scholarly journals Effects of two seminal fluid proteins on post-mating behavior in the simultaneously hermaphroditic flatwormMacrostomum lignano

2019 ◽  
Author(s):  
Michael Weber ◽  
Bahar Patlar ◽  
Steven A. Ramm
Keyword(s):  
Reproductive Success ◽  
Sperm Competition ◽  
Mating Behavior ◽  
Competitive Ability ◽  
Seminal Fluid ◽  
Genetic Correlations ◽  
Complex Mixture ◽  
Mating Frequency ◽  
Seminal Fluid Proteins ◽  
Knock Down

AbstractAlong with sperm, in many taxa male ejaculates also contain a complex mixture of proteins, peptides and other substances found in seminal fluid. Once seminal fluid proteins (SFPs) are transferred to the mating partner, they play crucial roles in mediating post-mating sexual selection, since they can modulate the partner’s behavior and physiology in ways that influence the reproductive success of both partners. One way in which sperm donors can maximize their own reproductive success is by changing the partners’ (sperm recipient’s) postcopulatory behavior to prevent or delay re-mating, thereby decreasing the likelihood or intensity of sperm competition. We therefore adopted a quantitative genetic approach combining gene expression and behavioral data to identify candidates that could mediate such a response in the simultaneously hermaphroditic flatwormMacrostomum lignano. We identified two putative SFPs - Mlig-pro46 and Mlig-pro63 - that exhibit a negative genetic correlation between transcript expression and mating frequency. Importantly, however, in one of the two different group sizes, differing in their sperm competition level, in which we measured genetic correlations, these same two transcripts are also linked to a second post-mating behavior inM. lignano, namely the ‘suck’ behavior of recipients in which, upon ejaculate receipt, the worm places its pharynx over its female genital opening and appears to attempt to remove ejaculate components. To therefore investigate directly whether these two candidates manipulate partner behavior, and test whether this impacts on competitive fertilization success, we performed a manipulative experiment using RNA interference-induced knockdown to ask how loss of Mlig-pro46 and Mlig-pro63 expression, singly and in combination, affects mating frequency, partner suck propensity and both defensive and offensive sperm competitive ability (P1andP2, respectively). None of the knock-down treatments impacted strongly on mating frequency or sperm competitive ability, but the knock-down of Mlig-pro63 resulted in a significantly decreased ‘suck’ propensity of mating partners. This suggests that Mlig-pro63 may normally act as a cue in the ejaculate to trigger recipient suck behavior, though the functional and adaptive significance of these two seminal proteins from a donor perspective remains enigmatic.

scholarly journals Genetic coordination of sperm morphology and seminal fluid proteins promotes male reproductive success in Drosophila melanogaster

2021 ◽  
Author(s):  
Jake Galvin ◽  
Erica Larson ◽  
Sevan Yedigarian ◽  
Mohammad Rahman ◽  
Kirill Borziak ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Reproductive Success ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Male Reproductive Success ◽  
Sperm Length ◽  
Seminal Fluid Proteins ◽  
Female Remating ◽  
Paternity Success

Spermatozoal morphology is highly variable both among and within species and in ways that can significantly impact fertilization success. In Drosophila melanogaster, paternity success depends on sperm length of both competing males and length of the female's primary sperm storage organ. We found that genes upregulated in long sperm testes are enriched for lncRNAs and seminal fluid proteins (Sfps). Transferred in seminal fluid to the female during mating, Sfps are secreted by the male accessory glands (AG) and affect female remating rate, physiology, and behavior with concomitant advantages for male reproductive success. Despite being upregulated in long sperm testes, they have no known function in testis tissue. We found that Sex Peptide and ovulin (Acp26Aa) knockouts resulted in shorter sperm, suggesting that Sfps may regulate sperm length during spermatogenesis. However, knockout of AG function did not affect sperm length, suggesting that AG expression has no influence on spermatogenic processes. We also found that long sperm males are better able to delay female remating, suggesting higher Sfp expression in AG. These results might suggest that long sperm males have a double advantage in sperm competition by both delaying female remating, likely through transfer of more Sfps, and by resisting sperm displacement. However, we also found that this extra advantage does not necessarily translate to more progeny or higher paternity success. Thus, we found that multiple components of the ejaculate coordinate to promote male reproductive success at different stages of reproduction, but the realized fitness advantages in sperm competition are uncertain.

scholarly journals Seminal fluid and accessory male investment in sperm competition

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200068
Author(s):  
Steven A. Ramm
Keyword(s):  
Sperm Competition ◽  
Seminal Fluid ◽  
Complex Mixture ◽  
Internal Fertilization ◽  
Animal Evolution ◽  
Male Investment ◽  
Trade Offs ◽  
Fluid Production ◽  
Alternative Routes ◽  
Paternity Success

Sperm production and allocation strategies have been a central concern of sperm competition research for the past 50 years. But during the ‘sexual cascade’ there may be strong selection for alternative routes to maximizing male fitness. Especially with the evolution of internal fertilization, a common and by now well-studied example is the accessory ejaculate investment represented by seminal fluid, the complex mixture of proteins, peptides and other components transferred to females together with sperm. How seminal fluid investment should covary with sperm investment probably depends on the mechanism of seminal fluid action. If seminal fluid components boost male paternity success by directly enhancing sperm function or use, we might often expect a positive correlation between the two forms of male investment, whereas trade-offs seem more likely if seminal fluid acts independently of sperm. This is largely borne out by a broad taxonomic survey to establish the prevailing patterns of seminal fluid production and allocation during animal evolution, in light of which I discuss the gaps that remain in our understanding of this key ejaculate component and its relationship to sperm investment, before outlining promising approaches for examining seminal fluid-mediated sperm competitiveness in the post-genomic era. This article is part of the theme issue ‘Fifty years of sperm competition’.

scholarly journals Conceptual developments in sperm competition: a very brief synopsis

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200061 ◽  
Author(s):  
Geoff A. Parker
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Female Reproduction ◽  
Internal Fertilization ◽  
Seminal Fluid Proteins ◽  
Competition Theory ◽  
Past Half Century ◽  
Mate Acquisition ◽  
Gamete Competition

The past half century has seen the development of the field of post-ejaculatory sexual selection, the sequel to sexual selection for mate-acquisition (pre-ejaculatory) described by Darwin. In richness and diversity of adaptations, post-ejaculatory selection rivals that of pre-ejaculatory sexual selection. Anisogamy—and hence two sexes—likely arose by primeval gamete competition, and sperm competition remains a major force maintaining high sperm numbers. The post-ejaculatory equivalent of male–male competition for matings, sperm competition was an intense ancestral form of sexual selection, typically weakening as mobility and internal fertilization developed in many taxa, when some expenditure became diverted into pre-ejaculatory competition. Sperm competition theory has been relatively successful in explaining variation in relative testes size and sperm numbers per ejaculate and is becoming more successful in explaining variation in sperm phenotype. Sperm competition has generated many other male adaptations such as seminal fluid proteins that variously modify female reproduction towards male interests, and copulatory plugs, prolonged copulations and post-ejaculatory guarding behaviour that reduce female remating probability, many of which result in sexual conflict. This short survey of conceptual developments is intended as a broad overview, mainly as a primer for new researchers. This article is part of the theme issue ‘Fifty years of sperm competition'.

scholarly journals Functional genome annotation of Drosophila seminal fluid proteins using transcriptional genetic networks

2011 ◽  
Vol 93 (6) ◽  
pp. 387-395 ◽  
Author(s):  
JULIEN F. AYROLES ◽  
BROOKE A. LAFLAMME ◽  
ERIC A. STONE ◽  
MARIANA F. WOLFNER ◽  
TRUDY F. C. MACKAY
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Seminal Fluid ◽  
Gene Annotation ◽  
Expression Patterns ◽  
Genetic Correlations ◽  
Seminal Fluid Proteins ◽  
High Throughput Method ◽  
Seminal Fluid Protein ◽  
Functional Genome Annotation

SummaryPredicting functional gene annotations remains a significant challenge, even in well-annotated genomes such as yeast and Drosophila. One promising, high-throughput method for gene annotation is to use correlated gene expression patterns to annotate target genes based on the known function of focal genes. The Drosophila melanogaster transcriptome varies genetically among wild-derived inbred lines, with strong genetic correlations among the transcripts. Here, we leveraged the genetic correlations in gene expression among known seminal fluid protein (SFP) genes and the rest of the genetically varying transcriptome to identify 176 novel candidate SFPs (cSFPs). We independently validated the correlation in gene expression between seven of the cSFPs and a known SFP gene, as well as expression in male reproductive tissues. We argue that this method can be extended to other systems for which information on genetic variation in gene expression is available.

scholarly journals Male reproductive ageing: a tale of the whole ejaculate

Reproduction ◽  
2019 ◽  
Vol 158 (6) ◽  
pp. R219-R229 ◽  
Author(s):  
Claudia Fricke ◽  
Mareike Koppik
Keyword(s):  
Reproductive Success ◽  
Conformational Changes ◽  
Seminal Fluid ◽  
Reproductive Capacity ◽  
Male Reproductive Success ◽  
Seminal Fluid Proteins ◽  
Area Of Interest ◽  
General Decline ◽  
Age Dependent ◽  
The Impact

Ageing is nearly ubiquitous and encompasses all biological functions. We here focus on age-dependent changes in male reproductive capacity across a broad range of animal taxa. While there has been a long-standing focus on mating ability and overall reproductive success, we here highlight the underlying mechanisms that explain loss in fertilisation capacity in ageing males. Fertilisation is mediated by not only the presence of sperm, but also the cocktail of seminal fluid proteins that ensure sperm survival, capacitation and interaction with female physiology. Sperm ageing has received much attention in studies of male reproductive senescence; however, post-mating processes include a number of interlocked steps that together cumulate in successful fertilisation. As such we consider male ability to elicit female post mating responses such as uterine conformational changes, sperm storage and ovulation and the components within the ejaculate that mediate these post-mating processes. For the latter seminal fluid proteins are key and hence we reflect on age-dependent changes in quality of the entire ejaculate and its consequences for male reproductive capacity. While first studies accrue and highlight that changes in the non-sperm fraction can explain substantial variation in senescent male reproductive success and male ability to induce post-mating responses necessary for fertilisation many open questions still remain that warrant further investigations. One being what the potential age-dependent changes in composition are or whether there is a general decline and how this interacts with sperm to affect fertilisation success. Further, the impact females might have to ameliorate these changes will be an area of interest.

Mating Behavior of the Bronze Birch Borer, (Coleoptera: Buprestidae)2

1992 ◽  
Vol 27 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Rodney C. Akers ◽  
David G. Nielsen
Keyword(s):  
Reproductive Success ◽  
Mating Behavior ◽  
Sexual Contact ◽  
Mating Frequency ◽  
Female Reproductive Success ◽  
Duration Of Copulation ◽  
Bronze Birch Borer

Mating behavior of the bronze birch borer, Agrilus anxius, was investigated under laboratory and outdoor conditions. Propensity to mate was greater for beetles more than 1-d-old. Duration of copulation tended to increase with increasing beetle age; 87% of mated females were inseminated and subsequently avoided sexual contact. Males mated more than once; previously mated males copulated sooner and for longer periods of time than naive males. Mating frequency did not influence female reproductive success.

scholarly journals Sperm wars and the evolution of male fertility

Reproduction ◽  
2012 ◽  
Vol 144 (5) ◽  
pp. 519-534 ◽  
Author(s):  
Leigh W Simmons ◽  
John L Fitzpatrick
Keyword(s):  
Sperm Competition ◽  
Swimming Speed ◽  
Male Fertility ◽  
Seminal Fluid ◽  
Future Research ◽  
Sperm Length ◽  
Seminal Fluid Proteins ◽  
Control Male ◽  
Form And Function ◽  
And Function

Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected to shape male expenditure on the ejaculate. Here, we review empirical data that illustrate the evolutionary consequences of sperm competition. Sperm competition favors the evolution of increased testes size and sperm production. In some species, males appear capable of adjusting the number of sperm ejaculated, depending on the perceived levels of sperm competition. Selection is also expected to act on sperm form and function, although the evidence for this remains equivocal. Comparative studies suggest that sperm length and swimming speed may increase in response to selection from sperm competition. However, the mechanisms driving this pattern remain unclear. Evidence that sperm length influences sperm swimming speed is mixed and fertilization trials performed across a broad range of species demonstrate inconsistent relationships between sperm form and function. This ambiguity may in part reflect the important role that seminal fluid proteins (sfps) play in affecting sperm function. There is good evidence that sfps are subject to selection from sperm competition, and recent work is pointing to an ability of males to adjust their seminal fluid chemistry in response to sperm competition from rival males. We argue that future research must consider sperm and seminal fluid components of the ejaculate as a functional unity. Research at the genomic level will identify the genes that ultimately control male fertility.

scholarly journals Genotype-by-environment interactions for seminal fluid expression and sperm competitive ability

2019 ◽  
Author(s):  
Bahar Patlar ◽  
Steven A. Ramm
Keyword(s):  
Sperm Competition ◽  
Natural Variation ◽  
Competitive Ability ◽  
Seminal Fluid ◽  
Expression Level ◽  
Mating Partner ◽  
Genotype By Environment Interactions ◽  
Genotype By Environment ◽  
Genetic And Environmental Factors ◽  
Paternity Success

AbstractSperm competition commonly occurs whenever females mate multiply, leading to variation in male paternity success. This can be due to variation in the various traits that might affect sperm competitive ability, which itself depends on both genetic and environmental factors, as well as on genotype-by-environment interactions (GEI). Seminal fluid is a major component of the male ejaculate that is often expected to mediate sperm competition, where different genotypes can differ in their seminal fluid expression as a response to different level of sperm competition (i.e., exhibit GEI). We therefore here focussed on testing for GEI in expression of two recently identified seminal fluid transcripts,suckless-1andsuckless-2, which potentially modulate sperm competitive ability in the simultaneously hermaphroditic flatwormMacrostomum lignanovia their effects on manipulating post-mating partner behaviour and ultimately the fate of transferred ejaculates. In addition, we sought to test for GEI in sperm competitive ability, to investigate the relationship between natural variation in the expression of these seminal fluid transcripts generated through GEI and relative paternity success. To do so, we manipulated social group size, which has been shown to successfully alter sperm competition level inM. lignano, in a set of inbred lines (genotypes) and then measured both the expression level ofsuckless-1andsuckless-2in focal worms together with their relative paternity success in a standardised sperm competition (P1&P2) assay. We found GEI for the expression level ofsuckless-1andsuckless-2, as well as for sperm competitive ability. Moreover, we found a positive relation between the expression ofsuckless-1and paternity success. This suggests that natural variation in the expression of this seminal fluid transcript indeed can influence sperm competition outcomes inM. lignano.

scholarly journals Divergent allocation of sperm and the seminal proteome along a competition gradient in Drosophila melanogaster

2019 ◽  
Vol 116 (36) ◽  
pp. 17925-17933 ◽  
Author(s):  
Ben R. Hopkins ◽  
Irem Sepil ◽  
Marie-Laëtitia Thézénas ◽  
James F. Craig ◽  
Thomas Miller ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Sperm Transfer ◽  
Male Mating ◽  
Compositional Change ◽  
Seminal Fluid Proteins ◽  
Allocation Rules ◽  
Offspring Production ◽  
Component Allocation

Sperm competition favors large, costly ejaculates, and theory predicts the evolution of allocation strategies that enable males to plastically tailor ejaculate expenditure to sperm competition threat. While greater sperm transfer in response to a perceived increase in the risk of sperm competition is well-supported, we have a poor understanding of whether males (i) respond to changes in perceived intensity of sperm competition, (ii) use the same allocation rules for sperm and seminal fluid, and (iii) experience changes in current and future reproductive performance as a result of ejaculate compositional changes. Combining quantitative proteomics with fluorescent sperm labeling, we show that Drosophila melanogaster males exercise independent control over the transfer of sperm and seminal fluid proteins (SFPs) under different levels of male–male competition. While sperm transfer peaks at low competition, consistent with some theoretical predictions based on sperm competition intensity, the abundance of transferred SFPs generally increases at high competition levels. However, we find that clusters of SFPs vary in the directionality and sensitivity of their response to competition, promoting compositional change in seminal fluid. By tracking the degree of decline in male mating probability and offspring production across successive matings, we provide evidence that ejaculate compositional change represents an adaptive response to current sperm competition, but one that comes at a cost to future mating performance. Our work reveals a previously unknown divergence in ejaculate component allocation rules, exposes downstream costs of elevated ejaculate investment, and ultimately suggests a central role for ejaculate compositional plasticity in sexual selection.

Identification of seminal proteins related to the inhibition of mate searching in female crickets

2020 ◽  
Vol 31 (6) ◽  
pp. 1344-1352 ◽  
Author(s):  
Joe A Moschilla ◽  
Joseph L Tomkins ◽  
Leigh W Simmons
Keyword(s):  
Sperm Competition ◽  
Behavioral Response ◽  
Seminal Fluid ◽  
Sexual Receptivity ◽  
Searching Behavior ◽  
Mate Searching ◽  
Seminal Fluid Proteins ◽  
Field Crickets ◽  
Competition Avoidance ◽  
Postmating Behavior

Abstract In response to the reduction in fitness associated with sperm competition, males are expected to evolve tactics that hinder female remating. For example, females often display a postmating reduction in their sexual receptivity that has been shown to be mediated by proteins contained in a male’s seminal fluid (sfps). However, although there has been comprehensive research on sfps in genetically well-characterized species, few nonmodel species have been studied in such detail. We initially confirm that female Australian field crickets, Teleogryllus oceanicus, do display a significant reduction in their mate-searching behavior 24 h after mating. This effect was still apparent 3 days after mating but was entirely absent after 1 week. We then attempted to identify the sfps that might play a role in inducing this behavioral response. We identified two proteins, ToSfp022 and ToSfp011, that were associated with the alteration in female postmating behavior. The knockdown of both proteins resulted in mated females that displayed a significant increase in their mate-searching behaviors compared with females mated to males having the full compliment of seminal fluid proteins in their ejaculate. Our results indicate that the female refractory period in T. oceanicus likely reflects a sperm competition avoidance tactic by males, achieved through the action of male seminal fluid proteins.

Sign in / Sign up

Export Citation Format

Share Document