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1
Powell, Bradford E. "Interactions between the ants Linepithema humile, Tapinoma sessile and aphid mutualists." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-11012008-082656/.
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Invasive species have major impacts on the ecosystems they invade. Among the most disruptive groups of invasive species are ants. Invasive ants have caused losses in biodiversity among a wide range of taxa, including birds, mammals, lizards, but especially towards ground nesting arthropods such as native ants. Why native ants are so susceptible to invasion and how invasive ants are able to sustain massive population growth remain unclear. It has been suggested that invasive ants utilize carbohydrate resources from hemipteran exudates to fuel aggressive foraging and colony expansion. Perhaps invasive ants are simply more proficient at usurping these resources, maintaining higher hemipteran populations, etc. Our work uses a model invasive, the Argentine ant, , Linepithema humile, and a native ant Tapinoma sessile to quantify hemipteran tending ability and competition. Through a series of laboratory and field experiments we were able to quantify 1) carbohydrate sequestering performance, 2) the effect either ant species had on hemipteran population growth rates in a predator-free space, 3) the defense ability of either ant against hemipteran predators and parasitoids, and 4) the proportion of invasive ants required to displace a native colony from a hemipteran resource. Neither ant demonstrated a better ability to sequester liquid resources; however recruitment strategies were much different. Hemipteran populations in the presence of L. humile grew larger in a predator free environment and populations exposed to predators were better defended by L. humile than T. sessile. L. humile was able to displace T. sessile from a nest site without having a majority of worker ants. Aggression of either ant species was significantly reduced without hemipterans present. Understanding factors that drive invasive species can give us insight into native areas that may be susceptible for invasion, how potential mutualist populations might respond and possibly provide us with an avenue for secondary control measures given the economic and ecological importance of invasive species.
2
Kaufmann, Bernard. "Organisation socio-génétique de la fourmi d'Argentine Linepithema humile (Hymenoptera, Formicidae)." Toulouse 3, 1996. http://www.theses.fr/1996TOU30053.
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Dans cette these nous etudions les repercussions des caracteristiques ecologiques de la fourmi d'argentine, linepithema humile, sur son organisation socio-genetique (= osg). Nous definissons l'osg comme l'ensemble des facteurs qui conduisent aux liens de parente entre les individus d'une societe. Nous montrons, en analysant les resultats de la litterature, que l'osg est tres variable chez les formicidae. Ainsi, la parente entre individus d'un meme nid varie autant entre especes d'un meme genre, qu'entre populations d'une meme espece. Les populations se regroupent autour de deux valeurs de parente, l'une proche de 0,6, l'autre de 0. La consanguinite a l'interieur des populations est en general proche de 0. Il n'y a pas de correlation entre parente a l'interieur des societes et consanguinite dans la population. La frequence d'insemination des reines de formicidae est toujours inferieure a 2. Enfin, la differentiation des populations de formicidae est habituellement faible, quelle que soit l'echelle de l'echantillonnage. La fourmi d'argentine fait partie du groupe d'especes appelees vagabondes pour leur propension au mouvement et a la migration. Cette strategie s'accompagne d'une perte des frontieres entre nids differents et une mise en commun des ressources: l'unicolonialite. Par l'emploi de marqueurs allozymatiques, nous determinons ici l'osg de la fourmi d'argentine. Dans toutes les populations etudiees, la parente entre ouvrieres ou entre reines, est proche de 0. La consanguinite est tres faible egalement, sauf chez une population, pour laquelle il reste difficile de trouver une explication valable. La frequence d'insemination des reines examinees est proche de 1. Aucun males diploide n'a ete decouvert. La differentiation genetique entre populations est faible, sauf si l'on inclut dans l'analyse une population sud-americaine. La fourmi d'argentine est donc une espece a l'osg peu variable, adaptee une strategie qui repose sur une capacite a deplacer des populations et a en fonder de nouvelles
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Buczkowski, Grzegorz Andrzej. "Nestmate recognition and population genetic structure in the Argentine ant, Linepithema humile." NCSU, 2003. http://www.lib.ncsu.edu/theses/available/etd-08182003-091509/.
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The Argentine ant, Linepithema humile, is a widespread invasive species characterized by reduced intraspecific aggression within its introduced range. To gain an understanding of mechanisms underlying nestmate recognition in the Argentine ant, I studied its population genetic structure and the role of genetic vs. environmental cues on aggression. I combine behavioral, genetic, and analytical data to explore the role of exogenous cues and recent changes in the population genetic structure on nestmate recognition in this ant. In Chapter II, I examined population genetic structure and intercolony aggression in two portions of the Argentine ant introduced range: California and the southeastern U.S. I describe factors that may have contributed to the present-day differences in genetic diversity between these two regions and I also suggest ecological factors that may have contributed to regional differences in current distribution patterns of the Argentine ant. In Chapter III, I examined the context-dependency of nestmate discrimination in the Argentine ant and the effect of action thresholds on exogenous cue recognition. I also tested hypotheses that explain a change in action thresholds as well as factors that affect action thresholds. I examined changes in intraspecific aggression in various discrimination contexts. I tested the importance of isolated nest referents on aggression thresholds. In Chapter IV, I examined the impact of different diet-derived hydrocarbons on intraspecific aggression in the Argentine ant and the potential of shared, diet-derived hydrocarbons to produce colony uniformity where intercolony genetic and/or environmental differences exist. In Chapter V, I examined the role of environmental cues on nestmate recognition in two populations of the Argentine ant. I tested the hypothesis that there is geographical variation in the response of Argentine ants to nestmate recognition cues derived from prey. In Appendix I, I use the Argentine ant to compare four aggression bioassays for consistency between replicates, similarity between assays, and ability to predict whole colony interactions. I tested four different aggression assays with two or three scoring methods per assay. I also determined whether isolated aggressive encounters could predict whole colony interactions.
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Luruli, Ndivhuwo Mord. "Distribution and impact of the Argentine ant, Linepithema humile (Mayr), in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19640.
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Thesis (MScAgric)--University of Stellenbosch, 2007.<br>ENGLISH ABSTRACT: Invasion by the notorious tramp species, the Argentine ant (Linepithema humile Mayr) (Hymenoptera: Formicidae) has caused major concern around the globe, owing to its displacement of native ant species and other invertebrates where it invades. This species was first recorded in South Africa in 1901 in Stellenbosch, Western Cape Province (WCP), and has now become a significant pest in most urban and agricultural areas in the country. The Argentine ant has received relatively little attention in South Africa compared to other countries (e.g. California, North America). To date the extent of invasion by this species countrywide, as well as its impact on the local ant fauna inside protected areas, has not been quantified. In this study, the impact of the Argentine ant on native ant fauna inside three protected areas in the WCP (Helderberg Nature Reserve (HNR), Jonkershoek Nature Reserve (JNR) and Kogelberg Biosphere Reserve KBR)) was assessed. Species richness and diversity were compared between invaded and uninvaded bait stations at each protected area. Several native ant species were found to be displaced by the Argentine ant from all three protected areas, although three species: Meranoplus peringueyi, Monomorium sp. 8 and Tetramorium quadrispinosum, were found coexisting with it. Invaded bait stations had significantly lower ant species richness and species turnover than uninvaded bait stations. Uninvaded bait stations contained eight times more native ant species than invaded bait stations. Thus, the invasion of protected areas by the Argentine ant has severe negative consequences for the species richness and assemblage structure of native ants, leading to the biotic homogenization of these local ant communities. The distribution range of the Argentine ant inside the three protected areas (HNR, JNR, KBR), as well as microhabitat preferences that may facilitate the spread of this species inside these reserves, was also assessed. Helderberg Nature Reserve was the most invaded protected area, with the highest level of the Argentine ant occupancy, while JNR and KBR had lower occupancy levels. At all the three protected areas, this species was dominant at lower altitudinal areas, and also showed a clear preference for areas with high anthropogenic disturbances, i.e. around buildings and on lawns (picnic areas). In this study, there was no evidence that moisture availability facilitates the distribution and spread of the Argentine ant inside these reserves. Finally, a combination of published literature records, museum records and records collected in the current study was used to quantify the current distributional extent of the Argentine ant throughout urban South Africa. This is the first study quantifying the distribution and extent of invasion by the Argentine ant throughout the country. The Argentine ant was found in six of the nine South African Provinces, and its extent of occurrence includes approximately half of the country’s land surface area. Discontinuities in the distribution of the Argentine ant across the country revealed that range expansion of the Argentine ant in South Africa is occurring predominantly via human-mediated jump dispersal, rather than naturally via nest diffusion. This study clearly demonstrated that the Argentine ant is well established across South Africa as well as inside protected areas. The Argentine ant invasion was influenced by the presence of human modified landscapes (i.e. buildings) both at low and high altitude, and this was associated with higher rates of native ant species displacement at these areas. Therefore, limiting the development of recreational areas, such as buildings and picnic sites inside protected areas will result in the lower rate of spread of the Argentine ant. This will in turn lower the extent of displacement of native ant species.<br>AFRIKAANSE OPSOMMING: Indringing deur die Argentynse mier (Linepithema humile Mayr) (Hymenoptera: Formicidae) is ‘n bron van groot kommer regoor die wêreld, as gevolg van sy vermoë om inheemse mier spesies en ander ongewerweldes te verplaas. Hierdie spesie is vir die eerste keer aangeteken in Suid-Afrika in 1901, in Stellenbosch, Weskaap Provinsie (WCP), en het ‘n belangrike pes geword in die meeste stedelike en landelike gebiede in die land. Die Argentynse mier het betreklik min aandag gekry in Suid-Afrika, in vergelyking met ander lande (bv. California, Noord Amerika). Tans is die omvang van die landwye indringing van hierdie spesie, sowel as sy impak op die plaaslike mier fauna binne beskermde areas, nog nie bepaal nie. In hierdie studie word die impak van die Argentynse mier op die inheemse mier fauna binne drie beskermde areas in die WCP (Helderberg Natuurreservaat (HNR), Jonkershoek Natuurreservaat (JNR) en Kogelberg Biosfeerreservaat (KBR)) bepaal. Spesierykheid en diversiteit was vergelyk tussen ingedringde en oningedringde lokaas stasies in elke beskermde area. Verskeie inheemse mier spesies was deur die Argentynse mier verplaas in al drie beskermde areas, alhoewel drie spesies: Meranoplus peringueyi, Monomorium sp. 8 en Tetramorium quadrispinosum het saam met dit voorgekom. Ingedringde lokaas stasies het beduidend laer mier spesierykheid en spesies omset gehad as oningedringde lokaas stasies. Dus, die indringing van beskermde areas deur die Argentynse mier het ernstige negatiewe gevolge vir die spesierykheid en gemeenskap struktuur van inheemse miere, wat lei tot die biotiese verarming van hierdie plaaslike mier gemeenskappe. Die verspreidingsarea van die Argentynse mier binne die drie beskermde areas (HNR, JNR, KBR), en die mikrohabitat voorkeure wat die verspreiding van die spesie binne hierdie reservate kan vergemaklik, was ook vasgestel. Helderberg Natuurreservaat was die mees ingedringde beskermde area, met die hoogste vlak van Argentynse mier besetting, terwyl JNR en KBR laer besettingsvlakke gehad het. By al drie die beskermde areas was hierdie spesie dominant by laer hoogtes bo seevlak en het ‘n duidelike voorkeur getoon vir areas met hoë menslike versteuring d.i. rondom geboue en op grasperke (piekniek areas). In hierdie studie was daar geen bewyse dat vog beskikbaarheid die voorkoms en verspreiding van die Argentynse mier binne die reservate vergemaklik nie. Ten slotte, ‘n kombinasie van gepubliseerde literatuur verslae, museum dokumente en verslae wat in hierdie studie versamel is, was gebruik om die huidige verspreidingsomvang van die Argentynse mier te bepaal. Dit is die eerste studie wat die verspreiding en omvang van indringing in stedelike Suid Afrika van die Argentynse mier dwarsdeur die land bepaal. Die Argentynse mier is gevind in ses van die nege provinsies in Suid-Afrika, en die omvang van sy voorkoms sluit bykans die helfte van die land se landoppervlaksarea in. Onderbrekings in die verspreiding van die Argentynse mier deur die land het blootgelê dat die uitbreiding van die voorkomsgebied van die Argentynse mier in Suid-Afrika hoofsaaklik gebeur deur mens bemiddelde verspreiding eerder as natuurlike nesverspreiding. Hierdie studie het duidelik gedemonstreer dat die Argentynse mier goed gevestig is regoor Suid-Afrika sowel as in beskermde areas. Die Argentynse mier indringing was beïnvloed deur mensgewysigde landskappe (d.i. geboue) by lae en hoë hoogtes bo seevlak, en dit was verwant aan hoër vlakke van verplasing van inheemse mier species in hierdie areas. Dus, die beperking van ontwikkeling van rekreasie areas, soos geboue en piekniekareas, in beskermde gebiede sal lei tot laer vlakke van verspreiding van die Argentynse mier. Dit sal, op sy beurt, die omvang van verplasing van die inheemse mier spesies verminder.
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Ellis, Brittany Russ. "Managing Linepithema humile (Mayr), the Argentine ant, in South Carolina state park campgrounds." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1249065615/.
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Haw, James. "Effects of Argentine Ant (Linepithema Humile) on Arthropod Fauna in New Zealand Native Forest." Thesis, University of Auckland, 2006. http://hdl.handle.net/2292/625.
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Although Argentine ant(Linepithema humile), a highly invasive ant species, has been in New Zealand for at least l4 years, little is known about their ecology and potential for invasion. Increasing spread and establishment of populations throughout New Zealand is disturbing because of the devastating impacts documented on native invertebrate biodiversity overseas. The primary aim of this study was to determine the impacts of Argentine ants on arthropods in native forest habitats in west Auckland. Pitfall traps at invaded and uninvaded sites were used to quantify ant and non-ant arthropod faunas. Argentine ants did not adversely affect native host ant communities. Moreover, two ant species appeared to be resistant to invasion. Argentine ant invasion reduced the abundance of a few orders of invertebrates while several taxa were more abundant in the presence of Argentine ants. Distribution and foraging activity of Argentine ant populations were monitored in this study from 2000-2003. Also, rate of spread was investigated to evaluate whether native forest habitats would be at risk from invasion. Measurements of foraging ant trails on monitored tree trunks revealed seasonal distribution patterns involving high activity in summer/autumn and low activity in winter/early spring. Argentine ants were found to be established primarily along the edge of the forest and did not invade into the interior of the forest during the study period. An Argentine ant poisoning operation on Tiritiri Matangi Island in January 2001 provided the opportunity to document the results of the eradication trial. In addition, pitfall traps placed at two treated sites and one untreated site were used to compare pre-poison and post-poison effects on ant and non-ant invertebrate communities. Fipronil baiting at 0.01% effectively reduced Argentine ants at the study sites and very few ants were observed in both tree count and pitfall trap recordings two months after poisoning. The invasion of Argentine ants on Tiritiri Matangi Island decimated native host ants and no recovery was detected throughout the study. Several groups of invertebrates appeared to benefit from the removal of Argentine ants while a few showed no detectable changes. Conservation implications resulting from the findings of this study are discussed Also, potential future research involving Argentine ants are outlined.
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Fleig, Eduardo Diehl. "Estrutura social e taxa de crescimento das colônias de Linepithema humile Mayr (Hymenoptera: Formicidae)." Universidade de São Paulo, 2005. http://teses.usp.br/teses/disponiveis/11/11146/tde-20181127-162146/.
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O presente trabalho teve por objetivos avaliar o comportamento agonístico entre operárias de ninhos distintos de Linepithema humile Mayr, determinar o período de produção de sexuados e a proporção sexual, estimar a variação do tamanho da população intranidal no verão e no inverno, e investigar a biologia reprodutiva, em especial, a taxa de crescimento de pequenas colônias. Para tal, coletaram-se em campo 26 ninhos de L. humile no município de Limeira, SP, transferidos para laboratório e mantidos em condições experimentais. Avaliaram-se os níveis de agressividade em pares de operárias de ninhos distintos (n = 11) em três tempos ao longo de um ano após as coletas. Avaliou-se a população intranidal através da contagem de todos os indivíduos de dez ninhos (cinco por estação). Estimou-se a taxa de crescimento para diferentes tamanhos de propágulos (10, 50, 100, 150, 200 e 500 operárias). A população de Limeira apresentou estrutura social unicolonial, com ausência de agressividade entre operárias de ninhos distintos. As operárias de L. humile foram altamente agressivas em relação a operárias de uma população proveniente do município de São Paulo. A produção de sexuados ocorreu durante o verão, com investimento sexual a favor das fêmeas (2,4 : 1). No inverno, encontrou-se um número de operárias cerca da metade do registrado no verão. O tamanho inicial dos propágulos influenciou positivamente a produção de prole total e, negativamente, a produção de prole |per capita. A taxa de crescimento per capita não variou entre os tamanhos de propágulos iniciais testados. A redução do número de operárias poderia ser decorrente de condições abióticas durante o inverno, especialmente da baixa umidade e precipitação. Algumas hipóteses são levantadas para explicar a proporção sexual a favor das fêmeas encontrada. Finalmente, destaca-se que este é o primeiro registro da existência da estrutura social unicolonial em uma população de L. humile no Brasil.<br>The aim of this work was to evaluate the aggressive behavior between workers from different nests of Linepithema humile Mayr, to determine the period of sexual production and the sexual ratio, to estimate the variation in the intranest population between summer and winter, and to investigate the reproductive biology, particularly the role of propagule sizes in the growth rates. For such, 26 nests collected in the Limeira population of the Argentine ant were set up in experimental nests in laboratory. The levels of aggressive behavior between workers from different nests (n = 11) were evaluated for three different periods during one year after nests collections. The intranest population was assessed by direct counting of total individuals in ten nests (five for each season). The growth rate was evaluated for different propagule sizes (10,50, 100, 150, 200 and 500 workers). The Limeira population structured as unicolonial, with absence of aggressive behavior to non nestmates workers. Workers from the Limeira population were highly aggressive to workers from another population (São Paulo). The population was strongly female-biased (2,4 : 1), with sexuals being produced during summer time. Worker number had a two fold reduction during winter compared to summer nests. The initial propagule size positively influenced the total brood production and negatively affected the per capita brood production. Per capita growth rates remained the same for all initial propagule sizes tested. Worker density reduction could be related to abiotic conditions during winter, especially relative humidity and rain falI. Several hypotheses are raised to explain the female-biased sexual ratio found in the studied population. This is the first record of unicoloniality in a Brazilian population of the Argentine ant.
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Cariou-Etienne, Annie. "Attraction royale chez la fourmi d'Argentine Linepithema humile (Mayr)(= Iridomyrmex humilis) : variations biologiques et physiologiques." Toulouse 3, 1993. http://www.theses.fr/1993TOU30207.
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On sait que la reine des insectes sociaux joue un role capital dans la reproduction. Son role dans l'attraction des ouvrieres et la realisation de la cour royale est moins connu. En choisissant comme modele la fourmi d'argentine linepithema humile nous avons etudie les conditions qui regissent l'agregation des ouvrieres autour des reines. Nous avons demontre que les ouvrieres sont beaucoup plus attirees par leurs propres reines que par des reines d'origine geographique eloignee. Des differences genetiques et/ou environnementales entre les complexes pheromonaux emis dans les deux situations pourraient etre a la base de cette discrimination. Des experiences menees sur des cadavres royaux et sur des reines vivantes ont permis de cerner les facteurs responsables de l'attraction royale. Elles mettent en evidence le role de substances chimiques, a court rayon d'action, emises par la reine et percues par les ouvrieres grace a une chimioreception de contact. L'hypothese que des hydrocarbures cuticulaires puissent etre a l'origine de cette attraction a ete envisagee. Nous avons donc essaye d'eliminer les substances impliquees dans cette attraction en lavant les cadavres de reines au moyen de solvants organiques. Ceci a entraine une forte reduction du pouvoir attractif royal, confirmant l'existence d'une substance chimique cuticulaire. D'autres experiences ont mis en evidence un lien etroit entre l'attraction royale, l'age de la reine et son statut physiologique. L'attractivite faible a l'emergence de la reine vierge, le reste encore au moment de la fecondation et de la perte des ailes. C'est au declenchement de l'ovogenese, c'est-a-dire au demarrage de l'activite de ponte que cette attractivite augmente de facon significative
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Blight, Olivier. "Ampleur et conséquences écologiques de l’envahissement du littoral corse par la fourmi d’Argentine (Linepithema humile, Mayr)." Aix-Marseille 3, 2010. http://www.theses.fr/2010AIX30049.
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Originaire d’Amérique du Sud, la fourmi d’Argentine, Linepithema humile, a su profiter de l’essor du commerce international à la fin du 19ème siècle pour envahir de très nombreuses régions du globe soumises à un climat méditerranéen ou subtropical. Elle est aujourd’hui présente en forte densité dans le sud-ouest de l’Europe, le long des côtes portugaises, espagnoles, françaises et italiennes. Malgré sa présence en Corse depuis près de 50 ans, très peu de données sont disponibles sur les causes et conséquences de cette invasion. En ce sens, le présent travail a pour but d’apporter un éclairage précis sur trois axes majeurs de recherche sur la fourmi d’Argentine, à savoir sa structure sociale, sa distribution et dynamique d’expansion, et ses impacts sur la faune et la flore indigènes. Il s’inscrit dans le cadre des problématiques de gestion et de contrôle des espèces invasives. Notre étude confirme le caractère invasif de la fourmi d’Argentine le long du littoral corse. Grâce à des analyses comportementales, chimiques et génétiques nous avons montré qu’elle est organisée en deux supercolonies en Corse dont la supercolonie « corse » qui constitue une nouvelle entité pour l’Europe. L’exploration de près de 80 sites le long du littoral a permis de souligner la forte expansion de son aire de distribution depuis ces 10 dernières années. L’Homme à travers ses différentes activités constitue le moteur de cette dynamique d’invasion. Nous avons également mis en évidence grâce à des tests comportementaux, la résistance d’une espèce dominante indigène, Tapinoma nigerrimum face à l’invasion, pouvant expliquer l’hétérogénéité de la distribution des fourmis d’Argentine en Corse. Une fois introduites, elles peuvent envahir les milieux naturels et conduire à une réduction de richesse des communautés indigènes qui peut atteindre près de 80 %. Deux facteurs peuvent expliquer ce succès écologique : l’occupation de l’espace qui permet aux fourmis d’Argentine de maintenir une forte pression de compétition dans l’habitat et leur forte agressivité interspécifique qui peut se traduire par des raids sur les nids ou des colonnes de fourmis indigènes. Enfin, nous avons étudié l’effet direct de l’élimination des fourmis indigènes pour la dispersion des graines d’Anchusa crispa, plante endémique corso-sarde, rare et menacée. Les fourmis d’Argentine dispersent plus de graines que les espèces natives, diminuent la pression de prédation d’espèces granivores et semblent faciliter la germination des graines. Ces résultats montrent pour la première fois qu’une plante indigène peut tirer bénéfice de la présence de cette espèce invasive. Ce travail apporte de nombreuses données sur la biologie et l’écologie de la fourmi d’Argentine, alimente la discussion en biologie des invasions et ouvre de nouvelles pistes de recherche<br>The Argentine ant, Linepithema humile, has spread with ease across many zones of the globe with a Mediterranean or subtropical climate, transported from its native range in South America mainly through trade at the end of the 19th century. Today, it is very densely represented in southwestern Europe, along the Portuguese, Spanish, French and Italian coasts. Despite its presence in Corsica for more than 50 years, little data is available on the causes and the consequences of the invasion. The present study therefore seeks to provide comprehensive information on three main axes of research on the Argentine ant, i. E. Its social structure, its distribution and expansion dynamics and how it affects native fauna and flora. As such, the aim here is to provide useful input for the management and control of invasive species. Our study confirms the invasiveness of the Argentine ant along the Corsican coast. Using behavioral, chemical and genetic analyses, we show that it is organized in two supercolonies in Corsica, one of which, the” Corsican” supercolony, constitutes a new entity for Europe. Exploring almost 80 coastal sites, we state the strong expansion of its distribution range over the last 10 years, fuelled by human activities. We also bring to light the resistance to invasion of a dominant native species, Tapinoma nigerrimum, using behavioral tests which may explain the mosaic distribution of the Argentine ant in Corsica. We show that Argentine ants have a major impact on native ants, being able to invade natural areas, and that they can bring about an almost 80% reduction in native community richness. Two factors may explain this ecological success: their wide space occupation, potentially allowing Argentine ants to maintain high competition pressure over the whole habitat, and their high interspecific aggressiveness, which can result in raids on native ant nests or columns. Finally, we studied the direct effect of the elimination of native ants on the seed dispersal of Anchusa crispa, a rare and threatened Corsican-Sardinian endemic species. Argentine ants disperse more seeds than native ants, reduce seed predation from native harvester ants and may facilitate seed germination. These results show for the first time that the Argentine ant can be beneficial to a native endemic plant. This work provides extensive information on the biology and ecology of the Argentine ant, contributes to the ongoing discussion on invasion biology and points towards new path of research
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Costa, Sofia Conde. "Antagonistic interactions between dominant invasive and native ant species in citrus orchards." Master's thesis, ISA, 2017. http://hdl.handle.net/10400.5/14836.
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Mestrado em Engenharia Agronómica - Proteção das plantas / Instituto Superior de Agronomia<br>The Argentine ant, Linepithema humile (Mayr) established in the South of Portugal (Algarve), about 120 years ago. Zina et al. (2017) compared the composition of ant communities foraging in tree canopy in citrus orchards among the three ecological subregions of Algarve (Litoral, Barrocal and Serra) and observed that the invasive dominant species L. humile was absent from Serra. In this work, we tested the hypothesis that dominant native ant species, such as Tapinoma nigerrimum (Nylander) and Lasius grandis Forel could prevent the Argentine ant from invading Serra. Laboratory experiments were carried out, using both Petri dish arenas and cages to assess the antagonistic interactions between the Argentine ant and two dominant native species, at the individual and colony level, respectively. Overall, our results support the tested hypothesis. At the individual level, both T. nigerrimum and L. grandis showed higher aggression and survival levels than Argentine ant. At the colony level, the results suggest that both the Argentine ant and T. nigerrimum were able to recruit a relative large number of individuals from the colony when trying to colonise a food resource defended by the competitor species. In our experimental conditions, T. nigerrimum showed to be more efficient than Argentine ant in this type of competition, as it was able to defend a food resource in four out of five times from the attack of the former species, as well as to dominate a resource defended by Argentine ant in four out of five times<br>N/A
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Menke, Sean B. "Predicting Argentine ant (Linepithema humile) invasions at multiple spatial scales the relative importance of abiotic and biotic factors /." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3259064.
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Thesis (Ph. D.)--University of California, San Diego, 2007.<br>Title from first page of PDF file (viewed June 21, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Abril, Sílvia. "Estudi d'aspectes biològics de la formiga argentina (Linepithema humile, Mayr) encarat al control de la plaga en ecosistemes naturals." Doctoral thesis, Universitat de Girona, 2008. http://hdl.handle.net/10803/7660.
Full textAbstract:
La present tesi intenta obtenir noves dades referents a la biologia i ecologia de la formiga argentina que poden arribar a ser cabdals per al disseny o millora de noves metodologies de control de l'expansió de la plaga en ecosistemes naturals. Així doncs, l'estudi de l'activitat de cerca d'aliment i del seu espectre dietari en ecosistemes naturals, juntament amb el de les fluctuacions estacionals de la densitat de reines en nius naturals, obre les portes a la millora de mètodes de control de la plaga mitjançant esquers tòxics d'efecte retardat i a l'aplicació de noves metodologies de control sense l'ús d'agents químics basats en l'eliminació massiva de reines. La tesi també aporta noves dades sobre la fisiologia reproductiva de l'espècie en relació a la temperatura, la qual cosa permet la integració de l'aspecte fisiològic en models de predicció del rang potencial d'establiment de la plaga en ecosistemes naturals, aspecte fins ara pràcticament oblidat en aquest tipus de models predictius.<br>The present work attempts to obtain new information about the biology and ecology of this species in order to improve or design new control methods to stop the expansion of the plague in natural ecosystems. In that sense, the study of its foraging activity and dietary spectrum in natural environments, as well as the report of its annual fluctuations in the queen's densities of natural nests, open the door to the improvement of control methodologies based on the use of toxic baits, as well as to the design of new control methods based on the mechanical elimination of queens without the use of chemical procedures. This work also provides new data about the species' reproductive physiology according to temperature, which allow the application in predictive models of the physiological needs of the species to establish in a certain natural area.
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Oliveras, Huix Jordi. "Efectes de la invasió de la formiga argentina, Linepithema humile (Mayr), sobre el procés de dispersió de llavors de plantes mediterrànies." Doctoral thesis, Universitat de Girona, 2005. http://hdl.handle.net/10803/7653.
Full textAbstract:
La formiga invasora Linepithema humile (Mayr), també coneguda com la formiga argentina, és una espècie present a la península Ibèrica. En aquesta tesi s'ha estudiat com afecta la presència d'aquesta espècie plaga a la comunitat de formigues autòctones y al procés de dispersió de llavors de plantes mediterrànies. L'estudi es va dur a terme en una àrea de sureda i brolla d'estepes i bruc boal situada al nord-est peninsular, prop de la línia de costa mediterrània. <br/>Un dels primers y més notables efectes de la invasió a les nostres àrees d'estudi és la dramàtica alteració de la comunitat de formigues, en forma de una reducció de la riquesa específica i de la homogeneïtat d'abundàncies. A més, a les zones envaïdes no hi queda cap espècie de formiga autòctona dispersant de llavors. A causa de la gran abundància d'obreres de la formiga argentina a les zones envaïdes, i del seu elevat ritme d'activitat, aquesta espècie efectua un intens rastreig del sòl, la qual cosa li permet localitzar els recursos en un temps menor que les formigues autòctones de les zones no envaïdes. No obstant, la obertura mandibular de la comunitat de formigues esdevé molt disminuïda a les zones envaïdes a causa de la desaparició de les espècies autòctones, la majoria d'elles de mida més grossa que la formiga argentina, la qual cosa podria limitar la capacitat de manipulació de l'entorn que té la comunitat de formigues a les zones envaïdes, i podria explicar la falta de reemplaçament d'alguns dels rols que duien a terme les espècies de formigues autòctones abans de la invasió.<br/>La formiga argentina es mostra atreta per les llavors de les nou espècies vegetals estudiades (dues euforbiàcies: Euphorbia biumbellata i E. characias; dues compostes: Cirsium vulgare i Galactites tomentosa; i cinc papilionàcies: Genista linifolia, G. monspessulana, G. triflora, Sarothamnus arboreus i Ulex parviflorus), arribant a transportar i fins i tot introduir al niu algunes llavors, però amb probabilitats inferiors a les realitzades per les formigues autòctones de les zones no envaïdes. No obstant, el seu comportament davant les nou espècies de llavors és variable, de manera que sembla que el seu efecte sobre la dispersió de llavors podria ser diferent per a cada espècie vegetal. L'alteració del procés de dispersió no sembla alterar l'èxit reproductiu d'una espècie concreta, Euphorbia characias, a les zones envaïdes; ni el seu reclutament, ni la distribució espacial, ni la supervivència de les plàntules són significativament diferents a les zones envaïdes que a les no envaïdes. <br/>La desaparició de les espècies de formigues granívores de les zones envaïdes pot afectar la dinàmica de les llavors de plantes no mirmecòcores. Així, les llavors de tres papilionàcies (Calicotome spinosa, Psoralea bituminosa i Spartium junceum) resulten amb un menor nivell de transports (i probablement menor depredació) a les zones envaïdes per la formiga argentina.<br>The invasive ant Linepithema humile (Mayr), known as the Argentine ant, is present in the Iberian peninsula. This thesis is focused on the effect of the presence of this pest ant over the native ant community and the seed dispersal process of Mediterranean plants. The study was carried out in a cork oak secondary forest situated in the north-eastern Iberian peninsula, near the Mediterranean coast.<br/>One of the first and most notorious effects of the invasion in our study areas is the dramatic alteration of the ant community, with a reduction of the ant species richness and the homogeneity of abundances. Moreover, any native seed dispersal ant remains at the invaded zones. Due to the higher abundance of Argentine ant workers in the invaded areas, and their higher "tempo" of activity, this species carries out an intense soil surface searching and can find resources in a lower time than native ants do in the non-invaded zones. However, the mandible gap of the ant community becomes highly reduced in the invaded zones due to the displacement of the native ant species, most of them bigger than the Argentine ant. This could limit the ability of ants in handling the environment in the invaded zones, and could explain the lack of replacement of some tasks carried out by the native ants before the invasion.<br/>The Argentine ant is attracted by the seeds of the nine studied plant species (two euforbiaceae: Euphorbia biumbellata and E. characias; two compositae: Cirsium vulgare and Galactites tomentosa; and five papilionaceae: Genista linifolia, G. monspessulana, G. triflora, Sarothamnus arboreus and Ulex parviflorus), transporting and even introducing some seeds to the nest, but with lower probabilities than the native ants in the non-invaded zones. However, its behavior in front of the nine seed species is variable, so the effect over the seed dispersal process could be different for each plant species. The alteration of the seed dispersal process appears not to affect the reproductive success of a single species, Euphorbia characias, in the invaded zones; neither recruitment, spatial distribution, nor survival of seedlings are significantly different between the invaded and the non-invaded zones. <br/>The disappearance of the native granivorous ant species from the invaded zones can affect the seed dynamics of non-myrmecochorous species. In this sense, seeds of three papilionaceae (Calicotome spinosa, Psoralea bituminosa and Spartium junceum) result with a lower level of transport (and probably lower predation) in zones invaded by the Argentine ant.
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Lado, Thomas Francis. "Molecular ecology of introduced species in South Africa : the bud gall-forming wasp Trichilogaster acaciaelongifoliae and the Argentine ant Linepithema humile." Thesis, Stellenbosch : Stellenbsoch University, 2008. http://hdl.handle.net/10019.1/4840.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 2008.<br>ENGLISH ABSTRACT: Introduced species displace native species and alter ecological communities, affect
agriculture as well as human health and are economically costly to eradicate. Long term
monitoring of introduced species including the documentation of levels of genetic variation is
therefore of the utmost importance. This study investigated the distribution of genetic variation
in two introduced species distributed across South Africa the bud gall-forming wasp
Trichilogaster acaciaelongifoliae and the Argentine ant Linepithema humile.
The bud gall-forming wasp was introduced into South Africa as a biological control
agent to curb the spread of the invasive long-leaved wattle Acacia longifolia. In addition to the
intended (target) host, the bud gall-forming wasp has also colonised A. floribunda, a noninvasive
ornamental plant. Limited genetic variation was found across South Africa based on
the mitochondrial DNA cytochrome oxidase subunit I (COI) gene. Only 3 haplotypes
characterized 53 individuals collected from 23 localities (nucleotide diversity £k = 0.002 ¡Ó
0.001, haplotype diversity h = 0.482 ¡Ó 0.045). No significant partitioning of genetic variation
was found across South Africa including between host plants (target host = A. longifolia, non
target host = A. floribunda) or between the core (sites of introduction) and edge (naturally
dispersed) sites (ĦST = 0.094, P = 0.288). The limited genetic variation and the absence of
significant genetic structure are congruent with patterns described for many other introduced
species and may suggest that propagule pressure plays only a minor role in species
establishment and spread of the gall-forming wasp across South Africa.
Mitochondrial and nuclear markers were used to describe the distribution of genetic
variation within Argentine ants across their introduced range in South Africa. For the
mitochondrial DNA, low genetic diversity was found for the COI gene with only five haplotypes, separated by single mutational changes, characterizing 101 specimens from 35
localities (nucleotide diversity π = 0.001 ± 0.001, haplotype diversity h = 0.151 ± 0.048).
Notwithstanding the low levels of genetic diversity, mitochondrial variation was significantly
structured (ST = 0.54, P < 0.001) across the landscape. In contrast, microsatellite analyses of
230 ants from 23 localities, employing six polymorphic microsatellite markers, revealed a
relatively high amount of genetic diversity (HE = 0.51 ± 0.22). Significant population structure
was similarly evident (RST = 0.14, P < 0.001) with the localities of Elim2, Porterville2 and
Bloemfontein2 clustering as a distinct population from the remainder of the localities.
Importantly, individuals from these localities also had a unique mitochondrial haplotype and,
when taken with the nuclear results, may indicate the occurrence of more than one introduction
event (and possibly more than one colony) in South Africa. This is further underscored by the
presence of unique microsatellite alleles in these three populations.
In an attempt to establish the source populations for the introduction of Argentine ants
into South Africa, mitochondrial cytochrome b sequences were generated for a subset of ants
representing the two major genetic clades across South Africa. A comparison with the
published data from across the world including the native range of the Argentine ant in South
America grouped Argentine ants from South Africa with three potential source populations
namely Ocampo and Rosario in Argentina and Passo do Lontra in Brazil.
The results of this study underscore the role of human-mediated dispersal in shaping the
levels of genetic variation in both species. Human-mediated dispersal can lead to genetic homogenization across populations.<br>AFRIKAANSE OPSOMMING: Indringer spesies verplaas of verander ekologiese gemeenskappe, beinvloed landbou
asook menslike gesondheid en is ekonomies duur om te verwyder. Langtermyn monitering van
indringer spesies asook die dokumentasie van genetiese variasie is dus baie belangrik. Hierdie
studie bestudeer die verspreiding van genetiese variasie in twee indringer spesies wat regoor
Suid-Afrika voorkom, naamlik die kroongal-vormende wespe Trichilogaster
acaciaelongifoliae en die Argentynse mier Linepithema humile.
Die kroongal-vormende wesp is na Suid Afrika gebring as biologiese beheeragent om
die verspreiding van indringer lang-blarige wattle Acacia longifolia te beveg. Die kroongalvormende
wespe het sowel die teiken spesies, asook A. floribunda, ‘n nie-indringer
ornamentele plant gekoloniseer. Beperkte genetiese variasie is gevind regoor Suid Afrika
gebasseer op die mitochondriale DNA sitokroom-oksidasie subeenheid I (COI) geen. Slegs 3
haplotipes karakteriseer 53 indiviue van 23 bevolkings (nukleotied diversiteit π = 0.002 ±
0.001, haplotiep diversiteit h = 0.482 ± 0.045). Geen beduinde groepering van genetiese variase
is gevind regoor Suid Afrika nie (ST = 0.094, P = 0.288). Hierdie bevinding geld onafhanklik
van die gasheer plant (teiken gasheer = A. longifolia, nie-teiken gasheer = A. floribunda). Ook
is geen beduidende genetiese groepering gevind tussen die sentrale (plek van inisiele
blootstelling) en perifêre (natuurlik verspreide) lokaliteite nie. Die kleinskaalse genetiese
variase en die afwesigheid van beduidende genetiese struktuur wat hier gevind is, verskil van
die patrone wat voorheen vir baie ander indringer-spesies beskryf is. Dit mag daarop dui dat
‘propagule’ druk slegs ’n klein rol speel in spesies-vestiging en verspreiding van die galvormende
wespe regoor Suid-Afrika. Mitochondriale asook kern merkers is gebruik om die verspreiding van genetiese
variasie in Argentynse miere in Suid Afrika te beskryf. Vir die mitochondriale DNA is lae
genetiese variase gevind vir die COI geen, met slegs 5 haplotipes, gedifferensieer deur enkele
mutasie veranderinge wat 101 monsters van 35 lokaliteite karakteriseer (nukleotied diversiteit
π = 0.001 ± 0.001, haplotiep diversiteit h = 0.151 ± 0.048). Desondanks die lae genetiese
variasie, is gevind dat mitochondriale variasie beduidend gestruktureerd is (ST = 0.54, P <
0.001) oor die landskap. Hierteenoor het mikrosatelliet analises van 230 miere van 23
lokaliteite, deur gebruik te maak van ses polimorfiese mikrosatelliet merkers, ’n relatiewe hoë
hoeveelheid genetiese diversiteit aangedui. Beduidende bevolkingstruktuur was ook gevind
(RST = 0.14, P < 0.001) in die areas Elim2, Porterville2 en Bloemfontein2 wat saam groepeer
as eiesoortige bevolkings vergeleke met die res van die areas. Ook van belang is dat individue
van die areas ’n unieke mitochondriale haplotipe besit, en in kombinasie met die kern resultate,
mag dit die voorkoms van meer as een blootstellingsgeleentheid (en moontlik meer as een
kolonie) in Suid Afrika aandui. Hierdie bevinding word verder beklemtoon deur die
teenwoordigheid van unieke mikrosatelliet allele in die drie bevolkings.
In ‘n poging om die oorsprong van die oorsprong-bevolking vir die blootstelling van
Argentynse miere in Suid Afrika vas te stel, is mitochondriale sitokroom b volgordes
gegenereer vir ’n substel miere wat die twee hoof genetiese klades in Suid Afrika voorstel.
Vergelyking met gepubliseerde data van regoor die wêreld, insluitende die endemiese gebied
van die Argentynse mier in Suid Amerika, het die Argentynse mier van Suid Afrika met drie
potensiele oorsprong-bevolking verbind, naamlik Ocampo en Rosario in Argentina en Passo do Lontra in Brazil.
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Choe, Dong-Hwan. "Necrophoric behavior of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae), and its implications for horizontal transfer of slow-acting insecticides." Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=106&did=1871866051&SrchMode=1&sid=1&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270485146&clientId=48051.
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Le, Goff Line. "Formation spontanée de chemins : des fourmis aux marches aléatoires renforcées." Thesis, Paris 10, 2014. http://www.theses.fr/2014PA100180/document.
Full textAbstract:
Cette thèse est consacrée à la modélisation de la formation spontanée de chemins préférentiels par des marcheurs déposant des traces attractives sur leurs trajectoires. Plus précisément, par une démarche pluridisciplinaire couplant modélisation et expérimentation, elle vise à dégager un ensemble de règles minimales individuelles permettant l'apparition d'un tel phénomène. Dans ce but, nous avons étudié sous différents angles les modèles minimaux que sont les marches aléatoires renforcées (MAR).Ce travail comporte deux parties principales. La première démontre de nouveaux résultats dans le domaine des probabilités et statistiques. Nous avons généralisé le travail publié par M. Benaïm et O. Raimond en 2010 afin d'étudier l'asymptotique d'une classe de MAR auxquelles les demi-tours sont interdits. Nous avons également développé une procédure statistique permettant, sous certaines conditions adéquates de régularité, d'estimer les paramètres de MAR paramétrées et d'évaluer des marges d'erreur.Dans la seconde partie, sont décrits les résultats et analyses d'une étude comportementale et expérimentale de la fourmi Linepithema humile. Une partie de notre réflexion est centrée sur le rôle et la valeur des paramètres du modèle proposé par J.-L. Deneubourg et al. en 1990. Nous nous sommes aussi demandés dans quelle mesure une MAR peut reproduire les déplacements d'une fourmi dans un réseau. Dans ces objectifs, nous avons mené des expériences confrontant des fourmis à des réseaux à une ou plusieurs bifurcations. Nous avons appliqué aux données expérimentales les outils statistiques développés dans cette thèse. Nous avons aussi effectué une étude comparative entre les simulations de plusieurs modèles et les expériences<br>This thesis is devoted to the modelisation of the spontaneous formation of preferential paths by walkers that deposit attractive trails on their trajectories. More precisely, through a multidisciplinary approach, which combines modelisation and experimentation, this thesis aims to bring out a set of minimal individual rules that allow the apparition of this phenomena. In this purpose, we study in several ways the minimal models, which are the Reinforced Random Walks (RRW).This work contains two main parts. The first one proves some new results in the field of probability and statistics. We have generalized the work published by M. Benaïm and O. Raimond in 2010 in order to study the asymptotics of a class of RRW, to which U-turns are forbidden. We developped also a statistical procedure that allows under some appropriate regularity hypotheses to estimate the parameters of parametized RRW and to evaluate margins of error.In the second part, we describe the results and the analyses of a experimental and behavioral study of the Linepithema humile ants. One part of our reflection is centered on the role and the value of the parameters of the model defined by J.-L. Deneubourg et al. in 1990. We investigated also the extent to which RRW could reproduce the moving of an ant in a network. To these purposes, we performed experiments that confront ants to a network of one or several forks. We applied to experimental data the statistical tools developed in this thesis and we performed a comparative study between experiments and simulations of several models
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Rossi, Natacha. "Pheromonal modulation as a drive for behavioral plasticity in two insects : honey bees and ants." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30355.
Full textAbstract:
Les phéromones sont des substances chimiques relâchées dans l'environnement par un individu qui déclenchent des comportements stéréotypés et/ou des processus physiologiques chez des individus de la même espèce. Cependant, une nouvelle hypothèse suggère que les phéromones non seulement suscitent des réponses innées mais contribuent également à la plasticité comportementale en agissant en "modulateurs" de phénomènes cognitifs. Nous avons étudié l'effet modulateur des phéromones sur les réponses réflexes, la prise de décision, et l'apprentissage chez trois espèces d'insectes qui sont des modèles emblématiques en recherche fondamentale et appliquée : l'abeille Apis mellifera, et les fourmis Camponotus aethiops and Linepithema humile. Dans une première étude, nous avons trouvé qu'une phéromone appétitive diminuait la sensibilité aversive, tandis qu'une phéromone d'alarme augmentait la sensibilité aversive chez l'abeille. Chez L. humile, une phéromone de piste synthétique augmentait la sensibilité au sucre et le temps de nourrissage. Globalement, nos résultats démontrent que certaines phéromones modulent la prépondérance des stimuli aversif et appétitif selon leur valence. De cette manière, elles affecteraient la motivation à s'engager dans des réponses aversives ou appétitives, agissant ainsi comme modulateurs de la plasticité comportementale. Nous avons ensuite déterminé l'effet d'une phéromone d'alarme (l'acide formique) sur la prise de décision et les systèmes de reconnaissance dans le cadre de la discrimination de congénères chez des fourmis charpentières. Nous avons trouvé que la phéromone d'alarme améliorait la discrimination en augmentant l'agressivité envers les non congénères et en la diminuant envers les congénères en même temps. Ces résultats remettent en question le modèle établi de reconnaissance de congénères. Nous proposons donc une version révisée de ce modèle. Enfin, nous avons teste l'effet de l'acide formique sur l'apprentissage et la généralisation. L'acide formique augmentait la discrimination en conditionnement différentiel olfactif aversif. En conditionnement différentiel olfactif appétitif, l'acide formique modulait les dynamiques d'acquisition et la perception de la similarité des odeurs. Nous suggérons que les phéromones affectent la perception des odeurs conditionnées et des renforcements selon la nature des odeurs et leurs valeurs intrinsèques pour l'individu, ainsi que la valence des renforcements. Cette thèse présente les premières analyses intégrées de la modulation phéromonale chez deux taxa : les abeilles et les fourmis. Les résultats présentés nous permettent de comprendre une partie des modes d'action des phéromones et ouvrent la voie à de futures études afin de comprendre les mécanismes qui sous-tendent l'effet modulateur des phéromones<br>Pheromones are chemical substances released into the environment by an individual, which trigger stereotyped behaviors and/or physiological processes in individuals of the same species. Yet, a novel hypothesis has suggested that pheromones not only elicit innate responses but also contribute to behavioral plasticity by acting as "modulators" of cognitive phenomena. We studied the modulator effect of pheromones on reflex responses, decision making and learning in three insect species that are emblematic models for fundamental and applied research: the honeybee Apis mellifera, and the ants Camponotus aethiops and Linepithema humile. In the first study, we found that an appetitive pheromone decreased aversive responsiveness, while an alarm pheromone increased aversive responsiveness in honey bees. In L. humile, a synthetic trail pheromone increased sucrose responsiveness and feeding time. Overall, our results demonstrate that certain pheromones modulate the salience of aversive and appetitive stimuli according to their valence. In this way, they would affect the motivation to engage in aversive or appetitive responses, thus acting as modulators of behavioral plasticity. We then determined the effect of an alarm pheromone (formic acid) on decision making and recognition systems in the frame of nestmate discrimination in carpenter ants. We found that the alarm pheromone improved discrimination by increasing aggressiveness towards non-nestmates and decreasing aggressiveness towards nestmates at the same time. These results challenge the established model of nestmate recognition. We therefore propose a revised version of this model. Eventually, we tested the effect of formic acid on learning and generalization. Formic acid increased discrimination in aversive olfactory differential conditioning. In appetitive olfactory differential conditioning, formic acid modulated the acquisition dynamics and perceived odor similarity. We suggest that pheromones affect the perception of conditioned odors and reinforcements depending on the nature of the odorants and their intrinsic values for the individual, as well as the valence of the reinforcements. This thesis presents the first integrated analyses of pheromone modulation in two insect taxa: honey bees and ants. The presented results allow us to understand some modes of action of pheromones and pave the way for future studies to understand the underlying mechanisms of this modulator effect of pheromones
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Enríquez, Lenis Martha Lucía. "The invasion of the Argentine ant Linepithema humile in Mediterranean ecosystems: impacts and efficacy of winter aggregations extirpation as a control methods." Doctoral thesis, Universitat de Girona, 2012. http://hdl.handle.net/10803/101512.
Full textAbstract:
We studied the characteristics and effects of the Argentine ant invasion on the native ants and other arthropods. Moreover, we assessed the effects of L. humile winter nest aggregations extirpation on its population dynamics. We measured the spread of its invasion and evaluated its nest-site preferences. Artificial nests used as a control tool were also assessed. Results indicate that the invasion causes important changes in the native ant community structure. The invasion spread is influenced by air temperature, and habitat perturbations could be favouring a faster expansion. The extirpation diminished the abundance of this ant and disturbed its population dynamics. In order to make this method more efficient, extirpation should be made in the edge of the invasion, and should focus on nests under larger rocks where mature nests are more likely to be found. Finally, this method is proposed mainly for controlling its invasion in closed or isolated areas.<br>Es van comparar les característiques i els efectes de la invasió de la formiga argentina sobre la comunitat de formigues natives, i altres artròpodes. Es va avaluar l'efecte de l'extirpació d’agregacions de nius d’hivern, la selecció de llocs de nidificació i l'ús de nius artificials com a eina de control, i es va mesurar la seva taxa d'expansió. Es va trobar que la invasió provoca canvis importants en la comunitat de formigues natives. La temperatura ambiental influeix en l'expansió, i les pertorbacions de l'hàbitat podrien afavorir una propagació més ràpida. L'extirpació disminueix la seva abundància i pertorba la seva dinàmica poblacional. L'extirpació s'ha de fer al marge de la invasió, i s'ha de centrar en nius situats sota les pedres més grans que és on hi ha més probabilitat de trobar nius madurs. Finalment, aquest mètode es proposa principalment per al control de la invasió en àrees tancades o aïllades.
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Andzeiewski, Simone. "Iscas tóxicas no controle de Linepithema micans (Forel, 1908) (Hymenoptera: Formicidae) e Eurhizococcus brasiliensis (Wille, 1922) (Hemiptera: Margarodidae) na cultura da videira." Universidade Federal de Pelotas, 2017. http://repositorio.ufpel.edu.br:8080/handle/prefix/3672.
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Previous issue date: 2017-02-24<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>A pérola-da-terra Eurhizococcus brasiliensis (Wille, 1922) (Hemiptera: Margarodidae)
é uma cochonilha subterrânea que ataca raízes de plantas cultivadas e silvestres. A
espécie é considerada a principal praga da videira no Brasil. No primeiro ínstar, a
dispersão da cochonilha é realizada com o auxílio de formigas doceiras principalmente
a Linepithema micans (Forel, 1908) (Hymenoptera: Formicidae) que se associa à
cochonilha na busca de excrementos açucarados. Nesse trabalho, foi avaliado o efeito
de iscas tóxicas a base de hidrametilnona no controle de L. micans, e
consequentemente, na infestação de E. brasiliensis em novos plantios de videira.
Inicialmente foi realizado um experimento em vasos em casa de vegetação em
outubro de 2014 com a finalidade de selecionar formulações de iscas tóxicas à base
de hidrametilnona (“grânulo pequeno”, “grânulo grande”, tipo “cereal” e gel) para o
controle de L. micans. As iscas tóxicas foram oferecidas ad libitum em porta-iscas com
substituição semanal. As avaliações foram realizadas semanalmente registrando o
número de formigas forrageando a cada 10 minutos durante uma hora sobre uma
solução aquosa de açúcar invertido 70%. A melhor formulação de isca tóxica
selecionada em casa de vegetação foi avaliada a campo em dois experimentos,
realizados em áreas naturalmente infestadas pela pérola-da-terra e por L. micans. No
primeiro, foram efetuadas aplicações semanais de 450 g/ha da isca tóxica em Flores
da Cunha, RS, e no segundo, foi avaliado uma e três aplicações semanais da mesma
dose em Caxias do Sul, RS. Mudas do porta enxerto Paulsen 1103 foram plantadas
em agosto de 2014 para o experimento em Flores da Cunha e em novembro de 2015
no experimento de Caxias do Sul, respectivamente. O monitoramento populacional
das formigas foi feito semanalmente através de armadilhas subterrâneas do tipo
“pitfall” utilizando mel e sardinha embebidos em algodão. A avaliação dos
experimentos foi realizada em maio de 2015 (Flores da Cunha) e 2016 (Caxias do
Sul), contando o número de cochonilhas presentes nas raízes. No experimento em
casa de vegetação, a isca tóxica a base de hidrametilnona formulada em “grânulo
pequeno” e “grânulo grande” controlaram a população de formigas nas primeiras
quatro semanas após o fornecimento da isca. A isca tóxica formulada em gel também
proporcionou mortalidade de 100% da população de formigas, no entanto seu controle
foi mais lento, quando comparado as outras formulações. A isca “cereal” não
proporcionou controle das formigas. A isca tóxica formulada em “grânulo pequeno”
selecionada como a mais eficaz em casa de vegetação, fornecida semanalmente no
campo, controlou a população de L. micans em 100% reduzindo a infestação da
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pérola-da-terra em 99,9%. Quando o número de aplicações da isca foi reduzido para
1 a 3, houve um controle de 100% na população de formigas no tratamento que
recebeu três aplicações até a quarta semana após o fornecimento da isca, porém as
colônias se restabeleceram ao longo do experimento e os tratamentos (uma e três
vezes) não foram eficazes no controle das espécies. Conclui-se que a formulação
granulada à base de hidrametilnona “grânulo pequeno” é eficiente no controle de L
micans em casa de vegetação e em aplicações semanais no campo. Aplicações de
uma e três vezes da isca tóxica não proporcionaram controle satisfatório das espécies
sendo necessário ajustar o número de tratamentos para um controle eficaz e
econômico de E. brasiliensis e L. micans.<br>In Brazil, Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae) is considered
to be the main pest of vine plants, attacking the roots of cultivated and wild plants.
Linepithema micans (Forel, 1908) (Hymenoptera: Formicidae) is the primary agent
responsible for spreading the Eurhizococcus brasiliensis, which are attracted by the
honeydew excreted by the scale insect. In this work, the effect of a hydramethylnonbased
granular toxic bait on the control of L. micans and E. brasiliensis in grapevines
was evaluated on young grapevines. An experiment was conducted in a greenhouse
in October 2014 and planted in individual pots were used to select different
formulations of toxic baits based on hydramethylnon (small granule, large granule,
cereal and gel) for the control of L. micans. The toxic baits were provided ad libitum in
bait holders, with baits being replaced weekly. Weekly evaluations were carried out
during a period of 10 weeks, with the number of foraging ants being counted every 10
minutes during 1 hour, in an aqueous solution of 70% inverted sugar. The best
formulation of toxic bait selected in greenhouse was evaluated in the field in two
experiments, carried out in areas naturally infested withe the scale and L. micans. In
the first experiment 450 g/ha/week of the toxic bait were applied in Flores da Cunha,
RS, and in the second, one and three weekly applications of the same dose were
evaluated in Caxias do Sul, RS. In August 2014, seedlings from the Paulsen 1103
rootstock were planted in Flores da Cunha and in November 2015 in Caxias do Sul.
The ants was monitored weekly in-ground pitfall traps using a honey and water solution
(70%) and sardine conserved in oil absorbed in cotton wool as food attractants.The
evaluation of the experiments was carried out in May of 2015 (Flores da Cunha) and
2016 (Caxias do Sul), counting the number of scale insects present in the roots.The
experiment conducted in a greenhouse, the hydramethylnon based toxic bait in the
formulation small granule and large granule controlled the ant population in the first 4
weeks of application.The gel formulation of the hydramethylnon toxic bait also provided
100% mortality of the population of ants; however, its control was slower when
compared with the other two formulations and the cereal formulation did not differ from
the control. The small granule toxic bait, applied weekly, effectively reduced the
infestation of L. micans, controlling 100% of the population of ants and reducing the
infestation of E. brasiliensis by 99.9%. When the number of bait applications was
reduced to 1 to 3, there was a 100% reduction in the ants in the treatment that received
three applications until the fourth week after application of the bait, but the colonies
were re-establishment.The small granule toxic bait, applied weekly, effectively reduced
the infestation of L. micans in greenhouse and field.The reduction of the number of
applications (one and three times) did not provide satisfactory control and it will be
10 necessary to adjust the number of treatments for an efficient and economical control
of the two species.
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Berville, Laurence. "La fourmi d’Argentine (Linepithema humile) face à une fourmi dominante du genre Tapinoma en milieu insulaire : écologie chimique, comportement et dynamique d’invasion." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4324.
Full textAbstract:
La fourmi d'Argentine (Linepithema humile) est une des espèces invasives parmi les plus nuisibles au monde. Dans le cadre des invasions biologiques, les résistances biotiques sont souvent les dernières barrières des écosystèmes. Une hypothèse, jamais testé in natura, de résistance de la part d'une fourmi du genre Tapinoma face à L. humile a été émise. Pour le démontrer, nous avons choisi d'expérimenter en laboratoire et in natura. Nos terrains d'études privilégiés ont été, outres des sites du littoral méditerranéen français, 4 îles situées en face du littoral envahi par la fourmi d'Argentine. Parmi celles-ci, deux contiennent à la fois la fourmi d'Argentine et des espèces du genre Tapinoma. L'identification difficile des espèces du genre Tapinoma étant sujette à une controverse scientifique, nous avons dû différencier de façon certaine cinq d'entre elles, par leurs morphologies et leurs signatures chimiques. En Provence, trois espèces ont été observées : T. erraticum, T. madeirense et T. nigerrimum. Sur l'île de Ratonneau, un suivi sur 2 ans de la vitesse d'invasion de L. humile en milieu naturel, avec ou sans T. nigerrimum, met en évidence une vitesse d'invasion très faible, voire un recul dans la zone à T. nigerrimum. Les colonies de T. nigerrimum de l'île de Ratonneau semblent faire obstacle à la progression de l'invasion. Des études comportementales préliminaires, conduites en laboratoire, entre fragments de nids de T. nigerrimum et L. humile nous avaient permis de confirmer les capacités de T. nigerrimum à résister face à l'invasive. Ainsi, les ouvrières T. nigerrimum défendent mieux leurs territoires, allant jusqu'à accaparer celui des L. humile<br>The Argentine ant (Linepithema humile) is one of the world's worst invasive species. We used various analyses to determine its invasion pattern on the Provence coast, confirming the presence of a second supercolony. Chemical and behavioral analyses of worker interactions on the supercolony border identified a peaceful border zone. When biological invasion occurs, biotic resistance is often ecosystems' last defense. Could a dominant ant from Tapinoma genus resist L. humile invasion? To demonstrate this possibility, we conducted both laboratory and in natura experiements. Besides the invaded Mediterranean coast, we selected four nearby islands, two of which were found to contain both L. humile and Tapinoma spp. Identification of Mediterranean Tapinoma being controversial, we used both morphological and chemical analyses to ensure reliable discrimination. On the coast, we found T. erraticum, T. madeirense and T. nigerrimum. In natura, on Ratonneau Island, two-year field monitoring showed a slow rate of Argentine ant invasion and even retreat, faced with T. nigerrimum. T. nigerrimum colonies seem to block L. humile invasion. Laboratory behavioral studies between nests of T. nigerrimum and L. humile confirm T. nigerrimum's ability to stand up to Argentine ants: T. nigerrimum workers protect and defend their territories better, even taking over Argentine ant nests
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Altfeld, Laura F. "Interspecific interactions among common insects of the salt myrtle, Baccharis halimifolia L. (Asteraceae)." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001578.
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Krahner, André. "Impact of the invasive ant Linepithema humile on native ant assemblages on the western slopes of Table Mountain and implications for ant-butterfly associations." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11046.
Full textAbstract:
The Argentine Ant, Linepithema humile (Hymenoptera: Formicidae), is one of the world's most successful invasive species and invades undisturbed Fynbos habitats in South Africa, displacing native arthropod species and affecting interspecific associations. In order to assess the impact of Li. humile on native ant assemblages and associations between ants and myrmecophilous butterflies (Lepidoptera: Lycaenidae) on the western slopes of Table Mountain (Cape Town, South Africa), adult butterfly density was scored and distribution of food plants were assessed at two sites.
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Diaz, Buitrago Mireia. "Ecological and biological strategies taken by the Argentine ant, Linepithema humile (Mayr, 1868), in cold seasons. Effects of winter nests management in natural invaded areas." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/123669.
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The winter nesting behaviour of the Argentine ant seems to be intrinsic, and its success as an invasive species does not rely on a shift in social organization, nor on a shift in its mode of nesting associated with the introduction to new habitats. Differences in energy investment in queens seem to respond to the different ecological contexts between studied zones. Therefore, L. humile could be experiencing a change in their biological strategies to become an invasive species. Regarding the management of the invasion by means of manual removal of nests, we suggest to do it in winter, at the front, and yearly. Finally, P. pygmaea seems to be affected by L. humile in the front, and to be benefitting in the centre, because L. humile reduces the competitive pressure on it by retracting other native species in the centre, and also because the existence of a certain degree of habituation between these two species<br>El comportament de L. humile per niar a l'hivern sembla ser intrínsec, i el seu èxit com a espècie invasora no basar-se ni en un canvi en l'organització social, ni en la seva manera de niar associada a la introducció en nous hàbitats. Les diferències en la inversió energètica en reines semblen respondre als diferents contextos ecològics de les zones estudiades. Per tant, L. humile podria patir un canvi en les seves estratègies biològiques per tal de convertir-se en una espècie invasora. Pel que fa a la gestió de la invasió mitjançant l'extirpació manual de nius, es suggereix fer-la a l'hivern, al front de la invasió i anualment. Finalment, sembla que L. humile perjudica P. pygmaea al front, i la beneficia al centre, gràcies a que li disminueix la pressió competitiva, al centre, retraient a les altres formigues natives, i a l'existència d'un cert grau d'habituació entre ambdues espècies
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Blancafort, Pujols Xavier. "Efecte de la formiga argentina en la pol·linització de diverses espècies mediterrànies." Doctoral thesis, Universitat de Girona, 2005. http://hdl.handle.net/10803/7657.
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Les inflorescències on és present la formiga argentina reben menys visitants, a les zones envaïdes, a més, desapareixen la majoria d'espècies de formigues autòctones, algunes de les quals podrien ser pol·linitzadores d'algunes espècies vegetals. Aquest efecte repel·lent i la desaparició de formigues autòctones es tradueix en una menor producció de fruits en plantes com Euphorbia characias o Euphorbia biumbellata<br>Argentine ant effects on pollination of several mediterranean species
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Estany-Tigerström, David. "Reproducció i desenvolupament de la mallerenga blava (Cyanistes caeruleus): conseqüències de la invasió de la formiga argentina (Linepithema humile) en la xarxa tròfica del bosc mediterrani." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/134599.
Full textAbstract:
We investigated whether the Argentine ant (Linepithema humile) invasion modifies the trophic web of the sclerophyllous Mediterranean forests to the point that impacts co-occurring bird communities. We studied if the invaded cork oak forests represent an ecological trap for the blue tit (Cyanistes caeruleus). The invasive ant dramatically impacts native ant communities in the areas studied. The Argentine ant alters the food supplies for the breeding foliage gleaning birds, basically through a depletion of the caterpillar availability in cork oaks. Nevertheless, the Argentine ant invasion does not affect the overall insectivorous birds’ communities. The detailed study of the reproductive dynamics of the blue tit do not provide evidences enough to assure that the blue tit is caught in an ecological trap in the Argentine ant invaded forests<br>S’avalua si la invasió de formiga argentina (Linepithema humile) modifica la xarxa tròfica dels boscos esclerofil·les mediterranis i arriba a afectar les comunitats d’ocells. Concretament s’estudia si les suredes envaïdes poden representar un parany ecològic per a la mallerenga blava (Cyanistes caeruleus). Els impactes de la invasió resulten ser dramàtics per a les formigues natives, a les que elimina gairebé del tot de les zones envaïdes. La invasió altera el proveïment de recursos alimentaris per a les pollades dels insectívors del fullatge, principalment a base de minvar la disponibilitat d’erugues en alzines sureres. La comparació de les poblacions reproductores d’ocells ens mostra, però, que la formiga argentina no sembla determinar en gran manera les comunitats d’ocells insectívors. L’estudi de la dinàmica reproductiva de la mallerenga tampoc proporciona evidències de què la invasió de formiga argentina constitueixi un parany ecològic per a la mallerenga blava
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Ludka, John T. "Protection and reliability an examination of the quality and quantity of ant protection in the food-for- protection mutualism between Ferocactus viridescens, Crematogaster californica and the invasive Linepithema humile /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p1460999.
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Thesis (M.S.)--University of California, San Diego, 2009.<br>Title from first page of PDF file (viewed February 10, 2009). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 60-62).
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Cournault, Laurent. "Regulation of reproduction in polygynous ants (Dolichoderinae): queen fertility signal and adult polyploidy." Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210332.
Full textAbstract:
Regulation of reproduction is one central feature of social life. In particular, only a few individuals are in charge of producing offspring in eusocial species. This division of the reproductive labour is mainly mediated by pheromones emitted by the queens in social insects. These queen pheromones may signal the presence of a fertile queen so that workers react accordingly by taking care of her and not reproducing. <p><p>Here I investigated two aspects of the reproduction of two polygynous ant species. The first one, Linepithema humile, is a unicolonial, highly polygynous and invasive species. It has been the focus of numerous studies about queen pheromones; in particular, it has been reported that queen cuticular hydrocarbons (CHC) profile is related to queen fertility. The other one, Tapinoma erraticum, is a multi-colonial, weakly polygynous and native species. Workers can lay haploid eggs in the absence of the queens which is impossible for Linepithema workers.<p><p>The major part of my thesis dealt with the queen fertility signalling issue. In the first two chapters I demonstrate the link between queen fertility and queen pheromone output. I first study a queen releaser pheromone, the queen retrieval behaviour. This behaviour is performed by the workers who lay a chemical trail toward a queen located outside the nest. I successfully show this behaviour to be related to queen fertility, and not mating status, in L. humile and T. erraticum since only fertile queens (mated or not) induce such recruitment. I then highlight the role of queen fertility in the prevention of worker reproduction in T. erraticum. Again, mated fertile queens and unmated fertile queens are both able to induce such primer effect. In a third chapter I report that CHC profiles may discriminate female castes (workers, queens, virgin queens, and virgin egg-laying queens) in T. erraticum. Finally, chapter 4 summarizes my attempts to prove that CHC may be involved in queen retrieval or queen attraction. None of the various bioassays tested allows me to demonstrate the putative role of CHC as queen pheromone.<p><p>In a second part, I was interested in the consequences of sex determination in T. erraticum. Chapter 5 presents the flow cytometry methodology (FC) which allowed me to score the number of sperm cells from spermathecae of several ant species, and to demonstrate that polygynous species (such as L. humile and T. erraticum) store less sperm than monogynous ones. FCM also allows determining the ploidy of sperm and adult somatic cells and chapter 6 which presents a large survey on the ploidy level within the species T. erraticum. This species displays diploid males that may produce diploid sperm which in turn can father a viable triploid female progeny. I report differences in the frequency of triploidy among female castes, the proportion of triploid workers being more important than triploid virgin queens whereas I never observed triploid mated fertile queens. Such results greatly suggest a putative regulatory mechanism involved in the rearing of triploid females. In the last chapter I investigated two populations that differ in the occurrence of triploid workers. I report these populations to vary in the number of queens and workers per nest.<p>/La régulation de la reproduction est un aspect essentiel de la vie sociale. En particulier, chez les espèces eusociales, seuls quelques individus sont impliqués dans la production de la descendance. Dans les sociétés d’insectes, une telle division du travail reproducteur est principalement assurée par l’émission de phéromones par les reines. Ces phéromones royales renseignent les membres de la colonie sur la présence d’une reine fertile, de telle sorte que les ouvrières réagissent en s’occupant d’elle et en s’abstenant de se reproduire. <p>Au cours de ce travail, je me suis intéressé à deux aspects de la reproduction au sein de deux espèces de fourmis polygynes. La première espèce, Linepithema humile, est invasive, unicoloniale et hautement polygyne dans les régions à climat méditerranéen. Elle a fait l’objet de nombreuses études portant notamment sur les phéromones royales. En particulier, il a été montré que le profil d’hydrocarbures cuticulaires (HCC) des reines est corrélé à leur fertilité. La seconde espèce, Tapinoma erraticum, est une espèce indigène, multi-coloniale et faiblement polygyne. Ses ouvrières sont capables de pondre des œufs mâles en absence de reines, ce dont sont incapables les ouvrières de Linepithema. <p>Je me suis principalement intéressé à la question de la signalisation de la fertilité des reines. Dans les deux premiers chapitres, je démontre le lien existant entre la fertilité des reines et la production de phéromone royale. J’ai d’abord étudié une phéromone incitatrice (releaser) qui provoque un recrutement royal. Ce comportement collectif très caractéristique correspond à la mise en place d’une piste chimique en direction d’une reine découverte par les ouvrières en dehors du nid. Je montre que ce comportement est lié à la fertilité de la reine chez les espèces L. humile et T. erraticum car seules les reines fertiles (fécondées ou non) sont capables de d’induire le recrutement royal. Je mets ensuite en évidence le rôle de la fertilité des reines dans la régulation de la reproduction des ouvrières de T. erraticum. A nouveau, les reines fécondées fertiles et les reines vierges fertiles sont toutes deux capables d’induire un même effet déclencheur (primer), en l’occurrence, l’inhibition de la reproduction des ouvrières. Dans un troisième chapitre, je montre que les profils d’hydrocarbures (HCC) permettent de distinguer sans ambiguïté les différentes castes femelles (ouvrières, reines fertiles, reines vierges et reines vierges pondeuses) chez T. erraticum. Enfin, le chapitre 4 résume mes tentatives pour démontrer le rôle des HCC dans les phénomènes de recrutement royal ou d’attractivité des reines. Aucun des bio-essais réalisés ne me permet de démontrer l’implication des HCC dans la phéromone royale. <p>Dans une seconde partie, je me suis intéressé aux conséquences du déterminisme du sexe chez T. erraticum. Le chapitre 5 présente cytométrie de flux (CF), une méthode qui me permet de compter les spermatozoïdes stockés dans les spermathèques de quelques espèces de fourmis et de montrer que les reines des espèces polygynes (telles que L. humile et T. erraticum) stockent moins de sperme que les espèces monogynes. La CF permet aussi de déterminer le niveau de ploïdie des cellules spermatiques ou somatiques chez l’adulte. Je me sers de cette application dans le chapitre 6 afin d’étudier le niveau de ploïdie au sein de l’espèce T. erraticum. Je montre que, dans les populations étudiées, il existe des mâles diploïdes et que ces mâles peuvent produire du sperme diploïde fertile, capable d’engendrer une descendance femelle triploïde. Je note des différences dans la fréquence des femelles triploïdes :la proportion d’ouvrières triploïdes est significativement plus importante que celle des reines vierges triploïdes. De plus, je n’ai jamais observé la présence de reines fécondées fertiles triploïdes. De tels résultats suggèrent fortement la présence d’un phénomène de régulation au cours de l’élevage du couvain triploïde. Dans le dernier chapitre, j’ai étudié deux populations de T. erraticum qui diffèrent au niveau de la proportion d’ouvrières triploïdes. Ces populations présentent des différences significatives dans le nombre de reines et d’ouvrières par nid. <p><br>Doctorat en Sciences<br>info:eu-repo/semantics/nonPublished
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Roura, i. Pascual Núria. "Predicting Argentine ant invasion across spatial scales via ecological niche models." Doctoral thesis, Universitat de Girona, 2006. http://hdl.handle.net/10803/7909.
Full textAbstract:
La formiga argentina (Linepithema humile) es troba entre les espècies més invasores: originària d'Amèrica del Sud, actualment ha envaït nombroses àrees arreu del món. Aquesta tesi doctoral intenta fer una primera anàlisi integrada i multiescalar de la distribució de la formiga argentina mitjançant l'ús de models de nínxol ecològic. D'acord amb els resultats obtinguts, es preveu que la formiga argentina assoleixi una distribució més àmplia que l'actual. Les prediccions obtingudes a partir dels models concorden amb la distribució actualment coneguda i, a més, indiquen àrees a prop de la costa i dels rius principals com a altament favorables per a l'espècie. Aquests resultats corroboren la idea que la formiga argentina no es troba actualment en equilibri amb el medi. D'altra banda, amb el canvi climàtic, s'espera que la distribució de la formiga argentina s'estengui cap a latituds més elevades en ambdós hemisferis, i sofreixi una retracció en els tròpics a escales globals.<br>Argentine ants (Linepithema humile) rank among the most successful invasive species: native to South America, they have invaded broad areas worldwide. This PhD thesis attempts to take the first step towards an integrated and multi-scalar analysis of the Argentine ant distribution using ecological niche models. According to our results, the Argentine ant is expected to occupy a broader distribution in its worldwide invaded ranges than is currently appreciated. Model predictions are in concordance with the currently known occurrence of the species, and indicate areas near the coast and following the main rivers as highly suitable for the species. These results give additional support to the idea that the Argentine ant is not currently in equilibrium with its environment. According to global climate change scenarios, the Argentine ant is expected to expand to higher northern and southern latitudes, and retract in the tropics at global spatial scales.
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Brightwell, Robert John. "Interactions of the invasive Linepithema humile and honeydew-producing hemiptera." 2008. http://www.lib.ncsu.edu/theses/available/etd-10312008-124509/unrestricted/etd.pdf.
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Powell, Bradford Edmund. "Interactions between the ants Linepithema humile, Tapinoma sessile and aphid mutualists." 2008. http://www.lib.ncsu.edu/theses/available/etd-11012008-082656/unrestricted/etd.pdf.
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Vasquez, Gissella Maria. "Non-nestmate adoption and colony fusion in the Argentine ant, Linepithema humile." 2006. http://www.lib.ncsu.edu/theses/available/etd-08172006-150843/unrestricted/etd.pdf.
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Ramos, Cândida Sofia Guerreiro. "Distribuição e Impacte da formiga-argentina (Linepithema humile) nas comunidades naturais do arquipélago da Madeira." Master's thesis, 2017. https://repositorio-aberto.up.pt/handle/10216/110705.
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Ramos, Cândida Sofia Guerreiro. "Distribuição e Impacte da formiga-argentina (Linepithema humile) nas comunidades naturais do arquipélago da Madeira." Dissertação, 2017. https://repositorio-aberto.up.pt/handle/10216/110705.
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(5930612), Mathew A. Dittmann. "Analysis of Gene Expression Changes in Response to Field-to-Lab Transition in the Argentine Ant, Linepithema humile." Thesis, 2019.
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Gene expression research is a valuable tool for investigating how gene regulation and expression control the underlying behaviors that structure a eusocial insect colony. However, labs that focus on ant research frequently keep ant colonies in the lab for ease of sampling. These laboratories typically do not attempt to completely emulate the ant's natural environment, and thus can expose the colonies to drastically different environmental conditions and food sources than they are used to in the wild. These shifts in diet and environment can cause changes in gene expression of the ants, affecting downstream behavioral and physiological systems. To examine the nature of these changes, colonies of the Argentine ant, <i>Linepithema humile, </i>(Mayr, 1868), were excavated from North Carolina and transferred to the lab, where they are sampled monthly. Illumina and qPCR analyses were conducted on forager samples to detect any changes in gene expression. Approximately six percent of the Argentine ant genome showed changes in gene regulation after six months in the laboratory environment. The subset of these genes examined via qPCR show that the expression of many genes are correlated with each other, indicating that these genes might be a part of a regulatory network. These findings showed that ant colonies kept in the lab experience changes in gene expression, resulting in downstream effects. Therefore, lab ant colonies are not necessarily representative of wild colonies when conducting experiments on the gene expression, behavior, and physiology of these colonies.<br>
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"Estudi d'aspectes biològics de la formiga argentina (Linepithema humile, Mayr) encarat al control de la plaga en ecosistemes naturals." Universitat de Girona, 2008. http://www.tesisenxarxa.net/TDX-0707108-135308/.
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"Efectes de la invasió de la formiga argentina, Linepithema humile (Mayr), sobre el procés de dispersió de llavors de plantes mediterrànies." Universitat de Girona, 2005. http://www.tesisenxarxa.net/TDX-0920105-164304/.
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