scholarly journals Plastic responses of male Drosophila melanogaster to the level of sperm competition increase male reproductive fitness

2009 ◽  
Vol 276 (1662) ◽  
pp. 1705-1711 ◽  
Author(s):  
Amanda Bretman ◽  
Claudia Fricke ◽  
Tracey Chapman

Evolutionary and plastic responses by males to the level of sperm competition (SC) are reported across widespread taxa, but direct tests of the consequences for male reproductive success in a competitive context are lacking. We varied male perception of SC to examine the effect on male competitive reproductive success and to test whether the outcomes were as predicted by theory. Exposure to rival males prior to mating increased a male's ejaculate investment (measured as mating duration); by contrast, exposure to rival males in the mating arena decreased mating duration. The results therefore suggested that SC intensity is important in shaping male responses to SC in this system, although the patterns were not strictly in accord with existing theory. We then tested whether males that responded to the level of SC had higher reproductive fitness in a competitive context. We found that males kept with rivals prior to mating again mated for longer; furthermore, they achieved significantly higher paternity share regardless of whether they were the first or second males to mate with a female. The plastic strategies employed by males therefore resulted in significantly increased reproductive success in a competitive context, even following subsequent rematings in which the majority of sperm were displaced.

2021 ◽  
Author(s):  
Jake Galvin ◽  
Erica Larson ◽  
Sevan Yedigarian ◽  
Mohammad Rahman ◽  
Kirill Borziak ◽  
...  

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.


2014 ◽  
Vol 281 (1782) ◽  
pp. 20132973 ◽  
Author(s):  
Julie M. Collet ◽  
Rebecca F. Dean ◽  
Kirsty Worley ◽  
David S. Richardson ◽  
Tommaso Pizzari

Bateman's principles explain sex roles and sexual dimorphism through sex-specific variance in mating success, reproductive success and their relationships within sexes (Bateman gradients). Empirical tests of these principles, however, have come under intense scrutiny. Here, we experimentally show that in replicate groups of red junglefowl, Gallus gallus , mating and reproductive successes were more variable in males than in females, resulting in a steeper male Bateman gradient, consistent with Bateman's principles. However, we use novel quantitative techniques to reveal that current methods typically overestimate Bateman's principles because they (i) infer mating success indirectly from offspring parentage, and thus miss matings that fail to result in fertilization, and (ii) measure Bateman gradients through the univariate regression of reproductive over mating success, without considering the substantial influence of other components of male reproductive success, namely female fecundity and paternity share. We also find a significant female Bateman gradient but show that this likely emerges as spurious consequences of male preference for fecund females, emphasizing the need for experimental approaches to establish the causal relationship between reproductive and mating success. While providing qualitative support for Bateman's principles, our study demonstrates how current approaches can generate a misleading view of sex differences and roles.


2010 ◽  
Vol 21 (2) ◽  
pp. 317-321 ◽  
Author(s):  
Amanda Bretman ◽  
Claudia Fricke ◽  
Primrose Hetherington ◽  
Rachel Stone ◽  
Tracey Chapman

2018 ◽  
Vol 103 ◽  
pp. 1-10 ◽  
Author(s):  
Hanna Ruhmann ◽  
Mareike Koppik ◽  
Mariana F. Wolfner ◽  
Claudia Fricke

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 231
Author(s):  
Melissah Rowe ◽  
Annabel van Oort ◽  
Lyanne Brouwer ◽  
Jan T. Lifjeld ◽  
Michael S. Webster ◽  
...  

Sperm competition is thought to impose strong selection on males to produce competitive ejaculates to outcompete rival males under competitive mating conditions. Our understanding of how different sperm traits influence fertilization success, however, remains limited, especially in wild populations. Recent literature highlights the importance of incorporating multiple ejaculate traits and pre-copulatory sexually selected traits in analyses aimed at understanding how selection acts on sperm traits. However, variation in a male’s ability to gain fertilization success may also depend upon a range of social and ecological factors that determine the opportunity for mating events both within and outside of the social pair-bond. Here, we test for an effect of sperm quantity and sperm size on male reproductive success in the red-back fairy-wren (Malurus melanocephalus) while simultaneously accounting for pre-copulatory sexual selection and potential socio-ecological correlates of male mating success. We found that sperm number (i.e., cloacal protuberance volume), but not sperm morphology, was associated with reproductive success in male red-backed fairy-wrens. Most notably, males with large numbers of sperm available for copulation achieved greater within-pair paternity success. Our results suggest that males use large sperm numbers as a defensive strategy to guard within-pair paternity success in a system where there is a high risk of sperm competition and female control of copulation. Finally, our work highlights the importance of accounting for socio-ecological factors that may influence male mating opportunities when examining the role of sperm traits in determining male reproductive success.


2006 ◽  
Vol 84 (4) ◽  
pp. 520-526 ◽  
Author(s):  
Emily E. Johnston ◽  
Matthew S. Rand ◽  
Stephan G. Zweifel

Reproductive success is a critical measure of an organism’s fitness. Determining reproductive success in vertebrates is confounded by the concealed mechanism and timing of fertilization (e.g., sperm competition and storage). To assess the relationship between observed mating behavior and reproductive success in the central Asian tortoise, Testudo horsfieldii Gray, 1844, we determined individual genotypes from a captive colony of adults and their offspring. We constructed a size-selected genomic library from T. horsfieldii and screened for polymorphic microsatellite markers. The screen resulted in identification of two novel microsatellite regions. Cross-species amplification of microsatellite markers using primers developed for the bog turtle, Glyptemys muhlenbergii (Schoepff, 1801), resulted in isolation of three additional polymorphic microsatellites for T. horsfieldii. The five loci, which have between 5 and 17 alleles and observed heterozygosities between 0.44 and 0.90, were used to determine the frequency of multiple paternity in the captive colony. We found evidence for multiple paternity in 27% of the clutches examined, as well as evidence for overwinter sperm storage and variance in adult male reproductive success. These data indicate that ample opportunity exists for sperm competition and female mate choice in T. horsfieldii.


2012 ◽  
Vol 279 (1741) ◽  
pp. 3201-3208 ◽  
Author(s):  
A. South ◽  
S. M. Lewis

Because females often mate with multiple males, it is critical to expand our view of sexual selection to encompass pre-, peri- and post-copulatory episodes to understand how selection drives trait evolution. In Photinus fireflies, females preferentially respond to males based on their bioluminescent courtship signals, but previous work has shown that male paternity success is negatively correlated with flash attractiveness. Here, we experimentally manipulated both the attractiveness of the courtship signal visible to female Photinus greeni fireflies before mating and male nuptial gift size to determine how these traits might each influence mate acceptance and paternity share. We also measured pericopulatory behaviours to examine their influence on male reproductive success. Firefly males with larger spermatophores experienced dual benefits in terms of both higher mate acceptance and increased paternity share. We found no effect of courtship signal attractiveness or pericopulatory behaviour on male reproductive success. Taken together with previous results, this suggests a possible trade-off for males between producing an attractive courtship signal and investing in nuptial gifts. By integrating multiple episodes of sexual selection, this study extends our understanding of sexual selection in Photinus fireflies and provides insight into the evolution of male traits in other polyandrous species.


2018 ◽  
Vol 14 (10) ◽  
pp. 20180474 ◽  
Author(s):  
David C. S. Filice ◽  
Tristan A. F. Long

In Drosophila melanogaster , males engage in both extensive pre- and post-copulatory competition for the opportunity to mate with females and subsequently sire offspring. The selection pressure for increased male reproductive success has resulted in the evolution of a wide diversity of sexual traits. However, despite strong selection, individuals often exhibit considerable phenotypic variation in the expression of these traits, and it is unclear if any of this variation is owing to underlying genetic trade-offs. Here, using hemiclonal flies, we examine how male reproductive success covaries with their ability to induce long-term stimulation of oogenesis and oviposition in their mates, and how this relationship may change over time. We found that males from hemiclone lines with phenotypes that were more successful in a short-term reproductive ‘scramble’ environment were less effective at stimulating long-term fecundity in females. Furthermore, we observed that males from hemiclone lines which showed the most improvement over a longer reproductive interaction period also tended to stimulate higher long-term fecundity in females. Together, these results indicate the presence of genetic trade-offs between different male reproductive traits and offer insights into the maintenance of their variation.


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