Submitted by (edna.saturno@ufrpe.br) on 2016-11-24T14:16:11Z No. of bitstreams: 1 Felipe Colares Batista.pdf: 401499 bytes, checksum: 66c8054daa99b1513bf4eeb2b13516c0 (MD5) / Made available in DSpace on 2016-11-24T14:16:11Z (GMT). No. of bitstreams: 1 Felipe Colares Batista.pdf: 401499 bytes, checksum: 66c8054daa99b1513bf4eeb2b13516c0 (MD5) Previous issue date: 2011-02-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of brassicas throughout the world. Prospective results toward DBM manage in cabbage have been achieved using host plant resistance and biological control. However, host plant characteristics conferring resistance against herbivores might also affect their natural enemies. Thus, this work evaluated the influence of red and green (Chato-de-quintal) cabbages on the biology and oviposition preference of P. xylostella and the interaction with the larval-pupal parasitoid Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae). Based on life history parameters for DBM, green cabbage was less favorable compared to red cabbage by delaying larval and pupal stages, and reducing female fecundity. However, under free choice tests for oviposition, DBM females preferred to lay eggs on green than red cabbage. Tests in olfactometer, isolating the color effect of the host plant, however, resulted in similar moth attraction between green and red cabbage. Foraging of O. sokolowskii females was similar on both cabbage cultivars infested with DBM larvae under large cage free choice tests. Furthermore, similar number of parasitized larvae, total number of emerged parasitoids, and adult female parasitoid longevity were found for DBM larvae reared on both cabbage cultivars under laboratory conditions. However, the period from parasitism to adult parasitoid emergence was one day shorter and a higher number of parasitoids produced per parasitized larva was achieved when parasitizing larvae reared on green cabbage. In conclusion, the results indicate a positive association of host plant resistance with the parasitism of O. sokolowskii to manage DBM and suggest that the cabbage color plays an important role on host preference for oviposition by the pest. / A traça-das-crucíferas, Plutella xylostella (L.) (Lepidoptera: Plutellidae), é considerada a principal praga das brássicas em todo o mundo. Resultados promissores para o manejo desta praga têm sido alcançados com o uso de cultivares resistentes e controle biológico. Entretanto, sabe-se que características conferindo resistência às plantas não afetam somente os herbívoros, mas também os inimigos naturais associados a eles. Assim, esse trabalho avaliou a influência das cultivares de repolho Roxo e Verde (Chato-de-quintal) na biologia e na preferência para oviposição de P. xylostella, e o efeito no desempenho do parasitóide Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae). Com base nos parâmetros da tabela de vida, a cultivar Chato-de-quintal mostrou-se menos favorável para o desenvolvimento de P. xylostella, por ocasionar maior duração das fases de larva e pupa e redução na fecundidade das fêmeas em relação a cultivar Roxo. Entretanto, a cultivar Chato-de-quintal foi a mais preferida por P. xylostella para oviposição em comparação a cultivar Roxo. Testes de livre escolha das mariposas em olfatômetro, isolando a coloração do hospedeiro, resultaram em semelhança de escolha entre repolho Roxo e Verde. O forrageamento de fêmeas de O. sokolowskii em plantas de ambas as cultivares infestadas com larvas da traça-das-crucíferas em testes de livre escolha foi similar. Também, não houve diferença no número de larvas parasitadas, número total de descendentes produzidos e longevidade média das fêmeas adultas do parasitóide em condições de laboratório. Entretanto, foi observado maior número de descendentes por larva parasitada e, aproximadamente, um dia a menos na duração do período ovo-adulto em larvas da traça-das-crucíferas criadas em repolho Chato-de-quintal. Assim, estes resultados mostram uma associação positiva entre a resistência de cultivares de repolho e o controle biológico com O. sokolowskii visando o manejo da traça-das-crucíferas e sugerem que a cor da cultivar possui papel importante na escolha do hospedeiro para oviposição pela praga.

Lors des interactions tri-trophiques impliquant une plante hôte, ses insectes phytophages et leurs ennemis naturels (parasitoïdes, prédateurs...), chaque niveau trophique est fortement dépendant des autres. La plante hôte peut influencer directement les traits d’histoire de vie des insectes phytophages et indirectement les ennemis naturels se développant aux dépens de ces insectes phytophages. Lorsque qu’un ennemi naturel comme un parasitoïde attaque l’insecte phytophage, son système immunitaire constitue sa dernière chance de survie. Une grande variation dans l’immunité des insectes est généralement observée dans les populations naturelles, suggérant que différentes pressions de sélection peuvent moduler et conduire à une adaptation des paramètres immunitaires. Ma thèse vise à déterminer les influences conjointes de la plante hôte et des parasitoïdes, sur les paramètres immunitaires des chenilles de deux ravageurs de la vigne, Cochylis (Eupoecilia ambiguella) et Eudémis (Lobesia botrana).Durant ces 3 années, nous avons mis en évidence une forte influence du cépage de vigne sur les effecteurs immunitaires des chenilles de vers de la grappe. De plus, le cépage de vigne semble être à l'origine d'un compromis entre les voies immunitaires constitutives et induites. La présence variable de bactéries à la surface des baies ne semble pas être à l'origine de ce compromis. Outre le cépage de vigne, nous avons démontré une forte action des parasitoïdes sur l'immunité des vers de la grappe. A l'échelle nationale, les populations d’Eudémis les plus immunocompétentes sont également les populations les plus parasitées. Cette corrélation positive entre le succès de parasitisme et les paramètres immunitaires des chenilles ne semble pas expliquée par une réponse plastique du système immunitaire des chenilles à la présence des parasitoïdes, mais plutôt par une sélection locale du système immunitaire, en réponse à la pression de parasitisme subie par ces chenilles sur plusieurs années. Les différentes études réalisées dans le cadre de ma thèse confirment la complexité des relations tri-trophiques entre la plante hôte, l’insecte phytophage et ses ennemis naturels. L’intégration du système immunitaire de l’insecte phytophage semble primordiale dans la compréhension des interactions unissant ces trois protagonistes. / In tritrophic interactions involving phytophagous insects, host plants and natural enemies, trophic levels are highly dependent on each other. Host plant may strongly affect directly phytophagous insect and indirectly natural enemies growing on these phytophagous insects. When a natural enemy attacks a phytophagous insect, the host immune system constitutes the last chance for the host to survive to an infection. A great variation of insect immune system is generally found in populations for susceptibility to pathogens, suggesting that variable selection pressures may have shaped and driven adaptation of immune traits. This project aims to determine the influence of both host plant and natural enemies on the larval immune system of grapevine moth pests, Lobesia botrana and Eupoecilia ambiguella.During these three years, we have demonstrated a strong influence of grape variety on immune effectors of grapevine moth larvae. In addition, the grape variety modulates a trade-off between the constitutive and induced immune pathways. The variable presence of microbes on the surface of grape berries does not explain the trade-off in immune function. Beyond the grape variety effect, we also demonstrated a strong influence of parasitoids on the immune parameters of the grapevine moth larvae. In France, the most immunocompetent populations of grapevine moth are also the most parasitized. This positive correlation between successful parasitism and larval immune parameters seems not explained by a plastic response of the larval immune system to parasitoids presence, but rather by a local selection of larval immune system in response to parasitism pressure suffered by larvae for several years.The different experiments realized in my thesis confirm the complexity of the tri-trophic interactions between host plant, phytophagous insects and natural enemies. The integration of phytophagous insect immune system seems essential in understanding the interactions linking these three protagonists.

MSc (Zoology) / Department of Zoology / Mopane worm (Gonimbrasia belina Westwood) is an indigenous edible insect that periodically has population eruptions in Mopane tree (Colosphermum mopane) dominated vegetation. This insect is a valuable source of food and has become an economic commodity for commercial harvesters. Despite its importance, little is known of the population dynamics of mopane worm. Considerable attention has been paid to the nutritional and social dimensions of mopane worm consumption. However, anecdotal evidence suggests there is a decline in the spatial extent of their distribution due to unsustainable utilization, land transformation, and commercialization. This is paralleled with a decrease of harvest yield, thereby affecting local communities, commercial harvesting operations, and market product availability. Partial domestication of this species may be a way of ensuring sustainable and reliable utilization of this edible insect because it improves natural survival rates. Here I explore mopane worm ecology by mainly focusing on understanding spatial structuring and the role of domestication in the development of sustainable harvest techniques of Mopane worms (G. belina). Spatial structuring of mopane worms was investigated at both a fine (10m x 10m) and medium-scale (1 km2) at sites with and without commercial harvesting. Mopane worm populations were experimentally treated through transplant experiments and manipulating access of predators to 1st – 3rd instar larvae. The role of tree characteristics (height, canopy volume and number of stems) on both spatial and experimental treatments were explored using generalized linear mixed models. Moran’s Eigenvector Maps (MEM’s) were used to represent spatial structures at various scales and the role of soil. Relative to control, seeding of worms was successful in establishing new populations in unoccupied areas while transplant and application of sleeve nets had no significant effect on larval survival. Populations at sites where no harvesting takes place were spatially structured, while this was not true where commercial harvesting takes place. Canopy volume also accounted for egg packets distribution although the relationship was ambiguous. The density of larvae increased with an increase in sodium concentration in soil. Seeding of the population provides a viable option for the sustainable utilization of mopane worms and educating people on how to domesticate mopane worms. This study also highlights that populations of mopane worms are not only clumped in time but also in space and at various spatial scales. / NRF

No description available.

Sammanfattning Nattfjärilar är en utsatt grupp när det kommer till nattbelysning, eftersom nattbelysning påverkar processer som födosök och reproduktion samt ökar deras mortalitet genom stress och ökad risk för predation. Mörka och belysta lokaler i Halmstads urbana grönområden undersöktes för att studera nattbelysningens påverkan på nattfjärilars individantal och artdiversitet. I studien visade vi på signifikanta skillnader hos både nattfjärilars individantal samt artdiversitet mellan de mörka och belysta lokalerna, där tillhörande analyser visade signifikant färre antal individer och likaså negativ trend för artdiversiteten. Analyserna visade att minskad artdiversitet och individantal i belysta lokaler inte var signifikant korrelerat med belysningsstyrkan i lokalerna. Dock finns det indikationer på att belysningsstyrkan eventuellt haft en negativ påverkan på individantalet och artdiversiteten av nattfjärilar i denna studie. Det fanns en belyst lokal som utmärkte sig med ovanligt hög diversitet där artdiversiteten var det tredje högsta uppmätta värdet i hela studien. Detta kan eventuellt bero på förekomsten av blommande buskage vilket återfanns i direkt anslutning till inventeringsområdet. Vi föreslår därför att blommande växter och buskage kan implementeras som åtgärd för att förebygga nattbelysningens påverkan på nattfjärilspopulationer. Kompletterande samt uppföljande studier av ämnet kring vilka växter som passar specifikt för nattfjärilar behövs, då det i dagsläget är ett ämne som i Sverige behöver utvecklas innan implementering av passande växter kan bli en lämplig åtgärd. / Abstract Moths are a vulnerable group when exposed to night lighting, it affects their basic drives such as foraging and reproduction and increases their mortality through stress and increased risk of predation. Dark and illuminated localities in Halmstads’ urban green areas were inventoried to study the impact of night illumination on the number of individuals and species diversity of moths. In the study, significant differences were found in the individual number of moths and species diversity between the dark and illuminated localities, which could not be significantly correlated to illuminance present in the localities. However, there were indications that illuminance may still have negatively affected the number of individuals and species diversity of moths in this study. There was one illuminated locality that stood out from the rest where species diversity was the third highest measurement from the entire study, which can possibly be attributed to the presence of flowering shrubs. Therefore we suggest that flowering shrubbery can be implemented as a measure to prevent the impact of night illumination on moth populations and becomes the basis for supplementary and follow-up studies of the subject.

No description available.

No description available.