Sperm velocity is one of the main determinants outcome sperm competition. Since vary considerably in their morphology between and within species, it seems likely that associated with velocity. Theory predicts may be increased by enlarged midpiece (energetic component) or flagellum length (kinetic component), particular ratios components, such as head size. However, associations have rarely been found empirical studies. In a comparative framework passerine birds, we tested these theoretical...

Spermatozoa are amongst the most variable cells, and three factors thought to account for this variation in design: fertilization mode, phylogeny, postcopulatory sexual selection. In addition, it has long been assumed that a tradeoff exists between sperm size number, although selection affects both traits, empirical evidence so far elusive. Our recent theoretical model predicts nature of direct number varies with competition mechanism risk. We test these predictions using comparative...

Urban regions are among the most human-altered environments on Earth and they poised for rapid expansion following population growth migration. Identifying biological traits that determine which species likely to succeed in urbanized habitats is important predicting global trends biodiversity. We provide first evidence intuitive yet untested hypothesis relative brain size a key factor predisposing animals successful establishment cities. apply phylogenetic mixed modelling Bayesian framework...

Background The evolutionary role of postcopulatory sexual selection in shaping male reproductive traits, including sperm morphology, is well documented several taxa. However, previous studies have focused almost exclusively on the influence competition variation among species. In this study we tested hypothesis that intraspecific morphology driven by level passerine birds. Methodology/Findings Using two proxy measures level, (i) relative testes size and (ii) extrapair paternity found strong...

Abstract Background Piwi-interacting RNAs (piRNA)s are non-coding small that post-transcriptionally affect gene expression and regulation. Through complementary seed region binding with transposable elements (TEs), piRNAs protect the genome from transposition. A tool to link TE targets will improve our understanding of role in maintenance Existing tools such as TEsmall can process sRNA-seq datasets produce differentially expressed piRNAs, piRScan developed for nematodes TEs but it requires...

Sperm design varies enormously across species and sperm competition is thought to be a major factor influencing this variation. However, the functional significance of many traits still poorly understood. The most murid rodents are characterised by an apical hook head that markedly in extent species. In European woodmouse Apodemus sylvaticus (Muridae), highly reflected used form groups, or "trains," which exhibited increased swimming velocity thrusting force compared individual sperm.Here we...

Journal Article INCREASED POSTCOPULATORY SEXUAL SELECTION REDUCES THE INTRAMALE VARIATION IN SPERM DESIGN Get access Simone Immler, Immler Department of Animal and Plant Sciences, University Sheffield, Western Bank, Sheffield S10 2TN, United KingdomE-mail: s.immler@sheffield.ac.uk Corresponding author. Search for other works by this author on: Oxford Academic Google Scholar Sara Calhim, Calhim Kingdom Tim R. Birkhead Evolution, Volume 62, Issue 6, 1 June 2008, Pages 1538–1543,...

Sperm morphometry (i.e., size and shape) function are important determinants of male reproductive success thought to be under stabilizing selection. However, recent studies suggest that sperm can a phenotypically plastic trait, which adjusted varying conditions. We tested whether different behavioral strategies in aggression between aggressive red nonaggressive black males the color polymorphic Gouldian finch (Erythrura gouldiae) influence morphometry. show pronounced within-individual...

Significance Diploid organisms produce haploid gametes for sexual reproduction, resulting in a biphasic life cycle. Although selection during the diploid phase is well understood, gametic stage and its consequences are largely ignored despite potential importance fundamental evolutionary processes, including rate of adaptation inbreeding depression, as applied research into fertilization technology. A current dogma assumes that animals on genotype minimal. We examined zebrafish found strong...

Evolutionary rates and strength of selection differ markedly between haploid diploid genomes. Any genes expressed in a state will be directly exposed to selection, whereas alleles may partially or fully masked by homologous allele. This difference shape key evolutionary processes, including adaptation inbreeding depression, but also the evolution sex chromosomes, heterochiasmy, stable ratio biases. All organisms carry genomes, most notably genomes gametes produced every sexually reproducing...

Sperm competition is thought to be a major force driving the evolution of sperm shape and function. However, previous studies investigating relationship between risk morphometry revealed inconclusive results marked differences taxonomic groups. In comparative study two families passerines (Fringillidae Sylviidae) also across species belonging different passerine families, we investigated relative importance phylogenetic background on competition. The was inferred from testis mass as an...

Despite two decades of research into over one hundred species, the function extrapair paternity to female birds remains unclear. Recent studies have demonstrated patterns between and genetic similarity females with social partners males. We believe that selection on gain genetically compatible fathers for their offspring offers a possible general explanation paternity. The idea sexual being driven by compatibility is widely considered workers other taxa but has been largely ignored birds....

• We previously selected for large and small brain size in guppies. Large-brained females outperformed small-brained a learning task. Healy Rowe challenged our interpretations of larger brains = better learning. Here we argue why think they are mistaken.

Significance Predominantly diploid organisms shape the extent to which their haploid gametes and gametophytes experience selection. Although animals are thought only mild selection in stage, plants often strong When should parents limit exposure of when they strengthen this selection? We develop mathematical models that consider “selective arena” within male or (sperm pollen) compete for fertilization, examining how intensity selective arena evolves controlled by mother father. These predict...

The brain is an energetically costly organ that consumes a disproportionate amount of resources. Species with larger brains relative to their body size have slower life histories, reduced output per reproductive event and delayed development times can be offset by increasing behavioral flexibility. "cognitive buffer" hypothesis maintains large decreases extrinsic mortality due greater flexibility, leading longer lifespan. Alternatively, slow long lifespan pre‐adaptation for the evolution...

The disposable soma theory is a central tenet of the biology aging where germline immortality comes at cost an [T. B. L. Kirkwood, Nature 270, 301–304 (1977); T. Proc. R. Soc. Lond. B Biol. Sci. 205, 531–546 (1979); S. N. Austad, 408, 233–238 (2000)]. Limited resources and possible trade-off between repair maintenance germ cells growth may explain deterioration over time. Here we show that removal allows accelerated somatic healing under stress. We tested “the expensive line” hypothesis by...

The inheritance of non-genetic factors is increasingly seen to play a major role in ecology and evolution. While the causes consequences epigenetic effects transmitted from mother offspring have received ample attention, much less known about how variation condition father affects offspring. Here, we manipulated intensity sperm competition experienced by male zebrafish Danio rerio investigate potential for sperm-mediated over relatively short period time. We found that rapid responses males...

It is generally believed that variation in sperm phenotype within a single ejaculate has no consequences for offspring performance, because phenotypes are thought not to reflect genotypes. We show individual function an affects the performance of resulting Atlantic salmon Salmo salar . experimentally manipulated time between activation and fertilization order select cohorts differing longevity ejaculates wild caught male salmon. found within-ejaculate significantly affected development hence...

The evolution of dimorphic sex chromosomes is driven largely by the reduced recombination and subsequent accumulation deleterious mutations. Although these processes are increasingly well understood in diploid organisms, haploid organisms (U/V) has been virtually unstudied theoretically. We analyze a model to investigate linkage between fitness loci sex-determining region U/V species. In second step, we test how prone nonrecombining regions degeneration due Our modeling predicts that decay...