984 resultados para Tartessos (Loc. ant.) - Civilização - Fontes


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen basado en el de la publicaci??n

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen basado en el de la publicaci??n

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen basado en el de la publicaci??n

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen basado en el de la publicaci??n

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The influence of temperature on the developmental times and survival of insects can largely determine their distribution. For invasive species, like the Argentine ant, Linepithema humile Mayr (Hymenoptera: Formicidae), these data are essential for predicting their potential range based on mechanistic models. In the case of this species, such data are too scarce and incomplete to make accurate predictions based on its physiological needs. This research provides comprehensive new data about brood survival and developmental times at a wide range of temperatures under laboratory conditions. Temperature affected both the complete brood development from egg to adult worker and each of the immature stages separately. The higher the temperature, the shorter the development times. Brood survival from egg to adult was low, with the maximum survival rate being only 16% at 26º C. Temperature also affected survival of each of the immature stages differently: eggs were negatively affected by high temperatures, while larvae were negatively affected by low temperatures, and the survival of pupae was apparently independent of environmental temperature. At 32º C no eggs survived, while at 18º C less than 2% of the eggs hatched into larva. The data from the present study are essential for developing prediction models about the distribution range of this tramp species based on its physiological needs in relation to temperature

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O objectivo deste artigo é demonstrar que as fontes de pressão no emprego podem ter um impacto potencial na qualidade de vida em fisioterapeutas. Para alcançar este objectivo recorreu-se a um tipo de investigação descritiva exploratória e transversal. Os instrumentos de recolha de dados utilizados foram a Escala SF-36 e a Escala de Fontes de Pressão no Emprego, cuja aplicação incidiu sobre 93 fisioterapeutas a exercerem funções em Hospitais portugueses. Neste estudo, verificou-se que as fontes de pressão no emprego têm um impacto na qualidade de vida (funcionamento físico, desempenho físico, dor corporal, saúde geral, vitalidade, função social, desempenho emocional e saúde mental) dos fisioterapeutas estudados. Os resultados obtidos e posteriores conclusões implicam ainda que se continue a dar mais atenção aos factores que podem interferir na qualidade de vida dos fisioterapeutas, para que estes possam prestar cuidados de saúde com qualidade.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

P>1. Ants show complex interactions with plants, both facultative and mutualistic, ranging from grazers through seed predators and dispersers to herders of some herbivores and guards against others. But ants are rarely pollinators, and their visits to flowers may be detrimental to plant fitness. 2. Plants therefore have various strategies to control ant distributions, and restrict them to foliage rather than flowers. These 'filters' may involve physical barriers on or around flowers, or 'decoys and bribes' sited on the foliage (usually extrafloral nectaries - EFNs). Alternatively, volatile organic compounds (VOCs) are used as signals to control ant behaviour, attracting ants to leaves and/or deterring them from functional flowers. Some of the past evidence that flowers repel ants by VOCs has been equivocal and we describe the shortcomings of some experimental approaches, which involve behavioural tests in artificial conditions. 3. We review our previous study of myrmecophytic acacias, which used in situ experiments to show that volatiles derived from pollen can specifically and transiently deter ants during dehiscence, the effects being stronger in ant-guarded species and more effective on resident ants, both in African and Neotropical species. In these plants, repellence involves at least some volatiles that are known components of ant alarm pheromones, but are not repellent to beneficial bee visitors. 4. We also present new evidence of ant repellence by VOCs in temperate flowers, which is usually pollen-based and active on common European ants. We use these data to indicate that across a wide range of plants there is an apparent trade-off in ant-controlling filter strategies between the use of defensive floral volatiles and the alternatives of decoying EFNs or physical barriers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A phylogenetic approach was taken to investigate the evolutionary history of seed appendages in the plant family Polygalaceae (Fabales) and determine which factors might be associated with evolution of elaiosomes through comparisons to abiotic (climate) and biotic (ant species number and abundance) timelines. Molecular datasets from three plastid regions representing 160 species were used to reconstruct a phylogenetic tree of the order Fabales, focusing on Polygalaceae. Bayesian dating methods were used to estimate the age of the appearance of ant-dispersed elaiosomes in Polygalaceae, shown by likelihood optimizations to have a single origin in the family. Topology-based tests indicated a diversification rate shift associated with appearance of caruncular elaiosomes. We show that evolution of the caruncular elaiosome type currently associated with ant dispersal occurred 54.0-50.5 million year ago. This is long after an estimated increase in ant lineages in the Late Cretaceous based on molecular studies, but broadly concomitant with increasing global temperatures culminating in the Late Paleocene-Early Eocene thermal maxima. These results suggest that although most major ant clades were present when elaiosomes appeared, the environmental significance of elaiosomes may have been an important factor in success of elaiosome-bearing lineages. Ecological abundance of ants is perhaps more important than lineage numbers in determining significance of ant dispersal. Thus, our observation that elaiosomes predate increased ecological abundance of ants inferred from amber deposits could be indicative of an initial abiotic environmental function.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Most studies aiming to determine the beneficial effect of ants on plants simply consider the effects of the presence or exclusion of ants on plant yield. This approach is often inadequate, however, as ants interact with both non-tended herbivores and tended Homoptera. Moreover, the interaction with these groups of organisms is dependent on ant density, and these functional relationships are likely to be non-linear. A model is presented here that segregates plant herbivores into two categories depending on the sign of their numerical response to ants (myrmecophiles increase with ants, non-tended herbivores decline). The changes in these two components of herbivores with increasing ant density and the resulting implications for ant-plant mutualisms are considered. It emerges that a wide range of ant densities needs to be considered as the interaction sign (mutualism or parasitism) and strength is likely to change with ant density. The model is used to interpret the results of an experimental study that varied levels of Aphis fabae infestation and Lasius niger ant attendance on Vicia faba bean plants. Increasing ant density consistently reduced plant fitness and thus, in this location, the interaction between the ants and the plant can be considered parasitic. In the Vicia faba system, these costs of ants are unlikely to be offset by other beneficial agents (e.g., parasitoids), which also visit extrafloral nectaries.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Some organisms can manipulate the nervous systems of others or alter their physiology in order to obtain benefit. Ants are known to limit alate aphid dispersal by physically removing wings and also through chemical manipulation of the alate developmental pathway. This results in reduced dispersal and higher local densities of aphids, which benefit ants in terms of increased honeydew and prey availability. Here, we show that the walking movement of mutualistic apterous aphids is also reduced by ant semiochemicals. Aphids walk slower and their dispersal from an unsuitable patch is hampered by ants. If aphid walking dispersal has evolved as a means of natural enemy escape, then ant chemicals may act as a signal indicating protection; hence, reduced dispersal could be adaptive for aphids. If, however, dispersal is primarily a means to reduce competition or to maintain persistent metapopulations, then manipulation by ants could be detrimental. Such manipulation strategies, common in host-parasite and predator-prey interactions, may be more common in mutualism than expected.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Os flebotomíneos são insetos hematófagos de grande importância médica e veterinária atuando como vetores de parasitas como Leishmania. O estudo do padrão alimentar desses vetores pode ajudar a compreender a sua interação com potenciais reservatórios de Leishmania. Neste estudo, desenvolvemos ensaios de PCR em tempo real para identificação de sangue em flebotomíneos. Seis pares de primers foram desenhados com base no gene citocromo b de sequencias disponíveis no GenBank dos seguintes hospedeiros potenciais: cão, gato, cavalo, galinha, rato e humano. Primeiramente, os ensaios de PCR em tempo real utilizando SYBR Green foram conduzidos usando uma curva padrão com oito concentrações diferentes (i.e., 10 ng, 1 ng, 100 pg, 10 pg, 1 pg, 100 fg, 10 fg e 1 fg por 2 µl) de amostras do DNA extraído do sangue com EDTA a partir de cada espécie de animal. Em seguida, o DNA foi extraído de 100 fêmeas de flebotomíneos ingurgitadas de campo pertencentes a três espécies (i.e., Lutzomyia longipalpis, L. migonei e L. lenti) foram testadas pelos protocolos aqui padronizados. Fêmeas de flebotomíneos foram experimentalmente alimentadas em um rato (Rattus rattus) e utilizadas para avaliar a detecção do ensaio. Os protocolos funcionaram de forma eficiente com limites de detecção de 10 pg a 100 fg. Fêmeas de flebotomíneos ingurgitadas coletadas no campo estavam alimentadas de humanos (73 por cento), galinhas (23 por cento), cães (22 por cento), cavalos (15 por cento), ratos (11 por cento) e gatos (2 por cento). Curiosamente, 76,1 por cento das fêmeas de L. longipalpis foram positivas para o sangue humano. No total, 48 por cento das fêmeas testadas estavam alimentadas em uma única fonte, 31 por cento em duas e 12 por cento em três. A análise do curso de tempo mostrou que a técnica de PCR em tempo real visando o DNA de roedor foi capaz de detectar pequenas quantidades de DNA do hospedeiro até 5 dias após o repasto sanguíneo. Esses protocolos representam ferramentas promissoras para a identificação da fonte alimentar de flebotomíneos de campo

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Nest site selection in arboreal, domatia-dwelling ants, particularly those coexisting on a single host plant, is little understood. To examine this phenomenon we studied the African savannah tree Vachellia erioloba, which hosts ants in swollen-thorn domatia. We found four ant species from different genera (Cataulacus intrudens, Tapinoma subtile, Tetraponera ambigua and an unidentified Crematogaster species). In contrast to other African ant plants, many V. erioloba trees (41 % in our survey) were simultaneously co-occupied by more than one ant species. Our study provides quantitative field data describing: (1) aspects of tree and domatia morphology relevant to supporting a community of mutualist ants, (2) how ant species occupancy varies with domatia morphology and (3) how ant colony size varies with domatia size and species. We found that Crematogaster sp. occupy the largest thorns, followed by C. intrudens, with T. subtile in the smallest thorns. Thorn age, as well as nest entrance hole size correlated closely with ant species occupant. These differing occupancy patterns may help to explain the unusual coexistence of three ant species on individual myrmecophytic trees. In all three common ant species, colony size, as measured by total number of ants, increased with domatia size. Additionally, domatia volume and species identity interact to predict ant numbers, suggesting differing responses between species to increased availability of nesting space. The proportion of total ants in nests that were immatures varied with thorn volume and species, highlighting the importance of domatia morphology in influencing colony structure.