Sperm competition represents an important component of post-copulatory sexual selection. It has been argued that the level of sperm competition declines in birds towards the equator. However, to date, sperm competition estimates have been available mainly for avian species inhabiting the northern temperate zone. Here we apply a novel approach, using the coefficient of between-male variation (CV...

It has long been recognized that male mating competition is responsible for the evolution of weaponry for mate acquisition. However, when females mate with more than one male, competition between males can continue after mating in the form of sperm competition. Theory predicts that males should increase their investment in sperm production as sperm competition is increased, but it assumes that ...

The collective cheetah (Acinonyx jubatus) population in zoological institutions has never been self-sustaining because of challenges in natural reproduction. A retrospective analysis of North American zoo-breeding records has revealed that >90% of litters produced since 2003 occurred in facilities 'off-display' from the public. We examined seminal, endocrine, and behavioral traits of 29 adult m...

To evaluate the effects of anesthesia with different concentrations of clove extract (0, 50, 200, 400 and 600 mg) on sperm function and some hematological parameters in Prussian carp, Carassius gibelio (Bloch, 1782), 30 mature male were examined. In this purpose, sperm motility traits and some hematological parameters ( Red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit (PCV)...

This review highlights the potential role that post-copulatory sexual selection plays in elasmobranch reproductive systems and the utility of this group to further understanding of evolutionary responses to the post-copulatory processes of sperm competition and cryptic female choice. The growing genetic evidence for female multiple mating (polyandry) in elasmobranchs is summarized. While polyan...

An extensive array of reproductive traits varies among species, yet the genetic mechanisms that enable divergence, often over short evolutionary timescales, remain elusive. Here we examine two sister-species of Peromyscus mice with divergent mating systems. We find that the promiscuous species produces sperm with longer midpiece than the monogamous species, and midpiece size correlates positive...

A linkage map of 40 linkage groups (LGs) was developed for brook charr, Salvelinus fontinalis, using an F(2) interstrain hybrid progeny (n = 171) and 256 coding gene SNP developed specifically for brook charr and validated from a large (>1000) subset of putative SNP, as well as 81 microsatellite markers. To identify quantitative trait loci (QTL) related to reproduction functions, these fish wer...

BACKGROUND Proximal cytoplasmic droplets (PCDs), a remnant of germ cell cytoplasm, are common non-specific morphological defects in bovine semen. This study evaluated the effect of higher percentages of PCDs on the quality of frozen-thawed bovine semen, embryo production and early embryo development. METHODS Three ejaculates from each of five (group 1: PCD ≤ 1%, control) and eight adult Bos i...

1. Abdelnour S.A., Abd El‐Hack M.E., Alagawany M., Taha A.E., Elnesr S.S., Elmonem O.M., Swelum A.A., 2020. Useful impacts of royal jelly on reproductive sides, fertility rate and sperm traits animals. J. Anim. Physiol. Nutr. 104, 1798–1808, https://doi.org/10.1111/jpn.13... CrossRef Google Scholar

Selection for 11 generations in swine for ovulation rate (OR) or uterine capacity (UC) resulted in significant changes in component traits of litter size. Our objective was to conserve the unique germplasm for the future and to characterize sperm quality as a correlated response to the selection criterion imposed compared to an unselected control line (CO). Boars representing genetic diversity ...