No description available.

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a polyphagous, invasive, and highly significant pest of mid-Atlantic fruit orchards. Its capacity to invade orchards season-long is believed to be facilitated by the availability of wild host plants near orchards and the high dispersal capacity of adults and nymphs. Interactions between H. halys and its hosts were investigated via laboratory and field experiments. Rearing H. halys nymphs in the laboratory on several of its known wild and tree fruit hosts used alone and in combination showed that peach was much more suitable for nymphal development and survival than was apple, tree of heaven, or catalpa and that nymphal performance was enhanced on mixed host diets. Nymphs reared on different host plant diets yielded adults that differed in protein, sugar or lipid content, offering new insights into plant diet effects on H. halys nutrition. The majority of tree species identified from unmanaged woodlands next to apple orchards in Virginia and West Virginia were known hosts of H. halys. Passive trunk traps were developed to capture H. halys nymphs walking up and down tree trunks and used to measure their temporal patterns of movement onto and off of wild and tree fruit hosts at the orchard-woodland interface via weekly assessments during two consecutive seasons. More upward- than downward-walking nymphs were captured, which may be partially explained by the positively phototactic and negatively geotactic behavior of H. halys nymphs demonstrated in laboratory studies. Most nymphs captured while walking up and down trunks were second instars, although the data also reflected temporal changes in the distribution of instars and temporal variation in the numbers of nymphs captured. A field study to characterize injuries to apple and peach fruit at harvest from feeding by young or older nymphs early or late in the season revealed that feeding by young nymphs early in the season resulted in least injury to both crops. In combination, these studies greatly improve our understanding of the biology and ecology of H. halys in eastern fruit orchards and provide relevant data that will inform the development of ecologically-based management programs for it. / Ph. D.

<p>Ispitivan je hemijski sastav etarskih ulja i vodenih ekstrakata tri vrste samoniklih biljaka familije Lamiaceae:&nbsp;<em> Satureja montana&nbsp;</em>L.,&nbsp; <em>Salvia sclarea&nbsp;</em>L.,<em>&nbsp; Clinopodium menthifolium</em>&nbsp; Host. Pored toga, ispitano je delovanje vodenih ekstrakata na korovske i ratarsko-povrtarske biljke, insekte i mikroorganizme, kao i etarskih ulja na insekte.<br />Potvrđeno je da ispitivane vrste imaju insekticidno dejstvoi da nemaju uticaj na rast korisnih mikroorganizama prisutnih u zemlji&scaron;tu.</p> / <p>The chemical composition of essential oils and aqueous extracts of three types of self-seeding plants of the Lamiaceae family are examined. Apart from the composition, the effects of aqueous extracts on weed and vegetable plants, insects and&nbsp; microorganisms are examined. The effects of essential oils on insects are also examined. Insecticidal activity of examined plants is confirmed. It is also confirmed that the examined plants have no effect on the growth of useful microorganisms present in the soil.</p>

Frugivorous insects, specialised herbivores that consume fruit and seeds, are considered detrimental to host plant fitness. Their direct link to genetic fitness via consumption of plant reproductive tissue, and their negative socioeconomic association with agriculture exacerbates their harmful status. However, empirical testing of insect frugivore effects on host plants, and ecological research on the contribution of insect frugivores to multitrophic frugivory systems, is lacking. In the current study, direct effects of a non-mutualistic, insect frugivore/host plant system were tested and results showed variable effects. Beneficial, detrimental, but predominantly neutral effects on germination and seed production were observed between the Queensland fruit fly (Bactrocera tryoni) and tomato and capsicum plants. Significant effects on seed production were unexpected because infestation occurs after seed set. It was also found that eggplant, although a recorded host of B. tryoni, is inconsistent in its ability to sustain B. tryoni larvae through to its final instar. These results confirmed a simplification and presumption associated with insect frugivore (specifically fruit fly)/host plant interactions. Larval movement, infestation-induced fruit decay, pulp removal and germination were then investigated. For all hosts (tomato, apple and paw paw), treatments infested by B. tryoni decayed significantly quicker and to a greater extent than uninfested treatments, with obvious but variable changes to the texture and appearance. The movement of B. tryoni larvae, pattern of infestation-induced decay and pulp removal was unique and host dependent for all hosts. Only seeds from infested tomato were shown to germinate during the experiment. This indicated that host fruit characteristics are responsible, in part, for variable direct effects on host plant fitness by insect frugivores. Variable direct effects between insect frugivores and host plants, combined with the more rapid decay of infested fruits is likely to have implications for seed dispersal and seed predation by a third trophic level. The characteristics of fruit that are changed by infestation by an insect frugivore were then tested for their effect on a vertebrate frugivore, to illustrate the importance of recognising multitrophic interactions and indirect effects in frugivory. Specifically, seed predating rodents were incorporated into the study and their response to infested and uninfested fruits were recorded, as well as their reaction to the changes in fruit caused by insect frugivores (i.e. texture, smell, larvae presence and sound). Apple and pear infested with B. tryoni larvae were found to attract rodents, while infested tomato and paw paw had a neutral effect on the native rats. This differed from the predominant finding in the literature, which was a deterrent effect on avian seed dispersers. Vertebrate response to fruit infested with insect frugivores therefore, is variable. Assessing the indirect effect of insect frugivores on host plant fitness by attracting or deterring another trophic level requires knowledge of the direct effect between the introduced trophic level and the host plant. For example, the attraction of a seed predator may be as detrimental to host plant fitness as the deterrence of a seed disperser. This illustrates the complexity associated with assessing insect frugivore effects on host plant fitness. Results also indicated that differences in pulp texture, caused by infestation, have a significant effect on rodent preference for infested or uninfested treatments. Pulp texture is likely to effect rodent foraging efficiency, whereas the presence of B. tryoni larvae was observed to be inconsequential to rodent response to fruits. For rodents, and indeed any trophic level motivated by foraging efficiency, this finding raises the issue that for long lived fruiting plants, outside factors such as food abundance and competition for food, may cause a variable response to fruits infested by insect frugivores. From these investigations it has become apparent that insect frugivores are not consistently harmful to host plant fitness, as suggested by their negative stigma, but are likely to contribute variable effects, directly and indirectly, on multiple components of plant fitness and multitrophic frugivory systems.

No description available.

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.

Les herbivores consomment les tissus végétaux et affectent la survie et la croissance des végétaux. Les ennemis naturels des herbivores peuvent réguler leurs populations et indirectement diminuer les dommages sur la végétation. Les relations entre plantes, herbivores et prédateurs sont liées aux caractéristiques intrinsèques des espèces végétales mais aussi influencées par la communauté végétale environnante. L'hypothèse de résistance par association stipule qu'une communauté végétale diversifiée entraîne une diminution des dégâts sur une plante cible par dilution, répulsion des herbivores et/ou favorisation des ennemis naturels. Inversement, les herbivores peuvent se concentrer sur la plante-cible dans une communauté végétale diversifiée (susceptibilité par association). L'objectif de cette thèse est d'évaluer 1) l'influence de la composition de la communauté végétale sur les herbivores et leurs dommages sur une plante-cible, 2) l'impact de la régulation des herbivores par les prédateurs et 3) les interactions entre herbivores, communauté végétale et prédateurs, et les conséquences pour les intensités d'herbivorie sur la plante-cible. Nous nous sommes focalisés sur les dommages causés par les insectes herbivores sur des plantules d'essences forestières feuillues (Betula pendula, Quercus robur et Q. ilex). La variété importante de communautés végétales, au niveau inter (essences dominantes) et intraparcellaire (présence, structure et composition), nous a permis de tester les effets du voisinage végétal sur les insectes herbivores et leurs dommages sur les plantules cibles. Les oiseaux insectivores sont les principaux prédateurs d'insectes et nous avons cherché à estimer les effets de leur exclusion sur les insectes et les conséquences pour les plantules, et ceci le long des gradients de composition du voisinage végétal. Enfin, le degré de spécialisation (spécialiste/généraliste) et le mode de vie (exo/endophyte) ont été caractérisés car ils conditionnent les réponses des insectes herbivores à la végétation voisine ainsi que la prédation avienne. Le voisinage végétal des plantules-cibles modifie la charge en herbivores et les dommages engendrés. Ces réponses sont liées à la spécialisation de l'insecte herbivore : la colonisation des plantules par les espèces spécialistes (mineuses de feuilles) est négativement affectée par la structure de la végétation locale (présence, recouvrement arbustif). Les dommages d'insectes généralistes augmentent avec la richesse spécifique des peuplements et dans les parcelles dominées par des espèces conspécifiques. Les abondances des insectes externes et leurs dommages sont régulés par les oiseaux insectivores mais cet effet indirect dépend de l'espèce de plantule-cible et de la composition de la communauté végétale. Les effets de cascade trophique sont les plus intenses dans les parcelles de pin maritime où les plantules constituent une ressource nouvelle pour les niveaux trophiques supérieurs. Plus localement, le voisinage végétal modifie la sensibilité des arthropodes à la prédation: les oiseaux insectivores bénéficient aux plantules lorsque les proies sont plus accessibles (végétation environnante supprimée).Pour conclure, une des principales richesses de ces résultats vient de la mise en évidence d'interactions très fortes existant entre les effets des oiseaux insectivores et la végétation environnante. Les effets indirects des prédateurs et directs de la végétation environnante sont très liés au degré de spécialisation des insectes phytophages et à leur mode de vie. / Herbivory is thought to depend on intrinsic plant resistance traits and negatively affect survival and growth of plants. Predators can depress herbivore populations and thereby indirectly limit the consumption of primary producers. The surrounding vegetation is also expected to modify the interactions between a focal plant, its herbivores and their natural enemies. The surrounding vegetation may disrupt the colonisation and the consumption of a focal plant by insect herbivores, providing associational resistance. Increasing diversity of neighbouring vegetation can decrease resource availability or enhance herbivores control by predators. By contrast, associational susceptibility may occur with higher levels of herbivory in a focal plant in more diverse plant communities. We tested 1) the effect of the neighbouring vegetation on the levels of herbivory on seedlings, 2) the indirect impact of predators on herbivores and subsequent herbivory, and 3) the interactions between surrounding vegetation, focal plants, herbivores and predators. We examined the damage caused by insect herbivores on three native broadleaved species. We then compared the importance of taxonomic similarity between seedlings and canopy tree species and the structure and composition of surrounding vegetation at both large- and small-scales. Birds are vertebrate predators likely to limit damage to plants and facilitate plant growth by consuming herbivorous insects. We estimated their effects by excluding them from focal plants, and compared their interactive effects with vegetation diversity or removal. The effects of surrounding vegetation and avian predation were also disentangled on concealed- vs. external-feeding guilds (predation sensitivity) and specialist- vs. generalist-insects.Surrounding vegetation of focal seedlings influences the abundance of insect herbivores and damage. Specialist insects (leaf miners) are affected by the understorey vegetation close to oak seedlings, decreasing with its presence or structural diversity. The damage caused by generalist insects depend on the large-scale composition of plant communities, and increase with tree species richness and cover or on conspecific forest habitats. Exclusion of insectivorous birds affects insect herbivory in a species-specific manner, and also greatly varies with forest habitats and presence of vegetation around focal plants. The indirect effect of bird predation on leaf damage is observed on seedlings beneath noncongeneric canopy trees. The removal of local surrounding vegetation affects the top-down effect of insectivorous birds on insect herbivores, according to their sensitivity to predation and the accessibility of preys. To conclude, our studies provide experimental evidences of interactive effects between bird predation and neighbouring vegetation on insect herbivores and levels of herbivory. These indirect effects are strongly related to the specialisation of herbivores and to their sensitivity to bird predation.

No description available.

Wir befinden uns inmitten einer globalen Biodiversitätskrise mit steigender Aussterberate, die die natürliche Hintergrundrate bereits jetzt um das Tausendfache überschreitet. In terrestri-schen Lebensräumen geht vom Landnutzungswandel die größte Gefahr für die Biodiversität aus. Besonders die ursprünglich hohe Vielfalt im mitteleuropäischen Grünland ist seit der In-dustrialisierung durch Nutzungsintensivierung und -aufgabe stark zurück gegangen. Traditionell genutztes, beweidetes Grünland ist in Mitteleuropa selten geworden. Dennoch deuten einige aktuelle Studien auf seine große Bedeutung für den Erhalt der Biodiversität in der Agrarland-schaft hin. Allerdings fehlen umfassende, systematische Untersuchungen für viele traditionelle Grünlandsysteme. Um diese Wissenslücke zu verringern, untersuchte ich in meiner Dissertation die Relevanz voralpiner, traditionell bewirtschafteter Allmendweiden als Refugium für bedrohte Zielarten (Baumpieper [Anthus trivialis], Blaukernauge [Minois dryas]) sowie für arten- und individuenreiche Zoozönosen (Heuschrecken [Orthoptera]) der mitteleuropäischen Agrarlandschaft. Gepaarte Vergleiche von Allmendweiden und angrenzenden Flächen mit identischen Standortbedingun-gen (Referenzflächen) ermöglichten den Vergleich der Arten bzw. -gruppe anhand von Umwelt-parametern in den Vegetationstypen Grünland auf Mineralboden und offenen Mooren. Der Un-tersuchungsraum in Südbayern stellt den Verbreitungsschwerpunkt für Allmendweiden und intakte bis naturnahe Moorökosysteme in Deutschland dar. Meine Analysen zeigen, dass sich der Landnutzungswandel drastisch auf die Referenzflä-chen, die früher überwiegend Teil der Allmendweiden waren, auswirkte: Im Vergleich zu den Weiden weisen sie (i) homogene Strukturen auf Landschafts- und Habitatebene, (ii) geringe Anteile nährstoffarmer Habitate und (iii) eine geringe Besiedlung von Vögeln und Insekten auf. Somit sind sie weitgehend ungeeignet für den Erhalt der Biodiversität. Die einzige Ausnahme innerhalb der Referenzflächen bilden traditionell genutzte Heu- und Streuwiesen. In den Allmendweiden sorgt die traditionelle Beweidung (0.5–2.0 Großvieheinheiten/ha von Mai–Oktober) für eine hohe strukturelle Vielfalt mit nährstoffarmen Habitaten und fließende Übergänge zwischen Wald und Offenland. So können saisonal bzw. innerhalb des Lebenszyklus wechselnde Ansprüche vieler typischer Agrarlandschaftsarten im eng verzahnten Mosaik wert-voller Habitate erfüllt werden. Der Erhalt der Allmendweiden ist für das Überleben von Agrar-landschaftsarten im Untersuchungsgebiet essenziell. Eine Ausdehnung der Allmendweiden-Nutzung auf angrenzende Flächen ist unbedingt zu empfehlen.

To refine our knowledge and to adequately test hypotheses concerning theoretical and applied aspects of invasion biology, successful and unsuccessful invaders should be compared. This study investigated insect establishment patterns by comparing the climatic preferences and biological attributes of two groups of polyphagous insect species that are constantly intercepted at New Zealand's border. One group of species is established in New Zealand (n = 15), the other group comprised species that are not established (n = 21). In the present study the two groups were considered to represent successful and unsuccessful invaders. To provide background for interpretation of results of the comparative analysis, global areas that are climatically analogous to sites in New Zealand were identified by an eco-climatic assessment model, CLIMEX, to determine possible sources of insect pest invasion. It was found that south east Australia is one of the regions that are climatically very similar to New Zealand. Furthermore, New Zealand shares 90% of its insect pest species with that region. South east Australia has close trade and tourism links with New Zealand and because of its proximity a new incursion in that analogous climate should alert biosecurity authorities in New Zealand. Other regions in western Europe and the east coast of the United States are also climatically similar and share a high proportion of pest species with New Zealand. Principal component analysis was used to investigate patterns in insect global distributions of the two groups of species in relation to climate. Climate variables were reduced to temperature and moisture based principal components defining four climate regions, that were identified in the present study as, warm/dry, warm/wet, cool/dry and cool/moist. Most of the insect species established in New Zealand had a wide distribution in all four climate regions defined by the principal components and their global distributions overlapped into the cool/moist, temperate climate where all the New Zealand sites belong. The insect species that have not established in New Zealand had narrow distributions within the warm/wet, tropical climates. Discriminant analysis was then used to identify which climate variables best discriminate between species presence/absence at a site in relation to climate. The discriminant analysis classified the presence and absence of most insect species significantly better than chance. Late spring and early summer temperatures correctly classified a high proportion of sites where many insect species were present. Soil moisture and winter rainfall were less effective discriminating the presence of the insect species studied here. Biological attributes were compared between the two groups of species. It was found that the species established in New Zealand had a significantly wider host plant range than species that have not established. The lower developmental threshold temperature was on average, 4°C lower for established species compared with non-established species. These data suggest that species that establish well in New Zealand have a wide host range and can tolerate lower temperatures compared with those that have not established. No firm conclusions could be drawn about the importance of propagule pressure, body size, fecundity or phylogeny for successful establishment because data availability constrained sample sizes and the data were highly variable. The predictive capacity of a new tool that has potential for eco-climatic assessment, the artificial neural network (ANN), was compared with other well used models. Using climate variables as predictors, artificial neural network predictions were compared with binary logistic regression and CLIMEX. Using bootstrapping, artificial neural networks predicted insect presence and absence significantly better than the binary logistic regression model. When model prediction success was assessed by the kappa statistic there were also significant differences in prediction performance between the two groups of study insects. For established species, the models were able to provide predictions that were in moderate agreement with the observed data. For non-established species, model predictions were on average only slightly better than chance. The predictions of CLIMEX and artificial neural networks when given novel data, were difficult to compare because both models have different theoretical bases and different climate databases. However, it is clear that both models have potential to give insights into invasive species distributions. Finally the results of the studies in this thesis were drawn together to provide a framework for a prototype pest risk assessment decision support system. Future research is needed to refine the analyses and models that are the components of this system.