Applied evolution: An integrated approach to studying life history traits in response to drug selection

The use of chemical control measures to reduce the impact of parasite and pest species has frequently resulted in the development of resistance. Thus, resistance management has become a key concern in human and veterinary medicine, and in agricultural production. Although it is known that factors such as gene flow between susceptible and resistant populations, drug type, application methods, and costs of resistance can affect the rate of resistance evolution, less is known about the impacts of density-dependent eco-evolutionary processes that could be altered by drug-induced mortality. The overall aim of this thesis was to take an experimental evolution approach to assess how life history traits respond to drug selection, using a free-living dioecious worm (Caenorhabditis remanei) as a model. In Chapter 2, I defined the relationship between C. remanei survival and Ivermectin dose over a range of concentrations, in order to control the intensity of selection used in the selection experiment described in Chapter 4. The dose-response data were also used to appraise curve-fitting methods, using Akaike Information Criterion (AIC) model selection to compare a series of nonlinear models. The type of model fitted to the dose response data had a significant effect on the estimates of LD50 and LD99, suggesting that failure to fit an appropriate model could give misleading estimates of resistance status. In addition, simulated data were used to establish that a potential cost of resistance could be predicted by comparing survival at the upper asymptote of dose-response curves for resistant and susceptible populations, even when differences were as low as 4%. This approach to dose-response modeling ensures that the maximum amount of useful information relating to resistance is gathered in one study. In Chapter 3, I asked how simulations could be used to inform important design choices used in selection experiments. Specifically, I focused on the effects of both within- and between-line variation on estimated power, when detecting small, medium and large effect sizes. Using mixed-effect models on simulated data, I demonstrated that commonly used designs with realistic levels of variation could be underpowered for substantial effect sizes. Thus, use of simulation-based power analysis provides an effective way to avoid under or overpowering a study designs incorporating variation due to random effects. In Chapter 4, I 3 investigated how Ivermectin dosage and changes in population density affect the rate of resistance evolution. I exposed replicate lines of C. remanei to two doses of Ivermectin (high and low) to assess relative survival of lines selected in drug-treated environments compared to untreated controls over 10 generations. Additionally, I maintained lines where mortality was imposed randomly to control for differences in density between drug treatments and to distinguish between the evolutionary consequences of drug treatment versus ecological processes affected by changes in density-dependent feedback. Intriguingly, both drug-selected and random-mortality lines showed an increase in survivorship when challenged with Ivermectin; the magnitude of this increase varied with the intensity of selection and life-history stage. The results suggest that interactions between density-dependent processes and life history may mediate evolved changes in susceptibility to control measures, which could result in misleading conclusions about the evolution of heritable resistance following drug treatment. In Chapter 5, I investigated whether the apparent changes in drug susceptibility found in Chapter 4 were related to evolved changes in life-history of C. remanei populations after selection in drug-treated and random-mortality environments. Rapid passage of lines in the drug-free environment had no effect on the measured life-history traits. In the drug-free environment, adult size and fecundity of drug-selected lines increased compared to the controls but drug selection did not affect lifespan. In the treated environment, drug-selected lines showed increased lifespan and fecundity relative to controls. Adult size of randomly culled lines responded in a similar way to drug-selected lines in the drug-free environment, but no change in fecundity or lifespan was observed in either environment. The results suggest that life histories of nematodes can respond to selection as a result of the application of control measures. Failure to take these responses into account when applying control measures could result in adverse outcomes, such as larger and more fecund parasites, as well as over-estimation of the development of genetically controlled resistance. In conclusion, my thesis shows that there may be a complex relationship between drug selection, density-dependent regulatory processes and life history of populations challenged with control measures. This relationship could have implications for how resistance is monitored and managed if life histories of parasitic species show such eco-evolutionary responses to drug application.

Body reserves mediate trade-offs between life-history traits: new insights from small pelagic fish reproduction

Limited resources in the environment prevent individuals from simultaneously maximizing all life-history traits, resulting in trade-offs. In particular, the cost of reproduction is well known to negatively affect energy investment in growth and maintenance. Here, we investigated these trade-offs during contrasting periods of high versus low fish size and body condition (before/after 2008) in the Gulf of Lions. Female reproductive allocation and performance in anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) were examined based on morphometric historical data from the 1970s and from 2003 to 2015. Additionally, potential maternal effects on egg quantity and quality were examined in 2014/2015. After 2008, the gonadosomatic index increased for sardine and remained steady for anchovy, while a strong decline in mean length at first maturity indicated earlier maturation for both species. Regarding maternal effects, for both species egg quantity was positively linked to fish size but not to fish lipid reserves, while the egg quality was positively related to lipid reserves. Atresia prevalence and intensity were rather low regardless of fish condition and size. Finally, estimations of total annual numbers of eggs spawned indicated a sharp decrease for sardine since 2008 but a slight increase for anchovy during the last 5 years. This study revealed a biased allocation towards reproduction in small pelagic fish when confronted with a really low body condition. This highlights that fish can maintain high reproductive investment potentially at the cost of other traits which might explain the present disappearance of old and large individuals in the Gulf of Lions.

Phronèsis et prudence : esquisse de la science pratique dans les textes de la tradition classique

Ce mémoire porte sur les transformations du concept de prudence, de l’Antiquité grecque au XVIIe siècle. Il souligne notamment le lien qui unit les manières d’être et l’art, tant chez les Grecs qu’au début de la modernité. La phronèsis se définissait tout d’abord en relation aux autres manières de faire, dont la technè fait partie. Si Platon et Aristote les distinguent, les auteurs de la modernité assimileront ces deux manières de faire. De plus, on peut voir dans la forme du langage employé pour écrire sur la prudence un reflet de la vertu antique. Il s’agit de donner, tant par le style que par le propos, un exemple de prudence. Cette vertu, qui est d’ailleurs la première des vertus cardinales, est donc fondamentale pour comprendre le rapport entre l’éthique et l’art, de l’Antiquité au début de la modernité. Elle annonce aussi les débuts de l’esthétique moderne, en ce qu’elle donne des règles à suivre pour arriver à ses fins, qu’il s’agisse de n’importe quelle manière de faire.

Neuroscience and Hindu Aesthetics: A Critical Analysis of V.S. Ramachandran’s “Science of Art”

Neuroaesthetics is the study of the brain’s response to artistic stimuli. The neuroscientist V.S. Ramachandran contends that art is primarily “caricature” or “exaggeration.” Exaggerated forms hyperactivate neurons in viewers’ brains, which in turn produce specific, “universal” responses. Ramachandran identifies a precursor for his theory in the concept of rasa (literally “juice”) from classical Hindu aesthetics, which he associates with “exaggeration.” The canonical Sanskrit texts of Bharata Muni’s Natya Shastra and Abhinavagupta’s Abhinavabharati, however, do not support Ramachandran’s conclusions. They present audiences as dynamic co-creators, not passive recipients. I believe we could more accurately model the neurology of Hindu aesthetic experiences if we took indigenous rasa theory more seriously as qualitative data that could inform future research.

Organizations in time:history, theory, methods

Book review: Organizations in Time, edited by R Daniel Wadhwani and Marcelo Bucheli, Oxford University Press, 2014. The title of this edited volume is slightly misleading, as its various contributions explore the potential for more historical analysis in organization studies rather than addressing issues associated with time and organizing. Hopefully this will not distract from the important achievement of this volume—important especially for business historians—in further expanding and integrating business history into management and organization studies. The various contributions, elegantly tied together by R. Daniel Wadhwani and Marcelo Bucheli in their substantial introduction (which, by the way, presents a significant contribution in its own right), opens up new sets of questions, especially in terms of future methodological and theoretical developments in the field. This book also reflects the changing institutional location of business historians, who increasingly make their careers in business schools rather than history departments, especially in Europe, reopening old questions of history as a social science. There have been several calls to teach more history in business education, such as the Carnegie Foundation report (2011) that found undergraduate business education too narrow in focus and highlighted the need to integrate more liberal arts teaching into the curriculum. However, in the contemporary research-driven environment of business and management schools, historical understanding is unlikely to permeate the curriculum if historical analysis cannot first deliver significant theoretical contributions. This is the central theme around which this edited volume revolves, and it marks a milestone in this ongoing debate. (In the spirit of full disclosure, I should add that even though I did not contribute to this volume, I have coauthored with several of its contributors and view this book as central to my current research practice.)

Phronèsis et prudence : esquisse de la science pratique dans les textes de la tradition classique

Ce mémoire porte sur les transformations du concept de prudence, de l’Antiquité grecque au XVIIe siècle. Il souligne notamment le lien qui unit les manières d’être et l’art, tant chez les Grecs qu’au début de la modernité. La phronèsis se définissait tout d’abord en relation aux autres manières de faire, dont la technè fait partie. Si Platon et Aristote les distinguent, les auteurs de la modernité assimileront ces deux manières de faire. De plus, on peut voir dans la forme du langage employé pour écrire sur la prudence un reflet de la vertu antique. Il s’agit de donner, tant par le style que par le propos, un exemple de prudence. Cette vertu, qui est d’ailleurs la première des vertus cardinales, est donc fondamentale pour comprendre le rapport entre l’éthique et l’art, de l’Antiquité au début de la modernité. Elle annonce aussi les débuts de l’esthétique moderne, en ce qu’elle donne des règles à suivre pour arriver à ses fins, qu’il s’agisse de n’importe quelle manière de faire.

Genetic architecture and sexual conflict in the life history of Drosophila

Because males and females of a species express many homologous traits, sex-specific selection on these traits can shift the opposite sex away from its phenotypic optimum. This mode of sexually antagonistic selection, known as intralocus sexual conflict (IaSC), arises when the evolution of sexual dimorphism is constrained by the two sexes sharing a common gene pool. As IaSC has been historically overlooked, many outstanding questions remain. For example, what is its contribution in maintaining genetic variation for fitness in populations? What characters underlie this variation in fitness? How does the selection history of the population influence the standing genetic variation? I used the model organism Drosophila melanogaster to attempt to resolve some of these questions. The first part of my Master’s project involved assessing the detectability of sexually antagonistic alleles in populations at different stages of adaptation to the laboratory. For the second part of my Master’s project, I looked for evidence of conflict during the development of body size, a well-known sexually dimorphic trait. While the first part of my thesis proved inconclusive, the second part revealed a surprising source of sexual conflict in pre-adult stages of D. melanogaster.

Life history of a native emydid turtle (Malaclemys terrapin centrata) on the remote oceanic islands of Bermuda

Diamondback terrapins (Malaclemys terrapin) are native to the remote oceanic islands of Bermuda and presently inhabit only four small brackish water ponds on a private golf course. The life history of this species is poorly understood on Bermuda and so the aim of this study was to fill these knowledge gaps, to compare the results with what is known from other areas in the North American range, and to inform the development of a local management plan. The results of a mark-recapture census revealed that ca. 100 individuals ≥81 mm straight carapace length live on Bermuda, of which nearly half (48.5%) were considered sexually mature. The population is dominated by females (sex ratio 2.9:1) and annual recruitment over the three year period was found to be extremely low (approximately two terrapins). Female diamondback terrapins in Bermuda nest almost exclusively within a limited number of sand bunkers on the golf course. Nesting commenced in late March or early April and ended in late August. Peak oviposition was observed in May and June. Clutch size averaged 5.1 eggs (range 0-10; SD 2.4) and the incubation period averaged 61.8 days (range 49-83; SD 10.5). Delayed emergence was documented, with 43.8% of the hatchlings remaining in their natal nests over the winter months. The mean annual hatching success rate was determined to be 19% (range 17.6-21; SD 1.9). Radio-telemetry was used to investigate the movements and survivorship of postemergent hatchling diamondback terrapins. The results indicated that mangrove swamps and grass-dominated marshes adjacent to the ponds are important developmental habitats for hatchlings. Yellow-crowned night herons (Nyctanassa violacea) were found to be significant predators of small terrapins during spring emergence. Small aquatic gastropods comprised 66.7% of the faecal samples analysed from the Bermudian population. Scavenged fish and vertebrate animal remains, terrestrial arthropods, polychaete worms and bivalves were consumed in lesser amounts. Sediment from the pond environment was found in 74% of the faecal samples analysed and is believed to have been incidentally ingested while foraging for the small benthic gastropods. Eco-toxicological analyses of the pond sediment, prey and terrapin eggs showed that the Bermudian diamondback terrapins live and feed in wetland habitats characterised by chronic, multifactorial contamination; principally total petroleum hydrocarbons, polycyclic aromatic hydrocarbons and a variety of heavy metals. This study found that some of those contaminants are accumulating in the gastropod prey as well as being transferred to terrapin eggs. This may be reducing the incidence of successful embryonic development for this species in Bermuda and may likely contribute to the observed low hatching rates. These collective findings indicate that the Bermudian population is very vulnerable to local extirpation.

Macrodynamics of economics: a bibliometric history

A history of specialties in economics since the late 1950s is constructed on the basis of a large corpus of documents from economics journals. The production of this history relies on a combination of algorithmic methods that avoid subjective assessments of the boundaries of specialties: bibliographic coupling, automated community detection in dynamic networks and text mining. these methods uncover a structuring of economics around recognizable specialties with some significant changes over the time-period covered (1956-2014). Among our results, especially noteworthy are (a) the clearcut existence of 10 families of specialties, (b) the disappearance in the late 1970s of a specialty focused on general economic theory, (c) the dispersal of the econometrics-centered specialty in the early 1990s and the ensuing importance of specific econometric methods for the identity of many specialties since the 1990s, (d) the low level of specialization of individual economists throughout the period in contrast to physicists as early as the late 1960s.

Using performance measurement models for benefit realization with enterprise systems: The Queensland Government approach (Case Study)

A range of influences, technical and organizational, has encouraged the wide spread adaption of Enterprise Systems (ES). Nevertheless, there is a growing consensus that Enterprise Systems have in the many cases failed to provide the expected benefits to organizations. This paper presents ongoing research, which analyzes the benefits realization approach of the Queensland Government. This approach applies a modified Balance Scorecard. First, history and background of Queensland Government’s Enterprise Systems initiative is introduced. Second, the most common reasons for ES under performance are related. Third, relevant performance measurement models and the Balanced Scorecard in particular are discussed. Finally, the Queensland Government initiative is evaluated in light of this overview of current work in the area. In the current and future work, the authors aim to use their active involvement in Queensland Government’s benefits realization initiative for an Action Research based project investigating the appropriateness of the Balanced Scorecard for the purposes of Enterprise Systems benefits realization.

Integrating science through Bayesian Belief Networks : case study of Lyngbya in Moreton Bay

Bayesian Belief Networks (BBNs) are emerging as valuable tools for investigating complex ecological problems. In a BBN, the important variables in a problem are identified and causal relationships are represented graphically. Underpinning this is the probabilistic framework in which variables can take on a finite range of mutually exclusive states. Associated with each variable is a conditional probability table (CPT), showing the probability of a variable attaining each of its possible states conditioned on all possible combinations of it parents. Whilst the variables (nodes) are connected, the CPT attached to each node can be quantified independently. This allows each variable to be populated with the best data available, including expert opinion, simulation results or observed data. It also allows the information to be easily updated as better data become available ----- ----- This paper reports on the process of developing a BBN to better understand the initial rapid growth phase (initiation) of a marine cyanobacterium, Lyngbya majuscula, in Moreton Bay, Queensland. Anecdotal evidence suggests that Lyngbya blooms in this region have increased in severity and extent over the past decade. Lyngbya has been associated with acute dermatitis and a range of other health problems in humans. Blooms have been linked to ecosystem degradation and have also damaged commercial and recreational fisheries. However, the causes of blooms are as yet poorly understood.