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Saturday, February 12, 2011

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CARNIVAL OF BIODIVERSITY ': mimicry

var _gaq _gaq = This post is in the project CARNIVAL of biodiversity '. This initiative aims to address issues related to the natural sciences to continue to emphasize the importance of the topic in question, both within the scientific community and among the general public. invite anyone to go read this post on the blog

Leucophaea CARNIVAL OF BIODIVERSITY ': II bet) you can find links to relevant posts of bloggers patecipanti initiative. biological adaptations are the result of interaction between the genetic pools of the populations selective factors and the environment. Predators and prey have evolved adaptations often very complex time in the first case to be made more efficient predation (hunting strategies, use of traps, criptismo, mimicry, the formation of so-called "image search") in the second case of escape capture (exit strategies, incommestibilità associated with visual cues, etc. ...).
In particular, the adaptations of this second type are very numerous, since predation has been and still is a real selective force of great importance to all organisms. In this post we will look at certain types of strategies used by organisms to chase or escape predators, especially we focus on the various forms of camouflage. aposematism. dell'aposematismo theory states that the potential prey have become forms of defense against predators, such as incommestibilità, benefit from giving these defenses with appropriate visual cues such as eye-catching colors. Darwin has long had raised the issue of eye-catching colors of the insect larvae can not be attributed to sexual selection. The combination of warning signs and incommestibilità (or other forms of defense) in potential prey is a very frequent phenomenon observed in nature in many terrestrial arthropods, especially insects. image An example: the Vespa cincta In fact, the warning signs are not only visual but also olfactory and acoustic.
Camouflage The camouflage is the imitation as a protective (or aggressive) that some bodies to take in relation to other species. In its simplest form, a mime mimicry includes a model that mimics the model taking advantage of the similarity with the model, c) species that are fooled by this imitation. We can divide the models in different types of mimicry:

1) Batesian mimicry This type of mimicry is the imitation of a model for predators inappetibile by mimi attractive, often phylogenetically distant. Bates said that in the Amazon rainforest eliconidi, common butterflies in bright colors, and slow flight were not attacked by insect-feeding birds, was also noted that another species of moths of the family Leptalis looked like so much in the behavior and appearance of the species eliconidi to be indistinguishable except to a close scrutiny. Bates drew the following conclusions: 1) eliconidi are inedible for insectivorous birds, and 2) there their bright colors to be seen as a warning to potential predators, which membership in eseperienze negative, and 3) that although the farlalle Such Leptalis are edible, those among them who imitate eliconidi have exchanged with them and from predators like these are avoided. Moreover, it was noted that the Leptalis camouflage were relatively rare. This is explained by the fact that the Batesian mimicry requires to maintain its protective efficacy that mimes are not many of their models, so that predators do more experienced models. Predators learn to avoid it and then tasted them inedible models very few times and then confuse them with their mimes. This phenomenon of mimicry is widespread in nature, ClassC example is a species of Lepidoptera and Diptera, edible and unprotected, that mimic the appearance and form of certain types of wasps, showing yellow-black, like the buzzing of wasps sting provided which are regularly avoided by predators who have had bad experiences with them.

In some types of Batesian mimicry imitation of models is confined solely to women workers. This phenomenon has a number of very specific reasons: 1) males are less important than the female reproductive economy in grao sonono dlela species and to fertilize more females, and 2) the presence in males of color in the design and not imitative, characteristic of species is advantageous in terms of sexual selection, thus facilitating the rinoscimento by the female and the success of the courtship and 3) the non-mimetic coloration of the male reduces the ratio of pure mime / model.
A much studied example is that of the butterfly Papilio Dardanus

. The females of these species mimic inedible and protected species of moths of the genus NYMPHALIDS

Danaus , which present an appearance so different from that of males has meant that they were even considered different species.

Mullerian mimicry

Another type of camouflage, is where to look alike species are inedible, and avoid predators. Muller was expected that the predators learn to recognize and avoid species inappetibili through bad experiences and that this learning process is sacrificed part of the population of each species inedible. If more species are similar to the point of being confused by predators will reduce the tax paid by each species.

Camouflage martensite

inedible species are generally not lethal to the predators. The camouflage is realized in fact as a result of learning by predators on the unpleasant quality of the model. The pace of learning by predators requires negative experiences, if the prey was the first fatal experiences would be lethal to the predator and can not esservi quindi apprendimento. Ciò spiega perchè le specie potenzialmente letali per i predatori non presentino segnali aposematici ma siano invece criptiche. Infatti la presenza di specie dotate di mimetismo e in grado di uccidere i predatori in natura è del tutto eccezzionale. Un classico esempio sono i serpenti corallo caratterizzati dall'avere una vistosa livrea ad anelli rossi neri e gialli.

Questi velenosi serpenti, troppo velenosi affinchè i predatori abbiano la possibilità di fare esperienza su di essi, rislta chiaro se si ammette che il loro ruolo el complesso mimetico non sia quello di modelli come si pensava in passato ma di mimi, non diversamente dalle specie innocue. Questo tipo di mimetismo not very common in nature is of great interest from the evolutionary point of view. In the case of coral snakes because the selection has favored the increase of the degree of venom that allows the killing of the predator size increased. Provesso However, this could not be extended to a number of species taken off because he would reduce the protection provided through mimicry, coral snakes have against their predators.

Other adaptations against predation.

In some cases a cryptic animal, no matter how well disguised, it can also be seen by a predator. Mimi Analogamete batesiani can be attacked by a predator inexperienced, or particolatmente hungry. Not surprisingly, in addition to mimetism there are several strategies by which potential prey more difficult to make their catch. Among these are "false eyes" typically consisting of conspicuous spots usually surrounded by a dark ring, having a central pupil of contrasting color. The eye spots are evoute indipendentemenre groups in different animals (birds, fish, butterflies, caterpillars, etc ...) starting from different morphological structures. An example is the caterpillar of sfingide Deilephila elpenor showing false eyes on the chest when the caterpillar is threatened expands the size of the thoracic segments by increasing the size of the eyes, the halyard up and lash the air like a snake. Some animals use of it with a fake head antipredatorie purposes, located at the rear of the body. Through it mislead predators that usually turn their attack on the cephalic region of the prey (an injury to the head knocks the prey). In this case the predator fails to blow and the PDA has the ability to escape predators fleeing in the unexpected direction. Other animals are able to spray, inject, rub, regurgitate, on predators of toxic substances irritating or disgusting by themselves synthesized. In other cases the strategy is to remove all traces of their passage, an example is the caterpillar

Catocala cerogama,

le larve dopo aver mangiatoparti di una foglia recidono il picciolo lasciando cadere a terra ciò che rimane del proprio pasto.
Mimetismo intraspecifico.

I segnali di incommestibilità possono essere osservati anche all'interno di una singola specie aposematica, con presenza di individui appetibili che di individui inappetibili. Ciò dipende dal fatto che le basi chimiche dell'incommestibilità sono rappresentate da sostanza vegetali secondarie presenti nelle piante di cui si nutrono. Individui delle farfalle Danaus plexippus
la cui inappetibilità dipende dalla pianta, Asclepias curassavica, di cui si nutre la larva which makes inappetibile birds. while people who eat different types of plants are desirable. The presence of individuals of the same species with imo functions of the model and is defined automimetismo or intraspecific mimicry.

Monday, February 7, 2011

Can You Use New Look Gift Cards Online

Municipal Museum and unity of Italy

Eravamo riuniti al secondo piano del edificio comunale, in attesa dell'inizio della visita guidata per conoscere le tracce dell'unità d'Italia lasciate dalla storia in questo luogo nel centro di Bologna. Ogni volta che torno in questa lunga e rettangolare sala, riscopro lo stupore, come la prima volta quando l'avevo vista. I muri coperti da affreschi delle tonalità calde della terra, dal marrone scuro al siena bruciato al nero, con in fondo la luce che entra dalle due finestre, è un luogo magico che mi incanta ogni volta.

Unità di Italia nel palazzo comunale di Bologna

La nostra guida era Mirtide Gavelli.  Lei aveva subito chiarito che non era una storica dell'arte, but only a historian, so we should not expect to know the artistic heritage of this wonderful museum of its tour.

Over the past 13 years, ever since we moved to Bologna, I went to the municipal museum of art several times. Each visit was a new discovery, to learn about the culture, history, art of the city. Now I try whenever I can, to join guided tours to the beautiful city that holds regular. These visits have dramatically changed my relationship with Bologna, but also with the world.

seems incredible, but I think you can not see it even an elephant, if you do not know what an elephant. When I arrived to live in Bologna, I thought that museums were boring places. Before coming to Bologna, I visited many museums in different cities around the world. I'm not saying that I had not appreciated the paintings of Van Gogh when they had visited the art museum in London, or the Sistine Chapel in the Vatican Museums, but it was an appreciation of art, a little 'detached and antiseptic.

Instead, feel the history as something alive, something that concerns me personally, I learned to feel at Bologna. The various museums of Bologna, the archeology museum, the medieval museum, and museum of contemporary art, little by little I discovered all through these tours.

Maybe it helped that in Bologna, the entry the museums is free. I do not think the issue of saving 4-5 Euros, but when you pay a ticket, you have the time to visit and see everything right. Do not pay the ticket to spend only 5-10 minutes in the museum. I do not feel like something that belongs to you, you get inside only for 5 minutes because you're going through and just want to see a picture that you liked.

my discovery of the history and culture of Bologna, I've kept to myself. Today Bologna has many foreign students, including those who come for specialized studies and doctorates. I had the opportunity to meet many Indian students come here only for a few months or maybe for a few years. Most of the time they do not speak Italian, and do not have time to learn the language, perhaps because they live among other students, where everyone speaks English, and study their subjects in English. So I feel my duty to let them know the city, beyond the superficial appearance. Already a few times I went with a small group of Indian students to go through a guided tour that I followed, to let them know a small part of this heritage.

The visit last night was very interesting. The history of the cardinal legate who ruled Bologna, the arrival of French troops in 1796, the paintings of the fasces in the town hall to symbolize the Jacobin republic, the choice of three colors of the flag that have been painted in different ways in the palace, and Cisalpine republics Cispadana, the start of the period of 60 years of revolution and attacks that led to the unification of Italy, I understand some parts of Italian history that did not know before.

The fasces from 1797

symbol of the Jacobin republic Cispadana

The colors of the Italian flag in the painting expressed

Cispadana cities of the republic (maybe), and then change repainted in the colors of the papal league

I want to express thanks to the city of Bologna for these experiences, e anche a Mirtide Gavelli, la nostra guida per questa visita.

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