Females often select mates on the basis of sexual signals, which can be reliable indicators of male quality when the costliness of these signals prevents cheating. The immunocompetence handicap hypothesis (ICHH) provides a mechanistic explanation of these costs, by proposing a trade-off between immune function and sexual displays. This trade-off arises because testosterone enhances sexual signa...

Evolutionary processes have shaped the vertebrate immune system over time, but proximal mechanisms control the onset, duration, and intensity of immune responses. Based on testing of the hygiene hypothesis, it is now well known that microbial exposure is important for proper development and regulation of the immune system. However, few studies have examined the differences between wild animals ...

Reproductive costs are an essential component of evolutionary theory. For instance, an increase in reproduction is generally coupled with a decrease in immunocompetence shortly after mating. However, recent work in Drosophila melanogaster suggests that the potential to mount an immune response, as measured by the levels of immune gene expression, increases after mating. These data are in contra...

Here, we provide a brief review of the mechanistic connections between immunity and aging-a fundamental biological relationship that remains poorly understood-by considering two intertwined questions: how does aging affect immunity, and how does immunity affect aging? On the one hand, aging contributes to the deterioration of immune function and predisposes the organism to infections ("immuno-s...

establishment of new neural connections rather than the modification of existing sets. Blinded octopuses can acquire certain kinds of discriminations based upon tactile or chemical stimulation. The results of a textual discrimination experiment with grooved cylinders suggest that the "discrimination of the topographical features of objects touched may be based simply upon the proportion of sens...

introduction hydrops fetalis is a serious condition in fetal period, characterized by the presence of serous fluid accumulation in at least two potential spaces in fetus including pleural effusion, pericardial effusion, and ascites. the incidence of hydrops fetalis is one per 2500-3000 pregnancies. this condition is followed by different diseases. fetal hemolytic anemia and its hypoxemia due to...

With the rapid development of the field of ecological and evolutionary immunology, a series of new techniques to measure different components of immune function is becoming commonplace. An important step for the interpretation of these new measures is to understand the kind of information about the animal that they convey. We showed that the microbicidal capacity of Stonechat (Saxicola torquata...

In this review, the authors examine the evidence linking social support to physiological processes and characterize the potential mechanisms responsible for these covariations. A review of 81 studies revealed that social support was reliably related to beneficial effects on aspects of the cardiovascular, endocrine, and immune systems. An analysis of potential mechanisms underlying these associa...