<p> Apple snails are in the Family Ampullariidae, a family of freshwater gastropods. Some species in the genus <i>Pomacea</i> have gained considerable notoriety as very destructive invasive species. Ampullariids have a gill and breathe water; in some species, the mantle cavity is modified into an air sack that may function as a lung or flotation device. Apple snails definitively identified as <i>Pomacea maculata</i> have successfully invaded numerous localities in Louisiana, and studies of the physiology of these animals may enhance our understanding of the biology of highly invasive species and suggest effective approaches to controlling the invasive populations. This study investigated respiration of <i>P. maculata</i> in water and in air and the ability of the animals to survive long-term emersion in a state of aestivation. The ability of the animals to disperse over dry ground was studied. Finally, the anatomy of the gill and lung were examined. The results of the study indicate that the gill and the lung in <i>P. maculata</i> are vascularized, capable of gas exchange, and fully functional, which permits survival and respiration in water and during long- and short-term exposure to air. Both the capacity to sustain travel over dry land and the ability to survive long term aerial exposure in an aestivated state were demonstrated by <i>P. maculata</i>. The major physiological changes observed during aestivation include a decrease in heart rate, a reduction in VO2, and the use of discontinuous respiration. A review of published literature suggests that extensive physiological variation exists among populations of native and invasive <i>P. maculata</i>. In conclusion, <i>P. maculata </i> in Louisiana is well-adapted to life in both water and air, can move overland, and can survive emersion for over a year. These physiological adaptations suggest that controlling the further spread of <i>P. maculata </i> will be very difficult.</p><p>

<p> The Lesser Sunda Archipelago, also known as Nusa Tenggara, lies in the southeastern portion of Indonesia and extends between Bali in the west, and New Guinea in the east. While the Lesser Sundas themselves are oceanic islands that have never been land bridged to a continent the islands on either side do. Bali and the other Greater Sunda Islands of Java, Sumatra, and Borneo become periodically land bridged with Asia during glacial maxima forming the Sunda Shelf. New Guinea and Aru become periodically land bridged to Australia during glacial maxima and form the Sahul Shelf. Given their current orientation, the Lesser Sundas may act as &lsquo;stepping stones&rsquo; for animals and plants dispersing between the Sunda and Sahul Shelves and may act as a two-way filter for organisms dispersing between two of the world&rsquo;s great biogeographical realms. Alfred Russel Wallace&rsquo;s discovery of a pattern of clinal mixture of species from different biogeographical realms was a key insight leading to his identification of the Wallace Line and to his creation of the field of biogeography. Even though the Lesser Sundas played a critical role in the development of the field, this region has received little subsequent attention from historical biogeographers and our current understanding of Lesser Sunda biogeography has only modestly improved relative to what was known at the time of Wallace. The reptiles and amphibians of the Lesser Sundas represent a particularly interesting group of vertebrates from a biogeographical standpoint because they appear to show distributional patterns that are most consistent with a stepping-stone model of island colonization caused by the two-way filter zone. In Chapter 1, I review the geological and biogeographical literature for the Lesser Sundas and use these sources to formulate hypotheses concerning the colonization of the archipelago by rafting terrestrial vertebrates. In Chapters 2 through 4, I investigate the possibility that flying lizards, forest skinks, and fanged frogs have colonized the archipelago in a stepping-stone manner using a phylogenomic approach (using sequence data from mtDNA and hundreds of nuclear loci) whereby the relationships among island-specific lineages can be used to infer the sequence of island colonization. Flying lizards of the genus <i>Draco</i> form a monophyletic group that colonized the western Inner Arc islands of Lombok or Sumbawa from the Sunda Shelf around 10 million years ago when Lombok and Sumbawa first became land-positive. <i> Draco</i> continued expanding eastward through the Inner Arc until they reached Lembata, while a series of dispersal events from Flores south to Sumba, east to Timor, north to Wetar, west to Alor, and finally west to Pantar (the island immediately west of Lembata). The islands of Sumbawa and Flores contain multiple non-sister lineages that are parapatrically distributed and are exchanging migrants within an island. Forest Skinks of the genus <i> Sphenomorphus</i> show relatively little morphological divergence across their range yet exhibit large levels of genetic divergence. The oldest lineages of <i>Sphenomorphus</i> within the Lesser Sundas occur on the islands of Lombok and Flores and they expanded eastward through the Inner Arc until they reached Pantar. But rather than reaching Alor from neighboring Pantar, <i> Sphenomorphus</i> dispersed from Flores south to Sumba, then east to Timor, Alor, and Wetar. There are multiple non-sister lineages of <i> Sphenomorphus</i> on Lombok, Flores, and Sumba, and estimates of migration between lineages within each island suggest that these lineages are not interbreeding. Fanged frogs of the genus <i>Limnonectes</i> have colonized the Inner Arc of the Lesser Sundas from the Sunda Shelf. It is possible that <i> Limnonectes kadarsani</i> and <i>L. dammermani</i> diverged <i> in situ</i> on Lombok after which <i>L. kadarsani</i> dispersed east all the way to Lembata. But rather although a tree topology consistent with a stepping-stone pattern of island colonization is suggested by the mtDNA data, the phylogenomic results suggest a leap-frog pattern where Lembata is derived from West Flores, and these two lineages are closer related to Sumbawa than they are to Eastern Flores. The parapatrically distributed lineages on Flores are experiencing asymmetrical gene flow with successful migrants moving from west to east. In summary, the oldest islands of the western Inner Arc tend to harbor the most divergent lineages for all three focal taxa, a pattern expected from lineages originating from the Sunda Shelf. In <i>Draco </i> and <i>Sphenomorphus,</i> the islands of the eastern Inner Banda Arc are colonized by way of the &lsquo;Sumba Route&rsquo; where they disperse into the Outer Banda Arc island of Sumba and then move east to Timor, and finally north into the eastern Inner Arc. All three focal taxa show multiple non-sister lineages on some of the larger islands, suggesting either that multiple colonization events of a single island occurred, or possibly that formerly separated paleo-islands have since merged allowing for secondary contact of lineages that diverged in allopatry. These studies have shown that the biogeography of reptiles and amphibians within the Lesser Sundas is extremely complex. By examining biogeographical patterns across many co-distributed taxa these studies have the potential to provide insights into the geological history of the archipelago. From an evolutionary perspective, these studies highlight the presence of multiple independently evolving lineages within a currently described species occurring on the same island, which suggests that species diversity within reptiles and amphibians of the Lesser Sundas is underestimated.</p>

Understanding how complex, adaptive behavior evolves is a major goal of biological research. Phenotypic differences between closely-related species often arise due to evolution by natural selection and can be a powerful resource for understanding biological diversity and its mechanistic underpinnings. In this dissertation, I capitalize on striking behavioral differences between two interfertile sister species of Peromyscus rodents. I pursue the proximate mechanisms underlying this behavioral adaptation by investigating both the ontogeny and genetics of innate differences in burrow construction behavior in Peromyscus polionotus and P. maniculatus. In Chapter 1, I compare the ontogeny of burrow construction behavior of Peromyscus polionotus and P. maniculatus across early development. I find that P. polionotus begins burrowing precociously (as early as 17 days of age) compared to P. maniculatus (27 days of age), despite P. polionotus being physically smaller and less active in a wheel running assay. Furthermore, juvenile P. polionotus constructed long burrows complete with species-specific escape tunnels. Interspecific cross-fostering did not alter the developmental trajectory of either species, indicating that these differences are innate. Moreover, F1 hybrids followed the behavioral ontogeny of P. polionotus, indicating that precocious burrow construction segregates in a P. polionotus-dominant manner. Finally, I show that a quantitative trait locus (QTL) associated with adult tunnel length in these species is predictive of precocious digging in recombinant F2 hybrids, demonstrating that either a single pleiotropic locus or a group of tightly-linked genes control behavioral differences across life stages in P. polionotus. In Chapter 2, I dissect the genetic architecture of this complex behavior in adult animals using an experimental cross. By introgressing the burrow architecture of P. polionotus into the genetic background of P. maniculatus, I analyze the underlying genetic architecture of differences in burrowing behavior, and show that escape tunnels are likely a threshold trait. Next, I use a novel image-based analysis to collect measurements of burrow shape and demonstrate the utility of a more rigorous measurement of extended phenotypes. Finally, in Chapter 3, I combine two forward-genetics approaches—QTL mapping and transcriptome analysis—to nominate specific candidate genes for the differences in burrowing behavior between P. polionotus and P. maniculatus. Using a large advanced backcross mapping population (n=751), I detect five QTL contributing to differences in burrow architecture between these species: three loci for entrance tunnel length variation, and two loci for escape tunnel length. In the transcriptome study, I focus on gene expression in F1 hybrids to detect allele-specific expression (ASE), as ASE in an F1 hybrid indicates cis-regulatory differences between the parental lineages. I find widespread bias favoring expression from the P. polionotus-allele in F1 hybrid brains, which may be a molecular reflection of P. polionotus-like burrowing behavior of hybrids. Finally, I use ASE to nominate candidate genes within the detected QTL regions, and find genes related to behavioral disorders, circadian rhythms, and activity patterns; these genes represent promising candidates for future functional studies. / Biology, Organismic and Evolutionary

Lungs were once thought to be a universal feature of tetrapods and essential for vertebrate life on land. This view changed in the late 19th century with the discovery of several salamander species that lack lungs. Since these species are descendants of lunged ancestors, the absence of lungs must represent an instance of evolutionary loss. Further study has revealed several independent losses of lungs across amphibians, including at the base of the salamander family Plethodontidae. Plethodontids comprise over two thirds of all living salamander species, yet many features of lungless salamander biology are unknown. My dissertation investigates the evolution and development of lung loss, including the genetic basis for lunglessness and the consequences of lunglessness for respiration and the circulatory system. I determined that plethodontid salamanders are not entirely lungless; lungs actually begin to form in the embryo. This includes lung specification, the formation of a lung primordium, and conserved expression of genetic markers of lung differentiation. However, the lung primordium subsequently regresses by apoptosis, yielding adults with no trace of a vestigial lung. Transcriptome sequencing of the lung primordia of lunged and lungless salamanders suggests a role for increased Tgf-beta signaling in lung regression. I established that Tgf-beta represses lung development in other species of salamanders, providing support for its role in lung loss. Plethodontid salamanders perform gas exchange through their skin and lining of the mouth (extrapulmonary respiration). I discovered a novel gene in salamanders that is potentially neofunctionalized for extrapulmonary respiration in plethodontids. The lung-specific gene encoding surfactant-associated protein C (SPC) is duplicated in salamanders. Both paralogs of this gene are expressed in the lung of lunged salamanders, representing the ancestral expression pattern of SPC in tetrapods. In contrast, lungless salamanders express a paralog of SPC in extrapulmonary sites of gas exchange. These sites include the skin during the aquatic larval stage and the lining of the mouth in terrestrial adults. I propose that extrapulmonary expression of this paralog in salamanders reduces the thickness of the mucus layer that covers the respiratory surfaces and aids gas exchange. The lungs function as part of an integrated cardiopulmonary system. In animals with lungs, the atrial septum helps to separate oxygenated and deoxygenated blood in the heart. I characterized cardiac anatomy within a broad sample of lunged and lungless salamanders. I found that independent lineages of lungless salamanders convergently evolved a reduced and non-functional atrial septum, resulting in blood flow between the two atrial chambers. In mammals, formation of the atrial septum is dependent on morphogens secreted from the developing lungs. I provide evidence that atrial septum reduction in plethodontid salamanders is a direct consequence of loss of these signaling interactions due to lung regression. Developmental interaction between the heart and lungs may mediate the coordinated evolution of the cardiopulmonary system, ensuring that the atrial septum develops in the presence of lungs but does not fully form in lungless species, where it would be disadvantageous. / Biology, Organismic and Evolutionary

The central goal of this study was to describe the habitat use and movement patterns of juvenile black ratsnakes and contrast them to those of adults to identify any ontogenetic changes that should be included in the management plan of the species. My results indicated a clear ontogenetic shift in the movement patterns and spatial ecology of black ratsnakes. I found that daily and seasonal movements, home range size and fidelity, behaviour, and fidelity to over-wintering sites all vary with size. The results suggested that juvenile black ratsnakes, especially males, may be in a dispersal stage. If juveniles are playing a significant role in maintaining gene flow through dispersal, then adequate protection requires sufficient protected habitat to allow juvenile dispersal. I also showed that juveniles rarely attend communal hibernacula and often switch between hibernacula. Therefore, habitat to be protected cannot simply be defined as a fixed radius around a communal hibernaculum because many juveniles do not attend these communal hibernacula. This study reinforces the importance of understanding ontogenetic changes in the ecology of species of conservation concern. Insight into an ontogenetic shift in habitat use would be essential for sound management of any species where juveniles have more specific structural needs than adults, due to intense predation risk, specific prey requirements, etc. Ontogenetic shifts in movement patterns and spatial ecology have to be considered in management decisions. (Abstract shortened by UMI.)

By the 1940s, fishers (Mustelidae, Martes pennanti) were extirpated in Ontario south of the French and Mattawa Rivers, probably as a result of overharvesting and habitat loss. However, during the last several decades fishers have recolonized much of their former range in Ontario. This recolonization, combined with (for the most part) conservative harvest management, has led to increases in abundance. Perhaps inevitably, these increases have resulted in requests by fur harvesters to increase fisher quotas. The question then arises as to what the effect of the current quota system is on fisher populations in eastern Ontario. Unfortunately, very little is known about fisher demographics in eastern Ontario; as a result, the current management system is based almost exclusively on information and data on well-studied fisher populations from other regions, notably Algonquin Park. The extent to which these data---and the inferences regarding effective management therefrom---reflect fisher population characteristics in eastern Ontario is unknown.

Understanding the spatial ecology and habitat use of declining species is essential for their management and successful recovery. I examined the movement patterns and habitat selection of map turtles (Graptemys geographica), a species at risk, in St. Lawrence Islands National Park. Adult females moved longer distances and had larger home ranges than juvenile females and males. The longest distances moved by adult females occurred during nesting excursions. Examining movements allowed for critical habitat locations to be found (nesting sites, hibernacula). My data on movements will allow St. Lawrence Islands National Park to mitigate development plans and regulate visitor impacts on these sites. I examined habitat selection at multiple spatial scales. Map turtles generally avoided deep water (>2 m) and selected home ranges in waters &lt;1 m deep with significantly more natural than developed shoreline. Adult females used deep water more often and males preferred areas with surface cover. Management effort should implement regulations concerning further shoreline development.

The family Poecilopsettidae (Pleuronectiformes) occurs in the Pacific, Indian and Atlantic oceans. A taxonomic revision of all 19 species considered valid up to now was completed. Type specimens and additional material known for all these valid species were examined and measured. One new species is described (Poecilopsetta dorsialta), two species are synonyms of previously described species: Nematops chui is a junior synonym of N. macrochirus and Poecilopsetta megalepis is a junior synonym of P. plinthus. There are now 18 valid species in the family: two in the genus Marleyella, three in the genus Nematops and 13 in the genus Poecilopsetta. The genera Nematops and Marleyella are monophyletic. However, the monophyly of the genus Poecilopsetta remains doubtful because of the absence of unique characters for all 13 species of the genus. The family Rhombosoleidae (Pleuronectiformes) (sensu Norman, 1934) is a group of 19 species distributed in Southern Australia, New Zealand, in the Indo-Pacific Ocean off Western Australia and South America. A data matrix of 87 morphological characters was analysed using cladistic methodology to assess the monophyly of the Rhombosoleidae and to determine the interrelationships within this family. Achiropsettidae and Poecilopsettidae were used as outgroups. The results (16 equally parsimonious trees; 118 steps; CI = 0.669) found the family Rhombosoleidae to be monophyletic on the basis of eight apomorphies. The Rhombosoleidae was not monophyletic with the genera Azygopus, Oncopterus and Psammodiscus and they were removed from the family and added to a data matrix of of pleuronectiform families to assess their relationship within the order. Azygopus is placed in the Achiropsettidae. Psammodiscus and Oncopterus form a trichotomy with a large clade formed by Rhombosoleidae, Poecilopsettidae, Achiropsettidae, Samaridae, Achiridae, Soleidae and Cynoglossidae (6 equally parsimonious trees; 109 steps; CI = 0.477). The family Paralichthodidae (sensu Cooper and Chapleau, 1998a) is the sister-group of a large clade formed by the families exhibiting a bothoid type of caudal skeleton (Scophthalmidae, Bothidae, Paralichthyidae and Pleuronectidae) and by clade III (Psammodiscus, Oncopterus, Poecilopsettidae, Rhombosoleidae, Achiropsettidae, Samaridae, Achiridae, Soleidae and Cynoglossidae).

No description available.

No description available.