The distinction between worker and reproductive castes of social insects is receiving increased attention from a developmental rather than adaptive perspective. In the wasp genus Polistes, colonies are founded by one or more females, and the female offspring that emerge in that colony are either non-reproducing workers or future reproductives of the following generation (gynes). A growing numbe...

Variation in the expression of reproductive traits provides the raw material upon which sexual selection can act. It is therefore important to understand how key factors such as environmental variation influence the expression of reproductive traits, as these will have a fundamental effect on the evolution of mating systems. It is also important to consider the effects of environmental variatio...

Traditional explanations for the evolution of menopause and post-reproductive lifespan in human females have been based on the benefits of maternal or grand-maternal care outweighing the cost of lost reproduction. These explanations assume an evolutionary origin of menopause since human divergence with the most recent common ancestor. In this study, I conduct a literature survey of studies of 4...

The objective of the present study was to detect quantitative trait loci (QTL) for male reproductive traits in a half-sib family from a Bos indicus (Brahman) x Bos taurus (Hereford) sire. The sire was mated with MARC III (1/4 Hereford, 1/4 Angus, 1/4 Red Poll and 1/4 Pinzgauer) cows. Testicular traits were measured from 126 male offspring born in 1996 and castrated at 8.5 months. Traits analyse...

The one trait that differentiates social and eusocial insects from solitary insects is reproductive division of labor (i.e., one or a few individuals of a group reproduce and others work). Currently, the general consensus of the molecular and behavioral underpinnings of social evolution is based on ideas in evolutionary developmental biology in which novel traits are linked to changes in regula...

We propose a model for the dynamics of frequencies costly defense trait. More precisely, we consider Lotka-Volterra-type models involving prey (or host) population consisting two types and predator parasite) population, where one type individuals - modeling carriers trait is more effective in defending against predators but has weak reproductive disadvantage. Under certain assumptions prove tha...

Natural selection commonly drives the origin of species, as Darwin initially claimed. Mechanisms of speciation by selection fall into two broad categories: ecological and mutation-order. Under ecological speciation, divergence is driven by divergent natural selection between environments, whereas under mutation-order speciation, divergence occurs when different mutations arise and are fixed in ...