Is Sexual Dimorphism in the Immune Response of Gryllodes sigillatus Related to the Quality of Diet?

Whereas some authors have proposed that sexual dimorphism in the immune response is fixed, others pose that it is dynamic and depends on diet. The aim of the present study was to explore the second hypothesis. Immunocompetence differences between females and males can be linked to resource availability. We tested this idea by providing a low or high quality diet to two groups of Gryllodes sigilatus during their developmental period. Then, at the adult phase half of each group was challenged with LPS from Serratia marcescens. The size, phenol oxidase (PO), and lytic activity were compared between groups according to diet, sex, and immune challenge. Results show that diet quality favor size in both sexes. However, the overall immune response did not seem to be significantly different based on diet, but instead on sex. Females showed greater phenol oxidase levels than males, but the opposite was found with lytic activity. Perhaps in G. sigillatus the differences in the pathogens commonly confronted by each sex in the distinct habitat of each could explain the differences on PO and lytic activity.

The Interaction between Base Compositional Heterogeneity and Among-Site Rate Variation in Models of Molecular Evolution

Many commonly used models of molecular evolution assume homogeneous nucleotide frequencies. A deviation from this assumption has been shown to cause problems for phylogenetic inference. However, some claim that only extreme heterogeneity affects phylogenetic accuracy and suggest that violations of other model assumptions, such as variable rates among sites, are more problematic. In order to explore the interaction between compositional heterogeneity and variable rates among sites, I reanalyzed 3 real heterogeneous datasets using several models. My Bayesian inference recovers accurate topologies under variable rates-among-sites models, but fails under some models that account for compositional heterogeneity. I also ran simulations and found that accounting for rates among sites improves topology accuracy in compositionally heterogeneous data. This indicates that in some cases, models accounting for among-site rate variation can improve outcomes for data that violates the assumption of compositional homogeneity.

Extensive Phenotypic Diversity among South Chinese Dogs

We describe here a broad diversity in phenotype among dogs in southern China’s rural areas, previously relatively unknown outside of China. These dogs display a much broader spectrum of diversity than is observed for the Indian Pariah Dog and the Australian Dingo, which are of a more uniform type and popularly thought to be typical for South Asian dogs and to represent the primitive morphology of the earliest domestic dogs. We show here that the village dog population of southern China harbors a broad diversity of morphological features, for color, body structure and size, coat texture, ear, and tail set, that are otherwise typically associated with the wide variety of Western dog breeds and assumed to be the result of intense selective breeding. The diversity of southern China’s dogs is cast in the light of mtDNA and Y-chromosome DNA studies showing that the genetic diversity is distinctly higher in southern East Asia than in the rest of the world, indicating that this was the geographical origins of today’s dog. These data suggest that the diverse morphologies of European dogs may have been formed from genetic “building blocks" still present in the dog population of rural southern China.

Some Remarks on Bird's Brain and Behavior under the Constraints of Domestication

The relationship between domestication and evolution is still a matter of discussion. In this review, we present some arguments for the assumption that domestication could be seen as an evolutionary process including the possibility that new species might evolve. In course of domestication, many breeds have been developed which show numerous alterations in different parameters such as body size, coloring, habitat, behavior, and brain size and composition. Here, we would like to give an overview particularly about alterations and varieties in (brain) morphology and behavior in domestic poultry and argue that these alterations could be seen as adaptations to the man-made environment.