Behavioral Ecology of an Invasive Species: Habitat and Mate Preference(s) in Drosophila Suzukii

The invasive Spotted-Wing fruit fly, Drosophila suzukii, has inflicted substantial economic losses to the soft-fruit agriculture industry worldwide due to the ability of females in this species to use a large, serrated ovipositor to cut the fruit’s skin and lay eggs directly into the mesocarp of ripening fruit. Once the eggs hatch, larvae consume the fruit flesh, ultimately leaving the fruit unmarketable. This species parasitizes numerous commercial fruit types (including blueberries, blackberries, strawberries, raspberries and occasionally grapes) as well as fruits from a variety of wild plant species. Since fruit types vary in their nutritional composition, as well as their spatial and temporal availability, this suggests that D. suzukii experiences considerable environmental heterogeneity. The environment can have a large influence on the development and evolution of morphological, physiological, and behavioural phenotypes and, thus, can have significant implications for individual variation and population growth and change over time. Thus to better understand success if this invasive species we have examined the behavioural and developmental and reproductive performance of D. suzukii as it relates to their local environment. Specifically we focused on the role of the nutritional developmental history (NDH), which can either hinder or support offspring growth and survival, and may be an important factor when selecting habitats. Secondly, as the juvenile NDH has the potential to greatly influence adult phenotypes, and consequently individual reproductive potential, we also examined if NDH influenced the operation of sexual selection. Here we report evidence that NDH is an important factor for D. suzukii females when choosing oviposition sites, and can have dramatic consequences for offspring development, mate-choice, offspring fitness, and ultimately population growth. Information on these two subject areas (habitat and mate choice) is of great potential importance to bettering future management strategies (e.g. by manipulating fly numbers based on host preference and reproductive strategies), which are currently limited by lack of knowledge on the biology of this species

Methods for measuring the acoustic response of wind instruments

This thesis studies methods to take acoustical measurements of wind instrument bodies and mouthpieces. Acoustic responses and existing measurement methods are reviewed. Multiple- and single-microphone measurement techniques are compared with a discussion of object-length limitations and frequency response. Impulse response measurements using a complex input signal are discussed and signals used for measuring room acoustics are reviewed. Construction and deconvolution methods for several types of signals are specified and the effects of signal degradation on measurements are discussed. A novel pulse reflectometry technique that can use these signals as stimulus is presented. The signals are used in a waveguide model which simulates adverse measurement scenarios and calculated impedances are compared. Model measurements are then compared with actual reflection function measurements of two fabricated test objects to show the limitations of pulse reflectometry when calculating the impedance of long objects. Viscothermal losses and open-end radiation characteristics measured using a pulse reflectometry setup are then compared with their theoretically predicted values. Finally, the input impedance calculated from several saxophone mouthpieces are presented and a novel method for measuring the reed resonance frequency of a mouthpiece is shown.Cette thèse étudie des méthodes pour prendre des mesures acoustiques des corps et embouchures d'instruments à vent. Les réponses acoustiques et les méthodes existantes de mesure sont passées en revue. Mesures de multiples pressions et pression unique sont contrastées par un discussion des limitations sur la longueur de l'objet et la réponse en fréquences. Les mesures de réponse d'impulsion employant un signal d'entrée complexe sont discutée et des signaux utilisés pour mesurer l'acoustique de salles sont passés en revue. Les méthodes de construction et de déconvolution pour plusieurs types de signaux sont spécifiés et les façons dont la dégradation des signaux affecte les mesures sont discutées. Une nouvelle technique de réflectométrie d'impulsion qui peut employer ces signaux comme stimulus est présentée. Les signaux sont employés dans un modèle de guide d'ondes qui simule les scénarios défavorables de mesures et calculent les impédances. Des mesures de modèles sont alors comparées aux mesures réelles de fonction de réflexion de deux prototypes fabriqués pour montrer les limitations de la réflectométrie d'impulsion lors de calculs de l'impédance de longs objets. Les pertes viscothermiques et les caractéristiques de rayonnement d'extrémité ouverte mesurées en utilisant une installation de réflectométrie d'impulsion sont alors comparées à leurs valeurs théoriques prévues. En conclusion, l'impédance d'entrée calculée à partir de plusieurs embouchures de saxophones sont présentées ainsi qu'une nouvelle méthode pour mesurer la fréquence tubulaire de résonance d'une embouchure

Application of Algebraic Combinatorics to Finite Spin Systems with Dihedral Symmetry

Properties of a given symmetry group G are very important in investigation of a physical system invariant under its action. In the case of finite spin systems (magnetic rings, some planar macromolecules) the symmetry group is isomorphic with the dihedral group D_N. In this paper group-theoretical `parameters' of such groups are determined, especially decompositions of transitive representations into irreducible ones and double cosets. These results are necessary to construct matrix elements of any operator commuting with G in an efficient way. The approach proposed can be usefull in many branches of physics, but here it is applied to finite spin systems, which serve as models for mesoscopic magnets.Comment: 3 eps figs, 24 page

T_minus_Development

Date of ecolosion from pupae of adult D. suzukii raised on eight different media types (that did not contain antimicrobials, T+ assay

EGGS_NO_CHOICE_STACKED

Number of eggs laid by individual D. suzukii females housed on one of eight different media type

Data from: Nutritional geometry and fitness consequences in Drosophila suzukii, the Spotted-Wing Drosophila

Since its arrival to North America less than a decade ago, the invasive Spotted-Wing Drosophila (Drosophila suzukii) has inflicted substantial economic losses on soft fruit agriculture due to its ability to oviposit into ripening fruits. More effective management approaches for this species are needed, but little is known about the factors that influence behavioral choices made by D. suzukii when selecting hosts, or the consequences that their offspring experience when developing in different environments. Using a nutritional geometry methodology, we found that the ratio of proteins-to-carbohydrates (P:C) present in media greatly influenced adult D. suzukii behavior and subsequent offspring development. Whereas adult flies showed a strong bias in their oviposition and association behaviors toward carbohydrate-rich foods, larval survival and eclosion rate were strongly dependent on protein availability. Here, we explore the preference–performance hypothesis (PPH), in which females are predicted to oviposit on medias that provide the greatest offspring benefits, in regard to its relevance in D. suzukii behavior and consequences for management. Our results provide valuable insight into the ecology and evolution of this species that may hopefully lead to more effective management strategies

Fly_weights

Dry weights of males and females D. suzukii collected from eight different media types