Male Gametic Strategies: Sperm Size, Testes Size, and the Allocation of Ejaculate Among Successive Mates by the Sperm-Limited Fly Drosophila pachea and Its Relatives

Females of many species mate with multiple males, thereby inciting competition among ejaculates from rival males for fertilization. In response to increasing sperm competition, males are predicted to enhance their investment in sperm production. This prediction is so widespread that testes size (correcting for body size) is commonly used as a proxy of sperm competition, even in the absence of any other information about a species' reproductive behaviour. By contrast, a debate about whether sperm competition selects for smaller or larger sperm has persisted for nearly three decades, with empirical studies demonstrating every possible response. Here, we synthesize nearly 40 years of sperm competition research in a meta-analytical framework to determine how the evolution of sperm number (i.e. testes size) and sperm size (i.e. sperm head, midpiece, flagellum and total length) is influenced by varying levels of sperm competition across species. Our findings support the long-held assumption that higher levels of sperm competition are associated with relatively larger testes. We also find clear evidence that sperm competition is associated with increases in all components of sperm length. We discuss these results in the context of different theoretical predictions and general patterns in the breeding biology and selective environment of sperm. This article is part of the theme issue ‘Fifty years of sperm competition’.

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Relative testis size and mating systems in anurans: large testis in multiple-male mating in foam-nesting frogs

Animal Biology ◽

10.1163/157075511x570312 ◽

2011 ◽

Vol 61 (2) ◽

pp. 225-238 ◽

Cited By ~ 15

Author(s):

Wen Bo Liao ◽

Zhi Ping Mi ◽

Cai Quan Zhou ◽

Ling Jin ◽

Xian Han ◽

...

Keyword(s):

Sperm Competition ◽

Published Data ◽

Male Mating ◽

Data Sets ◽

Testis Size ◽

Data Set ◽

Monogamous Species ◽

Large Testis ◽

Testes Size ◽

Testis Mass

AbstractComparative studies of the relative testes size in animals show that promiscuous species have relatively larger testes than monogamous species. Sperm competition favours the evolution of larger ejaculates in many animals – they give bigger testes. In the view, we presented data on relative testis mass for 17 Chinese species including 3 polyandrous species. We analyzed relative testis mass within the Chinese data set and combining those data with published data sets on Japanese and African frogs. We found that polyandrous foam nesting species have relatively large testes, suggesting that sperm competition was an important factor affecting the evolution of relative testes size. For 4 polyandrous species testes mass is positively correlated with intensity (males/mating) but not with risk (frequency of polyandrous matings) of sperm competition.

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Sperm Competition: Mating System, Not Breeding Season, Affects Testes Size of Primates

Functional Ecology ◽

10.2307/2390011 ◽

1995 ◽

Vol 9 (3) ◽

pp. 468 ◽

Cited By ~ 174

Author(s):

A. H. Harcourt ◽

A. Purvis ◽

L. Liles

Keyword(s):

Mating System ◽

Sperm Competition ◽

Breeding Season ◽

Testes Size

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Relationship among testosterone response to GnRH administration, testes size and sperm parameters in Holstein-Friesian bulls

Theriogenology ◽

10.1016/0093-691x(95)00116-p ◽

1995 ◽

Vol 43 (8) ◽

pp. 1317-1324 ◽

Cited By ~ 17

Author(s):

G. Gábor ◽

M. Mézes ◽

J. Tözsér ◽

S. Bozó ◽

E. Szücs ◽

...

Keyword(s):

Sperm Parameters ◽

Holstein Friesian ◽

Testes Size

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Early diversification of sperm size in the evolutionary history of the old world leaf warblers (Phylloscopidae)

Journal of Evolutionary Biology ◽

10.1111/jeb.12826 ◽

2016 ◽

Vol 29 (4) ◽

pp. 777-789 ◽

Cited By ~ 3

Author(s):

K. Supriya ◽

M. Rowe ◽

T. Laskemoen ◽

D. Mohan ◽

T. D. Price ◽

...

Keyword(s):

Evolutionary History ◽

Old World ◽

Early Diversification ◽

History Of ◽

Leaf Warblers ◽

Sperm Size

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Variation in sperm size within and between ejaculates in a cockroach

Functional Ecology ◽

10.1111/j.1365-2435.2007.01248.x ◽

2007 ◽

Vol 21 (3) ◽

pp. 598-602 ◽

Cited By ~ 11

Author(s):

W. E. HARRIS ◽

A. J. MOORE ◽

P. J. MOORE

Keyword(s):

Sperm Size

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In Utero Exposure to Di(n)butyl Phthalate Reduces Testicular Testosterone and Testes Size in a Dose-Dependent Manner in Harlan Sprague Dawley Fetal Rats.

Biology of Reproduction ◽

10.1093/biolreprod/81.s1.636 ◽

2009 ◽

Vol 81 (Suppl_1) ◽

pp. 636-636

Author(s):

Kembra L. Howdeshell ◽

Johnathan Furr ◽

Christy R. Lambright ◽

Vickie Wilson ◽

L. Earl Gray

Keyword(s):

In Utero ◽

In Utero Exposure ◽

Dependent Manner ◽

Sprague Dawley ◽

Fetal Rats ◽

Testes Size ◽

Butyl Phthalate ◽

Dose Dependent

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Repeated evolution of asymmetric genitalia and right-sided mating behavior in theDrosophila nannopteraspecies group

10.1101/553024 ◽

2019 ◽

Author(s):

Andrea Acurio ◽

Flor T. Rhebergen ◽

Sarah Paulus ◽

Virginie Courtier-Orgogozo ◽

Michael Lang

Keyword(s):

Related Species ◽

Current Data ◽

The Other ◽

Genital Morphology ◽

Closely Related Species ◽

Outgroup Species ◽

Repeated Evolution ◽

Drosophila Pachea ◽

Species Specific ◽

Group Species

AbstractBackgroundMale genitals have repeatedly evolved left-right asymmetries, and the causes of such evolution remain unclear. TheDrosophila nannopteragroup contains four species, among which three exhibit left-right asymmetries of distinct genital organs. In the most studied species,Drosophila pachea, males display asymmetric genital lobes and they mate right-sided on top of the female. Copulation position of the other species is unknown.ResultsTo assess whether the evolution of genital asymmetry could be linked to the evolution of one-sided mating, we examined phallus morphology and copulation position inD. pacheaand closely related species. The phallus was found to be symmetric in all investigated species exceptD. pachea, which display an asymmetric phallus with a right-sided gonopore, andD. acanthoptera, which harbor an asymmetrically bent phallus. In all examined species, males were found to position themselves symmetrically on top of the female, except inD. pacheaandD. nannoptera, where males mated right-sided, in distinctive, species-specific positions. In addition, the copulation duration was found to be increased innannopteragroup species compared to closely related outgroup species.ConclusionOur study shows that gains, and possibly losses, of asymmetry in genital morphology and mating position have evolved repeatedly in thenannopteragroup. Current data does not allow us to conclude whether genital asymmetry has evolved in response to changes in mating position, or vice versa.

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