Microsatellite evidence for high frequency of multiple paternity in the marine gastropod Rapana venosa. by Dongxiu Xue, Tao Zhang, Jin-Xian Liu

“…Strongly skewed distributions of fertilization success among sires also suggest that sperm competition and/or cryptic female choice might be important for post-copulatory paternity biasing in this species.…”
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Male reproductive senescence as a potential source of sexual conflict in a beetle by Carazo, P, Molina-Vila, P, Font, E

“…Compared with females mated to young males, females mated to old males were less receptive and decreased their allocation to spermatophore guarding (a crucial determinant of male reproductive success in this species), increasing the risk of sperm competition by other males. In contrast, old males increased their own investment in spermatophore guarding, which suggests the existence of antagonistic selection over sperm competition strategies. …”

Quantity Estimation Based on Numerical Cues in the Mealworm Beetle (Tenebrio molitor). by Carazo, P, Fernández-Perea, R, Font, E

“…Like other insect species, mealworm beetles adjust their reproductive behavior (i.e., investment in mate guarding) according to the perceived risk of sperm competition (i.e., probability that a female will mate with another male). …”

Female novelty and male status dynamically modulate ejaculate expenditure and seminal fluid proteome over successive matings in red junglefowl by Alvarez-Fernandez, A, Borziak, K, McDonald, G, Dorus, S, Pizzari, T

“…While strategic sperm allocation has been studied extensively, little is known about concomitant changes in seminal fluid (SF) and its molecular composition, despite increasing evidence that SF proteins (SFPs) are fundamental in fertility and sperm competition. Here, we show that in male red junglefowl, Gallus gallus, along with changes in sperm numbers and SF investment, SF composition changed dynamically over successive matings with a first female, immediately followed by mating with a second, sexually novel female. …”

The sexually-selected sperm hypothesis: sex-biased inheritance and sexual antagonism. by Pizzari, T, Birkhead, T

“…When females are inseminated by more than one male (polyandry) sexual selection continues after insemination in the form of sperm competition and cryptic female choice. The sexually-selected sperm hypothesis proposes that, under the risk of sperm competition, additive variation in male traits determining fertilising efficiency will select for female propensity to be polyandrous in order to increase the probability of producing sons with superior fertilising efficiency. …”

Female choice for males with greater fertilization success in the Swedish Moor frog, Rana arvalis. by Craig D H Sherman, Jörgen Sagvik, Mats Olsson

“…'small'), and their fertilization success in sperm competition and in isolation. Females' showed no significant preference for male size (13 small and six large male preferences) but associated preferentially with the male that subsequently was the most successful at fertilizing her eggs in isolation. …”
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Genetic and potential non-genetic benefits increase offspring fitness of polyandrous females in non-resource based mating system by Peuhkuri Nina, Figenschou Lars, Janhunen Matti, Rudolfsen Geir, Kekäläinen Jukka, Tamper Niina, Kortet Raine

“…This suggests that sperm competition environment may intensify the selection on genetically superior sperm which in turn may produce offspring that have superior yolk reserves. …”
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Influence of mating strategies on seminal material investment in crabs by Katrin Pretterebner, Luis Miguel Pardo, Kurt Paschke, Marcela Paz Riveros

“…Both species are characterised by large and complex vasa deferentia, and the formation of a remarkably large sperm plug deposited to the female after copulation as a sperm competition avoidance strategy. In contrast, Metacarcinus edwardsii and Taliepus dentatus invested little energy in their smaller-sized and simpler vasa deferentia. …”
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Condition-dependent ejaculate size and composition in a ladybird beetle. by Perry, J, Rowe, L

“…Theory predicts that males in good condition will produce larger ejaculates, but that ejaculate composition will depend on the relative production costs of ejaculate components and the risk of sperm competition experienced by low- and high-condition males. …”

Within-population variation in ejaculate characteristics in a prolonged breeder, Peron's tree frog, Litoria peronii. by Sherman, C, Uller, T, Wapstra, E, Olsson, M

“…Sperm number is often a good predictor of success in sperm competition; however, it has become increasingly clear that, for some species, variation in probability of paternity cannot be explained by sperm number alone. …”

Ejaculate expenditure strategies in a polygynandrous bird, the red junglefowl, Gallus gallus by Wang, Y

“…Secondly, social status mediates access to females and the level of sperm competition faced by the ejaculates of a male. Dominant males have a higher copulation success and face a lower risk of sperm competition than subordinate males. …”

Sexual selection: sperm in the fast lane. by Pizzari, T

“…Sperm competition has led to spectacular adaptations in males and their ejaculates. …”

Can cryptic female choice prevent invasive hybridization in external fertilizing fish? by Tyler H. Lantiegne, Craig F. Purchase

“…Polyandry also creates the potential for unintended matings and subsequent sperm competition with hybridizing species. Cryptic female choice allows females to bias paternity towards preferred males under sperm competition and may include conspecific sperm preference when under hybridization risk. …”
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Y-Chromosome variation in hominids: intraspecific variation is limited to the polygamous chimpanzee. by Gabriele Greve, Evguenia Alechine, Juan J Pasantes, Christine Hodler, Wolfram Rietschel, Terence J Robinson, Werner Schempp

“…We hypothesize that this is best explained by sperm competition that results in the variant DAZ and CDY haplotypes detected in this species. …”
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Energy Metabolism and Hyperactivation of Spermatozoa from Three Mouse Species under Capacitating Conditions by Ester Sansegundo, Maximiliano Tourmente, Eduardo R. S. Roldan

“…The decrease in ATP levels during capacitation was steeper in species with higher levels of sperm competition than in those with lower levels. Our results suggest that, during capacitation, sperm consume more ATP than under non-capacitating conditions. …”
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Population-specific, recent positive directional selection suggests adaptation of human male reproductive genes to different environmental conditions by Helmut Schaschl, Bernard Wallner

“…Conclusion Episodic diversifying selection, possibly driven by sperm competition, was not an important force driving the evolution of testis-enriched genes in the human lineage. …”
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Size- and context-dependent nest-staying behaviour of males of the Japanese dung beetle, Copris acutidens (Coleoptera: Scarabaeidae) by Mayumi AKAMINE

“…These results indicate that because of the risk of sperm competition, major males stay longer in nests if a rival male is present. …”
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The sexually selected ejaculate by Hopkins, B

“…Within this, males lose the ability to reduce female receptivity to remating, but gain an advantage in defensive sperm competition. Through a systematic dissection of different episodes influencing sperm competition outcome, I find that loss of these secretions influences sperm entry into storage and potentially enhances their resistance to displacement.…”

Sexual development and reproductive pattern of the Mutton hamlet, Alphestes afer (Teleostei: Epinephelidae): a dyandric, hermaphroditic reef fish by Simone Marques, Beatrice Padovani Ferreira

“…Males showed a high sperm competition rank (3.8), suggesting intense sperm competition. …”
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Testicular Structure and Spermatogenesis in the Naked Mole-Rat Is Unique (Degenerate) and Atypical Compared to Other Mammals by Gerhard van der Horst, Sanet H. Kotzé, M. Justin O’Riain, Liana Maree

“…These numerous atypical and often simplified features of the NMR further supports the notion of degenerative orthogenesis that was selected for due to the absence of sperm competition.…”
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