The rosy apple aphid Dysaphis plantaginea (Passerini) (Homoptera: Aphididae) is the most serious pest apple aphid in view of the scale of damages inflicted to the fruits by a small number of individuals. Although numerous natural enemies have been associated with D. plantaginea, they are unable to halt infestations soon enough in most commercial apple orchards obliging fruit growers to control it chemically to prevent severe economic losses. In order to reinforce the contribution of indigenous aphidophaga in regulating rosy apple aphids, the use of insectary plants selected to support two groups of specialist aphid antagonists, notably aphid parasitoids and aphidophagous monovoltine syrphids, was investigated. 1. A first step consisted in selecting appropriate plant species. The rowan tree Sorbus aucuparia L. and the common elder Sambucus nigra L. were selected for their ability to support substitute aphids for the rosy apple aphid parasitoid E. persicae Froggatt (Hymenoptera: Braconidae, Aphidiinae) and monovotine syrphids (Diptera: Syrphidae) respectively. 2. Next, trials were conducted to induce substitute aphid infestations on their host plants by introducing eggs of Dysaphis sorbi Kaltenbach on rowan and small colonies of Aphis sambuci L. on elder. The resulting aphid populations which developed on their respective host plants in spring proved to be exploited by the natural enemies expected, i.e. E. persicae and monovoltine syrphids of the genus Epistrophe. Besides, diapause mummies of E. persicae and diapausing last-instar Epistrophe larvac were recorded on rowan and in the elder litter respectively, indicating the successful settlement of the antagonists in the orchard environment. A complementary investigation devoted to syrphid adults indicated that females of all species recorded ovipositing on the eider shrubs, including Epistrophe spp. had consumed a large majority of apple pollen grains as a protein source required for egg maturation. 3. To comfort our choice in the two groups of aphidophaga considered, a study dedicated to their respective phenology versus the one of D. plantaginea showed that they could both potentially halt rosy apple aphid infestations by attacking the aphids while the latter still occupied the primary, fundatrix-induced rosette leaf colonies, i.e. a critical moment in rosy apple aphid control. 4. Finally, marking methods were tested to label E. persicae internally and the egg load of gravid syrphids. These trials were intended to pave the way towards future mark-release-recapture experiments aimed to evaluate the antagonists’ activity range and thus strategically position the insectary plants for optimal aphid biological control in the whole orchard. The first step of new approach in the biological control of D. plantaginea has been set with this study. Its originality lies in the induction of economically indifferent aphid infestations on selected plants introduced in the orchard to encourage well-targeted groups of specialist aphid antagonists. Further trials are still needed to validate the field efficacy of the insectary plant systems developed and evaluate their possible integration within the whole array of pest management tools in both organic and integrated apple production. / Doctorat en sciences, Spécialisation biologie animale / info:eu-repo/semantics/nonPublished

Plant-pollinator interaction assembly can be represented as so called pollination network. Using these networks, assembly of plant-pollinator communities and geographic patterns in pollination networks can be studied. During last years, a great progress in describing patterns in structure of plant-pollinator interaction webs and in describing their spatial variability was made. However, these results are mostly based on data from previous studies, which are not seamlessly comparable due to their nonuniformity. My thesis aims at the methodological concepts of study on pollination networks. Based on meta- analysis of previously published data and on data from four years detailed study of plant-pollination system from one locality, I show several methodological problems caused by dissimilarities in sam- pling method of current pollination-network data. These dissimilarities could be responsible for some observed patterns in the assembly of pollination networks. Thus, I propose a uniform method for observing pollination networks suitable for macroecolo- gical meta-analyses (pollination network samples). I tested this method in the field and I described 49 pollination networks from the central and eastern Europe by using such method. In these ne- tworks, no nonrandom structure character such as...

"Summary: The larvae of predatory hoverfly Episyrphus balteatus DeGeer (Diptera: Syrphidae), have limited dispersal ability to forage. The selection of the oviposition site by gravid females is crucial for the survival larvae. Therefore hoverfly females should optimise their foraging behaviour by choosing suitable oviposition sites. The aim of this PhD thesis was to understand how hoverfly females assess aphid patch quality during their egg-laying behaviour. The impact of several factors on the oviposition response of E. balteatus females including host plant, aphid species, aphid colony size, semiochemicals emitted from aphids or their association with host plants, presence of intra- or interspecific competitors and females age, was clearly demonstrated during this research. In the first part, we have shown that E. balteatus females select their oviposition site according to aphid-host plant and aphid species, which is also shown to be related to offspring performance (fitness). Aphid species Myzus persicae (Sulzer) infested-Solanum tuberosum L. was the most preferred aphid-plant combination as an oviposition site by syrphid females. The E. balteatus survival was enhanced in this system and females laid numerous eggs when larvae were reared with M. persicae as prey, especially when the host plant was potato. Broad bean plants Vicia faba infested with Megoura viciae (Buckton) or Acyrthosiphon pisum (Harris) were equally attractive for E. balteatus females. Aphis fabae (Scopoli) was the least preferred aphid. Higher hoverfly fitness was also observed when larvae were reared on M. viciae or A. pisum compared to those reared on A. fabae. Moreover, it was also demonstrated that foraging hoverfly females is guided by different infochemical cues emitted by aphid host plant, such as (E)-β-farnesene, enabling them to locate aphid infested plant and to select an adequate oviposition site. In the second part, the leaf disc system was found to be a practical and efficient method to assess the hoverfly reproductive behaviour under different laboratory conditions. Results also showed that there was a significant quadratic relationship between the released (E)-β-farnesene amounts and aphid colony size, which means that this molecule play important role in oviposition decision made by hoverfly females in response to aphid colony size. In the third part, we have highlighted that the E. balteatus females avoid aphid colonies in which conspecific larvae or their tracks were already present. Similar response was also shown by females to the presence of Harmonia axyridis (Pallas) larval tracks. This oviposition deterring stimulus was also shown to be mediated by odourant cues emitted from larval tracks extracts. It was also demonstrated that the foraging behaviour of hoverfly females was modified by the presence of parasitoids Aphidius ervi (Haliday) in aphid colonies. Females did not exhibit any preference for plants infested with unparasitised or parasitised aphids for 7 days, but they are reluctant to lay eggs in response to the presence of mummies or their exuvia on broad bean plants. Oviposition preference of predatory hoverfly females according to the developmental state of the parasitoid larvae in aphid prey was also found to be related with larval performance. Finally, the age of hoverfly females was found to be an important factor affecting their reproduction ability, suggesting that younger E. balteatus females (2 to 5 weeks old) could be have potential to play a role in biological control of aphids because of their higher reproductive efficiency. All experiments were performed in a laboratory environment and most results obtained are discussed in relation to the context of biological control efforts/Résumé : Les larves du syrphe aphidiphage Episyrphus balteatus (Diptère, Syrphidae) ont une capacité de déplacement limitée. Le choix du site doviposition des femelles est donc crucial pour la survie larvaire. Pour cela, les femelles de ce diptère devraient optimiser leurs choix de sites doviposition pour maximiser les chances de survie de leurs progénitures. Le but de cette thèse de doctorat était de comprendre comment les femelles dE. balteatus évaluent la qualité de patches de pucerons au cours de leur comportement de ponte. La réponse de ponte des femelles dE. balteatus observées à travers plusieurs facteurs a été réalisée, parmi lesquels: la plante hôte, lespèce de pucerons, la taille de la colonie de pucerons, les substances sémiochimiques émises par les pucerons et leurs associations avec leurs plantes hôtes, la présence de compétiteurs intra- ou interspécifiques et l'âge de la femelle. Dans la première partie de ce travail, les résultats obtenus ont permis de mettre en évidence que les femelles dE. balteatus sélectionnent le site de ponte en fonction de la plante hôte et lespèce de puceron, et ce comportement a été aussi montré comme étant lié avec la performance du prédateur (fitness). La combinaison puceron/plante M. persicae/Solanum tuberosum a été la plus préférée par les femelles dE. balteatus, et le fitness de ce prédateur était plus élevé en particulier lorsque les larves sont nourries avec M. persicae élevées sur une plante de pomme de terre. De même, les femelles dE. balteatus ont montré une même préférence pour les deux combinaisons M. viciae/V. faba et A. pisum /V. faba, et un fitness supérieur du prédateur adulte a été aussi observé lorsque les larves sont nourries avec les deux espèces de pucerons. De plus, nous avons aussi montré que les femelles dE. balteatus en recherche de site de ponte sont guidées par des substances volatiles, en particulier le E-(β)-farnésène, émises par les pucerons infestant leur plante hôte. Dans la deuxième partie, le système feuille-disque est démontré comme étant une méthode pratique et efficace pour évaluer le comportement de ponte dE. balteatus au laboratoire sous différentes conditions. Les résultats ont aussi démontré quil y a une relation quadratique entre lémission du E-(β)-farnésène et la taille de colonie de pucerons, ce qui permet de seffectuer que cette molécule a un rôle important dans le comportement de ponte des femelles dE. balteatus en réponse à la taille de la colonie de pucerons. Les résultats obtenus dans la troisième partie, nous ont permis de montrer que les femelles dE. balteatus réduisent leurs pontes dans une colonie de pucerons contenant préalablement des larves de leur propre espèce ou leurs traces. Une réponse similaire a été aussi montrée en présence des substrats préalablement visitées par les larves de coccinelle Harmonia axyridis. Ainsi, la réduction de la ponte des femelles dE. balteatus est provoquée par des substances volatiles émises par les substrats des larves de syrphe. Nous avons aussi démontré que la présence du parasitoïde Aphidius ervi dans une colonie de pucerons a un effet significatif sur le comportement de ponte des femelles dE. balteatus. Les femelles dE. balteatus ne distinguent pas les plants infestées par les pucerons parasités ou non parasités, cependant les femelles réduisent leur pontes en réponse à la présence des pucerons momifiés ou des exuvies de momies. De plus, un fitness supérieur du prédateur a été aussi observé lorsque les larves sont nourries avec lespèce de pucerons A. pisum parasités ou non parasités. Enfin dans la dernière partie, lâge de la femelle dE. balteatus influence significativement leur reproduction, ce qui permet de proposer que les jeunes femelles (2 à 5 semaines) peuvent être plus efficaces dans la lutte biologique contre les pucerons car elles ont une grande efficacité de reproduction. Toutes les expériences ont été effectuées au laboratoire et la plupart des résultats obtenus sont discutés en relation avec le contexte de la lutte biologique".

Four key aspects of the relationship between predatory hoverflies and the aphid pest Brevicoryne brassicae L. on broccoli were investigated in the Willamette Valley, Oregon USA: 1) the relationship between aphid density and hoverfly oviposition, 2) the larval voracity of key hoverfly species, 3) the preferences of hoverflies and broccoli pests for candidate insectary plant species, and 4) the role of insectary plantings in enhancing hoverfly oviposition in aphid colonies in broccoli fields. Hoverfly oviposition at two commercial broccoli field sites increased at aphid densities greater than 50 aphids per plant, but did not peak at the highest aphid densities. A logistic regression model, selected with Akaike's Information Criterion, of the odds of oviposition in relation to aphid density included effects for sampling date and aphid species (B. brassicae and Myzus persicae (Suizer)). The magnitude of the response was similar for B. brassicae and M persicae. The oviposition response was greater in the upper part of the plant canopy, and different on individual leaves from that seen on whole plants. The voracity and development rate of Scaeva pyrastri (L.) were greater than those of Eupeodes fumipennis (Thomson), and both exceeded Syrphus opinator Osten Saken and Sphaerophoria suiphuripes (Thomson). Both E. fumipennis and S. opinator reduced aphid populations to low levels on plants over two weeks, but E. fumipennis spent much of the time foraging away form the caged plants. Alyssum (Lobularia maritima (L.) Desv.), coriander (Coriandrum sativa L.), buckwheat (Fagropyrum esculentum Moench), and phacelia (Phacelia tanacetifolia Benth.) were screened for arthropod visitation frequency. The three pest species Pieris rapae (L.), Diabrotica undecimpunctata undecimpunctata Mannerheim, and Lygus hesperus Knight visited phacelia the most frequently, while the hoverfly species visited mostly coriander, which was possibly influenced by competition from other foragers. Hoverfly oviposition was increased near within-field blocks of alyssum in broccoli fields at the end of the season however, hoverflies arriving at the field had pollen in their guts and were oviparous four to five weeks before their eggs were detected in aphid colonies. This late oviposition may have occurred because threshold densities for oviposition were not reached until this stage. / Graduation date: 2006

This project examined multiple aspects of the reproductive biology of the wetland invasive species, purple loosestrife (<i>Lythrum salicaria</i> L.), in central Saskatchewan. An examination of insect taxa visiting the three floral morphs of <i>Tristylous</i> L. <i>salicaria</i>, as well as a ranking of the pollination efficiency of individual insect species, an apparent first for L salicaria, was undertaken. Surface features of the floral nectary of L. <i>salicaria</i>, as well as floral nectar secretion dynamics, were also investigated. This project also re-visited some of the previous work done on this invasive species, including various floral organ morphometrics in relation to heterostyly, and aspects of the tristylous breeding system including self-fertilization, and fertilization potential of both illegitimate pollination and legitimate pollination.<p>The trimorphic nature of the sexual floral organs of L. <i>salicaria</i> were well defined in Saskatchewan. Significant differences in length (long-, intermediate- and short-style lengths) exist between all three floral morphs. Lengths of the staminal filaments (long, intermediate, and short) were also significantly different. Also the floral nectary in L. <i>salicaria</i> is located in a depression formed at the interface of the hypanthium and the gynoecium. Several stomata are located at regular intervals along the nectary surface, and may constitute the escape route for floral nectar. No morphological differences in nectary structure were apparent among the three floral morphs.<p>Nectar secretion dynamics of L. <i>salicaria</i> were examined between the three floral morphs throughout two summer days in 2006. Peak average nectar volumes and nectar sugar quantities were detected at 3:00 pm, and, interestingly, no significant differences were detected between floral morphs, in accordance with nectary morphology. The estimated secretion rates for L. <i>salicaria</i> ranged from 61 83 µg of nectar sugar per flower per hour.<p>Hand-pollination experiments carried out over the summers of 2006 and 2007 at three field sites in and around Saskatoon have verified the strong self-incompatibility in the breeding system of this tristylous species. Intramorph pollination, using illegitimate pollen, did not result in fertilisation, whereas legitimate hand-pollination experiments yielded multiple pollen tubes at the style base, without exception.<p><i>Lythrum salicaria</i> in central Saskatchewan was visited by several bee taxa including honeybees (<i>Apis mellifera</i> L.), bumblebees (Bombus spp.), leafcutter bees (Megachile spp.), and sweat bees (Lasioglossum spp.). A single visit by <i>Anthophora furcata</i> (Panzer) was also recorded in 2007. Generally, bee visits led to high levels of pollination success as determined by fluorescence microscopy of pollen tubes following single insect visits to previously-unvisited flowers. However, most visits by hoverflies (Syrphidae) were non-pollinating. Visits by Pieris rapae (L.), yellowjacket wasps (Vespidae) and some non-syrphid flies (Diptera) also yielded no pollen tubes at the style base.<p>A study of the ultrastructure and development of the floral nectary of the purple loosestrife cultivar Morden Gleam (<i>Lythrum virgatum</i> L. x L. alatum Pursh.) showed that starch build up in pre-secretory nectary tissues declined throughout secretion, and is virtually absent in post-secretory nectary tissues. The lack of a direct vascular supply to the floral nectary suggests that the starch breakdown products likely make up most of the floral nectar carbohydrates. Surface features of the floral nectary in Morden Gleam closely resembled those of L. salicaria, located in the valley formed between the hypanthium and gynoecium. Nectary stomata, occasionally in pairs, likely serve as outlets for nectar in this cultivar.

This project examined multiple aspects of the reproductive biology of the wetland invasive species, purple loosestrife (<i>Lythrum salicaria</i> L.), in central Saskatchewan. An examination of insect taxa visiting the three floral morphs of <i>Tristylous</i> L. <i>salicaria</i>, as well as a ranking of the pollination efficiency of individual insect species, an apparent first for L salicaria, was undertaken. Surface features of the floral nectary of L. <i>salicaria</i>, as well as floral nectar secretion dynamics, were also investigated. This project also re-visited some of the previous work done on this invasive species, including various floral organ morphometrics in relation to heterostyly, and aspects of the tristylous breeding system including self-fertilization, and fertilization potential of both illegitimate pollination and legitimate pollination.<p>The trimorphic nature of the sexual floral organs of L. <i>salicaria</i> were well defined in Saskatchewan. Significant differences in length (long-, intermediate- and short-style lengths) exist between all three floral morphs. Lengths of the staminal filaments (long, intermediate, and short) were also significantly different. Also the floral nectary in L. <i>salicaria</i> is located in a depression formed at the interface of the hypanthium and the gynoecium. Several stomata are located at regular intervals along the nectary surface, and may constitute the escape route for floral nectar. No morphological differences in nectary structure were apparent among the three floral morphs.<p>Nectar secretion dynamics of L. <i>salicaria</i> were examined between the three floral morphs throughout two summer days in 2006. Peak average nectar volumes and nectar sugar quantities were detected at 3:00 pm, and, interestingly, no significant differences were detected between floral morphs, in accordance with nectary morphology. The estimated secretion rates for L. <i>salicaria</i> ranged from 61 83 µg of nectar sugar per flower per hour.<p>Hand-pollination experiments carried out over the summers of 2006 and 2007 at three field sites in and around Saskatoon have verified the strong self-incompatibility in the breeding system of this tristylous species. Intramorph pollination, using illegitimate pollen, did not result in fertilisation, whereas legitimate hand-pollination experiments yielded multiple pollen tubes at the style base, without exception.<p><i>Lythrum salicaria</i> in central Saskatchewan was visited by several bee taxa including honeybees (<i>Apis mellifera</i> L.), bumblebees (Bombus spp.), leafcutter bees (Megachile spp.), and sweat bees (Lasioglossum spp.). A single visit by <i>Anthophora furcata</i> (Panzer) was also recorded in 2007. Generally, bee visits led to high levels of pollination success as determined by fluorescence microscopy of pollen tubes following single insect visits to previously-unvisited flowers. However, most visits by hoverflies (Syrphidae) were non-pollinating. Visits by Pieris rapae (L.), yellowjacket wasps (Vespidae) and some non-syrphid flies (Diptera) also yielded no pollen tubes at the style base.<p>A study of the ultrastructure and development of the floral nectary of the purple loosestrife cultivar Morden Gleam (<i>Lythrum virgatum</i> L. x L. alatum Pursh.) showed that starch build up in pre-secretory nectary tissues declined throughout secretion, and is virtually absent in post-secretory nectary tissues. The lack of a direct vascular supply to the floral nectary suggests that the starch breakdown products likely make up most of the floral nectar carbohydrates. Surface features of the floral nectary in Morden Gleam closely resembled those of L. salicaria, located in the valley formed between the hypanthium and gynoecium. Nectary stomata, occasionally in pairs, likely serve as outlets for nectar in this cultivar.

[EN] Aphis spiraecola Patch. (Hemiptera: Aphididae) is a key pest of clementines. Biological control of A. spiraecola is still poorly known and efforts were based on the use and conservation of parasitoids but it did not success. With all this said, the aims of this thesis were: i) to disentangle the reasons behind the low parasitism of A. spiraecola; ii) to determine when and how predators can control A. spiraecola populations; and, finally, iii) to evaluate whether a ground cover of Poaceae plants can enhance the biological control of this aphid in clementines by improving the establishment of its predators. In the first objective we sampled four orchards and determine the parasitoid complex and parasitism (and hyper-) rates weekly. Binodoxys angelicae Haliday (Hymenoptera: Braconidae) was the unique primary parasitoid emerged from mummies of A. spiraecola. At least six hymenopteran hyperparasitoid species were identified attacking this primary parasitoid: Syrphophagus aphidivorus (Mayr) (Encyrtidae), Alloxysta sp. (Forster) (Figitidae), Asaphes sp. (Walker) (Pteromalidae), Pachyneuron aphidis (Bouché) (Pteromalidae), Dendrocerus sp. (Ratzeburg) (Megaspilidae) and Phaenoglyphis villosa (Hartig) (Figitidae). We developed a DNA-based approach to untangle the structure of the aphid-parasitoid food web in citrus. This methodology confirmed that all six species hyperparasitized B. angelicae And they dominated this food web and they were abundant from the beginning of the season. Thus, hyperparasitism probably explains the low impact of B. angelicae on A. spiraecola populations. For the second objective we sampled three clementine orchards to determine the effect of aphid predators on A. spiraecola colonies over a three-year period. Life parameters of A. spiraecola colonies varied among the orchards over the three years. The maximum number of aphids and the longevity of A. spiraecola colonies were negatively correlated with the time of first attack by predators. More importantly, the percentage of shoots occupied by A. spiraecola (damages) remained below or close to the intervention threshold when colonies were attacked prior to ~200 degree days (DD) since the beginning of the aphid colonization. These results suggest that: i) the presence of predators at the beginning of the season should be considered to develop new intervention thresholds and ii) biological control programs should promote the early presence of predators in clementine orchards. To promote the early presence of predators in clementine orchards, in the third objective we evaluated ground cover management. This ground cover management may provide alternative preys to natural enemies. The effect of a sown ground cover (based on Poaceae plants) on the biological control of A. spiraecola was evaluated in four orchards with ground cover management compared with four orchards with bare soil management. This sown Poaceae cover coexists with a complex of wild plants that might also affect biological control of A. spiraecola. Finally, we compared the presence of A. spiraecola and its natural enemies in these orchards. While Poaceae plants represented ~66% of the ground cover, the rest of the cover comprised mainly Malva sp. (13%), Oxalis sp. (5%) and Sonchus sp. (2%). Poaceae plants harbored aphids which appeared sooner in the system than citrus aphids. These aphids serve as alternative prey/hosts for natural enemies. By contrast, Malva sp. and Sonchus sp. harbored aphids with potential to become citrus pest. Although these wild plants may act as reservoirs for A. spiraecola as well as other aphid species that can disrupt the biocontrol services of natural enemies, overall, the sown cover was effective in terms of biological control of A. spiraecola in the citrus canopy. It promoted the early presence of predators in citrus canopies. These attacks resulted in satisfactory aphid control, because citrus orchards with ground cover never exceeded the aphid economic threshold. / [ES] Aphis spiraecola Patch. (Hemiptera: Aphididae) es una de las plagas claves en el cultivo de clementinos. Los esfuerzos realizados hasta la fecha se han centrado en el uso y conservación de parasitoides aunque se desconocen las causas de su baja eficacia. Por todo ello, los objetivos de esta tesis han sido i) desentrañar las razones por las que se dan bajos niveles de parasitismo de A. spiraecola ii) determinar cuándo y cómo los depredadores pueden controlar las poblaciones de A. spiraecola y finalmente iii) determinar si una cubierta de poáceas puede mejorar el control biológico de este pulgón en clementinos mediante la mejora en el establecimiento de sus depredadores. En el primer objetivo se muestrearon semanalmente cuatro parcelas y se identificó el complejo de parasitoides y las tasas de parasitismo (e hiperparasitismo). Los porcentajes de parasitismo fueron bajos (~menos del 5%) y Binodoxys angelicae Haliday (Hymenoptera: Braconidae) fue el único parasitoide primario emergido de las momias de A. spiraecola. Se identificaron al menos seis especies de hiperparasitoides atacando este parasitoide primario: Syrphophagus aphidivorus (Mayr) (Encyrtidae), Alloxysta sp. (Forster) (Figitidae), Asaphes sp. (Walker) (Pteromalidae), Pachyneuron aphidis (Bouché) (Pteromalidae), Dendrocerus sp. (Ratzeburg) (Megaspilidae) y Phaenoglyphis villosa (Hartig) (Figitidae). Se desarrolló un método basado en la detección de ADN con el cual se confirmó que todas las especies de hiperparasitoides hiperparasitan B. angelicae. Los hiperparasitoides dominaron esta red trófica y fueron abundantes desde el inicio de la estación. De este modo, el hiperparasitismo probablemente explica el bajo impacto que B. angelicae tiene sobre las poblaciones de A. spiraecola. Para el segundo objetivo se muestrearon tres campos de clementinos donde se determinó el efecto de los depredadores en las colonias de A. spiraecola. Los parámetros de vida de las colonias de A. spiraecola variaron entre los diferentes cultivos los tres años. El máximo número de pulgones y la longevidad de las colonias de A. spiraecola se correlacionaron negativamente con el momento del primer ataque del depredador a la colonia. Cabe destacar que el porcentaje de brotes ocupados por A. spiraecola permaneció por debajo o cerca del umbral de tratamiento cuando las colonias fueron atacadas antes de los 200 grados días (GD) desde el inicio de formación de la colonia. Estos resultados sugieren: i) la presencia de depredadores al inicio de la temporada de pulgón debes ser considerado para el desarrollo de nuevos umbrales de tratamiento y ii) los programas de control biológico deben promover el adelanto de la presencia de depredadores en los campos de clementinos. Para promover la presencia anticipada de depredadores en los campos de clementinos, como tercer objetivo se evaluó el manejo de cubiertas vegetales a base de poáceas. Con este manejo se persigue aportar presas alternativas para los enemigos naturales de A. spiraecola. Para ello, se compararon cuatro campos de cítricos con cubierta vegetal frente a cuatro con suelo desnudo. En los campos con cubierta sembrada apareció además de las poáceas sembradas, un complejo de plantas salvajes que podrían afectar también el control biológico de A. spiraecola. Las poáceas representaron un 66% de la cubierta vegetal. Las poáceas y Oxalis sp. albergaron respectivamente pulgones estenófagos de plantas poáceas y Macrosiphum euphorbiae Thomas (Hemiptera: Aphididae). Estas especies de pulgones aparecieron más pronto en el ecosistema que los pulgones de cítricos y sirvieron como presas/hospederos alternativos para los enemigos naturales. Al contrario, Malva sp. y Sonchus sp. albergaron especies de pulgón que podrían ser potenciales plagas de cítricos. El efecto total de la cubierta sembrada resultó positivo para el control de A. spiraecola. Por lo tanto, las parcelas de cítricos con cubierta vegetal tendieron a no / [CAT] Aphis spiraecola Patch. (Hemiptera: Aphididae) és una de les plagues clau en el cultiu de clementins. Els esforços realitzats fins ara s'han centrat en el us i conservació de parasitoids encara que es desconeix les causes de la seua baixa eficàcia. Tenint en compte estos antecedents, els objectius d'esta tesis foren: i) desentrampar les raons per les quals els parasitoids no són efectius; ii) determinar quan i com els depredadors poden controlar les poblacions d'A. spiraecola; i finalment iii) determinar si una coberta de poàcies pot millorar el control biològic d'este àfid en clementins mitjançant la millora en el establiment del seus depredadors. En el primer objectiu es van mostrejar setmanalment quatre parcel·les i s'identificà el complex de parasitoids i les taxes de parasitisme (i hiperparasitisme). Binodoxys angelicae Haliday (Hymenoptera: Braconidae) va ser l'únic parasitoid primari emergit de les mòmies d'A. spiraecola. Se van identificar al menys sis especies d' hiperparasitoids atacant este parasitoid primari: Syrphophagus aphidivorus (Mayr) (Encyrtidae), Alloxysta sp. (Forster) (Figitidae), Asaphes sp. (Walker) (Pteromalidae), Pachyneuron aphidis (Bouché) (Pteromalidae), Dendrocerus sp. (Ratzeburg) (Megaspilidae) i Phaenoglyphis villosa (Hartig) (Figitidae). Se desenvolupà un mètode basat en la detecció de DNA amb el que es confirmà que totes les especies d'hiperparasitoids hiperparasiten B. angelicae. Els hiperparasitoids dominaren aquesta xarxa tròfica i foren abundants a l'inici de l'estació. Per tant, l'hiperparasitisme podria explicar el baix impacte que B. angelicae té sobre les poblacions d'A. spiraecola. Per al segon objectiu es mostrejaren tres camps de clementins on es determinà l'efecte dels depredadors en les colònies d'A. spiraecola. Els paràmetres de vida de les colònies d'A. spiraecola variaren entre les tres parcel·les els tres anys. El màxim número d'àfids i la longevitat de les colònies d'A. spiraecola es correlacionaren negativament amb el moment del primer atac del depredador a la colònia. Caldria destacar que el percentatge de brots ocupats per A. spiraecola es mantingué per baix o prop del llindar de tractament quan les colònies foren atacades abans dels ~200 graus dia (GD) des de l'inici de formació de la colònia. Estos resultats sugereixen que: i) la presència de depredadors a l'inici de la estació de l'àfid podria ser considerada per al desenvolupament de nous llindars de tractament i ii) els programes de control biològic deurien promoure l'avançament de la presència de depredadors en els camps de clementins. Per promoure la l'avançament de la presència de depredadors en els camps de clementins, com tercer objectiu s'avaluà el maneig de cobertes vegetals basades en poàcies. Amb aquest maneig es persegueix aportar preses alternatives per als enemics naturals d'A. spiraecola. Se compararen quatre camps de clementins amb coberta vegetal front a quatre amb sol nu. En els camps amb coberta sembrada creix, junt a les Poáceas sembrades, un conjunt de plantes salvatges que podrien afectar també el control biològic d'A. spiraecola. S'investigà quines especies de plantes componien la coberta vegetal així com les especies d'àfids que les habitaven. Les poàcies representaren un 66% de la coberta vegetal, sent les plantes salvatges més abundants Malva sp. (13%), Oxalis sp. (5%) i Sonchus sp. (2%). Les poàcies hostejaren àfids estenòfags de poàcies. Estes espècies d'àfid aparegueren més prompte en l'ecosistema que aquells àfids associats a cítrics. Al contrari, Malva sp. i Sonchus sp. hostejaren especies d'àfids que podrien ser potencials plagues de cítrics. Este últim grup pot atenuar l'atac dels enemics naturals a les poblacions d'A. spiraecola que habiten les copes. Encara així, l'efecte total de la coberta sembrada a base de poàcies va resultar positiu per al control d'A. spiraecola. En conseqüència les parcel·les de cítrics am / Gómez Marco, F. (2015). Integrated Pest Management of Aphis spiraecola (Hemiptera: Aphididae) in clementines: enhancing its biological control [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/53732 / TESIS

<p>Osolike muve predstavljaju veliku familiju dvokrilaca koja u ekosistemu ima važnu ulogu opra&scaron;ivača biljaka i razlaganja organske materije. One su takođe dobar indikator naru&scaron;enosti ekosistema.&nbsp; Stoga je poznavanje njihove taksonomije i<br />ekologije od izuzetnog značaja. Jedan od tri najbrojnija roda osolikih muva&nbsp; predstavlja rod <em>Eumerus</em>, čija revizija na Balkanskom poluostrvu je predmet ove disertacije. Balkansko poluostrvo predstavlja izuzetan centar raznovrsnosti živog<br />sveta, između ostalih familija i za osolike muve. Za rod<em> Eumerus</em>, ono je pored Srednje Azije i Južne Afrike, jedan od centara specijacije.Predstavnici roda Eumerus su uglavnom sitnije crne muve, ponekad sa crvenim trbuhom. Karakteri&scaron;u ih bele popra&scaron;ene&nbsp; trake na tergitima, dva reda trnova na metafemuru&nbsp; apikoventralno i uvučena gornja spolja&scaron;nja poprečna vena na&nbsp; krilu, često sa dva kratka ispusta na ispupčenoj strani, okrenuta ka spolja. Cilj ove disertacije bio je utvrđivanje tačnog broja&nbsp; vrsta na Balkanskom poluostrvu i razre&scaron;avanje njihove&nbsp; taksonomije. Kao rezultat, utvrđeno je 44 prisutne vrste na&nbsp; istraživanom području koje su na osnovu morfolo&scaron;ke sličnosti&nbsp; podeljene u deset grupa. Tri utvrđene vrste ne pripadaju&nbsp; nijednoj grupi. U toku ovog istraživanja otkriveno je 12 vrsta novih za nauku:<em> E. aurofinis, E. banaticus</em>, in litt., <em>E. <span id="cke_bm_182S" style="display: none;">&nbsp;</span><span id="cke_bm_185S" style="display: none;">&nbsp;</span>bicornis</em><span id="cke_bm_185E" style="display: none;">&nbsp;</span><span id="cke_bm_182E" style="display: none;">&nbsp;</span>, in<span id="cke_bm_183S" style="display: none;">&nbsp;</span> litt., <span id="cke_bm_186S" style="display: none;">&nbsp;</span><em>E. crassus</em><span id="cke_bm_186E" style="display: none;">&nbsp;</span>, <span id="cke_bm_187S" style="display: none;">&nbsp;</span><em>E. kar<span id="cke_bm_183E" style="display: none;">&nbsp;</span>yates</em><span id="cke_bm_187E" style="display: none;">&nbsp;</span>, in li<span id="cke_bm_188S" style="display: none;">&nbsp;</span>tt., <em>E. montanum</em>, <em>E.&nbsp;<span id="cke_bm_188E" style="display: none;">&nbsp;</span> montenegr<span id="cke_bm_184E" style="display: none;">&nbsp;</span>inus, E. <span id="cke_bm_189E" style="display: none;">&nbsp;</span>nigrorufus</em>, in litt.<em>, E. phaeacus</em>, in litt., <span id="cke_bm_202S" style="display: none;">&nbsp;</span><em>E. rubrum, E. tenuitarsis</em><span id="cke_bm_202E" style="display: none;">&nbsp;</span>, in litt. i<em> E. torsicus.</em> Geometrijska morfometrija krila je d<span id="cke_bm_203E" style="display: none;">&nbsp;</span>ala odlične rezultate za razdvajanje&nbsp; kriptičnih taksona u okviru roda <em>Eumerus,</em> primenjena na&nbsp; vrstama grupe minotaurus. Utvrđeni su najznačajniji morfolo&scaron;ki karakteri za razlikovanje vrsta. Jedan od veoma&nbsp; značajnih rezultata ove disertacije je ključ za identifikaciju&nbsp; vrsta roda<em> Eumerus</em> na Balkanskom poluostrvu. Na osnovu morfolo&scaron;ke analize donet je zaključak da tricolor grupa&nbsp; predstavlja morfolo&scaron;ki zasebnu taksonomsku celinu sa jasnim&nbsp; indicijama da je njen rang iznad grupe vrsta. Centre diverziteta&nbsp; vrsta roda <em>Eumerus</em> na istraživanom području predstavljaju, prema bogastvu vrsta grčka ostrva Lezbos i Krf i jugoistočni&nbsp; deo Crne Gore uključujući Skadarsko jezero. Na osnovu &Scaron;enonovog indeksa diverziteta, područja sa najvećim indeksom su sledeća: ostrva Hios, Lezbos i Krf, zatim Peloponez i veći&nbsp; deo Crne Gore.</p> / <p>Hoverflies represents a large family of Diptera that have in the ecosystem an important role of pollinators and decomposer of organic matter. They are also a good indicator of ecosystem disruption. Therefore, knowledge of their taxonomy and ecology is of great importance. One of the three most numerous genus of hoverflies is the genus<em> Eumerus</em>, whose revision in the Balkan Peninsula is the subject of this dissertation. The Balkan Peninsula is an exceptional center of biodiversity, for&nbsp; hoverflies among other families. For the genus&nbsp;<em> Eumerus</em>, Balkan Peninsula is next to&nbsp; Central Asia and South Africa, one of the centers of speciation. Representatives of the genus&nbsp; Eumerus&nbsp; are mostly small black flies, sometimes with red abdomen. They are characterized by white stripes on the tergites, two rows of spines on the metafemur apico-ventrally and recessed upper outer transverse wing vein. The aim of&nbsp; this dissertation was to determine the number of species on the Balkan&nbsp; Peninsula and to resolve their taxonomy. As a result, 44 species were identified in the investigated area, which are divided into ten groups based on the&nbsp; morphological similarity. The three species identified do not belong to any group. In the course of this study, 12 new species were discovered for the science:&nbsp; <em>E. aurofinis, E. banaticus,</em> in litt.,&nbsp; <em>E. bicornis</em>, in litt.,&nbsp;<em> E. crassus,&nbsp; E. karyates</em>, in litt.,&nbsp; <em>E. montanum,&nbsp; E. montenegrinus,&nbsp; E. nigrorufus,</em> in litt.,&nbsp; <em>E. phaeacus</em>, in litt.,&nbsp; <em>E. rubrum,</em> <em>E. tenuitarsis</em>, in litt. and&nbsp; <em>E. torsicus</em>. The geometric&nbsp; morphometry of the wings gave excellent results for the separation of cryptic taxons within the genus&nbsp; Eumerus, applied to the species of the&nbsp; minotaurus&nbsp; group. The most important morphological characters for differentiating species were determined. One of the very important results of this dissertation is the identification key for species of the genus&nbsp; <em>Eumerus&nbsp;</em> on the Balkan Peninsula. Based on morphological analysis, conclusion is that the tricolor&nbsp; group represents a morphologically separate taxonomic entity with clear indications that its rank is above a group of species. The centers of diversity of the genus&nbsp;<em> Eumerus</em>&nbsp; in the research area represent, according to the species richness of the Greek island of Lesbos and Corfu and the southeastern&nbsp; part of Montenegro including the Skadar Lake. Based on the Shannon&rsquo;s Diversity Index, the areas with the highest index are as follows: the islands of Hios, Lesbos and Corfu, then Peloponnese and most of Montenegro.</p>

In present thesis, I treat the topic of impacts of plant-animal interactions, namely herbivory and pollination, on plant life cycle and lifetime fitness. First, I identify the components of the impact of plant-animal interactions: i) interaction frequency; ii) per-interaction effect; iii) sensitivity of the plant's life cycle to the changes in vital rate impacted by the animals. Furthermore, I also classify other causes changing the outcome of a plant-animal interaction into two categories: i) plant's traits; ii) plant's environment. A review of extant literature on the topic revealed that especially the role of plant's environment in changing the outcome of plant-animal interactions is largely understudied and I attempt to reduce this gap in knowledge in the five detailed studies encompassed in this thesis. The detailed studies focus on a model system of Central European wet grasslands and especially on three species typical to it: Succisa pratensis, Achillea millefolium and A. ptarmica. The first two studies examine the effects of environment on frequency of plant- animal interactions. The next two studies are more integrative, one focusing on the impacts of different herbivore groups on the complete life cycle and the other on interaction of herbivory and pollination on plant lifetime fitness....

Plants often occur aggregated into clusters and this spatial pattern is supposed to affect pollinator behaviour and pollen dispersal. Such pollinator reaction may influence reproductive success of zoogamous plant species both in terms of number of available mates and their genetic diversity (nearby growing plant individuals are also often closely related, especially in clonal plants). In the present thesis, I investigated the influence of plant spatial aggregation on pollinator behaviour and how this translates into pollen transfer. For that purpose, I carried three experiments. In the Experiment 1, I used potted plants placed into arrays and aggregated into four patches in order to track the pollen dispersal by means of a UV-dye pollen analogue. I manipulated distances between plants within clusters (dense × loose) and between clusters (near × far). I conducted this experiment for three plant species differing in their pollinator spectra. In the Experiment 2, I observed pollinator foraging sequences (sequences of visited plant individuals) under the same experimental design as for the first experiment, but I carried out this experiment for five plant species. In addition in one study species, Dianthus carthusianorum, I conducted the Experiment 3 to get better insight into pollination effectiveness...