scholarly journals Structural variation in Drosophila melanogaster spermathecal ducts and its association with sperm competition dynamics

2020 ◽  
Vol 7 (3) ◽  
pp. 200130
Author(s):  
Ben R. Hopkins ◽  
Irem Sepil ◽  
Stuart Wigby
Keyword(s):  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Structural Variation ◽  
Reproductive Tract ◽  
Distal Portion ◽  
Mating Status ◽  
Spermathecal Duct ◽  
Male Sperm ◽  
Storage Organs ◽  
Single Mating

The ability of female insects to retain and use sperm for days, months, or even years after mating requires specialized storage organs in the reproductive tract. In most orders, these organs include a pair of sclerotized capsules known as spermathecae. Here, we report that some Drosophila melanogaster females exhibit previously uncharacterized structures within the distal portion of the muscular duct that links a spermatheca to the uterus. We find that these ‘spermathecal duct presences' (SDPs) may form in either or both ducts and can extend from the duct into the sperm-storing capsule itself. We further find that the incidence of SDPs varies significantly between genotypes, but does not change significantly with the age or mating status of females, the latter indicating that SDPs are not composed of or stimulated by sperm or male seminal proteins. We show that SDPs affect neither the number of first male sperm held in a spermatheca nor the number of offspring produced after a single mating. However, we find evidence that SDPs are associated with a lack of second male sperm in the spermathecae after females remate. This raises the possibility that SDPs provide a mechanism for variation in sperm competition outcome among females.

scholarly journals Structural variation in Drosophila melanogaster spermathecal ducts and its association with sperm competition dynamics

2019 ◽  
Author(s):  
Ben R. Hopkins ◽  
Irem Sepil ◽  
Stuart Wigby
Keyword(s):  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Structural Variation ◽  
Reproductive Tract ◽  
Distal Portion ◽  
Mating Status ◽  
Spermathecal Duct ◽  
Male Sperm ◽  
Storage Organs ◽  
Single Mating

AbstractThe ability of female insects to retain and use sperm for days, months, or even years after mating requires specialised storage organs in the reproductive tract. In most orders these organs include a pair of sclerotised capsules known as spermathecae. Here, we report that some Drosophila melanogaster females exhibit previously uncharacterised structures within the distal portion of the muscular duct that links a spermatheca to the uterus. We find that these ‘spermathecal duct presences’ (SDPs) may form in either or both ducts and can extend from the duct into the sperm-storing capsule itself. We further find that the incidence of SDPs varies significantly between genotypes, but does not change significantly with the age or mating status of females, the latter indicating that SDPs are not composed of or stimulated by sperm or male seminal proteins. We show that SDPs affect neither the number of first male sperm held in a spermatheca nor the number of offspring produced after a single mating. However, we find evidence that SDPs are associated with a lack of second male sperm in the spermathecae after females remate. This raises the possibility that SDPs provide a mechanism for variation in sperm competition outcome among females.

scholarly journals Acp36DE is required for uterine conformational changes in mated Drosophila females

2009 ◽  
Vol 106 (37) ◽  
pp. 15796-15800 ◽  
Author(s):  
Frank W. Avila ◽  
Mariana F. Wolfner
Keyword(s):  
Reproductive Success ◽  
Sperm Competition ◽  
Conformational Changes ◽  
Reproductive Tract ◽  
Sperm Storage ◽  
Internal Fertilization ◽  
Content Type ◽  
Storage Organs ◽  
Subsequent Storage ◽  
And Behavior

In a multitude of animals with internal fertilization, including insects and mammals, sperm are stored within a female's reproductive tract after mating. Defects in the process of sperm storage drastically reduce reproductive success. In Drosophila males, “Acp” seminal proteins alter female postmating physiology and behavior, and are necessary for several aspects of sperm storage. For example, Acps cause a series of conformational changes in the mated female's reproductive tract that occur during and immediately after mating. These conformational changes have been hypothesized to aid both in the movement of sperm within the female and in the subsequent storage of those sperm. We used RNAi to systematically knock down several Acps involved in sperm storage to determine whether they played a role in the mating-induced uterine conformational changes. Mates of males lacking the glycoprotein Acp36DE, which is needed for the accumulation of sperm in the storage organs, fail to complete the full sequence of the conformational changes. Our results show that uterine conformational changes are important for proper accumulation of sperm in storage and identify a seminal protein that mediates these changes. Four Acps included in this study, previously shown to affect sperm release from storage (CG9997, CG1656, CG1652, and CG17575), are not necessary for uterine conformational changes to occur. Rather, consistent with their role in later steps of sperm storage, we show here that their presence can affect the outcome of sperm competition situations.

scholarly journals Apical Sperm Hook Morphology Is Linked to Sperm Swimming Performance and Sperm Aggregation in Peromyscus Mice

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2279
Author(s):  
Kristin A. Hook ◽  
Lauren M. Wilke ◽  
Heidi S. Fisher
Keyword(s):  
Sperm Competition ◽  
Reproductive Tract ◽  
Swimming Performance ◽  
Structural Diversity ◽  
Female Reproductive Tract ◽  
Eutherian Mammal ◽  
Male Sperm ◽  
Specific Variation ◽  
Sperm Swimming Speed

Mammals exhibit a tremendous amount of variation in sperm morphology and despite the acknowledgement of sperm structural diversity across taxa, its functional significance remains poorly understood. Of particular interest is the sperm of rodents. While most Eutherian mammal spermatozoa are relatively simple cells with round or paddle-shaped heads, rodent sperm are often more complex and, in many species, display a striking apical hook. The function of the sperm hook remains largely unknown, but it has been hypothesized to have evolved as an adaptation to inter-male sperm competition and thus has been implicated in increased swimming efficiency or in the formation of collective sperm movements. Here we empirically test these hypotheses within a single lineage of Peromyscus rodents, in which closely related species naturally vary in their mating systems, sperm head shapes, and propensity to form sperm aggregates of varying sizes. We performed sperm morphological analyses as well as in vitro analyses of sperm aggregation and motility to examine whether the sperm hook (i) morphologically varies across these species and (ii) associates with sperm competition, aggregation, or motility. We demonstrate inter-specific variation in the sperm hook and then show that hook width negatively associates with sperm aggregation and sperm swimming speed, signifying that larger hooks may be a hindrance to sperm movement within this group of mice. Finally, we confirmed that the sperm hook hinders motility within a subset of Peromyscus leucopus mice that spontaneously produced sperm with no or highly abnormal hooks. Taken together, our findings suggest that any adaptive value of the sperm hook is likely associated with a function other than inter-male sperm competition, such as interaction with ova or cumulous cells during fertilization, or migration through the complex female reproductive tract.

scholarly journals Female Genetic Contributions to Sperm Competition in Drosophila melanogaster

Genetics ◽  
2019 ◽  
Vol 212 (3) ◽  
pp. 789-800 ◽  
Author(s):  
Dawn S. Chen ◽  
Sofie Y. N. Delbare ◽  
Simone L. White ◽  
Jessica Sitnik ◽  
Martik Chatterjee ◽  
...  
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Link Type ◽  
Female Genotype ◽  
Mechanistic Basis

In many species, sperm can remain viable in the reproductive tract of a female well beyond the typical interval to remating. This creates an opportunity for sperm from different males to compete for oocyte fertilization inside the female’s reproductive tract. In Drosophila melanogaster, sperm characteristics and seminal fluid content affect male success in sperm competition. On the other hand, although genome-wide association studies (GWAS) have demonstrated that female genotype plays a role in sperm competition outcome as well, the biochemical, sensory, and physiological processes by which females detect and selectively use sperm from different males remain elusive. Here, we functionally tested 26 candidate genes implicated via a GWAS for their contribution to the female’s role in sperm competition, measured as changes in the relative success of the first male to mate (P1). Of these 26 candidates, we identified eight genes that affect P1 when knocked down in females, and showed that five of them do so when knocked down in the female nervous system. In particular, Rim knockdown in sensory pickpocket (ppk)+ neurons lowered P1, confirming previously published results, and a novel candidate, caup, lowered P1 when knocked down in octopaminergic Tdc2+ neurons. These results demonstrate that specific neurons in the female’s nervous system play a functional role in sperm competition and expand our understanding of the genetic, neuronal, and mechanistic basis of female responses to multiple matings. We propose that these neurons in females are used to sense, and integrate, signals from courtship or ejaculates, to modulate sperm competition outcome accordingly.

scholarly journals A QTL analysis of female variation contributing to refractoriness and sperm competition in Drosophila melanogaster

2005 ◽  
Vol 86 (2) ◽  
pp. 107-114 ◽  
Author(s):  
MARA K. N. LAWNICZAK ◽  
DAVID J. BEGUN
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Sperm Competition ◽  
Competitive Ability ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Phenotypic Variance ◽  
Fitness Component ◽  
Male Sperm ◽  
Trait Locus

Sperm competition is an important fitness component in many animal groups. Drosophila melanogaster males exhibit substantial genetic variation for sperm competitive ability and females show considerable genetic variation for first versus second male sperm use. Currently, the forces responsible for maintaining genetic variation in sperm competition related phenotypes are receiving much attention. While several candidate genes contributing to the variation seen in male competitive ability are known, genes involved in female sperm use remain largely undiscovered. Without knowledge of the underlying genes, it will be difficult to distinguish between different models of sexual selection such as cryptic female choice and sexual conflict. We used quantitative trait locus (QTL) mapping to identify regions of the genome contributing to female propensity to use first or second male sperm, female refractoriness to re-mating, and early-life fertility. The most well supported markers influencing the phenotypes include 33F/34A (P2), 57B (refractoriness) and 23F/24A (fertility). Between 10% and 15% of the phenotypic variance observed in these recombinant inbred lines was explained by these individual QTLs. More detailed investigation of the regions detected in this experiment may lead to the identification of genes responsible for the QTLs identified here.

scholarly journals Female genetic contributions to sperm competition in Drosophila melanogaster

2018 ◽  
Author(s):  
Dawn S. Chen ◽  
Sofie Y.N. Delbare ◽  
Simone L. White ◽  
Jessica L. Sitnik ◽  
Martik Chatterjee ◽  
...  
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Physiological Processes ◽  
Female Genotype ◽  
Mechanistic Basis

In many species, sperm can remain viable in the reproductive tract of a female well beyond the typical interval to remating. This creates an opportunity for sperm from different males to compete for oocyte fertilization inside the female’s reproductive tract. In Drosophila melanogaster, sperm morphology and seminal fluid content affect male success in sperm competition. On the other hand, although genome-wide association studies (GWAS) have demonstrated that female genotype plays a role in sperm competition outcome as well, the biochemical, sensory and physiological processes by which females detect and selectively use sperm from different males remain elusive. Here, we functionally tested 27 candidate genes implicated via a GWAS for their contribution to the female’s role in sperm competition, measured as changes in the relative success of the first male to mate (P1). Of these 27 candidates, we identified eight genes that affect P1 when knocked down in females, and also showed that six of them do so when knocked down in the female nervous system. Two genes in particular, Rim and caup, lowered P1 when knocked down in sensory pickpocket (ppk)+ neurons and octopaminergic Tdc2+ neurons, respectively. These results establish a functional role for the female’s nervous system in the process of sperm competition and expand our understanding of the genetic, neuronal and mechanistic basis of female responses to multiple matings. We propose that through their nervous system, females actively assess male compatibility based on courtship or ejaculates and modulate sperm competition outcome accordingly.

scholarly journals Functional morphology of immature mating in a widow spider

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Lenka Sentenská ◽  
Aileen Neumann ◽  
Yael Lubin ◽  
Gabriele Uhl
Keyword(s):  
Sperm Competition ◽  
Storage Conditions ◽  
Sperm Storage ◽  
Sperm Transfer ◽  
Costs And Benefits ◽  
Micro Computed Tomography ◽  
Mating Tactics ◽  
Adult Females ◽  
Storage Organs ◽  
Widow Spider

Abstract Background Mating generally occurs after individuals reach adulthood. In many arthropods including spiders, the adult stage is marked by a final moult after which the genitalia are fully developed and functional. In several widow spider species (genus Latrodectus), however, immature females may mate a few days before they moult to adulthood, i.e. in their late-subadult stage. While the “adult” mating typically results in cannibalism, males survive the “immature” mating. During both “immature” and “adult” matings, males leave parts of their paired copulatory organs within female genitalia, which may act as mating plugs. To study potential costs and benefits of the two mating tactics, we investigated female genital morphology of the brown widow spider, L. geometricus. Light microscopy, histology and micro-computed tomography of early-subadult, late-subadult and adult females were conducted to determine the overall pattern of genital maturation. We compared genitalia of mated late-subadult and adult females to reveal potential differences in the genitalic details that might indicate differential success in sperm transfer and different environments for sperm storage and sperm competition. Results We found that the paired sperm storage organs (spermathecae) and copulatory ducts are developed already in late-subadult females and host sperm after immature mating. However, the thickness of the spermathecal cuticle and the staining of the secretions inside differ significantly between the late-subadult and adult females. In late-subadult females mating plugs were found with higher probability in both spermathecae compared to adult females. Conclusions Sperm transfer in matings with late-subadult females follows the same route as in matings with adult females. The observed differences in the secretions inside the spermathecae of adult and late-subadult females likely reflect different storage conditions for the transferred sperm which may lead to a disadvantage under sperm competition if the subadult female later re-mates with another male. However, since males mating with late-subadult females typically transfer sperm to both spermathecae they might benefit from numerical sperm competition as well as from monopolizing access to the female sperm storage organs. The assessment of re-mating probability and relative paternity will clarify the costs and benefits of the two mating tactics in light of these findings.

SPERM PREFERENCE IN DROSOPHILA MELANOGASTER  †

Genetics ◽  
1972 ◽  
Vol 71 (3) ◽  
pp. 417-427
Author(s):  
D Childress ◽  
D L Hartl
Keyword(s):  
Drosophila Melanogaster ◽  
Reproductive Tract ◽  
Meiotic Drive ◽  
Prior Exposure ◽  
Different Types

Abstract A mating is described in which the females appear actively to discriminate against one of the genotypes of sperm. The males in the mating carry T(1;4)B  S  , and the sperm type selected against is the B  S+4-bearing segregant. Prior exposure of the reproductive tract of the females to B  S+4-bearing sperm seems to enhance the ability of the females to subsequently discriminate against B  S+4-bearing sperm. Thus it appears that at least some females of Drosophila melanogaster do possess a mechanism whereby different types of sperm can be distinguished—the sperm preference observed in this system appears to be independent of the meiotic drive in the T(1;4)B  S males.

Effects of condition and sperm competition risk on sperm allocation and storage in neriid flies

2019 ◽  
Author(s):  
Zachariah Wylde ◽  
Angela Crean ◽  
Russell Bonduriansky
Keyword(s):  
Sperm Competition ◽  
Perceived Risk ◽  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
The Body ◽  
Condition Dependence ◽  
Ejaculate Size ◽  
Sperm Competition Risk ◽  
High Condition ◽  
Allocation Strategies

Abstract Ejaculate traits can be sexually selected and often exhibit heightened condition-dependence. However, the influence of sperm competition risk in tandem with condition-dependent ejaculate allocation strategies is relatively unstudied. Because ejaculates are costly to produce, high-condition males may be expected to invest more in ejaculates when sperm competition risk is greater. We examined the condition-dependence of ejaculate size by manipulating nutrient concentration in the juvenile (larval) diet of the neriid fly Telostylinus angusticollis. Using a fully factorial design we also examined the effects of perceived sperm competition risk (manipulated by allowing males to mate first or second) on the quantity of ejaculate transferred and stored in the three spermathecae of the female reproductive tract. To differentiate male ejaculates, we fed males nontoxic rhodamine fluorophores (which bind to proteins in the body) prior to mating, labeling their sperm red or green. We found that high-condition males initiated mating more quickly and, when mating second, transferred more ejaculate to both of the female’s posterior spermathecae. This suggests that males allocate ejaculates strategically, with high-condition males elevating their ejaculate investment only when facing sperm competition. More broadly, our findings suggest that ejaculate allocation strategies can incorporate variation in both condition and perceived risk of sperm competition.

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