Stefan Lüpold

Stefan Lüpold
University of Zurich | UZH · Department of Evolutionary Biology and Environmental Studies

PhD

About

64
Publications
12,552
Reads
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2,526
Citations
Additional affiliations
September 2015 - present
University of Zurich
Position
  • Group Leader
March 2015 - September 2015
The University of Manchester
Position
  • Researcher
February 2010 - March 2015
Syracuse University
Position
  • Research Assistant

Publications

Publications (64)
Article
Success in sperm competition, occurring whenever females mate with multiple males [1], is predicted to be influenced by variation in ejaculate quality and interactions among competing sperm [2]. Yet, apart from sperm number, relevant ejaculate characteristics and sperm-sperm interactions are poorly understood, particularly within a multivariate fra...
Article
Full-text available
How females store and use sperm after remating can generate postcopulatory sexual selection on male ejaculate traits. Variation in ejaculate performance traits generally is thought to be intrinsic to males but is likely to interact with the environment in which sperm compete (e.g., the female reproductive tract). Our understanding of female contrib...
Article
Full-text available
Theory predicts a trade-off between investments in precopulatory (ornaments and armaments) and postcopulatory (testes and ejaculates) sexual traits due to the costs associated with their growth and maintenance within the finite energy resources available. Empirical studies, however, have revealed considerable inconsistency in the strength and direc...
Article
Full-text available
Post-copulatory sexual selection (PSS), fuelled by female promiscuity, is credited with the rapid evolution of sperm quality traits across diverse taxa1. Yet, our understanding of the adaptive significance of sperm ornaments and the cryptic female preferences driving their evolution is extremely limited1,2. Here we review the evolutionary allometry...
Article
Males must partition their limited reproductive investments between traits that promote access to females (sexual ornaments and weapons) and traits that enhance fertilization success, such as testes and ejaculates. Recent studies show that if the most weaponized males can monopolize access to females through contest competition, thereby reducing th...
Article
The significant similarities in airway epithelial cells between mammals and the fruit fly Drosophila melanogaster have rendered the latter an important model organism for studies of chronic inflammatory lung diseases. Focusing on the chronic obstructive pulmonary disease (COPD), we here mapped human gene orthologs associated with this disease in D....
Article
The significant similarities in airway epithelial cells between mammals and the fruit fly Drosophila melanogaster have rendered the latter an important model organism for studies of chronic inflammatory lung diseases. Focusing on the chronic obstructive pulmonary disease (COPD), we here mapped human gene orthologs associated with this disease in D....
Article
Species with intense male–male competition for access to females often show alternative reproductive tactics (ARTs) where males of lower competitive ability adopt a sneaky behavior to gain access to mates. These ARTs are usually associated with intrasexual dimorphisms, in that males with distinct morphologies show different tactics. In some cases,...
Article
Full-text available
Nutrient limitation during development can restrict the ability of adults to invest in costly fitness traits, and genotypes can vary in their sensitivity to developmental nutrition. However, little is known about how genotype and nutrition affect male ability to maintain ejaculate allocation and achieve fertilization across successive matings. Usin...
Article
Full-text available
Female and male reproductive traits co-evolve through pre- and post-copulatory sexual selection and sexual conflict. Although males typically transfer many sperm during copulation, only a small proportion reach the fertilization site because females often actively or passively reduce sperm number in their reproductive tract. Males may transfer acce...
Article
Full-text available
In polyandrous species, males face reproductive competition both before and after mating. Sexual selection thus shapes the evolution of both pre- and postcopulatory traits, creating competing demands on resource allocation to different reproductive episodes. Traits subject to strong selection exhibit accelerated rates of phenotypic divergence, and...
Article
Precise mechanisms underlying sperm storage and utilization are largely unknown, and data directly linking stored sperm to paternity remain scarce. We used competitive microsatellite PCR to study the effects of female morphology, copula duration and oviposition on the proportion of stored sperm provided by the second of two copulating males (S2) in...
Article
Dietary restriction during development can affect adult body size and condition. In many species, larger (high‐condition) males gain higher mating success through male‐male competition and female choice, and female condition can affect the extent of both female mate choice and male investment in courtship or ejaculates. However, few studies have ex...
Article
Full-text available
Females of many species mate with multiple males, thereby inciting competition among ejaculates from rival males for fertilization. In response to increasing sperm competition, males are predicted to enhance their investment in sperm production. This prediction is so widespread that testes size (correcting for body size) is commonly used as a proxy...
Article
Full-text available
How males and females contribute to joint reproductive success has been a long‐standing question in sexual selection. Under postcopulatory sexual selection, paternity success is predicted to derive from complex interactions among females engaging in cryptic female choice and males engaging in sperm competition. Such interactions have been identifie...
Article
The involvement of Septate Junctions (SJs) in critical cellular functions that extend beyond their role as diffusion barriers in the epithelia and the nervous system has made the fruit‐fly an ideal model for the study of human diseases associated with impaired Tight Junction (TJ) function. In this study, we summarized current knowledge of the Droso...
Article
Competition over mates is a powerful force shaping trait evolution. For instance, better cognitive abilities may be beneficial in male-male competition and thus be selected for by intrasexual selection. Alternatively, investment in physical attributes favoring male performance in competition for mates may lower the resources available for brain dev...
Article
Full-text available
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 th...
Preprint
Full-text available
How males and females contribute to joint reproductive success has been a long-standing question in sexual selection. Under postcopulatory sexual selection (PSS), paternity success is predicted to derive from complex interactions among females engaging in cryptic female choice and males engaging in sperm competition. Such interactions have been ide...
Article
Full-text available
Sperm morphological variation has attracted considerable interest and generated a wealth of (mostly descriptive) studies over the past three centuries. Yet, apart from biophysical studies linking sperm morphology to swimming velocity, surprisingly little is known about the adaptive significance of sperm form and the selective processes underlying i...
Article
Support for macroecological rules in insects is mixed, with potential confounding interrelations between patterns rarely studied. We here investigate global patterns in body and wing size, sexual size dimorphism and range size in common fruit flies (Diptera: Drosophilidae) and explore potential interrelations and the predictive power of Allen's, Be...
Article
Recent theoretical models predict that the evolutionary diversification of the weapons and ornaments of pre-mating sexual selection should be influenced by trade-offs with male expenditure on ejaculates. However, the patterns of association between secondary sexual traits and ejaculate expenditure are frequently inconsistent in their support of thi...
Article
Sexual size dimorphism (SSD) can vary drastically across environments, demonstrating pronounced sex-specific plasticity. In insects, females are usually the larger and more plastic sex. However, the shortage of taxa with male-biased SSD hampers the assessment of whether the greater plasticity in females is driven by selection on size or represents...
Article
Full-text available
The evolution of sperm quality and quantity is shaped by various selective processes, with sperm competition generally considered the primary selective agent. Particularly in external fertilizers, however, sperm limitation through gamete dispersal can also influence gamete investments, but empirical data examining this effect are limited. Here, we...
Article
Full-text available
Sexual selection theory predicts a trade-off between premating (ornaments and armaments) and postmating (testes and ejaculates) sexual traits, assuming that growing and maintaining these traits is costly and that total reproductive investments are limited. The number of males in competition, the reproductive gains from investing in premating sexual...
Article
Full-text available
Spermatozoa exhibit considerable interspecies morphological variation across mammals, especially among murid rodents. In Australasia, most murids in the tribe Hydromyini have a spermatozoon with a highly complex head exhibiting an apical hook, characteristic of most murids, and two projections that extend from its upper concave surface, the ventral...
Article
Full-text available
There is substantial comparative and growing experimental evidence that the competition for fertilization among sperm from different males can drive variation in male reproductive investments. However, less is known about the extent of natural variation in these investments relative to environmental variables affecting resource availability and mat...
Article
Males must carefully allocate the energy they devote to sex. A new study of howler monkeys shows that males who use vocalizations to ward off rivals invest less in producing large numbers of sperm.
Article
Full-text available
Postcopulatory sexual selection is widely accepted to underlie the extraordinary diversification of sperm morphology. However, why does it favour longer sperm in some taxa but shorter in others? Two recent hypotheses addressing this discrepancy offered contradictory explanations. Under the sperm dilution hypothesis, selection via sperm density in t...
Article
Full-text available
Male ornaments and armaments that mediate success in mate acquisition and ejaculate traits influencing competitive fertilization success are under intense sexual selection. However, relative investment in these pre- and postcopulatory traits depends on the relative importance of either selection episode and on the energetic costs and fitness gains...
Article
Full-text available
Many songbirds are socially monogamous but genetically polyandrous, mating with individuals outside their pair bonds. Extra-pair paternity (EPP) varies within and across species, but reasons for this variation remain unclear. One possible source of variation is population genetic diversity, which has been shown in interspecific meta-analyses to cor...
Article
Full-text available
Sperm experience intense and varied selection that dramatically impacts the evolution of sperm quality. Selection acts to ensure that sperm are fertilization-competent and able to overcome the many challenges experienced on their way towards eggs. However, simply being able to fertilize an egg is not enough to ensure male fertility in most species....
Article
Full-text available
Recent work suggests that the yellow dung fly mating system may include alternative patroller-competitor mating tactics in which large males compete for gravid females on dung, whereas small, non-competitive males search for females at foraging sites. Small males obtain most matings off pasture, yet the behavioural mechanism(s) giving rise to this...
Article
Full-text available
Abstract How sperm from competing males are used to fertilize eggs is poorly understood yet has important implications for postcopulatory sexual selection. Sperm may be used in direct proportion to their numerical representation within the fertilization set or with a bias toward one male over another. Previous theoretical treatments have assumed a...
Article
Full-text available
The outcome of sperm competition is influenced by the relative quantity and quality of sperm among competing ejaculates. Whereas it is well established that individual ejaculate traits evolve rapidly under postcopulatory sexual selection, little is known about other factors that might influence the evolution of ejaculates. For example, the metaboli...
Article
Full-text available
Identifying traits that reproductively isolate species, and the selective forces underlying their divergence, is a central goal of evolutionary biology and speciation research. There is growing recognition that postcopulatory sexual selection, which can drive rapid diversification of interacting ejaculate and female reproductive tract traits that m...
Article
Full-text available
Postcopulatory sexual selection is credited with driving rapid evolutionary diversification of reproductive traits and the formation of reproductive isolating barriers between species. This judgment, however, has largely been inferred rather than demonstrated due to general lack of knowledge about processes and traits underlying variation in compet...
Article
Full-text available
Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e., fitness traits) are expected...
Article
Full-text available
Post-copulatory sexual selection arises when females mate with multiple males, resulting in competition between ejaculates to fertilize the female's eggs. Such selection is recognized as an important engine of evolutionary diversification and speciation, yet the mechanisms underlying sperm competition are poorly known due to dual challenges of obse...
Article
Full-text available
Many reproductive traits, including ejaculate characteristics, usually show remarkable seasonal variation, but the potential for such dynamics in sperm morphology has been overlooked. Several studies have revealed high within-male repeatability in sperm morphology, but samples have typically been collected within a few hours or days, and the consis...
Article
Full-text available
In polyandrous mating systems, male fitness depends on success in premating, post-copulatory and offspring viability episodes of selection. We tracked male success across all of these episodes simultaneously, using transgenic Drosophila melanogaster with ubiquitously expressed green fluorescent protein (i.e. GFP) in a series of competitive and nonc...
Article
Full-text available
Sperm biology pervades numerous research areas from clinical research to evolutionary biology and animal conservation. Integrating these fields for a better understanding of each is one of the main goals of the Biology of Spermatozoa meeting, a conference held biennially outside of Sheffield in the United Kingdom. This September, at the 11th meetin...
Article
Full-text available
Selection to avoid inbreeding is predicted to vary across species due to differences in population structure and reproductive biology. Over the past decade, there have been numerous investigations of postcopulatory inbreeding avoidance, a phenomenon that first requires discrimination of mate (or sperm) relatedness and then requires mechanisms of ma...
Article
Full-text available
Spermatozoa are amongst the most variable cells, and three factors are thought to account for this variation in design: fertilization mode, phylogeny, and postcopulatory sexual selection. In addition, it has long been assumed that a tradeoff exists between sperm size and number, and although postcopulatory sexual selection affects both traits, empi...
Article
Full-text available
Many species differ genetically, physiologically, and morphologically between geographically distinct populations, typically in response to variation in ecological and climatic variables. Little is known, however, about geographical variation in sperm morphology. Sperm morphology is under strong sexual selection, has been shown to evolve rapidly, a...
Article
Cellular membranes are composed of highly variable lipid molecules, mainly cholesterol and phospholipids (PLs). The cholesterol moiety and the saturation degree of the fatty acyl residues of PL determine the fluidity of the membrane, which is particularly important for sperm because they have to undergo characteristic membrane-dependent processes (...
Article
Full-text available
The outcome of sperm competition (i.e. competition for fertilization between ejaculates from different males) is primarily determined by the relative number and quality of rival sperm. Therefore, the testes are under strong selection to maximize both sperm number and quality, which are likely to result in trade-offs in the process of spermatogenesi...
Article
Full-text available
In contrast to early predictions, it is now widely accepted that males incur substantive costs from ejaculate production. Hence, males are predicted to allocate their reproductive investments, including ejaculate size, relative to the risk of sperm competition and to female quality. The study of sperm allocation, however, has been technically chall...
Article
Full-text available
Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other taxa, these relationships are negative, and the causes of these different patterns across taxa...
Article
Full-text available
Sperm velocity is one of the main determinants of the outcome of sperm competition. Since sperm vary considerably in their morphology between and within species, it seems likely that sperm morphology is associated with sperm velocity. Theory predicts that sperm velocity may be increased by enlarged midpiece (energetic component) or flagellum length...
Article
Full-text available
Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other taxa, these relationships are negative, and the causes of these different patterns across taxa...
Article
Sperm morphology varies considerably across taxa, and postcopulatory sexual selection is thought to be one of the main forces responsible for this diversity. Several studies have investigated the effects of the variation in sperm design on sperm function, but the consequences of variation in sperm design on testis morphology have been overlooked. T...
Article
Male genitalia are typically highly variable across species, for which sexual selection is thought to be responsible. Sexually selected traits characteristically show positive allometry and high phenotypic variation, although genitalia seem to be typified by negative allometry due to stabilizing selection. Additionally, while sexual selection appea...
Article
Male genitalia are typically highly variable across species, for which sexual selection is thought to be responsible. Sexually selected traits characteristically show positive allometry and high phenotypic variation, although genitalia seem to be typified by negative allometry due to stabilizing selection. Additionally, while sexual selection appea...
Article
Full-text available
Tadpoles of many species develop enlarged tail fins in the presence of insect predators, but the function of this response is not known. Because large tails do not improve swimming performance, we tested the hypothesis that the tail attracts predator strikes away from the more vulnerable head and body region. We first confirmed the assumption that...
Article
Full-text available
Although sociality is common in bats, few studies have investigated individual social behaviour in free-ranging colonies. This study quantifies social interactions among wild female Bechstein’s bats (Myotis bechsteinii) belonging to one maternity colony. Our main goal was to analyse allogrooming and nose rubbing, which are both regularly displayed...