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

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.

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Conceptual developments in sperm competition: a very brief synopsis

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0061 ◽

2020 ◽

Vol 375 (1813) ◽

pp. 20200061 ◽

Cited By ~ 2

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'.

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Sperm wars and the evolution of male fertility

Reproduction ◽

10.1530/rep-12-0285 ◽

2012 ◽

Vol 144 (5) ◽

pp. 519-534 ◽

Cited By ~ 210

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.

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

10.1101/2021.11.15.468624 ◽

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.

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Gene Expression and Alternative Splicing Dynamics Are Perturbed in Head Transcriptomes of Heterospecifically Mated Females

10.21203/rs.3.rs-149189/v1 ◽

2021 ◽

Author(s):

Fernando Diaz ◽

Carson Allan ◽

Therese Markow ◽

Jeremy Bono ◽

Luciano Matzkin

Keyword(s):

Gene Expression ◽

Alternative Splicing ◽

Reproductive Tract ◽

Seminal Fluid ◽

Intron Retention ◽

Transcriptional Responses ◽

Seminal Fluid Proteins ◽

Genome Wide ◽

Amino Acid Balance ◽

Postmating Behavior

Abstract Background Despite the growing interest in the female side of copulatory interactions, the roles played by alternative splicing mechanisms of pre-RNA and the epistatic effects of these interactions on tissues outside of the reproductive tract have remained largely unknown. Here we addressed these questions in the context of con- vs heterospecific matings between Drosophila mojavensis and its sister species, D. arizonae. We analyzed transcriptional responses in female heads using an integrated investigation of genome-wide patterns of gene expression, including differential expression (DE), alternative splicing (AS) and intron retention (IR). Results Our results indicated that early transcriptional responses were largely congruent between con- and heterospecific matings but are substantially perturbed over time. Conspecific matings induced functional pathways related to amino acid balance previously associated with the brain’s physiology and female postmating behavior. Heterospecific matings often fail to activate regulation of some of these genes and induce expression of additional genes when compared with those of conspecifically-mated females. These results are consistent for all transcriptional mechanisms with some distinctions: DE genes were mostly linked to pathways of proteolysis and nutrient homeostasis, while AS genes are more related to photoreception and muscle assembly pathways. Conclusions IR seem to be an important mechanism of DE regulation during the female postmating response. While AS genes evolve at slower evolutionary rates than the genome background, DE genes evolve at much higher rates, similar or even higher than those of seminal fluid proteins, which unveil their potential role for reproductive barriers and the extent of sexual conflict.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1906149116 ◽

2019 ◽

Vol 116 (36) ◽

pp. 17925-17933 ◽

Cited By ~ 24

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.

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Duration and dose-dependency of female sexual receptivity responses to seminal fluid proteins in Aedes albopictus and Ae. aegypti mosquitoes

Journal of Insect Physiology ◽

10.1016/j.jinsphys.2012.07.003 ◽

2012 ◽

Vol 58 (10) ◽

pp. 1307-1313 ◽

Cited By ~ 24

Author(s):

Michelle E.H. Helinski ◽

Prasit Deewatthanawong ◽

Laura K. Sirot ◽

Mariana F. Wolfner ◽

Laura C. Harrington

Keyword(s):

Aedes Albopictus ◽

Seminal Fluid ◽

Sexual Receptivity ◽

Dose Dependency ◽

Seminal Fluid Proteins ◽

Female Sexual Receptivity

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

10.1101/734301 ◽

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.

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The Drosophila seminal proteome and its role in postcopulatory sexual selection

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0072 ◽

2020 ◽

Vol 375 (1813) ◽

pp. 20200072 ◽

Cited By ~ 2

Author(s):

Stuart Wigby ◽

Nora C. Brown ◽

Sarah E. Allen ◽

Snigdha Misra ◽

Jessica L. Sitnik ◽

...

Keyword(s):

Sexual Selection ◽

Sperm Competition ◽

Seminal Fluid ◽

Current Knowledge ◽

Future Research ◽

Seminal Fluid Proteins ◽

Scale Functions ◽

Postcopulatory Sexual Selection ◽

Evolutionary Force ◽

Protein Classes

Postcopulatory sexual selection (PCSS), comprised of sperm competition and cryptic female choice, has emerged as a widespread evolutionary force among polyandrous animals. There is abundant evidence that PCSS can shape the evolution of sperm. However, sperm are not the whole story: they are accompanied by seminal fluid substances that play many roles, including influencing PCSS. Foremost among seminal fluid models is Drosophila melanogaster , which displays ubiquitous polyandry, and exhibits intraspecific variation in a number of seminal fluid proteins (Sfps) that appear to modulate paternity share. Here, we first consolidate current information on the identities of D. melanogaster Sfps. Comparing between D. melanogaster and human seminal proteomes, we find evidence of similarities between many protein classes and individual proteins, including some D. melanogaster Sfp genes linked to PCSS, suggesting evolutionary conservation of broad-scale functions. We then review experimental evidence for the functions of D. melanogaster Sfps in PCSS and sexual conflict. We identify gaps in our current knowledge and areas for future research, including an enhanced identification of PCSS-related Sfps, their interactions with rival sperm and with females, the role of qualitative changes in Sfps and mechanisms of ejaculate tailoring. This article is part of the theme issue ‘Fifty years of sperm competition’.

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