursing female big brown bats. We found that echolocation call duration increases over pregnancy and nursing pups, while frequency range and the centre frequency decreases.

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Numerous bats species have evolved biosonar to obtain information from their habitats with dense vegetation. Different from man-made sensors, such as stereo cameras and LiDAR, bats' biosonar has much lower spatial resolution and sampling rates. Their biosonar is capable of reliably finding narrow gaps in foliage to serve as a passageway to fly through. To investigate the sensory information under such capability, we have used a biomimetic sonar robot to collect the narrow gap echoes from an artificial hedge in a laboratory setup and from the natural foliage in outdoor environments respectively. The work in this dissertation presents the performance of a conventional energy approach and a deep-learning approach in the classification of echoes from foliage and gap. The deep-learning approach has better foliage versus passageway classification accuracy than the energy approach in both experiments, and it also shows good robustness than the latter one when dealing with data with great varieties in the outdoor experiments. A class activation mapping approach indicates that the initial rising flank inside the echo spectrogram contains critical information. This result corresponds to the neuromorphic spiking model which could be simplified as times where the echo amplitude crosses a certain threshold in a certain frequency range. With these findings, it could be demonstrated that the sensory information in clutter echoes plays an important role in detecting passageways in foliage regardless of the wider beamwith than the passageway geometry. / Doctor of Philosophy / Many bats species are able to navigate and hunt in habitats with dense vegetation based on trains of biosonar echoes as their primary sources for sensory information on the environment. Drones equipped with man-made sensory systems such as optical, thermal, or LiDAR sensors, still face challenges when navigating in dense foliage. Bats are not only able to achieve higher reliability in detecting narrow gaps but accomplish this with much lower spatial resolutions and data rates than those of man-made sensors. To study which sensory information is accessible to bat biosonar for detecting passageways in foliage, a robot consisting of a biomimetic sonar and a camera system has been used to collect a large number of echoes and corresponding images (∼130k samples) from an artificial hedge constructed in the laboratory and various natural foliage targets found outdoors. We have applied a conventional energy approach which is widely used in engineered sonar but is limited by the biosonar's wide beamwidth and only achieves a foliage-versus-passageway classification accuracy of ∼70%. To deal with this situation, a deep-learning approach has been used to improve performance. Besides that, a transparent AI approach has been applied to overcome the black-box property and highlight the region of interest of the deep-learning classifier. The results achieved in detecting passageways were closely matched between the artificial hedge in the laboratory setup and the field data. With the best classification accuracy of 97.13% (artificial hedge) and 96.64% (field data) by the deep-learning approach, this work indicates the potential of exploring sensory information based on clutter echoes from complex environments for detecting passageways in foliage.

published_or_final_version / Microbiology / Doctoral / Doctor of Philosophy

Ten species of bats occur in the Oregon Coast Range and are hypothesized to be associated with late-successional forests. The development of characteristics of late-successional forests in young forest stands can be accelerated through silvicultural practices such as thinning I examined the effects of thinning on the use of forests by bats in the Oregon Coast Range. I used automated ultrasonic detectors to record bat calls in 50- to 100-year-old thinned and =thinned stands as well as in old-growth (2200-year-old) stands in 11 sites in the Oregon Coast Range during the summers of 1994 and 1995. I compared bat activity levels among the 3 stand types. In addition, I classified bat calls into 1 of 5 species groups: Eptes/Las, Myev/vo, Myyu/ca, MythCory, and Mysp. I measured selected vegetation and environmental variables in conjunction with bat activity. I also compared bat activity on roads with activity in the stand interior at 1 site. Bat activity was higher in old growth than in young stands, and higher in thinned than in =thinned stands in 1995 and over both seasons combined. I did not detect a difference in bat activity among stand types in 1994, until I removed 1 site from the analysis. The Mysp and MythCory species groups exhibited differences among stand types. Bat activity along roads was higher than activity within stands. Tree density, tree diameter, tree height, shrub cover, and shrub height varied significantly between old-growth and young stands. Tree density, tree diameter, shrub cover, canopy cover, and crown height varied significantly between thinned and unthinned stands. Bat activity, overall or by species group, was significantly related to structural variables, including mean snag diameter, mean distance from the detector to snags, and percent shrub cover. My results suggest that bats are sensitive to stand structure and that silvicultural practices, such as thinning, which promote development of structural characteristics found in old-growth stands, would benefit bat populations. Further study is needed to clarify the habitat preferences of separate bat species and to specify habitat elements required by bat species. / Graduation date: 1997

In the temperate region, bats have evolved the strategy of hibernation to survive the harsh winter. During hibernation, bats enter the vulnerable state of torpor that requires specific environmental conditions to function optimally. Bats are known to use caves and anthropogenic structures as hibernation sites. However, the majority of the bat population cannot be accounted for when such structures are surveyed. There is evidence that bats use other natural structures as hibernation sites. To examine bat’s choices of hibernation sites and activity, acoustic monitoring of bats in south-west Sweden was performed during the winter of 2022-2023. Bat activity was measured in areas with potential hibernation sites in natural structures (rock outcrops), as well as inside and outside of known hibernation sites (anthropogenic structures). The level of activity and the ambient temperature were tested for a possible correlation. Additionally, data from 2006-2022 of surveys of bats in hibernation sites were examined for a possible relationship with outside ambient temperature. Bats were found to be active during the winter inside the known sites of hibernation. There was also activity recorded outside one of the known hibernation sites, but no bat activity was found in the areas of potential hibernation sites. No significant correlation was shown between bat activity and outside temperature, nor between number of bats inside a hibernation site and outside temperature. Further research is needed to develop the knowledge about bats’ hibernation behavior which in turn will aid more effective conservation of temperate bat species.