A preocupação com novos conceitos de produção é importante devido às mudanças observadas no mundo. Para isto, o conhecimento da diversidade dos ambientes se torna uma ferramenta de comparação entre diferentes ambientes, sendo onde se encaixa o uso das formigas como bioindicadoras, pela sua fácil coleta e identificação. O objetivo deste projeto foi identificar as espécies da família Formicidae (Hymenoptera), presentes no solo em cultivo orgânico de café (Coffea arabica), com a finalidade de determinar a riqueza e a diversidade de espécies, e as espécies que possam ser consideradas bioindicadoras dentro deste sistema. Os experimentos foram desenvolvidos em área de plantio do sistema de cultivo orgânico de café (Coffea arabica) no município de Dois Córregos, SP, em dois períodos distintos do ano: chuvoso (fevereiro/2008) coleta I e seco (julho/2008) coleta II. A coleta da mirmecofauna foi realizada utilizando-se dois tipos de armadilhas a de solo Pitfall e a do tipo Winkler. Posteriormente o material foi triado e identificado. As áreas de café foram separadas em duas a pleno sol e sombreada. Foram coletados 7101 espécimes distribuidos em 38 espécies. Poucas espécies foram constantes e freqüentes ao longo do estudo. Com relação ao índice de diversidade apenas dois pontos se destacaram ao longo do estudo na coleta I a pleno sol e na coleta II na sombra, de acordo com os índices de Shanon-Wiener e Simpson. O único ponto que teve maior dominância foi na coleta I a pleno sol. Através da análise de agrupamento dois grupos distintos foram formados a partir dos tipos de armadilha utilizados. Linepthema humile foi considerada como espécie bioindicadora para o cultivo orgânico de café. / This paper deals with a survey and identification of soil ant species (Hymenoptera, Formicidae) occurring in organic coffee (Coffea arabica) crop in order to determine species richness and diversity, as well as the ant species to be used as bioindicators of habitat disturbance in the coffee agroecosystem. Two experiments were set in an organic coffee (Coffea arabica) plantation in Dois Corregos, State of São Paulo, Brazil, one in rainy season (experiment I, February/2008) and other in the dry season (experiment II, July/2008). The ants were collected by using Pitfall trap and Winkler trap and the material was brought to the laboratory were the ant species were identified. There were two coffee areas: sun exposed crop and shadowed crop. One collected 7.101 specimens distributed in 38 species. Few species were constant and frequent ones along the research: Collect I-sun exposed and Collect II-shadowed crop, according to Shanon- Wiener and Simpson indices. The only point to present high dominance was observed in Collect I-sun exposed. One conclude that Linepthema humile is the ant species to be used as bioindicator of habitat disturbance in the organic coffee.

Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Several ant species may be associated with the same honeydew producing insect in citrus orchards. Recently antagonism and competition between two such ants were reported from Letaba. This report stimulated the present study, the purpose of which is to ascertain which ant species are most numerous in citrus orchards ln the Eastern Cape Province; the reasons for these ants being able to occupy orchards; and, finally, their relationships. A survey of the Sundays River Valley and the Fish River Valley revealed that three species - Anoplolepis custodiens Smith, Anoplolepis steingroeveri Forel, and Pheidole megacephala Fabricius - were commonly found in citrus orchards in association with Soft Brown Scale insects. The territorial relationships of these ants were determined by plotting their distribution at intervals for over a year. It was found that this distribution could be correlated with seasonal climatic conditions, the effects of farming practices, brood rearing requirements and behavioural differences between the three species. The ant, A.steingroeveri, had not been previously studied, and since foraging is an integral part of territorial behaviour, some aspects of its biology, and more especially its foraging activity, were investigated to compare it with the known biology of the other two species. Observations on the foraging activity of A. steingroeveri were made at monthly lntervals for almost a year, and correlated with climatic conditions prevailing at the time. Some seasonal and dally variations in foraging behaviour could not be readily explained in terms of the effects of temperature and humidity on the ants. Other factors, includ1ng trophallactic stimulation and overcast skies, were found to influence ant activity. Owing to the apparent lack of information in the literature and possibility of periodic honeydew production by Soft Brown Scale insects controlling ant activity was investigated in the laboratory. The results of this study showed that it was not likely that honeydew excretion restricted the activity of the ants. Several investigators have also found that many interrelated climatic factors correlated with ant foraging behaviour, but have expressed dissatisfaction at not being able to reach the crux of the matter. To clarify the issue a constant temperature chamber was constructed in which a colony of Crematogaster ants was housed and the ants were subjected to a series of temperatures at different humidities, all other factors were eliminated or kept constant. The effects of these two factors on the thermokinetics and foraging activity of the ants were registered. This thesis contains several sections and at the end of each the results are discussed in the light of the available literature and comparisons are drawn between the species under investigation. The main results are given in the summary. After the summary two appendices are included. One is an attempt to compare the effect on ant size of the honeydew diet of orchard colonies with the proteinaceoue diet of veld ants. The other appendix is an experiment to control citrus ants with an insecticide.

Due to a lack of in-situ methods capable of detecting sub-lethal effects of pollutants on soil organisms, many polluted environments are not identified prior to pollution-induced changes in the soil fauna. Therefore, there is a need to develop new non-invasive methods to measure the health of soil organisms. This study aimed to assess to what extent surface borne vibrations can inform about ant health effects from exposure to sublethal doses of a pesticide (imidacloprid). Twelve ant colonies were set up with artificial nests and fed a glucose and imidacloprid solution (0.01 mg/L, 0.1 mg/L, 1 mg/L and 10 mg/L imidacloprid). After two days, five random ants were placed in an arena where the vibrations were recorded in five one-minute blocks using a Laser Doppler Vibrometer (LDV). No significant difference was found in activity per minute between the different concentrations, although there was a measurable increase in mortality between the concentrations from the second day of exposure to the fifth. Even so, the LDV may still be a viable method, as it clearly recorded vibrations caused by ant movement. If more ants were recorded for longer periods, and more replicates were used, it seems likely the method would have been sensitive enough to detect the effect of the studied pesticide. With an improved experiment design, using the LDV for this purpose may be possible, and the current lack of such a method necessitates further research on the subject.

No description available.

The butterfly family Lycaenidae (including the Riodinidae) contains an estimated 30% of all butterfly species and exhibits a diverse array of life history strategies. The early stages of most lycaenids associate with ants to varying degrees, ranging from casual facultative coexistence through to obligate association where the long-term survival of the butterfly is dependent on the presence of its attendant ants. Attendant ants guard the butterflies against predators and parasites during their vulnerable period of larval growth and pupation. The caterpillars, in return, reward the ants by providing attractive secretions from specialized glands in their cuticle. The prevalence of caterpillar-ant associations in the species rich Lycaenidae is in contrast with other Lepidoptera, where ant association appears only as isolated cases in otherwise non ant-associated lineages. This has led to the proposal that ant association may have influenced lycaenid diversification or even enhanced the rates of speciation in the group. In contrast, facultative ant-associated butterflies exhibit high levels of host plant integrity, so it is reasonable to assume that host plants may have played a significant role in their diversification. Since the influence of ants (or plants) on diversification is independent of geographic speciation modes such as vicariance or peripheral isolates, there is an underlying inference of sympatric speciation. Certain prerequisites thought to be important for sympatric speciation, such as mating on the host plant (or in the presence of the appropriate ant) as well as ant dependent oviposition preferences are characteristic of many obligate myrmecophiles. Not surprisingly, it has been suggested that evidence for sympatric speciation is more likely to be found in the Insecta since this additional mode of diversification could account for the large numbers of insect species. This thesis tested the diversification processes in obligate and facultative ant associated lycaenids using comparative methodologies in hierarchical molecular phylogenetic analyses. First, several hypotheses relating to the influence of ants on diversification in obligately ant associated lycaenid butterflies were tested in a phylogeographic analysis of the Australian endemic Jalmenus evagoras. The phylogeographic analysis revealed that regional isolation of butterfly subpopulations coincident with locally adapted ant taxa could generate a phylogenetic pattern in which related lycaenids would be seen to associate with related or ecologically similar ants. Likewise, ecological shifts in habitat preferences by lycaenids could lead to co-diversification with habitat specialist ants, even though in both cases, the ants may play only an incidental role in the diversification process. A comparative methodology was then applied in a molecular phylogenetic analysis of the genus Jalmenus to test for a signal of diversification consistent with shifts in ant partners, and to infer the processes by which ants could influence speciation. Several other specific hypotheses relating to monophyly and taxonomy were also examined. Comparative analysis of the Jalmenus phylogeny found that attendant ant shifts coincided with high levels of sympatry among sister species. This pattern could be explained by sympatric speciation; however, data suggested it was more likely that ant shifts occurred during butterfly population expansions as a result of vegetation and climate changes in the Pleistocene. Fragmentation of populations associating with novel ants could promote rapid ecological and behavioural changes and this could result in reproductive isolation of conspecifics when in secondary contact. Diversification would then continue in sympatry. In contrast, secondary contact of populations associating with the same ant species would result in homogenisation of the two lycaenid lineages or the extinction of one. A phylogeographic analysis of the facultative myrmecophiles, Theclinesthes albocincta/T. hesperia, was then undertaken to infer the evolutionary processes (such as the effects of host plant shifts) that could result in extant demographics. Species-specific questions of taxonomy, relative population ages and dispersal routes in arid Australia were also addressed. Results from the analysis suggested the two taxa were conspecific and had diversified in the late Pleistocene as a consequence of isolation in refugia in and around the arid areas of mainland Australia. However, as was the case in the J. evagoras population analysis in which attendant ant shifts were not detected, host plant shifts were not detected in the population analysis of T. albocincta/hesperia. Host plant or attendant ant shifts manifest more frequently at the species level, thus it was necessary to test the influence of host plant shifts at this higher level. The comparative methodology was then applied to a molecular phylogenetic analysis of the facultative ant-associated section Theclinesthes (comprising Theclinesthes, Sahulana and Neolucia) to test for modes of diversification consistent with host plant shifts. The relative importance of other influences on diversification was also assessed. Akin to the Jalmenus analysis, the prediction that sister species ranges should broadly overlap when a shift in host plants had taken place was upheld in the comparative analysis. Species in the genera Jalmenus and Theclinesthes were found to have diversified in the Pleistocene so were subject to the same climatic oscillations that influenced patterns of vegetation expansion and contraction across much of Australia. Thus, the similarity and predictability of relationships in the comparative analyses based on biological data suggested that host plant shifts have influenced diversification in facultative myrmecophiles by inhibiting gene flow in secondary contact in similar fashion to that of attendant ant shifts identified in the Jalmenus phylogeny. Interpretation of data in these analyses suggested that allopatric diversification was the most common mode of speciation. Isolation was inferred to be the result of fragmentation following long distance dispersal across wide expanses of marginal habitat, or vicariance following the closing of biogeographical barriers. However, attendant-ant and host-plant shifts clearly played an important role in the diversification process, and in the maintenance of species integrity among lycaenid butterflies. Furthermore, exceptions to the predicted patterns of range overlap and ecological shifts provided clues to additional modes of diversification including shifts in habitat preferences and an unusual temporal shift following changes in specific host plant phenology resulting in allochronic diversification. Inferring modes of diversification using comparative methods based on range overlap and biological traits in a phylogenetic context is not new; however, the interpretation presented in this thesis is in contrast with contemporary methods. It is clear that the patterns of species range overlap and the ecological preferences of sister taxa are intimately related among lycaenid species that diversified during the Pleistocene. As a result, different influences on diversification can be highlighted in phylogenies when applying existing comparative methodologies but without necessarily drawing the same conclusions about modes of diversification. A more inclusive explanation for patterns of range overlap among sister taxa is detailed, a consequence of which is a method for estimating rates of extinction in a phylogeny where comprehensive distributional, biological and taxonomic data are available. These patterns and predictions may be applicable to a range of taxa, especially those that have diversified in the Pleistocene. Plans for future studies are outlined.

Orientador: João Vasconcellos Neto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T19:51:55Z (GMT). No. of bitstreams: 1 Alves_TatianeGisele_M.pdf: 798527 bytes, checksum: 1a4e43c431da929637d06a17913050d8 (MD5) Previous issue date: 2011 / Resumo: A maior parte dos ambientes naturais têm sido convertidos para uso humano. Estas mudanças estão ocorrendo num ritmo nunca antes experimentado pela natureza. O aumento do conhecimento sobre a estrutura e o funcionamento dos ecossistemas auxilia na busca de respostas de como e que forma estas ações estão afetando os sistemas naturais, e consequentemente no planejamento de melhores estratégias de conservação. Uma das maneiras de acessar os processos ecológicos que são difíceis de monitorar é buscar grupos ou organismos que facilitem o entendimento destas intervenções. A sensibilidade das assembleias de formigas, combinada com a sua importância funcional e amostragem fácil, fazem delas bons organismos para estudos de conservação. O estudo avaliou a estrutura das assembleias de formigas em três unidades de conservação na Floresta Atlântica. As formigas foram amostradas em uma floresta contínua no Parque Estadual da Serra do Mar, sudeste do Brasil, em áreas mais preservadas e menos preservadas. O objetivo foi determinar se a riqueza, a composição e a abundância destes organismos diferem entre as áreas contrastantes em relação ao grau de perturbação antrópica. Os resultados mostraram que a riqueza não foi afetada nas áreas com diferentes históricos de perturbação, mas a composição mudou drasticamente em duas das três áreas. A abundância de formigas cortadeiras foi baixa em todas as áreas e não mostrou diferenças significativas, e a abundância de Ponerinae foi semelhante entre os diferentes contrastes. Os resultados do estudo sugerem que nos sistemas estudados, os efeitos nas assembleias são dependentes da intensidade e da frequência da perturbação, e do tempo de recuperação da área alterada / Abstract: The majority of the natural environments have been converted for human use. These changes are occurring in a level never experienced before by nature. Increased the knowledge about the structure and functioning of ecosystems helps in finding answers about how to and in what way these actions can affecting natural systems, and consequently in the planning of better conservation strategies. One way to access the ecological processes that are difficult to monitor is to find groups of organisms that are affect by these changes. The sensitivity of ant assemblages, combined with their functional importance and easy of sampling makes them excellent organisms for conservation studies. The present study evaluated the structure of ant assemblages in three protect areas in the Brazilian Atlantic Forest. Ants were sampled within a continuous forest in the Serra do Mar State Park, southeastern Brazil, in disturbed and undisturbed areas. The objective was to determine if richness, composition and abundance of ant assemblages differ between contrasting areas in relation to the degree of human disturbance. Results showed that ant richness has not changed between areas with different disturbance history, while the composition has changed dramatically in two of the three areas. The abundance of leaf-cutting ants was low in all sites and showed no significant differences, and the abundance of Ponerinae was similar across the contrasting areas surveyed. Results suggest that in the studied systems, the effects are dependent of the intensity and frequency of disturbance, and also of the recovery time of disturbed area / Mestrado / Ecologia / Mestre em Ecologia

Les fourmis, comme tous les Hyménoptères, sont caractérisées par un mode de détermination du sexe de type haplodiploïde. Les femelles sont issues d’œufs fertilisés et sont diploïdes alors que les mâles se développent à partir d’œufs non fertilisés par parthénogenèse arrhénotoque, et sont haploïdes. A quelques rares exceptions près, le déterminisme de la caste au sein du sexe femelle est réalisé de manière épigénétique :seules les larves diploïdes les mieux nourries et/ou celles produites après le repos hivernal se développent en femelles sexuées (reines), les autres en femelles non reproductrices (ouvrières). Récemment, plusieurs travaux ont montré que les reines de quelques espèces de fourmis sont capables de maximiser leur succès reproductif en exploitant de manière conditionnelle la reproduction sexuée et asexuée. Alors que les ouvrières sont produites à partir d’œufs fertilisés par reproduction sexuée classique, les jeunes femelles reproductrices sont issues d’œufs diploïdes produits par parthénogenèse thélytoque et sont, par conséquent, génétiquement très similaires à leur mère. L’espèce Cataglyphis cursor est le premier modèle chez lequel cette stratégie reproductrice a été mise en évidence (Pearcy et al. 2004b). Les sociétés de C. cursor sont strictement monogynes, les reines sont hautement polyandres et utilisent la reproduction sexuée et asexuée pour la production d’ouvrières et de femelles reproductrices, respectivement. La combinaison de la polyandrie et de la reproduction thélytoque permet aux reines de C. cursor d’optimiser le taux de transmission de leurs gènes via des filles reproductrices, tout en assurant une diversité génétique maximale au sein de la force ouvrière. Par ailleurs, les ouvrières de C. cursor ont conservé leurs ovaires et se reproduisent en l’absence de reine. Elles produisent alors des mâles (par parthénogenèse arrhénotoque), des femelles sexuées et des ouvrières (par parthénogenèse thélytoque) (Cagniant, 1973)<p>Les travaux réalisés dans le cadre de cette thèse de doctorat visent à déterminer si les stratégies reproductrices remarquables exploitées par C. cursor sont propres à l’espèce ou si elles ont évolué au sein de plusieurs espèces du genre. A cette fin, nos recherches s'articulent autour de 2 axes complémentaires. Premièrement, nous avons approfondi l'étude des stratégies reproductrices chez C. cursor en nous concentrant sur deux aspects. (i) Plusieurs hypothèses ont été proposées pour justifier l’évolution de la polyandrie chez les fourmis. Nos travaux ont testé et éliminé trois d’entre elles pour C. cursor :l’hypothèse de la limitation spermatique, celle des coûts des mâles diploïdes et celle selon laquelle une plus grande variabilité génétique des ouvrières améliorerait la division du travail. (ii) Nous avons mis en évidence l’existence d’un contrôle des reines dans le déterminisme de la caste chez cette espèce. Les reines ne produisent des œufs thélytoques qu’au début du printemps, lorsque les ouvrières élèvent les œufs en sexués. Plus tard dans la saison, les reines ne produisent plus que des œufs fertilisés qui se développeront en ouvrières. <p>Deuxièmement, à titre comparatif, nous avons analysé la structure socio-génétique de deux autres espèces de Cataglyphis :C. sabulosa et C. livida. Ces deux espèces sont monogynes et polyandres. Leurs ouvrières sont capables de pondre des œufs haploïdes mais seules les ouvrières de C. sabulosa ont produits des œufs diploïdes thélytoques. Aucune des reines des deux espèces n’utilisent la parthénogenèse thélytoque pour produire des femelles sexuées.<p>L’ensemble des résultats obtenus dans notre étude ont été replacés dans une perspective évolutive afin de préciser quand la polygynie, la polyandrie et la thélytoquie seraient apparues dans la phylogénie des Cataglyphis. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The odorous house ant (<i>Tapinoma sessile</i>) is an adaptive and widespread pest ant species found in North America. Despite the economic and ecological impact of pest ants, effective management still faces many challenges and control failures with liquid spray insecticides in urban and natural environments. In many insects such as bed bugs and cockroaches, chemical control measures have resulted in insecticide resistance. However, in contrast to non-social insects, insecticide resistance has never been documented in social insects. The current study had three main goals. The first objective was to examine regional variation in <i>T. sessile</i> insecticide susceptibility to three classes of insecticides commonly used in urban ant control. The second objective was to compare insecticide susceptibility in <i>T. sessile</i> colonies collected in natural vs. urban areas. The final objective was to determine if insecticide susceptibility varies in workers vs. queens. A total of 30 <i>T. sessile</i> colonies were collected within a 50-mile radius of Purdue University campus, Tippecanoe County, Indiana. Fifteen colonies were collected in natural areas and 15 in urban areas. Insecticide susceptibility of all 30 colonies was tested using residual exposure assays. Urban and natural colonies showed no significant differences in tests with lambda-cyhalothrin and fipronil. In tests with dinotefuran, urban colonies were significantly more tolerant relative to natural colonies. These results suggest that habitat type does not reliably predict susceptibility levels in individual populations. Queens were found to be significantly more tolerant relative to their worker counterparts across all three insecticides. Lower insecticide susceptibility in the queens may explain why <i>T. sessile</i> is such a persistent pest in urban environments. This 15 study’s results can in part provide a foundation for the development of more effective and efficient control methods for <i>T. sessile</i>.

La vie en société offre de nombreux avantages, mais comporte toutefois certains risques comme celui de la prolifération des pathogènes. Cette susceptibilité accrue s'explique notamment par la densité élevée des individus au sein des colonies, la proximité génétique et la fréquence des interactions sociales. Au sein du nid, les cadavres peuvent être porteurs de pathogènes :ils représentent un risque important pour la survie de la colonie entière et doivent donc en être écartés en permanence. L’objectif général de cette thèse est d’améliorer la compréhension des mécanismes individuels et collectifs qui régissent le rejet de ces cadavres à l’extérieur de la colonie chez la fourmi rouge, Myrmica rubra. <p><p>Tout d’abord, nous avons mis en évidence l’importance du rejet des déchets pour la survie des fourmis (Chapitre 1). Le rejet des cadavres, même exempts de pathogènes, permet d’augmenter légèrement la survie des ouvrières. La nécrophorèse prend toute son importance lorsque la colonie est exposée à des cadavres infectés par le champignon Metarrhizium anisopliae. Une limitation du rejet de ces cadavres porteurs de pathogènes entraîne une mortalité des ouvrières relativement importante (jusqu’à 30% après 50 jours) tandis que celle des larves reste très limitée. Nous avons également cherché à identifier les composés chimiques susceptibles de déclencher le rejet des cadavres par leurs congénères (Chapitre 2). Les cadavres fraîchement tués n’étaient pas rejetés rapidement. Par contre, des cadavres vieux de 1 à 6 jours étaient presque toujours éloignés du nid. Sur ces corps « âgés » de 1 à 6 jours, on constate l’apparition de deux composés :les acides oléique et linoléique. L’adjonction sur des cadavres frais d’acide oléique et/ou d’acide linoléique en quantités équivalentes à celles trouvées sur un cadavre de plus de 24h en provoque le rejet par les ouvrières. Nous avons ensuite étudié les facteurs susceptibles d’influencer le lieu de dépôt des cadavres à l’extérieur du nid (Chapitre 3). Les cadavres ne sont pas entassés dans un endroit particulier, mais dispersés autour du nid, relativement loin de l’entrée de celui-ci. De plus, le marquage passif des zones explorées par les ouvrières -qui sont un indice de fréquentation de cette zone par la colonie- n’influence pas la décision des ouvrières d’y déposer le cadavre. Lors du transport des corps, nous avons étudié quels sont les moyens utilisés par les fourmis pour leur orientation (Chapitre 4). Aucune clé chimique n’intervient dans l’orientation des fourmis transporteuses mais celles-ci utilisent leur mémoire spatiale en retournant préférentiellement dans la direction déjà visitée. Enfin, nous avons testé s’il existe une spécialisation à court ou moyen terme des ouvrières dans le transport de cadavres (Chapitre 5). Nous avons pu montrer que les fourmis transporteuses de corps peuvent se spécialiser lors de transports successifs à court terme (de l’ordre d’une heure). Par contre, aucune spécialisation dans les activités de nécrophorèse n’a pu être mise en évidence à moyen terme (de l’ordre de quelques semaines). Les fourmis transporteuses de cadavres sont le plus souvent des ouvrières actives à l’extérieur du nid qui n’ont que peu de contacts avec leurs congénères au sein du nid ou avec les stades particulièrement sensibles aux pathogènes tels que les larves.<p><p>L’ensemble des comportements liés au rejet et au transport des cadavres s’inscrivent dans les stratégies prophylactiques et hygiéniques de la colonie. Nous discuterons des liens entre le rejet des cadavres et l’ensemble des comportements appartenant à l’immunité sociale, qui permettent de limiter la prévalence et la propagation des pathogènes chez les insectes sociaux.<p> / Doctorat en Sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished