Sperm and egg proteins constitute a remarkable paradigm in evolutionary biology: despite their fundamental role in mediating fertilization (suggesting stasis), some of these molecules are among the most rapidly evolving ones known, and their divergence can lead to reproductive isolation. Because of strong selection to maintain function among interbreeding individuals, interacting fertilization ...

Producing equal amounts of male and female offspring has long been considered an evolutionarily stable strategy. Nevertheless, exceptions to this general rule (i.e. male and female biases) are documented in many taxa, making sex allocation an important domain in current evolutionary biology research. Pinpointing the underlying mechanism of sex ratio bias is challenging owing to the multitude of...

As an anthropologist, I am intrigued by the possibility that culture shapes how biological scientists describe what they discover about the natural world. If this were so, we would be learning about more than the natural world in high school biology class; we would be learning about cultural beliefs and practices as if they were part of nature. In the course of my research I realized that the p...

Understanding mosquito mating biology is essential for studies of mosquito behavior, gene flow, population structure, and genetic control. In the current study, we examine the effect of age and body size on spermatozoa number in two laboratory strains of the dengue vector, Aedes aegypti (L.), Thailand and Rockefeller (ROCK), and in wild-collected mosquitoes from Thailand. Body size was a major ...

Andrology is one of few fields of medicine and biology in which biochemical and molecular tools are not routinely used for evaluation and diagnostics (discussed by Eliasson, 2003). Accurate evaluation of an infertile male is of paramount importance for proper diagnosis of couples in human infertility, but also for an accurate estimation of current fertility and prediction of future fertility in...

Centrioles are conserved, self-replicating, microtubule-based, 9-fold symmetric subcellular organelles that are essential for proper cell division and function. Most cells have two centrioles and maintaining this number of centrioles is important for animal development and physiology. However, how animals gain their first two centrioles during reproduction is only partially understood. It is we...

Although today, there is a general consensus that egg activation involves the release of a “sperm factor” that follows gamete fusion, the identity of the molecule involves in this process is still under discussion. Recently, Asian Journal of Andrology got three successive commentary articles which target the problem of the molecular nature of the “sperm factor.” Is it PAWP, PLC zeta, or both? A...

BACKGROUND C. elegans male sexual behaviors include chemotaxis and response to hermaphrodites, backing, turning, vulva location, spicule insertion, and sperm transfer, culminating in cross-fertilization of hermaphrodite oocytes with male sperm. The LOV-1 and PKD-2 transient receptor potential polycystin (TRPP) complex localizes to ciliated endings of C. elegans male-specific sensory neurons and...

H sperm are approximately 6000th of a centimeter long, a small fraction of a man’s total body length. By contrast, fruit fly (Drosophila spp.) sperm can reach nearly 6 cm, roughly twenty times the total length of their bodies. This dramatic variation in male reproductive biology is explored in a recent paper from the journal Nature.1 While the literature on sperm competition has for decades emp...

Female sperm storage was studied in a population of Notophthalmus viridescens from South Carolina. Spermathecae initiate production of a glycoprotein secretory product in October. At this time ovarian follicles are immature (0.5-0.9 mm dia), and mating does not occur despite spermiation in males. Six of the 10 females collected in December had sperm in their spermathecae, indicating onset of ma...