Once a Batesian mimic, not always a Batesian mimic: mimic reverts back to ancestral phenotype when the model is absent

Batesian mimics gain protection from predation through the evolution of physical similarities to a model species that possesses anti-predator defences. This protection should not be effective in the absence of the model since the predator does not identify the mimic as potentially dangerous and both the model and the mimic are highly conspicuous. Thus, Batesian mimics should probably encounter strong predation pressure outside the geographical range of the model species. There are several documented examples of Batesian mimics occurring in locations without their models, but the evolutionary responses remain largely unidentified. A mimetic species has four alternative evolutionary responses to the loss of model presence. If predation is weak, it could maintain its mimetic signal. If predation is intense, it is widely presumed the mimic will go extinct. However, the mimic could also evolve a new colour pattern to mimic another model species or it could revert back to its ancestral, less conspicuous phenotype. We used molecular phylogenetic approaches to reconstruct and test the evolution of mimicry in the North American admiral butterflies (Limenitis: Nymphalidae). We confirmed that the more cryptic white-banded form is the ancestral phenotype of North American admiral butterflies. However, one species, Limenitis arthemis, evolved the black pipevine swallowtail mimetic form but later reverted to the white-banded more cryptic ancestral form. This character reversion is strongly correlated with the geographical absence of the model species and its host plant, but not the host plant distribution of L. arthemis. Our results support the prediction that a Batesian mimic does not persist in locations without its model, but it does not go extinct either. The mimic can revert back to its ancestral, less conspicuous form and persist

Uma nova disciplina: o direito sanitário A new (Brazilian) academic discipline: health law

A reivindicação da saúde como direito tem levado o Estado a assumir responsabilidades crescentes pela promoção, proteção e recuperação da saúde do povo. A atuação do Estado contemporâneo - de Direito - é orientada por normas jurídicas. O conhecimento das normas que regulam a ação estatal no campo da saúde é indispensável ao sanitarista, profissional designado pela sociedade para trabalhar especificamente pela elevação de seu nível de saúde. Nessa linha, foram analisadas experiências estrangeiras com o ensino do direito sanitário, juntamente com as recomendações dos organismos internacionais de saúde. Conclui-se que a implementação do ensino do direito sanitário, no Brasil, é urgente.<br>The demand for health seen as the citizen's right, has led the State to accept increasing responsabilities regarding the health of the people, as evidenced by policies of health promotion, protection and recovery. The activity of a modern State ("State of law") is exercised according to juridical principles. It is highly advisable, therefail, that health workers-those professionals that society has appointed to work on its behalf for the raising of its health levels should have knowledge of the rules which guide the State's performance in the health area. Thus, foreign experiences in teaching health law as well as the recommendations of International Health Agencies, analysed in this paper, lead us to conclude that the teaching of health law is a must among the Brazilian academic priorities

Identification and dynamics of a cryptic suture zone in tropical rainforest

Suture zones, shared regions of secondary contact between long-isolated lineages, are natural laboratories for studying divergence and speciation. For tropical rainforest, the existence of suture zones and their significance for speciation has been controversial. Using comparative phylogeographic evidence, we locate a morphologically cryptic suture zone in the Australian Wet Tropics rainforest. Fourteen out of 18 contacts involve morphologically cryptic phylogeographic lineages, with mtDNA sequence divergences ranging from 2 to 15 per cent. Contact zones are significantly clustered in a suture zone located between two major Quaternary refugia. Within this area, there is a trend for secondary contacts to occur in regions with low environmental suitability relative to both adjacent refugia and, by inference, the parental lineages. The extent and form of reproductive isolation among interacting lineages varies across species, ranging from random admixture to speciation, in one case via reinforcement. Comparative phylogeographic studies, combined with environmental analysis at a fine-scale and across varying climates, can generate new insights into suture zone formation and to diversification processes in species-rich tropical rainforests. As arenas for evolutionary experimentation, suture zones merit special attention for conservation