No description available.

Memoria para optar al Título Profesional de Médico Veterinario. / Los coccinélidos (Coleoptera: Coccinellidae) son insectos importantes por su capacidad y eficacia como controladores de plagas agrícolas. Dentro de ellos, Harmonia axryridis o chinita arlequín es una especie invasora proveniente de Asia que ha sido introducida intencional o accidentalmente en muchas partes del mundo. A pesar de su potencial como controlador biológico, ha causado gran revuelo a nivel mundial debido a que se ha transformado en una amenaza para la biodiversidad de otros insectos, especialmente otros coccinélidos, en los lugares en los que coloniza. Además, afecta al ser humano al hibernar en casas durante el invierno, causando daños estéticos y reacciones alérgicas por mordeduras. También produce daños en la agricultura al colonizar frutos blandos como la uva y afectar la calidad del vino y jugos. En Chile las primeras poblaciones silvestres se observaron el año 2003 y hoy ya han invadido gran parte del país. El objetivo de este trabajo fue analizar la relación entre la abundancia de H. axyridis y la riqueza, diversidad y abundancia de coccinélidos nativos, exóticos y de áfidos, asociados a campos de alfalfa de la zona sur-poniente de la Región Metropolitana durante la época de otoño del año 2015. Los coccinélidos y áfidos fueron muestreados con trampas pegajosas ubicadas en 20 alfalfales (5 trampas por alfalfal), dejándolas actuar por dos semanas. Se colectaron 2143 coccinélidos de 14 especies, 6 exóticas y 8 nativas. Las más abundantes fueron Hippodamia variegata y H. axyridis. La abundancia de H. axyridis no se relacionó significativamente con la abundancia total de coccinélidos, ni con la de exóticos, ni en general con las características comunitarias del ensamble (i.e. riqueza de exóticas, equitabilidad total, de nativas o exóticas, diversidad de nativas y de exóticas). Contrario a lo esperado, la abundancia de H. axyridis se relacionó positiva y significativamente con la abundancia de coccinélidos nativos, la riqueza total, la riqueza de nativos y con la diversidad total. Además, se relacionó negativa y significativamente con H. variegata, confirmando lo encontrado en estudios anteriores. Harmonia axyridis presentó una relación positiva con la abundancia de áfidos presente en los alfalfales, demostrando que es una especie denso dependiente de sus presas extragremio. Además, la relación negativa observada entre las abundancias relativas de H. axyridis y H. variegata se asoció positiva y significativamente con la abundancia de áfidos. Estos resultados sugieren que H. axyridis no estaría ejerciendo el efecto depresor esperado en coccinélidos en plantaciones de alfalfa durante el otoño y que la abundancia de áfidos modularía la relación entre las dos especies exóticas más abundantes. Es necesario continuar con estudios a largo plazo para tener mayor claridad de si los resultados obtenidos en otoño en alfalfales se repiten en otras épocas del año y otros hábitats y así contar con mayores antecedentes a la hora de manejar esta invasión biológica. / Coccinellids (Coleoptera: Coccinellidae) are important for their capacity and effectiveness as agricultural pest controllers. Among them, Harmonia axryridis or Harlequin ladybird is an invasive species from Asia that has been intentionally or accidentally introduced in several countries around the world. Despite its potential as a biological control agent, it has caused a worldwide negative impact because it has become a threat to biodiversity of other insects, especially other coccinellids, in places where H. axyridis has colonized. In addition, this species affects humans as a household pest during the winter, causing cosmetic damage and allergic reactions by bites, and also causes problems to agriculture damaging soft fruits, such as grapes, thus affecting the quality of wine. In Chile the first wild populations were observed in 2003 and today they have already invaded the majority of the country. The aim of this study was to analyze the relationship between H. axyridis abundance and the richness, diversity and abundance of native and exotic ladybird beetles and aphids in alfalfa fields in the south west of the Metropolitan Region during the autumn of 2015. Coccinellids and aphids were sampled with sticky traps located in 20 alfalfa fields (5 traps per field), leaving them deployed for two weeks. A total of 2143 coccinellids of 14 species (6 exotics and 8 natives), were collected. The most abundant were Hippodamia variegata and H. axyridis. The abundance of H. axyridis was not significantly related with most of the community characteristics of the coccinellids in general (i.e. exotic richness, total, native or exotic equitability, native and exotic diversity). Contrary to expectations, the abundance of H. axyridis was related positively and significantly with the abundance of native ladybirds, total richness, the native species richness and total diversity. In addition, there was a negative and significant relation with H. variegata, confirming what was found in previous studies. Harmonia axyridis had a positive relationship with the abundance of aphids present in the alfalfal fields, showing that the abundance of this coccinellid depends on the density of its prey. Furthermore, the negative relation observed between the relative abundances of H. axyridis and H. variegata was associated positively and significantly with the abundance of aphids. These results suggest that H. axyridis would not trigger the expected depression on the coccinellid population on alfalfa fields during autumn and that the aphid abundance modulates the relationship between the two most abundant exotic species. It is necessary to continue long-term studies to have clarity on whether the results obtained in alfalfa fields during the autumn repeat in other seasons and other habitats and thus, have more background when handling this biological invasion. / Financiamiento: Proyecto Fondecyt No. 1140662.

La lutte biologique est souvent présentée comme une méthode de lutte contre les ravageurs respectueuse de l'environnement, même si la lutte par acclimatation (introduction d'une espèce exotique) peut être à l'origine d'invasion biologique. La coccinelle asiatique Harmonia axyridis Pallas (Coleoptera : Coccinellidae) a été utilisée comme agent de lutte biologique introduit en Amérique et en Europe pour lutter contre les pucerons. Actuellement, cette espèce est considérée comme envahissante, et a des impacts négatifs sur l'environnement. L'objectif principal de cette thèse est d'améliorer notre connaissance des processus évolutifs pouvant accompagner l'élevage en captivité, ainsi que ceux qui sont liés aux invasions biologiques. J'ai pour cela utilisé une approche expérimentale au travers d'études permettant de caractériser les différences de traits d'histoire de vie entre les trois compartiments populationnels d'H. axyridis (populations natives, envahissantes et de lutte biologique). Les résultats obtenus montrent que les changements évolutifs les plus importants concernent le compartiment de lutte biologique par rapport aux compartiments sauvages (natifs et envahissants). Ce compartiment a subi des changements phénotypiques remarquables en réponse aux conditions d'élevage en laboratoire. Les changements évolutifs les plus spectaculaires concernent différents traits liés à la reproduction. Par exemple, les femelles de lutte biologique se reproduisent plus tôt, ont une fécondité journalière plus élevée, ainsi qu'une longévité et une durée de vie reproductive plus courte. Nous avons également mis en évidence des changements évolutifs entre des populations sauvages natives et envahissantes. Les adaptations aux conditions d'élevage peuvent parfois être désavantageuses dans l'environnement naturel. Par exemple, la résistance au froid et aux pathogènes est moins importante que celle des populations sauvages. Nos résultats montrent aussi que, même si la souche de lutte biologique européenne est incapable de s'implanter dans la nature, l'hybridation avec les populations envahissantes américaines pourrait avoir jouer un rôle positif au cours de l'invasion en Europe. / Biological control is generally considered as an environmentally low-impact solution for pest control. However, the use of foreign control agents may ultimately lead to undesired biological invasions. The Asian harlequin ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae) was originally used as a biological control agent of aphids in North America and Europe. This species is now considered as invasive, and can have harmful effects on the environment. The main objective of this thesis is to better understand the impact of mass rearing on life-history traits, with a focus on traits that may be associated with invasion success. To do so, experimental approaches were carried out to monitor changes in life-history traits for three types of populations (biocontrol, native or invasive). The corresponding results indicate that the most important evolutionary changes occur in the biocontrol populations (by contrast with the invasive and native populations). Mass rearing appears to induce significant phenotypic changes in the biocontrol populations, with the most spectacular changes being related to reproductive life-history traits. For instance, biocontrol females reproduce significantly earlier, have a higher daily fecundity, but also exhibit lower life expectancy and lower reproductive lifespan. We also evidence other differences between the native and invasive populations. Cold tolerance and pathogen resistance are also lower in biocontrol populations than in wild populations. Altogether, our findings indicate that adaptations to mass rearing conditions may affect the fitness of H. axyridis populations in natural environments. This suggests that, even if the European biocontrol strain is unable to successfully colonize a natural environment, it may nonetheless impact the invasion dynamics of the species in Europe thanks to the admixture with the invasive American population

Memoria para optar al Título Profesional de Médico Veterinario / Los coccinélidos (Coleoptera: Coccinellidae) son insectos beneficiosos al controlar plagas importantes de la agricultura. Una de las especies que ha sido introducida en diferentes países es Harmonia axyridis (Pallas), conocida como “Chinita Arlequín” la cual es un excelente controlador biológico pero que es capaz de generar tres efectos adversos: i) desplazamiento de otros enemigos naturales de plagas, ii) daño a cultivos de frutos blandos y iii) molestias a la población humana al hibernar en hogares. En Chile esta especie ha aumentado su rango de distribución significativamente por lo que en esta memoria de Titulo se pretende establecer como ha colonizado los distintos hábitats en función de su perturbación y su actual relación con las diferentes especies de coccinélidos presentes en nuestro país enfocándose en la conservación biológica. Con este fin se realizó un estudio en primavera del año 2014 en la zona sur poniente de la Región Metropolitana, seleccionando ocho coberturas en un gradiente de perturbación: Matorral Esclerófilo, Setos Arbóreos, Bosquetes de Eucaliptus, Franjas de Zarzamoras, Viñedos Orgánicos, Frutales, Trigo y Campos de Alfalfa, donde se instalaron trampas amarillas pegajosas para la captura de coccinélidos adultos y áfidos, las trampas se recolectaron luego de dos semanas. Se evaluó el efecto de éstas coberturas sobre las abundancias de los coccinélidos en donde se encontró que las especies exóticas, entre ellas H. axyridis, prefirieron las coberturas más perturbadas, en cambio las especies nativas fueron más generalistas. Los resultados de la relación entre las abundancias de especies totales, nativas y exóticas con la abundancia de H. axyridis por cobertura indicarían que al menos en Chile central, esta especie no estaría generando los efectos adversos que ha generado en otras partes del mundo. Sin embargo, H. axyridis se relacionó negativamente con la especie exótica H. variegata en Alfalfa, lo que abre interrogantes sobre posibles interacciones negativas entre ellas. Contrario a lo esperado, los índices comunitarios no disminuyeron por lo que no existiría un empobrecimiento de coccinélidos en presencia de H. axyridis. Por último, la abundancia de áfidos podría explicar en parte la presencia de H. axyridis en dos de los tres ambientes en donde ella fue más abundante / Financiamiento: Proyecto Fondecyt 1140662

optar al Título de: Bióloga con mención en Medio Ambiente / Uno de los factores que favorecen el éxito de una especie invasora es la ausencia de control por parte de enemigos naturales en los lugares invadidos, como lo predice la Hipótesis del Escape de Enemigos Naturales. Harmonia axyridis (Coleoptera: Coccinellidae) invadió el país recientemente, dominando en cultivos de alfalfa en Chile central, donde coexiste con Hippodamia variegata, otra especie introducida, y Eriopis chilensis, especie nativa, las cuales disminuyeron su abundancia luego de la llegada de H. axyridis. Un enemigo natural de coccinélidos es el parasitoide Dinocampus coccinellae (Hymenoptera: Braconidae), el cual está presente en varias regiones del mundo, incluido Chile. El éxito de la parasitación de D. coccinellae puede fluctuar considerablemente dependiendo de la especie de coccinélido. En otras regiones, H. axyridis ha sido catalogada como un hospedero menos adecuado para D. coccinellae en comparación con especies de coccinélidos nativas en la zona invadida, sugiriendo distintos mecanismos por medio de los cuales esta especie podría evitar el desarrollo exitoso de este parasitoide y, por lo tanto, presentar una menor proporción de individuos afectados por este enemigo natural. El presente estudio buscó dilucidar si H. axyridis es un hospedero menos adecuado para D. coccinellae en comparación con H. variegata y E. chilensis. Para esto se compararon la formación de pupa del parasitoide, parasitoidismo exitoso (i.e. emergencia de parasitoide adulto), desarrollo larval fallido (i.e. parasitoidismo con muerte de larva) y parasitoidismo total (i.e. formación de pupa del parasitoide o desarrollo larval fallido) en las tres especies de coccinélidos, capturados en campos de alfalfa en la Región Metropolitana y mantenidos en laboratorio. Además, individuos criados en el laboratorio fueron expuestos al parasitoide para comparar en las tres especies la oviposición por parte del parasitoide y, al igual que en campo, la formación de pupa del parasitoide, parasitoidismo exitoso, desarrollo larval fallido y parasitoidismo total. En campo, H. axyridis presentó menor parsitoidismo exitoso (7 %) que H. variegata (33 %) y E. chilensis (36 %), además, H. axyridis fue la única especie en que el porcentaje desarrollo larval fallido fue mayor al porcentaje de parasitoidismo exitoso. En condiciones de laboratorio los resultados fueron similares ya que D. coccinellae nunca ovipuso en H. axyridis, en cambio sí lo hizo en H. variegata (40%) y E. chilensis (33%), obteniéndose eventos de formación de pupa, parasitoidismo exitoso y desarrollo larval fallido en laboratorio sólo en estas últimas. Esto indicaría que H. axyridis en Chile, al igual que en otras latitudes, sería un hospedero menos adecuado para el parasitoide D. coccinellae en comparación con las otras especies, nativas e introducidas, abundantes en campos de alfalfa, lo que podría constituir una ventaja para su establecimiento y dominancia en este ecosistema. / One of the factors favoring the success of an invasive species is the absence of control by natural enemies in the invaded areas, as predicted by the Enemy Release Hypothesis. Harmonia axyridis (Coleoptera: Coccinellidae) recently invaded the country, dominating alfalfa fields in central Chile, where it coexists with Hippodamia variegata, another introduced species, and Eriopis chilensis, a native species, both decreasing in abundance after the arrival of H. axyridis. A natural enemy of coccinellids is the parasitoid Dinocampus coccinellae (Hymenoptera: Braconidae), which is present in several regions of the world, including Chile. The success of D. coccinellae parasitization can fluctuate considerably depending on the species of coccinellid. In other regions, H. axyridis has been classified as a less suitable host for D. coccinellae compared to native coccinellid species in the invaded area, suggesting different mechanisms by which this species could prevent the successful development of this parasitoid, and, therefore, present a lower proportion of individuals affected by this natural enemy. The present study attempted to elucidate whether H. axyridis is a less suitable host for D. coccinellae compared to H. variegata and E. chilensis. For this purpose, parasitoid pupa formation, successful parasitism (i.e. adult parasitoid emergence) and failed larval development (i.e. parasitism with larval death) were compared in the three coccinellid species, from insects captured in alfalfa fields in the Metropolitan Region and maintained in the laboratory. In addition, individuals reared in the laboratory were exposed to the parasitoid to compare parasitoid oviposition and, as in the field, parasitoid pupa formation, successful parasitism and failed larval development in all three species. In the field, H. axyridis had less successful parasitism (7%) than H. variegata (33%) and E. chilensis (36%), in addition, H. axyridis was the only species in which the percentage of failed larval development was greater than the percentage of successful parasitism. In laboratory conditions, the results were similar, since D. coccinellae never oviposited in H. axyridis, while it did in H. variegata (40%) and E. chilensis (33%), obtaining events of pupa development, successful parasitism and failed larval development in the laboratory species. This would indicate that H. axyridis in Chile, as in other regions, would be a less suitable host for the parasitoid D. coccinellae compared to the other most abundant native and introduced species in alfalfa fields, which could be an advantage for its establishment and dominance in this ecosystem.

Insect-human interactions are very complex; one example is the relationship between humans and the multicolored Asian lady beetle (ALB; Harmonia axyridis). ALB, a native to Asia, was introduced into North American agricultural fields and orchards as a biological control agent for aphids and other soft-bodied insects. However, it is considered a pest by some humans as it invades houses in the fall and winter months. Additionally, ALBs feed on fruits when aphids are scarce, and the hemolymph secreted by ALBs contaminates fruit and affects the taste of fruit products. ALBs invasive behavior has led to concern that this non-native species may be outcompeting native lady beetle species, perhaps leading toward the latter’s extinction. Our study aims to provide genomic and proteomic framework for further study and management of ALB. Insect genomes represent gateways into their complex physiological, behavioral, and structural characteristics, and consequently can be leveraged in the development of highly targeted strategies for the control of pests, the propagation/protection of beneficial species, and responsible stewardship of insect biodiversity. For this study, ALBs were collected on the Mississippi State University campus in Starkville, MS, and their DNA was sequenced using Illumina and Oxford Nanopore technologies. The data was assembled and annotated using multiple computational biology techniques. Over 40K protein-coding genes were predicted with high confidence from the ALB sequence assembly. To complement the genome assembly, the proteome of ALB was explored using LC-MSMS analysis and 2-D electrophoresis. Annotation was used to characterize and identify the proteins found in the proteomic analysis of ALB. Before completing our study, a Japanese H. axyridis genome assembly was published by the Beijing Institute of Science. The Japanese ALB genome had a higher assembly quality than ours, but it was not annotated. We annotated both the Japanese and Mississippi ALB genomes. Comparative analyses were performed to identify possible variations that could have resulted from adaptation, but the data revealed no significant differences between Japanese and Mississippi assemblies. Overall, the results from our study, including the annotation of the Japanese ALB assembly, provide a better understanding of the biology of the ALB and inform further research aimed at managing interactions of this species with humans, their crops, and the environment.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Invasive arthropod predators are one of the largest and most diverse groups of invasive insects in the world. Many are generalist predators, with cosmopolitan distributions due to their use as biological control agents in agriculture. Harmonia axyridis (Coleoptera: Coccinellidae), an invasive arthropod predator species native to Asia, which now has a world-wide distribution. It is considered one of the most successful biological control predator species and is generally considered to be economically beneficial. However, negative effects have recently emerged in agricultural and natural systems. Harmonia axyridis poses a threat to biodiversity as it outcompetes native species for food resources. It can also feed directly on native predatory arthropods that disrupt natural ecosystem processes. Their movement in-and-out of agricultural landscapes may depend on food availability with natural vegetation alongside agricultural areas often utilised for refuge and alternative food resources. This beetle has also been recorded in urban areas. The aim of this study was to determine how the invasive H. axyridis beetle uses the local landscape in the Western Cape province, South Africa, and to determine its threat to native species. I sampled urban landscapes, vineyards, natural vegetation/vineyard edge zones and pristine natural areas for arthropods every second month using a suction sampler. Data collected included the abundance and diversity of H. axyridis, herbivores, local predators and non-Harmonia ladybeetles. Most H. axyridis were collected in urban areas during all sampling periods. Highest abundance was recorded in May and July (winter). This indicates that urban areas were the preferred landscape feature and that these act as ovipositing areas, particularly as larval H. axyridis were also only collected in urban areas. Significantly, vineyards and natural vegetation had very low abundance of H. axyridis, questioning their value as a biological control agent in this region. Harmonia axyridis had a negative effect on the overall local arthropod community, as well as the predator and herbivore guilds, although it was positively correlated with the abundance of non-Harmonia ladybeetles. This suggests that H. axyridis and non-Harmonia ladybeetles are responding to the same resources in these landscapes. A negative correlation found between H. axyridis and the abundance of predators is most likely due to competition for the same resources (e.g. prey items). These negative impacts, along with their negligible value as biological control agents in agriculture, suggest that a programme should be implemented to control this invasive species. More specifically, control should be aimed in urban areas during winter when and where the species aggregates and when larvae are present. / AFRIKAANSE OPSOMMING: Geleedpotige roofdiere is een van die grootste en mees diverse groepe van uitheemse insekte in die wêreld. Die meeste is veelsydige roofdiere, met wêreldwye verspreiding te danke aan hul gebruik as biologiese beheer agente in landbou gebiede. Byvoorbeeld, Harmonia axyridis (Coleoptera: Coccinellidae), 'n indringer geleedpotige roofdier spesies inheems aan Asië, het nou 'n wêreldwye verspreiding. Dit word beskou as die mees suksesvolle roofdier spesies wat gebruik word vir biologiese beheer en word oor die algemeen beskou as ekonomies voordelig. Negatiewe effekte was onlangs aangeteken beide in landbou gebiede en natuurlike areas. Harmonia axyridis hou 'n bedreiging in vir inheemse biodiversiteit as dit inheemse spesies uitkompeteer vir voedsel bronne. Dit kan ook direk voed op plaaslike roofsugtige geleedpotiges wat trofiese vlakke ontwrig en uiteindelik, biodiversiteit. Hulle beweging in-en-uit landbou landskappe kan gekoppel word aan die beskikbaarheid van voedsel, en gebruik natuurlike plantegroei langs landbou gebiede dikwels as 'n toevlugs oord en area vir alternatiewe voedsel bronne. Harmonia axyridis word ook in stedelike gebiede aangeteken. Die doel van hierdie studie was om te bepaal hoe die indringer Harlekynkewer die plaaslike landskap gebruik met die fokus op wingerde in die Wes-Kaap provinsie van Suid-Afrika, en tweedens om die bedreiging wat hierdie kewer moontlik vir inheemse spesies te bepaal. Ek het arthropoda in stedelike landskappe, wingerde, natuurlike plantegroei / wingerd rand sones en ongerepte natuurlike areas elke twee maande met behulp van 'n D-vac versamel. Monsters was ontleed deur gebruik te maak van die getalle van H. axyridis, herbivore, plaaslike roofdiere en nie-Harmonia liewenheers kewers. Die meeste H. axyridis was in stedelike gebiede versamel gedurende al die seisoene, maar meeste individue was gedurende Mei en Julie (winter) versamel. Hierdie toon dat stedelike gebiede die voorkeur-landskappe is vir hierdie kewers en dat hierdie gebiede opgetree as eierleggende gebiede, veral omdat larwes van H. axyridis slegs in hierdie gebiede aangeteken was. Wingerde en die natuurlike plantegroei het baie lae getalle H. axyridis gehuisves wat hul waarde as biobeheermiddel bevraagteken. Harmonia axyridis het 'n negatiewe uitwerking op die algehele plaaslike geleedpotige gemeenskappe gehad, asook op die die roofdier en herbivoor gildes, maar hul getalle was positief gekorreleer met die getalle van nie-Harmonia liewenheerskewers. Dit dui daarop dat H. axyridis en nie-Harmonia liewenheerskewers beide reageer op dieselfde hulpbronne in hierdie landskappe. 'n Negatiewe korrelasie was gevind tussen die getalle van H. axyridis en die getalle van ander predatoriese geleedpotiges at waarskynlik te danke was aan mededinging tussen hierdie groepe vir dieselfde hulpbronne (bv prooi). Hierdie negatiewe invloede, asook hul verminderde waarde as biobeheeragente in die landbou, dui daarop dat 'n program in werking gestel moet word om hierdie indringerspesies te beheer. Meer spesifiek, beheer moet gedurende die winter en in stedelike gebiede geskied, waar en wanneer hierdie spesie op sy volopste is en waar larwes teenwoordig is.

Native to Asia, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an invasive non-native ladybird in Europe and North America, where it was widely introduced as a biological control agent of aphids and coccids. There were three main objectives of this study: firstly, to investigate the spread and distribution of H. axyridis in Europe from the start of the invasion process; secondly, to study its ecology in Great Britain; and thirdly, to examine its effects on native ladybirds in Britain. In Europe, collaborations with a network of scientists allowed the collation of H. axyridis occurrence data from across the continent. In Great Britain, a web-based public survey (www.harlequin-survey.org) was used, leading to the receipt of over 10,000 verified records of H. axyridis between 2004 and 2008. National land cover data enabled the habitats used by H. axyridis to be identified across Great Britain. These datasets were analysed in order to study the spread and ecology of H. axyridis in Europe and Britain. Fieldwork over a three year period (2006 to 2008) was carried out to examine changes in ladybird species assemblages during the invasion phase of H. axyridis in eastern England. Laboratory work was conducted to detect intraguild predation by H. axyridis, through PCR analyses of gut contents of field-collected ladybirds. In Europe, H. axyridis has spread since 2001 at the rate of approximately 200km yr-1. It has become established in at least 23 European countries. The established range extends from Norway in the north to southern France in the south, and from Ukraine in the east to Great Britain in the west. In the first five years of establishment H. axyridis spread north through Britain at the rate of 105km yr-1 and west at the rate of 145km yr-1. Evidence of the production of two generations per year was found, giving H. axyridis an advantage over most native ladybirds in Britain. Although H. axyridis was very common in urban habitats, it increasingly used semi-natural habitats. In addition, whilst the species was most common on deciduous trees, it was increasingly found on herbaceous plants. Aceraceae, Rosaceae and Malvaceae were the dominant plant families used by H. axyridis, especially for breeding. In eastern England H. axyridis increased from 0.1% to 40% of total ladybirds in three years, whilst native aphidophagous ladybirds declined from 84% to 41% of total ladybirds in the same period. Three species in particular experienced declines: Adalia 2-punctata, Coccinella 7-punctata and Propylea 14-punctata. Harmonia axyridis was the most abundant species by the end of the study. Detection of intraguild predation by one coccinellid on another, in the field in Europe, was shown for the first time using PCR techniques: A. 2-punctata DNA was detected in the gut of one of 112 field-collected H. axyridis. Harmonia axyridis has spread very quickly since 2001 and has become one of the most widely distributed coccinellids in Europe. Populations of native aphidophagous ladybirds were negatively affected by the arrival of H. axyridis, partly through intraguild predation.

Memoria para optar al Título Profesional de Médico Veterinario / Harmonia axyridis o chinita arlequín es un coccinélido invasor que ha provocado numerosos efectos negativos en otras regiones del mundo, tales como pérdidas económicas para la agricultura, perjuicios ecológicos, daños estéticos a nivel domiciliario y reacciones alérgicas o mordeduras en humanos. En Chile se han registrado hallazgos sucesivos de la especie desde 2008 y se ha detectado un aumento progresivo de estos a través del tiempo. La presente memoria de título consistió en la creación, mantención y difusión de un sitio en Internet donde se informó a la población general sobre el fenómeno H. axyridis en Chile y se recopiló información sobre su distribución y otras características de la especie mediante una encuesta electrónica. Entre Julio de 2011 y Julio de 2012 se recibieron 508 reportes de hallazgos de H. axyridis distribuidos entre las regiones de Coquimbo y del Libertador General Bernardo O’Higgins. El número de comunas confirmadas con la presencia de la especie se incrementó 2,6 veces entre los años 2010 y 2012. No obstante, reportes posteriores al periodo de estudio de esta memoria indican que esta especie ha aumentado su distribución hacia el sur, llegando hasta la Región de Los Ríos. En total, el portal web recibió 10.122 visitas, las que según el análisis realizado mediante Google Analytics ® fueron de buena calidad. El sitio en Internet resultó ser un medio eficiente para difundir el fenómeno de H. axyridis en Chile y mejorar el conocimiento sobre su dinámica de distribución en el país, la que se ha expandido considerablemente en los últimos años. Sin embargo, esta estrategia de difusión debe ser complementada con otros métodos, de manera de mejorar el acceso a la información sobre este fenómeno en la población / Financiamiento: Proyecto Fondecyt 1100159

The success of an invasive alien species is often attributed to the ecological advantage gained from natural enemy release. Numerous factors have been suggested as contributing to the success of Harmonia axyridis as an invasive alien species, including enemy release. This thesis studied the interactions of several parasites with H. axyridis, investigating parasite transmission, growth and virulence as well as host immune responses, thereby shedding light on the potential role of enemy release in the invasion biology of this ladybird. Benefits gained by invasive alien species from enemy release diminish if parasites of native species shift hosts to exploit the novel invader. The fungal ectoparasite Hesperomyces virescens began infecting H. axyridis shortly after it invaded the UK, probably as a result of a host shift from Adalia bipunctata. This study found a rapid increase in H. virescens prevalence over three years in London H. axyridis populations. Laboratory study showed H. virescens transmission and growth to be more efficient on A. bipunctata than the novel host. In addition, reciprocal interspecific transfers of H. virescens strains isolated from A. bipunctata and H. axyridis revealed that the infection characteristics of the fungi from these two hosts differed, suggesting strains may have diverged after the initial shift from A. bipunctata to better exploit the host from which they were derived. Laboulbenialian fungi were previously thought to have negligible impacts on host fitness. A detailed examination of H. virescens infecting H. axyridis found distinct virulence, with infections resulting in a 50% reduction in host lifespan. In addition, chronic H. virescens infection in males caused acceleration in the age-associated decline in body condition while for females, infection triggered fecundity senescence and a faster age-related decline in fertility. While their role in accelerating ageing is debated, the results presented here provide evidence that infectious diseases can drive the ageing process in this insect species. In nature, multiple parasites affecting a single host are common. The effect of co-infection on the virulence caused by two fungal infections was characterised using H. axyridis and A. bipunctata hosts. The ability of two ladybird species to defend against an acute fungal parasite, while infected with the relatively avirulent H. virescens was found to be sex-specific. While for females, the presence of co-infection did not alter the virulence seen in singly infected females, a higher mortality rate existed for co-infected males compared with those infected singly. Previously, H. virescens has been considered to be avirulent, however, this study provides evidence that this chronic fungal parasite may be important when considering the mortality associated with co-infections in the field. The invasive success of H. axyridis has, in part, been attributed to a more vigorous immune ability compared with other competitor species. Previously, field studies have shown that the prevalence of the parasitoid wasp Dinocampus coccinellae in H. axyridis is considerably lower than in the UK primary host of this wasp, Coccinella septempunctata. The extent to which the prevalence asymmetry in the field is driven by differences in host encapsulation response was tested by first comparing the encapsulation ability of C. septempunctata and H. axyridis directed against an artificial implant. Following this, the encapsulation response of D. coccinellae parasitized individuals was assessed and compared between the two host species. While encapsulation ability did not differ between the host species, and D. coccinellae did not affect the immune response of H. axyridis, wasp parasitism did alter the encapsulation ability of C. septempunctata, although it was inconsistent across sexes and populations. Overall, this thesis furthers our understanding of the fungal parasite H. virescens and its association with the notorious invader H. axyridis. The research presented here also demonstrates the use of H. axyridis as a model system in areas other than invasion ecology and furthermore, contributes to understanding the role of infectious disease in the rate of ageing. Finally, sex-specific effects were found across the chapters of this thesis, demonstrating the use of H. axyridis in the study of sex-specific effects of infections.