The life history and behavioral ecology of Myiopharus doryphorae (Riley) and Myiopharus aberrans (Townsend), important parasitoids of the Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say), were investigated through a series of field and laboratory studies. The recruitment-recruitment method of determining percentage parasitism was compared with traditional methods in assessing population dynamics of the CPB and Myiopharus. Over the three-year period of the study, percentage parasitism calculated from traditional foliage sampling showed an erratic pattern. Revised estimates employing the recruitment method revealed a consistent 30-50% mortality of CPB larvae due to parasitism even when the CPB prepupal population density reached 80 per square meter per generation, showing that Myiopharus spp. can cause high levels of mortality to CPB larvae at higher host densities than has been reported in most previous field studies. Field sampling demonstrated that M. doryphorae and M. aberrans overwinter as first-instar larvae within adult diapausing CPB and complete their development the following spring after the emergence of the parasitized beetles. Growth-chamber studies were conducted to quantify development of summer-generation M. doryphorae at different life stages. During the first four days after being larviposited, these M. doryphorae remain as first-instar larvae but grow an average of 0.45 $\pm$ 0.03 mm prior to the prepupal stage of their hosts, in which the parasitoids complete development. During this latter period, development rates of M. doryphorae were found to track closely those of the CPB itself when modeled as a nonlinear function of temperature assuming cessation of growth outside the approximate range of 4-34$\sp\circ$C. The model appears to require additional adjustment at temperatures below 10$\sp\circ$C. Laboratory studies showed that M. doryphorae do not discriminate between CPB larvae fed sublethal doses of B. thuringiensis and larvae not fed with B. thuringiensis. M. doryphorae appear more sensitive to CPB larval movement than to the presence or absence of B. thuringiensis. Through field studies a series of behaviors was identified and their frequency and duration were quantified for the two Myiopharus spp., which appeared not to vary their allocation of time in response to each other's presence in the same field. A significant difference was found between the frequencies of larviposition by the two Myiopharus species across ranges of temperature and time of day. Behavioral studies led to the discovery that larvipositing M. doryphorae and M. aberrans females discriminate between parasitized and non-parasitized host larvae, rejecting the former on contact and failing to larviposit in them when other potential hosts are available. This discrimination breaks down to some extent late in the growing season when CPB larvae of appropriate stages are rare; breakdown of host discrimination is accompanied, however, by the defense of recently parasitized hosts by females of both Myiopharus species, and is followed by the switch of larvipositing M. aberrans from larval hosts to adult CPB which are more common at this time of year.

<p> This dissertation tests two methods to obtain information of the distribution and movement of cetaceans. The first method uses vessels of opportunity as platforms to conduct acoustic surveys between the main Hawaiian Islands, with the ultimate goal of providing a method that can be used in future studies to contribute to mapping distribution and habitat modeling of data-poor cetacean species in the areas of the ocean which are infrequently surveyed. The distribution of a well-studied species, the humpback whale <i> Megaptera novaeangliae</i> was mapped and analyzed in relation to remotely sensed data on ocean depth, sea surface temperature, sea surface height, wind speed, chlorophyll-A, and surface currents. The results agreed with previous research on humpback whales, indicating that acoustic surveys from vessels of opportunity are a viable method for collecting distribution data on cetaceans. The predicted species of odontocete whistles collected during vessel of opportunity surveys was determined using the Real-time Odontocete Call Classification Algorithm, and analyzed in respect to remotely sensed data. The sighting rate for odontocete surveys in this study is comparable to that of previous survey methods, and cryptic species are identified at a higher relative rate than when using visual sighting methods. The biases inherent in concentrating survey effort primarily in the calm waters on the leeward sides the Hawaiian Islands are discussed, as well as the drawbacks of relying on visual sighting methods for detecting species with low visual detection probability. In addition, the potential impacts of anthropogenic noise and ship strikes from commercial vessels are discussed during the case study of a high-speed craft. This dissertation also discusses a second methodology involving the use of DIFAR sonobuoys to track multiple singing humpback whales, with the end goal of learning more about the function about humpback song. This method is also applicable to other cetacean species.</p>

<p> This thesis qualifies functional and ecological aspects of mucus trails deposited by <i>Elimia potosiensis</i> collected from the Meramec River. Freshwater snails are most often recognized for their significant role in river and stream ecosystem function as primary consumers and prey items. However, their form of locomotion is the most energetically expensive found in the animal kingdom. Found in large numbers and densities, <i> E. potosiensis</i> is capable of coating large swaths of substratum with carbohydrate- and protein-rich mucus. This has the potential to affect ecosystem function at the most basal trophic level both energetically, by contributing nutrients and energy to the surrounding water body, and functionally, as a sticky substance to which microheterotrophs become adhered. </p><p> In marine studies, researchers have found that bacteria can readily degrade gastropod mucus and that it can act as the basis for biofilm formation. There have also been studies that show unique employment of energy saving strategies by snails that use their trails to capture food items and to reduce production needs by following trails laid by conspecifics. Very little research has been conducted on freshwater gastropods. This study is the first to focus solely on the ecological and functional aspects of freshwater snail mucus. </p><p> For this study, collections of <i>E. potosiensis</i> were made from a single site along the Meramec River to qualify the effect deposited mucus has on the adherence of microalgae and its potential for formation of biofilms. Overall, mucus-coated surfaces significantly more particles in flow than non-coated surfaces. The water velocity at which a trail is laid was not found to have an affect on the thickness, adhesive ability or persistence of a trail. However, the water velocity in which a trail is incubated in stream does have effect on the adherence rate of a trail. In this study, it was found that this was most likely due to the fact that trails in high water velocity come into contact with more particles during a given period of time due, in part, to its higher carrying capacity.</p>

<p>Recreational activities have been shown repeatedly to have negative effects on wildlife. Appropriate management to minimize the effects of such activities, especially to species of conservation concern, is therefore a goal of utmost importance. This study characterized the visual ecology and anti-predator behaviors of the California Towhee, <i>Melazone crissalis</i>, in the context of parameterizing models for estimating the size and shape of wildlife buffer areas. Contrary to expectation, explicitly incorporating species-specific data on the towhee's visual system and individual-level data on physiological condition and life history traits did not significantly alter estimated buffer area requirements relative to models based solely on behavior. Similarly, towhees exhibited no differences in average alert or flight initiation distances with respect to direct versus tangential approaches. In contrast, data collected across a variety of habitat types in the field suggest that minimum approaching distances for the birds were highly dependent upon local vegetation parameters that included percent cover, density, and height. In general, more vegetative cover was associated with smaller alert and flight initiation distances. Together, these results suggest that a simple management solution (e.g., calculating buffer areas based on mean alert distance alone) may be adequate for this species, but that local habitat conditions will need to be taken into consideration for optimal management solutions. </p>

No description available.

The ability to traverse barriers of high water velocity limits the distributions of many diadromous and other migratory fish species, and is central to effective fishway design. This dissertation provides a detailed analysis of volitional sprinting behavior of six migratory fish species (American shad Alosa sapidissima, alewife A. pseudoharengus, blueback herring A. aestivalis, striped bass Morone saxatilis , walleye Stizostedion vitreum, and white sucker Catostomus commersoni), against controlled water velocities of 1.5–4.5 m · s−1 in a large, open-channel flume. In Chapter 1, I develop models of maximum distance traversed ( Dmax) by fish ascending these flows, accounting for water velocity and other covariate effects. I then demonstrate the application of these models, using them to predict proportions of active migrants capable of traversing a range of distances and flow velocities. Chapter 2 focuses on behavior and swimming performance of American shad, analyzing covariate effects on attempt rate as well as Dmax, and formalizing how rate and distance jointly affect overall rates of passage. Models describe a complex pattern of varying responses of attempt rate and Dmax to hydraulics, temperature, effort expended on and recovery time since the previous attempt. In Chapter 3, I use the effect of swimming speed on fatigue time to calculate an optimal swimming speed that maximizes the over-ground distance fish can traverse, and hence defines their maximum ability to traverse velocity barriers. This speed reduces to a constant groundspeed within a given gait, regardless of the speed of flow. Data from all six species support this view, although only American shad exhibit a clear shift from the optimum prolonged speed to the optimum sprint speed at the predicted critical flow velocity. Throughout this dissertation I make extensive and novel use of statistical techniques developed for survival analysis to analyze and model behavioral data, both with respect to attempt rate and to D max. Chapter 4 provides an overview of these methods and demonstrates their application to a fish passage study of downstream-migrating Atlantic salmon (Salmo salar) smolts. An understanding of the principles described here will help the reader to better understand the findings of the previous three chapters.

The Eurasian woodcock Scolopax rusticola (hereon woodcock) is a wader adapted to woodland and farmland habitats. It is an important quarry species, widely hunted across Europe, but owing to its cryptic plumage and elusive nature, there exists only poor information concerning its natural history. As such, the conservation status of the woodcock remains uncertain. One area that is particularly lacking is knowledge of its ecology outside the breeding season. Generally, avian ecological studies have focused on breeding season events due to the importance of reproductive success in determining fitness. However, it is now apparent that the non-breeding season represents an equally important period of the annual cycle. For example, recent studies have shown that declines in some migratory bird populations were due to events during the non-breeding season, either during migration, or on the wintering grounds. In Britain, the non-breeding woodcock population comprises both British breeding and non-British breeding birds, yet the origins and relative distribution of these sub-populations is not fully understood. Nor is it known whether ecological differences exist between them. This thesis addresses these two aspects of woodcock biology, using stable isotope and radio-tracking methods. The former was used to assign birds to their likely origins and determine population-specific distributions across Britain. The latter was used, in conjunction with the former, to determine whether ecological differences exist between locally-breeding and non-locally breeding birds residing in Hampshire in winter. A large degree of mixing between birds from different breeding populations was apparent for woodcock residing in Britain over winter. Russia and Fennoscandia comprised the most likely origins of migratory birds and regional differences in distributions were apparent. The highest proportions of birds from Russia were found in Norfolk and Wales, whilst the highest proportions of birds from Fennoscandia were found in Scotland. The presence of non-breeding residents in Cornwall and Ireland also provided strong evidence for the short-distance, south-westerly movements of resident birds, which probably originated from Scotland. Locally, the movements and behaviour of birds were found to vary with age (adult vs. juvenile) and/or predicted migratory status (resident vs. migrant), with adult residents potentially representing the dominant group. Differences in habitat use, commuting flights, home range size and activity patterns were all apparent. As such, these findings might have important consequences for the relative survival rates and breeding success of resident and migrant woodcock. This work has provided new insights into the non-breeding ecology of woodcock in Britain and contributes significantly to European efforts to better understand this bird species. Given the importance of seasonal interactions, an understanding of events throughout the annual cycle is necessary and this can only be achieved through concerted efforts. Indeed, an integrated approach is imperative to develop the conservation plans necessary to ensure the sustainability of the woodcock.

Laboratory bacterial populations provide ideal opportunities to experimentally test theories in ecology and evolutionary biology. I used a model laboratory microbial system, Pseudomonas fluorescens SBW25, to address an array of questions on the origin, maintenance, and functional role of biodiversity, and the evolution of biotic interactions. My thesis reports experiments with the following conclusions. (1) The extent of diversification in P. fluorescens populations is not affected by the presence of an interspecific competitor P. putida, although the early stage of the diversification in one environment (spatially homogeneous environment) could be speeded up by the competitor. (2) Niche and neutral mechanisms simultaneously contribute to the maintenance of phenotypic diversity in P. fluorescens populations; but the operation of niche processes does not lead to a positive effect of biodiversity on ecosystem functioning. (3) The competitive interactions among bacterial phenotypes are generally transitive, and competitive hierarchies inferred from pair-wise competition are fairly consistent to those from multi-species competition. (4) The niche complementarity and selection effects evaluated by random assembly biodiversity experiments can be used to predict the functional consequences of particular non-random species extinction scenarios. (5) P. fluorescens does not show an evolutionary trade-off in using several carbon substrates (glucose, galactose and trehalose), and evolution in environments containing these resources results in imperfect generalists; migration among populations may speed up fitness evolution of some generalists. (6) Biofilm formation at the air-broth interface by wrinkly spreader phenotypes in P. fluorescens is a cooperative behaviour which is costly to individuals but benefits the group; this behaviour could be exploited by smooth morph phenotypes. The cooperators and cheats in this system show reciprocal antagonistic coevolution in resistance and cheating performance.

Seabirds are vulnerable to a wide range of impacts at sea and function as important indicators of ocean health. A detailed understanding of their movements and distributions at sea, as well as the types of behaviour in which they engage and the extent to which those activities make them vulnerable to different impacts is critical in effective conservation planning. But their elusive lifestyles and mobility have hampered studies of their at-sea behaviour. Using miniature data loggers deployed on Manx shearwaters Puffinus puffinus this thesis explores the movements, distribution and behaviour of a small-medium pelagic, procellariiform seabird during foraging trips at sea. Foraging distributions were most variable during the pre-laying period when females departed the colony to build their egg. Females foraged close to the colony when local resources were adequate, but more typically foraged in distant shelf edge waters. Males returned frequently to the colony during this period and typically foraged close by, but also in shelf edge waters when local resources were poor. During incubation and chick-rearing the foraging movements of birds tracked from up to four colonies showed considerable inter-annual variability, but were largely constrained to the Irish and Celtic Seas and the inshore waters of west Scotland. Birds from each of the colonies foraged in waters local to their own colony, but also in more distant locations, including the productive Western Irish Sea and Western Irish Sea Front where birds from multiple colonies co-foraged, presumably at high densities. At-sea behaviour was organized into three principal activities representing: (1) sustained direct flight, (2) sitting on the sea surface, and (3) foraging, comprising tortuous flight interspersed with periods of immersion and diving in pursuit of prey. Foraging was highly constrained to daylight hours during which birds engaged in bouts of diving separated by periods of flight or rest on the surface. Most dives were up to 6 m deep, lasting up to 13 s, but some much deeper dives (maximum 55.5 m) were also made. During chick-rearing the use of short and long duration trips may allow parents to control provisioning effort and their own body condition. However, reducing parents’ requirement to provision their chick (by supplemental chick feeding) did not appear to alter the at-sea movements and behaviour of parents, suggesting that at-sea behaviour probably is controlled more by foraging conditions and prey distributions than by the nutritional demands of the chick.

Genetic transformation techniques for pest insects have enabled the development of novel methods to mitigate the enormous harm done by insects to human health (through transmission of diseases) and to agriculture (through damage to crops or livestock). I use mathematical modelling to analyse strategies using autocidal genetic constructs (dominant lethal genes that are repressible during mass-rearing); in parallel several research groups are developing the strains and the laboratory and field experimental work. Engineered insects would be released in large numbers and compete for mates, and their progeny would inherit one copy of a dominant lethal gene and die. The lethal mechanism can be made stage- or sex-specific. The aim is to reduce the number of pest insects in a population, suppressing numbers to a less harmful level or local elimination. I examine the evolutionary, ecological, and economic cost and benefit aspects of these novel interventions. I consider application of this genetic technology against agricultural pest insects, combined with genetically modified crop plants engineered to produce insecticidal toxins, to which field-evolved resistance is emerging. Using a theoretical framework, I analyse the gene frequency evolution of resistant alleles and show that strategies using genetic constructs that are selectively lethal only to females could help to manage both pests and resistance. I investigate potential resistance to the lethal mechanism of the genetic construct itself. I use population genetics and population dynamics models to explore the impact of heritable biochemically-based resistance on the effectiveness of genetic strategies for reducing populations of important pests in agriculture or public health. Released insects are homozygous for susceptibility to the lethal construct; this has an inherent element of resistance dilution. Finally, I analyse genetic vector control methods to reduce the transmission of human disease. I combine vector population dynamics and epidemiological models with techniques for assessing cost-effectiveness of a genetic strategy for controlling a vector mosquito, and show that disease elimination is feasible on a practical timescale and economically beneficial.