The relationships between testes asymmetry, seminiferous composition and the quality and quantity of sperm produced in a precocial bird

Theory assumes that postcopulatory sexual selection favours increased investment into testes size, as larger testes produce ejaculates that provide a competitive advantage when rival males compete for fertilisation. However, the relationship between relative increases in testes size with the organisation of sperm-producing tissue, and how such changes influence sperm quality and quantity is not fully understood. Male Japanese quail (Coturnix japonica) originating from lines artificially selected for high female reproductive investment experienced higher fertilisation success, as well as a relatively larger left testis than males from low reproductive investment lines. The aim of this study was to determine the origin of this increased fertility from a morphological perspective. For males from both lines and in both testis, we measured the proportion and absolute amount of seminiferous tissue, as well as the quantity and quality of sperm within the sperm reserves, including sperm length and proportions that were alive and morphologically normal. The left testis of high line males had higher proportions of interstitial tissue, but not seminiferous tissue, and did not produce different sperm morphologies that could explain the enhanced fertilisation success. On the contrary, the right testis had higher proportions of seminiferous tissue and produced more alive sperm. There was no difference in sperm quantity or proportions of sperm with normal morphology in either testis of males from divergent lines. Independently of line origin, the right testis contained sperm with larger tails, total lengths, and shorter ratios of the head : tail, indicating a specialisation to produce faster sperm. Overall, we found no clear difference in the quality or quantity of sperm produced by high line males that could explain their reproductive success. However, because ejaculates are complex, interactive, multivariate traits, fertilisation success could have been influenced by other traits not measured here, such as the composition of copulatory fluids, functions of somatic cells in the testes, provisioning against oxidative stress or the regulation of sperm use by the females. Altogether, these results highlight unusual relationships between testes size with testes and sperm morphology and demonstrate that relatively larger testes do not necessarily have more seminiferous tissue or produce more, or better quality sperm

The evolutionary genetics of sexually selected plumage colour traits in the galliform birds

Extravagant male plumage traits in birds are a classic example of sexual selection. However we know very little about the units that selection is acting upon, the genes themselves – what are they and how are they influenced by sexual selection? In this study I focused on in the evolution and genetics of colouration the galliform birds. Several novel loci were used to create a well resolved phylogeny of this group. This was then used to investigate and reconstruct the evolution of sexual plumage dichromatism. Four pigmentation genes were sequenced in an array of galliform species. A measure of the rate of evolutionary change (dN/dS) at these loci was then compared between lineages with different strengths of sexual selection, using sexual dichromatism as the main index of sexual selection. I found evidence for sexual selection acting at the MC1R locus, in the form of a robust correlation between dN/dS and sexual plumage dichromatism that was not found at any of the other loci. I then went on to investigate the evolution and population genetics of MC1R in the grouse, focusing on the strongly dichromatic black grouse and the relatively monochromatic red grouse. I found some evidence for an adaptive change at this locus between these species. Finally I used a candidate gene approach to investigate the role of several genes in avian pigmentation using the Japanese quail (Coturnix japonica) as a model system. I found evidence that the avian agouti gene is involved in dorso-ventral pigmentation patterning and a regulatory mutation at this locus that produces a yellow phenotype. In addition point mutations at MC1R and TYRP1 were found to be responsible for producing pigmentation variants. I then compared the expression of several of these candidate genes in male and female common pheasants (Phasianus colchicus) and found lower TYRP1 expression in males. Knowledge of the genetic basis of secondary sexual traits and the action of sexual selection at this level could have important implications for our understanding of the process of sexual selection as a whole.This work was funded by the Natural Environment Research Council under the Environmental Genomics programme [grant number NER/T/S/2002/00020]

Das Reproduktionssystem der Lanzenfliegen (Diptera: Lonchopteridae)

Diese aus insgesamt drei Publikationen bzw. Kapiteln bestehende Dissertation soll zum allgemeinen Verständnis der Mechanismen der postkopulatorischen sexuellen Selektion beitragen, die zur Entstehung von Riesenspermien geführt haben. Zu diesem Zweck wurde das Fortpflanzungssystem der Lanzenfliegen (Diptera: Lonchopteridae) eingehender untersucht. Bei den Vertretern dieser Familie gibt es hierbei bemerkenswerte Unterschiede, wobei einige Arten Riesenspermien produzieren und die entsprechenden Weibchen extrem lange Spermatheken besitzen. Mit einer Länge von 7.500 µm und einer Dicke von 1,3 µm gehört das Spermium von Lonchoptera fallax zu den größten bisher bekannten überhaupt. Die Weibchen dieser Art besitzen Spermatheken mit einer Gesamtlänge von etwa 14.000 µm, womit diese etwa viermal so lang wie deren Körper sind. Anhand von 3D-Rekonstruktionen und Erkenntnissen aus der Elektronenmikroskopie wird in Kapitel I die Morphologie und Ultrastruktur der Spermien der nahe verwandten Art Lonchoptera lutea näher beschrieben. Mit einer Länge von 2.200 μm und einer Dicke von 1,4 μm sind diese zwar deutlich kleiner als die von L. fallax, können aber dennoch als riesig bezeichnet werden. Anders als die typischen Spermien anderer Fliegen haben sie einen stark asymmetrischen Querschnitt mit nur einem, wenn auch sehr großen Mitochondrienderivat und einem Paar massiver akzessorischer Körper, von denen sich aber nur einer über die gesamte Länge des Flagellums erstreckt. Um die Entstehung von Riesenspermien in dieser Fliegen-Familie näher zu erforschen, wurden für Kapitel II die Körpergröße, die Hodengröße, die Spermiengröße und die Anzahl der Spermien pro Bündel und pro Hoden bei insgesamt elf Lonchoptera-Arten untersucht. Anhand dieser Ergebnisse wird diskutiert, wie diese Merkmale miteinander in Beziehung stehen und wie ihre Entwicklung die Ressourcenverteilung unter den Spermien beeinflusst. Auf Grundlage der Spermienmerkmale und unterstützt durch einen aus DNA-Barcodes abgeleiteten molekularen Stammbaum wird zudem eine phylogenetische Hypothese für die Gattung Lonchoptera formuliert. Um die postkopulatorischen Prozesse zu verstehen, die zur Entstehung von riesigen Spermien bei Lonchopteridae geführt haben, wurden für Kapitel III die Abmessungen der Spermatheken, die wiederum in vier morphologisch, histologisch und funktionell unterschiedliche Abschnitte unterteilt werden können, bei elf Lonchoptera-Arten untersucht und mit den Maßen der entsprechenden Spermien ins Verhältnis gesetzt. 3D-Rekonstruktionen machten es zudem möglich, das Volumen in diese Überlegungen mit einzubeziehen, was einen neuen Ansatz in diesem Kontext darstellt. Die Ergebnisse zeigen, dass die Spermatheken immer deutlich länger sind als die entsprechenden Spermien und dass ein hochsignifikanter, positiv linearer Zusammenhang zwischen beiden Größen besteht, was auf einen zugrundeliegenden koevolutiven Prozess hindeutet. Auf Grundlage aller Ergebnisse werden einige evolutive Szenarien inklusive eines neuen Ansatzes zu den selektiven Vorteilen längerer Spermien aufgezeigt, um zu diskutieren, wie Spermien- und Spermathekenlänge bei Lonchopteridae abhängig voneinander entstanden sein könnten

Pohlavní promiskuita, skrytá volba samice a biologie pěvčí spermie

The discovery of postcopulatory mechanisms of mate choice has fundamentally altered our understanding of sexual selection. Passerines are an ideal group for studying two basic mechanisms of postcopulatory sexual selection, sperm competition and cryptic female choice. This doctoral thesis focuses on postcopulatory sexual selection in passerines from three different angles. In this study, we investigated (1) age-related changes in traits that can affect male reproductive success (sperm morphology, velocity and production) and a trade-off between these traits and lifespan in male barn swallows (Hirundo rustica); (2) variation in seminal fluid and sperm proteins in six selected passerine species and whether these differences are caused by phylogeny or postcopulatory sexual selection; and (3) the protein composition of female barn swallow cloacal fluids in four phases of the reproductive season, changes in protein composition in individual phases, and identification of phase-specific proteins. Our results show that there is no unified trend for changes in sperm traits or sperm production across male lifespan. While sperm morphology and velocity do not change considerably, sperm production increases in first years of life. However, excessive investment in sperm production could reduce the male's chances...Objev postkopulačních mechanizmů výběru partnera zásadně změnil pohled na pohlavní selekci. Pěvci tvoří ideální skupinu pro studium dvou mechanizmů postkopulační pohlavní selekce, kompetice spermií a skryté volby samice. Tato dizertační práce se zabývá postkopulační selekcí ze třech různých uhlů právě u tohoto taxonu. V této práci jsme se zabývali (1) životními změnami znaků, které mohou ovlivňovat reprodukční úspěch samců (morfologie a velocita spermií, produkce spermií) a zároveň trade-off mezi těmito znaky a délkou dožití u samců vlaštovky obecné (Hirundo rustica); (2) variabilitou v proteinech seminální tekutiny a spermií u šesti vybraných druhů pěvců a zda jsou tyto rozdíly způsobeny fylogenezí či vlivem postkopulační pohlavní selekce a (3) popisem proteinového složení samičích kloakálních tekutin vlaštovky obecné ve čtyřech fázích reprodukčního cyklu, změnami v zastoupení proteinů v jednotlivých fázích a stanovením proteinů specifických pro jednotlivé reprodukční fáze. Naše výsledky ukazují, že neexistuje jednotný trend pro změny ve znacích spermií či produkce spermií napříč životem samce. Zatímco morfologie ani velocita spermií se zásadně nemění, produkce spermií v prvních letech života stoupá. Přílišná investice do produkce spermií však může snížit šance samce na delší život, což...Department of ZoologyKatedra zoologieFaculty of SciencePřírodovědecká fakult

Third Report on Chicken Genes and Chromosomes 2015

Following on from the First Report on Chicken Genes and Chromosomes [Schmid et al., 2000] and the Second Report in 2005 [Schmid et al., 2005], we are pleased to publish this long-awaited Third Report on the latest developments in chicken genomics. The First Report highlighted the availability of genetic and physical maps, while the Second Report was published as the chicken genome sequence was released. This report comes at a time of huge technological advances (particularly in sequencing methodologies) which have allowed us to examine the chicken genome in detail not possible until now. This has also heralded an explosion in avian genomics, with the current availability of more than 48 bird genomes [Zhang G et al., 2014b; Eöry et al., 2015], with many more planned

Bryophyte Ecology

Bryophyte Ecology is an ebook comprised of 5 volumes written by Janice Glime, Professor Emerita of Biological Sciences at Michigan Technological University. Chapter coauthors include Irene Bisang, S. Robbert Gradstein, J. Lissner, W. J. Boelema, and D. H. Wagner. To download smaller sections of Bryophyte Ecology, visit: https://digitalcommons.mtu.edu/bryophyte-ecology/https://digitalcommons.mtu.edu/oabooks/1003/thumbnail.jp

Factors affecting maternal provisioning to the pre-natal environment

Maternal effects are important mechanisms by which mothers’ may influence the phenotype of their offspring. Females may vary in the resources they can provide during offspring development and understanding the factors responsible for this variation is key to understanding offspring success- in early life as well as later life. Differential allocation has been reported to occur, however how it impacts on offspring and mother’s future reproduction still remains unclear. This is also true for maternal transferred substances like maternally transferred immunity. Contributions to date have been limited to snapshots in time, mean level of transfer and/or limited information regarding other maternal traits. For my thesis, I aim to further the understanding of maternal allocation effects and explore the transfer of maternal antibodies over an immune response of a mother, across multiple breeding attempts and accounting for embryo, maternal and paternal traits. Furthermore, I determine the effect of key male traits on general egg traits along with maternal antibodies. I examine this at the individual level using Chinese painted quail (Coturnix chinensis) who are prolific layers and sexually dimorphic. To date the majority of differential allocation studies have not necessarily addressed the assumptions of differential allocation theory. In Chapter 2 of this thesis I attempt to address some of these assumptions and explore the impact of male characteristics across a number of clutches and find separate effects of initial pairing and subsequent pairings. I found that mothers can create, by differential allocation, clutches of varying size but egg components (egg mass) appears to be largely influenced by initial clutch pairing and not by paternal traits. Furthermore, the effect on egg mass appears to be a secondary effect mediated by females adjusting their condition based on their initial pairing. I demonstrate that unlike general clutch traits (clutch size, egg mass) maternal antibodies are not affected by male characteristics (Chapter 3) carry-over effects of egg size means antibody levels may be influenced throughout life by early experiences. However, maternal immune response may be detrimentally linked to viability of offspring. Whereas maternally transferred antibodies appear to have no relationship with maternal or paternal traits, oocyte yolk antibodies during development were found to correlate with female antibodies up to 48hr prior to lay. In Chapter 4, I examine a neglected area regarding maternal effect- exploring variation between female in their transfer of antibodies. Individual females were highly consistent in the relative level of specific blood antibodies transferred to eggs across different phases of their immune response, across challenge types (bacterial and viral) and that some females consistently transfer significantly more than others. The relative level of circulating antibody transferred was independent of the individual’s overall strength of antibody response and related to the female’s body condition (while the individual’s own antibody responses were not). We found no evidence for any trade-offs between the amount transferred and overall reproductive investment in this chapter. In Chapter 5, I discuss the wider implications of my findings and suggest future research directions

Sperm quality and quantity evolve through different selective processes in the Phasianidae

Sperm competition is often considered the primary selective force underlying the rapid and diversifying evolution of ejaculate traits. Yet, several recent studies have drawn attention to other forms of selection with the potential of exceeding the effects of sperm competition. Since ejaculates are complex, multivariate traits, it seems plausible that different ejaculate components vary in their responses to different selective pressures. Such information, however, is generally lacking as individual ejaculate traits tend to be studied in isolation. Here, we studied the macroevolutionary patterns of ejaculate volume, sperm number, sperm length and the proportion of viable normal sperm in response to varying levels of sperm competition, body size and the duration of female sperm storage in pheasants and allies (Phasianidae). Ejaculate volume, sperm number and sperm viability were all relatively higher in polygamous than in monogamous mating systems. However, whereas ejaculate volume additionally covaried with body size, sperm number instead increased with the female sperm-storage duration, in conjunction with a decrease in sperm length. Overall, our results revealed important details on how different forms of selection can jointly shape ejaculates as complex, composite traits