ORCID Profile
0000-0003-4676-9950
Current Organisations
University of Regina
,
Liverpool John Moores University
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Publisher: Springer Science and Business Media LLC
Date: 15-07-2012
DOI: 10.1038/NMETH.2104
Abstract: Dispersal of organisms generates gene flow between populations. Identifying factors that influence dispersal will help predict how species will cope with rapid environmental change. We developed an innovative infrastructure, the Metatron, composed of 48 interconnected patches, designed for the study of terrestrial organism movement as a model for dispersal. Corridors between patches can be flexibly open or closed. Temperature, humidity and illuminance can be independently controlled within each patch. The modularity and adaptability of the Metatron provide the opportunity for robust experimental design for the study of 'meta-systems'. We describe a pilot experiment on populations of the butterfly Pieris brassicae and the lizard Zootoca vivipara in the Metatron. Both species survived and showed both disperser and resident phenotypes. The Metatron offers the opportunity to test theoretical models in spatial ecology.
Publisher: University of Chicago Press
Date: 12-2018
DOI: 10.1086/593001
Abstract: Mate choice is often based on multiple signal traits and can be influenced by context-dependent factors. Understanding the importance of these signals and factors can be difficult because they are often correlated and might interact. Here, we experimentally disentangle the effects of familiarity, kinship, pattern rarity, and ornament patterns on mate choice in guppies. We estimate whether these factors alter sexual selection on six phenotypic traits known to influence male attractiveness. Rarity of the male's phenotype is the only context-dependent factor that significantly influenced female mating decisions, with common patterns being least attractive. This preference for rare male patterns is a source of negative frequency-dependent selection that may contribute to maintaining the extreme polymorphism in male guppy coloration. Neither visual familiarity nor relatedness between mating partners had any significant effect on mate choice decisions. There was significant linear and nonlinear sexual selection on ornamental traits, but this was not influenced by the context-dependent measures. Our approach highlights the complexity of female mate choice and sexual selection, as well as the value of combining multifactorial experiments with multivariate selection analyses. Our study shows that both negative frequency-dependent selection and disruptive selection contribute to the maintenance of extreme polymorphism in guppies.
Publisher: Wiley
Date: 10-10-2019
DOI: 10.1111/JEB.13529
Abstract: In Drosophila, long sperm are favoured in sperm competition based on the length of the female's primary sperm storage organ, the seminal receptacle (SR). This sperm-SR interaction, together with a genetic correlation between the traits, suggests that the coevolution of exaggerated sperm and SR lengths may be driven by Fisherian runaway selection. Here, we explore the costs and benefits of long sperm and SR genotypes, both in the sex that carries them and in the sex that does not. We measured male and female fitness in inbred lines of Drosophila melanogaster derived from four populations previously selected for long sperm, short sperm, long SRs or short SRs. We specifically asked: What are the costs and benefits of long sperm in males and long SRs in females? Furthermore, do genotypes that generate long sperm in males or long SRs in females impose a fitness cost on the opposite sex? Answers to these questions will address whether long sperm are an honest indicator of male fitness, male post-copulatory success is associated with male precopulatory success, female choice benefits females or is costly, and intragenomic conflict could influence evolution of these traits. We found that both sexes have increased longevity in long sperm and long SR genotypes. Males, but not females, from long SR lines had higher fecundity. Our results suggest that sperm-SR coevolution is facilitated by both increased viability and indirect benefits of long sperm and SRs in both sexes.
Publisher: Wiley
Date: 10-2022
DOI: 10.1002/ECE3.9423
Abstract: The obesity epidemic is concerning as obesity appears to negatively impact cognition and behavior. Furthermore, some studies suggest that this negative effect could be carried across generations from both mothers and fathers although evidence is not consistent. Here, we attempt to address how obesogenic diets in the parental generation (F0) can impact offspring's cognition and anxiety intergenerationally (F1) in a zebrafish model. We compare both mean trait values and their variances. Using a multifactorial design, we created a total of four groups: F1T (treatment mothers × treatment fathers) F1M (treatment mothers × control fathers) F1P (treatment fathers × control mothers) and F1C (control mothers × control fathers, F1C) and subjected them to anxiety tank tests and aversive learning assays. When both parents were exposed, offspring (F1T) displayed the poorest aversive learning, while offspring that only had one parent exposed (F1P and F1M) learnt the aversive learning task the best. Zebrafish in all groups displayed no statistically significant differences in anxiety‐associated behaviors. Males and females also performed similarly in both anxiety and aversive learning assays. While all F1 groups had similar levels of fasting blood glucose, variance in glucose levels were reduced in F1P and F1T indicating the importance of investigating heteroskedasticity between groups. Furthermore, anxiety behaviors of these two groups appeared to be less repeatable. To our knowledge, this is the first study to test the intergenerational effects of an obesogenic diet on zebrafish cognition. Our multifactorial design as well as repeated tests also allowed us to disentangle maternal and paternal effects (as well as combined effects) and accurately detect subtle information such as between‐in idual variation.
Publisher: Cold Spring Harbor Laboratory
Date: 29-05-2019
DOI: 10.1101/652248
Abstract: In the Drosophila lineage , both sperm and the primary female sperm storage organ, the seminal receptacle (SR), may reach extraordinary lengths. In D. melanogaster , long SRs bias fertilization toward long sperm during the displacement stage of sperm competition. This sperm-SR interaction, together with a genetic correlation between the traits, suggests that the coevolution of exaggerated sperm and SR lengths may be driven by Fisherian runaway selection. To further understand the costs and benefits of long sperm and SR genotypes in both sexes, we measured male and female fitness in inbred lines of D. melanogaster derived from four populations previously selected for long sperm, short sperm, long SRs, or short SRs. We specifically asked: do long SRs impose costs or benefits on the females that bear them? Do genotypes that generate long sperm in males impose a fitness cost on females sharing those genotypes? Is long sperm an honest indicator of male viability and associated with increased fitness? And finally, are the benefits of long sperm restricted to competitive fertilization success, or do long-sperm males also have increased mating success and fecundity in single matings? We found that both sexes have increased longevity in long sperm and long SR genotypes, with fewer reproduction-related benefits and evidence for trade-offs in males, compared to females. Our results suggest that sperm length and SR length are both indicators of increased viability.
Publisher: The Royal Society
Date: 24-02-2016
Abstract: Dietary restriction (DR), a reduction in nutrient intake without malnutrition, is the most reproducible way to extend lifespan in a wide range of organisms across the tree of life, yet the evolutionary underpinnings of the DR effect on lifespan are still widely debated. The leading theory suggests that this effect is adaptive and results from reallocation of resources from reproduction to somatic maintenance, in order to survive periods of famine in nature. However, such response would cease to be adaptive when DR is chronic and animals are selected to allocate more resources to reproduction. Nevertheless, chronic DR can also increase the strength of selection resulting in the evolution of more robust genotypes. We evolved Drosophila melanogaster fruit flies on ‘DR’, ‘standard’ and ‘high’ adult diets in replicate populations with overlapping generations. After approximately 25 generations of experimental evolution, male ‘DR’ flies had higher fitness than males from ‘standard’ and ‘high’ populations. Strikingly, this increase in reproductive success did not come at a cost to survival. Our results suggest that sustained DR selects for more robust male genotypes that are overall better in converting resources into energy, which they allocate mostly to reproduction.
Publisher: Springer Science and Business Media LLC
Date: 15-07-2012
Publisher: Wiley
Date: 23-06-2023
Abstract: Moderate dietary restriction often prolongs life in laboratory animals, and this response has been interpreted as an adaptive strategy that promotes survival during famine. However, dietary restriction can also increase frailty, and it therefore remains unclear whether restricted diets prolong life under stressful conditions like those experienced by wild animals. We manipulated adult dietary protein of Drosophila melanogaster across a gradient of ambient temperature, and examined effects on survival. To test for trade‐offs, we also quantified reproduction, and performance of F1, F2 and F3 descendants. We found that protein restriction increased longevity of one or both sexes at benign ambient temperatures (25°C and 27°C), but failed to extend longevity of flies maintained in cold (21°C and 23°C) or hot (29°C) conditions. Instead, in females, protein restriction resulted in strongly elevated mortality at cold temperatures. Protein restriction also generally reduced reproductive performance, and did not consistently enhance performance of F1, F2 or F3 descendants. Taken together, our results challenge the long‐held idea that extended longevity of diet‐restricted laboratory animals represents an adaptive survival strategy in natural populations. Our findings suggest instead that this response is an artefact of benign laboratory conditions, and that DR‐induced life extension might not be achieved in the more stressful conditions experienced in the wild. Read the free Plain Language Summary for this article on the Journal blog.
Publisher: Wiley
Date: 21-07-2020
Publisher: The Royal Society
Date: 07-2017
Publisher: Cold Spring Harbor Laboratory
Date: 30-03-2022
DOI: 10.1101/2022.03.29.486193
Abstract: Sex differences in the lifetime risk and expression of disease are well-known. Preclinical research targeted at improving treatment, increasing health span, and reducing the financial burden of health care, has mostly been conducted on male animals and cells. The extent to which sex differences in phenotypic traits are explained by sex differences in body weight remains unclear. We quantify sex differences in the allometric relationship between trait value and body weight for 375 phenotypic traits in male and female mice, recorded in .1 million measurements from the International Mouse Phenotyping Consortium. We find sex differences in allometric parameters (slope, intercept, residual SD) are common (76% traits). Body weight differences do not explain all sex differences in trait values but scaling by weight may be useful for some traits. Our results support a trait-specific patterning of sex differences in phenotypic traits, promoting case-specific approaches to drug dosage scaled by body weight.
Publisher: The Royal Society
Date: 22-06-2014
Abstract: The inheritance of non-genetic factors is increasingly seen to play a major role in ecology and evolution. While the causes and consequences of epigenetic effects transmitted from the mother to the offspring have received le attention, much less is known about how variation in the condition of the father affects the offspring. Here, we manipulated the intensity of sperm competition experienced by male zebrafish Danio rerio to investigate the potential for sperm-mediated epigenetic effects over a relatively short period of time. We found that the rapid responses of males to varying intensity of sperm competition not only affected sperm traits as shown previously, but also the performance of the resulting offspring. We observed that males exposed to high intensity of sperm competition produced faster swimming and more motile sperm, and sired offspring that hatched over a narrower time frame but exhibited a lower survival rate than males exposed to low intensity of sperm competition. Our results provide striking evidence for short-term paternal effects and the possible fitness consequences of such sperm-mediated non-genetic factors not only for the resulting offspring but also for the female.
Publisher: Proceedings of the National Academy of Sciences
Date: 11-07-2017
Abstract: Diploid organisms produce haploid gametes for sexual reproduction, resulting in a biphasic life cycle. Although selection during the diploid phase is well understood, selection during the haploid gametic stage and its consequences are largely ignored despite its potential importance for fundamental evolutionary processes, including the rate of adaptation and inbreeding depression, as well as for applied research into fertilization technology. A current dogma assumes that in animals selection on the haploid gametic genotype is minimal. We examined the importance of haploid selection in the zebrafish and found strong fitness consequences of selection on sperm phenotype in the resulting offspring. Genomic data support the idea that these effects may well be the consequence of selection on the haploid sperm genotype.
Publisher: Cold Spring Harbor Laboratory
Date: 26-05-2020
DOI: 10.1101/2020.05.23.106146
Abstract: Biomedical and clinical sciences are experiencing a renewed interest in the fact that males and females differ in many anatomic, physiological, and behavioral traits. Sex differences in trait variability, however, are yet to receive similar recognition. In medical science, mammalian females are assumed to have higher trait variability due to estrous cycles (the ‘estrus-mediated variability hypothesis’) historically in biomedical research, females have been excluded for this reason. Contrastingly, evolutionary theory and associated data support the ‘greater male variability hypothesis’. Here, we test these competing hypotheses in 218 traits measured in ,900 mice, using meta-analysis methods. Neither hypothesis could universally explain patterns in trait variability. Sex-bias in variability was trait-dependent. While greater male variability was found in morphological traits, females were much more variable in immunological traits. Sex-specific variability has eco-evolutionary ramifications including sex-dependent responses to climate change, as well as statistical implications including power analysis considering sex difference in variance.
Publisher: eLife Sciences Publications, Ltd
Date: 17-11-2020
DOI: 10.7554/ELIFE.63170
Abstract: Biomedical and clinical sciences are experiencing a renewed interest in the fact that males and females differ in many anatomic, physiological, and behavioural traits. Sex differences in trait variability, however, are yet to receive similar recognition. In medical science, mammalian females are assumed to have higher trait variability due to estrous cycles (the ‘estrus-mediated variability hypothesis’) historically in biomedical research, females have been excluded for this reason. Contrastingly, evolutionary theory and associated data support the ‘greater male variability hypothesis’. Here, we test these competing hypotheses in 218 traits measured in ,900 mice, using meta-analysis methods. Neither hypothesis could universally explain patterns in trait variability. Sex bias in variability was trait-dependent. While greater male variability was found in morphological traits, females were much more variable in immunological traits. Sex-specific variability has eco-evolutionary ramifications, including sex-dependent responses to climate change, as well as statistical implications including power analysis considering sex difference in variance.
Publisher: Emerald
Date: 15-01-2021
Abstract: This research aims to propose a framework for measuring customer loyalty for third party logistics (3PL) industry by exploring the attributes that are more attractive to customers and ascertain the mechanisms for increasing customer loyalty in 3PL industry. Data were collected from one hundred and thirty-three (133) respondents who were employees of different industries that outsource 3PL services. The partial least square structural equation modeling (PLS–SEM) was deployed for analysis. The results showed that service quality has a significant positive impact on customer orientation, customer satisfaction and relationship quality. On the other hand, customer orientation has been observed to positively impact customer satisfaction but an insignificant impact on customer loyalty and relationship quality. Customer satisfaction has a significant positive impact on relationship quality but an insignificant impact on customer loyalty. Also, relationship quality has a significant positive impact on customer loyalty. The results recommend that 3PL companies' managers focus more on developing quality relationships with their customers, delivering exemplary service quality and offering customer orientation. This study will help the stakeholders gain much more understanding and insights on how competitive advantage can be achieved and, consequently, help 3PL become the market leaders.
Publisher: Springer Science and Business Media LLC
Date: 2012
Publisher: Wiley
Date: 11-2008
DOI: 10.1111/J.1558-5646.2008.00496.X
Abstract: A growing number of studies highlight the nontransitive properties of ejaculates when they are in competition to fertilize a female's eggs. Increasingly, these studies suggest that postcopulatory processes act as a filter against sperm from closely related males or those with similar genotypes, limiting the deleterious effects of inbreeding on offspring fitness. We investigated the potential for such postcopulatory mechanisms of inbreeding avoidance in the guppy (Poecilia reticulata), a promiscuous livebearing fish. We used artificial insemination as a method of delivering to a female the combined ejaculates from a first cousin (relatedness coefficient r = 0.125) and an unrelated male. This method of sperm delivery controls behavioral processes of pre- and postcopulatory female choice, which can bias paternity toward unrelated males. Our genetic analysis revealed no effect of parental relatedness on paternity outcomes. The observed mean paternity share for related males (0.47) and associated variance did not differ significantly from an expected binomial distribution that assumes no biased use of sperm with respect to relatedness (0.5). Although our data provide no evidence for postcopulatory mechanisms of inbreeding avoidance, the ability of female guppies to influence ejaculate transfer and retention offers an alternative and easily testable mechanism of inbreeding avoidance in this species.
Publisher: eLife Sciences Publications, Ltd
Date: 29-10-2020
Publisher: Oxford University Press (OUP)
Date: 31-07-2006
Publisher: Springer Science and Business Media LLC
Date: 25-05-2018
Publisher: Oxford University Press (OUP)
Date: 25-04-2018
Publisher: Oxford University Press (OUP)
Date: 2010
Publisher: Cold Spring Harbor Laboratory
Date: 21-10-2022
DOI: 10.1101/2022.10.17.512576
Abstract: Moderate dietary restriction often prolongs life in laboratory animals, and this response has been interpreted as an adaptive strategy that promotes survival during famine. However, dietary restriction can also increase frailty, and it therefore remains unclear whether restricted diets prolong life under stressful conditions like those experienced by wild animals. We manipulated adult dietary protein of Drosophila melanogaster across a gradient of ambient temperature. We found that protein restriction increased longevity of both sexes at benign ambient temperatures (25-27°C), but failed to extend or even reduced longevity of flies maintained in cold (21-23°C) or hot (29°C) conditions. Protein restriction also generally reduced reproductive performance, and did not consistently enhance performance of F1, F2 or F3 descendants. Our results challenge the long-held idea that extended longevity of diet-restricted laboratory animals represents an adaptive survival strategy in natural populations, and suggest instead that this response is an artefact of benign laboratory conditions.
Publisher: Wiley
Date: 23-01-2014
DOI: 10.1111/JEB.12313
Publisher: Elsevier BV
Date: 2013
Publisher: Public Library of Science (PLoS)
Date: 17-01-2007
Publisher: Springer Science and Business Media LLC
Date: 12-12-2022
DOI: 10.1038/S41467-022-35266-6
Abstract: Sex differences in the lifetime risk and expression of disease are well-known. Preclinical research targeted at improving treatment, increasing health span, and reducing the financial burden of health care, has mostly been conducted on male animals and cells. The extent to which sex differences in phenotypic traits are explained by sex differences in body weight remains unclear. We quantify sex differences in the allometric relationship between trait value and body weight for 363 phenotypic traits in male and female mice, recorded in million measurements from the International Mouse Phenotyping Consortium. We find sex differences in allometric parameters (slope, intercept, residual SD) are common (73% traits). Body weight differences do not explain all sex differences in trait values but scaling by weight may be useful for some traits. Our results show sex differences in phenotypic traits are trait-specific, promoting case-specific approaches to drug dosage scaled by body weight in mice.
Publisher: Springer Science and Business Media LLC
Date: 03-07-2017
Publisher: Wiley
Date: 05-07-2010
DOI: 10.1111/J.1420-9101.2010.02042.X
Abstract: In recent years, it has become evident that frequency dependence in the attractiveness of a particular phenotype to mates can contribute to the maintenance of polymorphism. However, these preferences for rare and unfamiliar male phenotypes have only been demonstrated in small, controlled experiments. Here, we tested the preference for unfamiliar mates in groups of six to 96 in iduals over 13 days, in the guppy (Poecilia reticulata). We observed in idual behaviour in situ to test whether fish discriminate two unfamiliar in iduals among many familiar ones. We found that unfamiliar males and females were preferred over the familiar fishes in all groups and that this effect decayed over time. Increasing group sizes and levels of sexual activity did not h er the preference for unfamiliar mates, providing further support for the role of frequency dependent mate choice in the maintenance of trait polymorphism in natural populations.
Publisher: Wiley
Date: 11-2022
DOI: 10.1002/ECE3.9511
Abstract: The obesity epidemic, largely driven by the accessibility of ultra‐processed high‐energy foods, is one of the most pressing public health challenges of the 21st century. Consequently, there is increasing concern about the impacts of diet‐induced obesity on behavior and cognition. While research on this matter continues, to date, no study has explicitly investigated the effect of obesogenic diet on variance and covariance (correlation) in behavioral traits. Here, we examined how an obesogenic versus control diet impacts means and (co‐)variances of traits associated with body condition, behavior, and cognition in a laboratory population of ~160 adult zebrafish ( Danio rerio ). Overall, an obesogenic diet increased variation in several zebrafish traits. Zebrafish on an obesogenic diet were significantly heavier and displayed higher body weight variability fasting blood glucose levels were similar between control and treatment zebrafish. During behavioral assays, zebrafish on the obesogenic diet displayed more exploratory behavior and were less reactive to video stimuli with conspecifics during a personality test, but these significant differences were sex‐specific. Zebrafish on an obesogenic diet also displayed repeatable responses in aversive learning tests whereas control zebrafish did not, suggesting an obesogenic diet resulted in more consistent, yet impaired, behavioral responses. Where behavioral syndromes existed (inter‐class correlations between personality traits), they did not differ between obesogenic and control zebrafish groups. By integrating a multifaceted, holistic approach that incorporates components of (co‐)variances, future studies will greatly benefit by quantifying neglected dimensions of obesogenic diets on behavioral changes.
Publisher: Oxford University Press (OUP)
Date: 10-08-2012
Publisher: The Company of Biologists
Date: 06-2021
DOI: 10.1242/JEB.240846
Abstract: Aversive learning – avoiding certain situations based on negative experiences – can profoundly increase fitness in animal species, yet no studies have systematically quantified its repeatability. Therefore, we assessed the repeatability of aversive learning by conditioning approximately 100 zebrafish (Danio rerio) to avoid a colour cue associated with a mild electric shock. Across eight different colour conditions, zebrafish did not show consistent in idual differences in aversive learning (R=0.04). Within conditions, when zebrafish were conditioned to the same colour, blue conditioning was more repeatable than green conditioning (R=0.15 and R=0.02). Overall, aversive learning responses of zebrafish were weak and variable. We speculate that the effect of aversive learning might have been too weak to quantify consistent in idual differences, or directional selection might have eroded additive genetic variance. We also discuss how confounded repeatability assays and publication bias could have inflated estimates of repeatability in the literature.
Publisher: Wiley
Date: 11-03-2015
DOI: 10.1111/JEB.12608
Publisher: University of Chicago Press
Date: 06-2009
DOI: 10.1086/598486
Abstract: Males and females differ in their reproductive strategies. Accordingly, sexually dimorphic optima in the allocation of resources to reproduction should select for sex-specific life histories, including sex-specific resolution of the key trade-off between reproduction and longevity. While males are expected to increase reproductive effort with increasing age under sexual selection theory, female reproductive effort should rather decrease after maturity, due to waning selection pressure at older ages. Sex differences in reproductive trade-offs and in the external mortality hazards experienced during the population's evolutionary history are both likely to shape sex differences in reproductive and actuarial (age-specific mortality) aging. Despite the importance of small-bodied, short-lived animals as laboratory models for life-history and aging studies, very little is known about sex differences in life-history patterns under natural conditions. Here, we tested for sex-specific patterns of reproductive and actuarial aging in field crickets under near-natural conditions. Both males and females showed actuarial senescence, with females exhibiting more rapid aging than males but with a later onset. Female and male reproductive effort showed a senescent decrease, with the peaks at different ages. Our findings provide the first demonstration of sexual dimorphism in age-dependent patterns of both survival and reproduction in an insect under near-natural conditions.
Publisher: Elsevier BV
Date: 12-2016
Publisher: University of Chicago Press
Date: 12-2022
DOI: 10.1086/721873
Abstract: AbstractMaternal effects can give newborns a head start in life by adjusting natal phenotypes to natal environments, yet their strength and adaptiveness are often difficult to investigate in natural populations. Here, we studied anticipatory maternal effects and their adaptiveness in common lizards in a seminatural experimental system. Specifically, we investigated how maternal environments (i.e., vegetation cover) and maternal phenotype (i.e., activity levels and body length) can shape offspring phenotype. We further studied whether such maternal effects influenced offspring survival in natal environments varying with respect to vegetation cover, conspecific density, and, consequently, maternal fitness. More active females from dense vegetation habitats produced bigger offspring than their less active counterparts, the contrary being true for sparse vegetation habitats. Moreover, females from dense vegetation habitats produced more active offspring and more active offspring survived better in dense vegetation habitats, resulting in greater maternal fitness through maternal effects. These results suggest adaptive anticipatory maternal effects, induced by vegetation structure and mediated by activity levels that may shape early-life prospects in natal environments.
Publisher: The Royal Society
Date: 22-06-2014
Abstract: Organisms show great variation in ploidy level. For ex le, chromosome copy number varies among cells, in iduals and species. One particularly widespread ex le of ploidy variation is found in haplodiploid taxa, wherein males are typically haploid and females are typically diploid. Despite the prevalence of haplodiploidy, the regulatory consequences of having separate haploid and diploid genomes are poorly understood. In particular, it remains unknown whether epigenetic mechanisms contribute to regulatory compensation for genome dosage. To gain greater insights into the importance of epigenetic information to ploidy compensation, we examined DNA methylation differences among diploid queen, diploid worker, haploid male and diploid male Solenopsis invicta fire ants. Surprisingly, we found that morphologically dissimilar diploid males, queens and workers were more similar to one another in terms of DNA methylation than were morphologically similar haploid and diploid males. Moreover, methylation level was positively associated with gene expression for genes that were differentially methylated in haploid and diploid castes. These data demonstrate that intragenic DNA methylation levels differ among in iduals of distinct ploidy and are positively associated with levels of gene expression. Thus, these results suggest that epigenetic information may be linked to ploidy compensation in haplodiploid insects. Overall, this study suggests that epigenetic mechanisms may be important to maintaining appropriate patterns of gene regulation in biological systems that differ in genome copy number.
Publisher: Wiley
Date: 05-05-2009
DOI: 10.1111/J.1420-9101.2009.01738.X
Abstract: The effects of inbreeding on sperm quantity and quality are among the most dramatic ex les of inbreeding depression. The extent to which inbreeding depression results in decreased fertilization success of a male's sperm, however, remains largely unknown. This task is made more difficult by the fact that other factors, such as cryptic female choice, male sperm allocation and mating order, can also drive patterns of paternity. Here, we use artificial insemination to eliminate these extraneous sources of variation and to measure the effects of inbreeding on the competitiveness of a male's sperm. We simultaneously inseminated female guppies (Poecilia reticulata) with equal amounts of sperm from an outbred (f = 0) male and either a highly (f = 0.59) or a moderately inbred (f = 0.25) male. Highly inbred males sired significantly fewer offspring than outbred males, but share of paternity did not differ between moderately inbred and outbred males. These findings therefore confirm that severe inbreeding can impair the competitiveness of sperm, but suggest that in the focal population inbreeding at order of a brother-sister mating does not reduce a male's sperm competitiveness.
Publisher: Oxford University Press (OUP)
Date: 28-04-2018
Abstract: One of the key tenets of life-history theory is that reproduction and survival are linked and that they trade-off with each other. When dietary resources are limited, reduced reproduction with a concomitant increase in survival is commonly observed. It is often hypothesized that this dietary restriction effect results from strategically reduced investment in reproduction in favor of somatic maintenance to survive starvation periods until resources become plentiful again. We used experimental evolution to test this “waiting-for-the-good-times” hypothesis, which predicts that selection under sustained dietary restriction will favor increased investment in reproduction at the cost of survival because “good-times” never come. We assayed fecundity and survival of female Drosophila melanogaster fruit flies that had evolved for 50 generations on three different diets varying in protein content—low (classic dietary restriction diet), standard, and high—in a full-factorial design. High-diet females evolved overall increased fecundity but showed reduced survival on low and standard diets. Low-diet females evolved reduced survival on low diet without corresponding increase in reproduction. In general, there was little correspondence between the evolution of survival and fecundity across all dietary regimes. Our results contradict the hypothesis that resource reallocation between fecundity and somatic maintenance underpins life span extension under dietary restriction.
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 05-2021
Publisher: Springer Science and Business Media LLC
Date: 2009
Publisher: The Royal Society
Date: 02-2017
Abstract: Parental environment can widely influence offspring phenotype, but paternal effects in the absence of parental care remain poorly understood. We asked if protein content in the larval diet of fathers affected paternity success and gene expression in their sons. We found that males reared on high-protein diet had sons that fared better during sperm competition, suggesting that postcopulatory sexual selection is subject to transgenerational paternal effects. Moreover, immune response genes were downregulated in sons of low-protein fathers, while genes involved in metabolic and reproductive processes were upregulated.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Susanne Zajitschek.