Sperm competition, when sperm from different males compete to fertilize a female's ova, is a widespread and fundamental force in the evolution of animal reproduction. The earliest prediction of sperm competition theory was that sperm competition selected for the evolution of numerous, tiny sperm, and that this force maintained anisogamy. Here, we empirically test this prediction directly by usi...

The Suretka glass frog, Hyalinobatrachium chirripoi, has been recently rediscovered in the southeastern region of Costa Rica. This species was last reported in Costa Rica in the 1950's. H. chirripoi is distinguished from H. colymbiphyllum, which appears to be its most closely Costa Rican related taxon, by having extensive webbing between fingers II-III.

BACKGROUND Sperm vitrification is a technique of ice and cryoprotectant free cryopreservation by direct plunging of sperm suspension into liquid nitrogen (LN2). The aim of this study was to investigate the influence of cryoprotectant free-vitrification on human sperm fine structure by MSOME technology and the fertility potential by zona binding assay (ZBA). METHODS 20 normo-ejaculates were pr...

Abstract Study question What percentage of people use types medically assisted reproduction (MAR) in Germany? Is MAR unequally distributed by social categories and stage treatment? Summary answer The lifetime prevalence Germany is 11.4%. Treatment varies treatment. known already Increasing postponement births to higher ages most European countries contributes risk infertility seeking reproducti...

OBJECTIVE To compare label-free interferometric phase microscopy (IPM) to label-free and label-based bright-field microscopy (BFM) in evaluating sperm cell morphology. This comparison helps in evaluating the potential of IPM for clinical sperm analysis without staining. DESIGN Comparison of imaging modalities. SETTING University laboratory. PATIENT(S) Sperm samples were obtained from heal...

background: use of cellular phones emitting radiofrequency electromagnetic field (rf-emf) has been increased exponentially and become a part of everyday life. this study aimed to investigate the effects of in vitro rf-emf exposure emitted from cellular phones on sperm motility index, sperm dna fragmentation and seminal clusterin (clu) gene expression. materials and methods: in this prospective ...

therefore, sperm size appears to have evolved as a secondary adaptation to sperm competition that is independent of the initial increase in sperm velocity. The reasons for this macroevolutionary pattern remain unclear. One possibility is that an increment in speed may initially arise by morphological rearrangements of the sperm cell leading to higher thrust and reduced drag, for example through...

OBJECTIVE To test whether sperm with abnormal head morphology are more likely to undergo DNA damage and/or chromatin modification during the process of freeze-thawing. DESIGN In this prospective study, the semen samples from forty-four men attending the infertility clinic were included. Samples were divided into aliquots to allow direct comparison of fresh and frozen spermatozoa from the same...

The purpose of this study was to investigate the efficiency of the water test to evaluate the functional membrane integrity of ejaculated canine sperm after collecting, cooling, and freezing-thawing. Twenty-five ejaculates were obtained from 12 stud dogs by digital manipulation. Sperm-rich fractions were evaluated, diluted, cooled at 5oC and frozen-thawed. A conventional hypo-osmotic swelling t...