Temporal dynamics of competitive fertilization in social groups of red junglefowl (
            Gallus gallus
            ) shed new light on avian sperm competition

Studies of birds have made a fundamental contribution to elucidating sperm competition processes, experimentally demonstrating the role of individual mechanisms in competitive fertilization. However, the relative importance of these mechanisms and the way in which they interact under natural conditions remain largely unexplored. Here, we conduct a detailed behavioural study of freely mating replicate groups of red junglefowl, Gallus gallus , to predict the probability that competing males fertilize individual eggs over the course of 10-day trials. Remating frequently with a female and mating last increased a male's probability of fertilization, but only for eggs ovulated in the last days of a trial. Conversely, older males, and those mating with more polyandrous females, had consistently lower fertilization success. Similarly, resistance to a male's mating attempts, particularly by younger females, reduced fertilization probability. After considering these factors, male social status, partner relatedness and the estimated state of male extragonadal sperm reserves did not predict sperm competition outcomes. These results shed new light on sperm competition dynamics in taxa such as birds, with prolonged female sperm storage and staggered fertilizations. This article is part of the theme issue ‘Fifty years of sperm competition’.

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The role of female reproductive fluid in sperm competition

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0077 ◽

2020 ◽

Vol 375 (1813) ◽

pp. 20200077 ◽

Cited By ~ 1

Author(s):

Clelia Gasparini ◽

Andrea Pilastro ◽

Jonathan P. Evans

Keyword(s):

Sperm Competition ◽

Seminal Fluid ◽

Fertilization Success ◽

Sperm Velocity ◽

Theme Issue ◽

Diverse Range ◽

Diverse Species ◽

Selected Functions ◽

Sperm Traits

The role of non-gametic components of the ejaculate (seminal fluid) in fertility and sperm competitiveness is now well established. Surprisingly, however, we know far less about female reproductive fluid (FRF) in the context of sexual selection, and insights into male–FRF interactions in the context of sperm competition have only recently emerged. Despite this limited knowledge, evidence from taxonomically diverse species has revealed insights into the effects of FRF on sperm traits that have previously been implicated in studies of sperm competition. Specifically, through the differential effects of FRF on a range of sperm traits, including chemoattraction and alterations in sperm velocity, FRF has been shown to exert positive phenotypic effects on the sperm of males that are preferred as mating partners, or those from the most compatible or genetically diverse males. Despite these tantalizing insights into the putative sexually selected functions of FRF, we largely lack a mechanistic understanding of these processes. Taken together, the evidence presented here highlights the likely ubiquity of FRF-regulated biases in fertilization success across a diverse range of taxa, thus potentially elevating the importance of FRF to other non-gametic components that have so far been studied largely in males. This article is part of the theme issue ‘Fifty years of sperm competition'.

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Studying the genetic basis of masting

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2021.0116 ◽

2021 ◽

Vol 376 (1839) ◽

Cited By ~ 4

Author(s):

Akiko Satake ◽

Dave Kelly

Keyword(s):

Genetic Basis ◽

Molecular Mechanisms ◽

Mast Seeding ◽

Ecological Genomics ◽

Theme Issue ◽

Natural Conditions ◽

Genetic Level ◽

Seed Crops

The mechanisms underlying mast seeding have traditionally been studied by collecting long-term observational data on seed crops and correlating seedfall with environmental variables. Significant progress in ecological genomics will improve our understanding of the evolution of masting by clarifying the genetic basis of masting traits and the role of natural selection in shaping those traits. Here, we summarize three important aspects in studying the evolution of masting at the genetic level: which traits govern masting, whether those traits are genetically regulated, and which taxa show wide variation in these traits. We then introduce recent studies on the molecular mechanisms of masting. Those studies measure seasonal changes in gene expression in natural conditions to quantify how multiple environmental factors combine to regulate floral initiation, which in many masting plant species is the single largest contributor to among-year variation in seed crops. We show that Fagaceae offers exceptional opportunities for evolutionary investigations because of its diversity at both the phenotypic and genetic levels and existing documented genome sequences. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

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Parental food-calling and the role of the young in the Burmese red junglefowl (Gallus gallus spadiceus)

Animal Behaviour ◽

10.1016/0003-3472(77)90109-9 ◽

1977 ◽

Vol 25 ◽

pp. 594-601 ◽

Cited By ~ 41

Author(s):

D.F. Sherry

Keyword(s):

Gallus Gallus ◽

Red Junglefowl

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Sperm competition when transfer is dangerous

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0073 ◽

2020 ◽

Vol 375 (1813) ◽

pp. 20200073

Author(s):

Cristina Tuni ◽

Jutta Schneider ◽

Gabriele Uhl ◽

Marie E. Herberstein

Keyword(s):

Sperm Competition ◽

Female Choice ◽

Male Mating ◽

Theme Issue ◽

Sperm Activation ◽

Proximate Mechanisms ◽

Mating Order ◽

Seminal Fluids ◽

Sperm Depletion

Aggressive and cannibalistic female spiders can impose strong selection on male mating and fertilization strategies. Furthermore, the distinctive reproductive morphology of spiders is predicted to influence the outcome of sperm competition. Polyandry is common in spiders, leading to defensive male strategies that include guarding, plugging and self-sacrifice. Paternity patterns are highly variable and unlikely to be determined solely by mating order, but rather by relative copulation duration, deployment of plugs and cryptic female choice. The ability to strategically allocate sperm is limited, either by the need to refill pedipalps periodically or owing to permanent sperm depletion after mating. Further insights now rely on unravelling several proximate mechanisms such as the process of sperm activation and the role of seminal fluids. This article is part of the theme issue ‘Fifty years of sperm competition’.

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Sperm competition and sperm cooperation: the potential role of diploid and haploid expression

Reproduction ◽

10.1530/rep-07-0482 ◽

2008 ◽

Vol 135 (3) ◽

pp. 275-283 ◽

Cited By ~ 60

Author(s):

Simone Immler

Keyword(s):

Sperm Competition ◽

Potential Role ◽

Focal Point ◽

Relative Importance ◽

Selective Force ◽

Potential Conflict ◽

Evolutionary Response ◽

And Function ◽

Diploid Organism

Sperm competition is a powerful selective force driving the evolution of sperm shape and function. Recent findings suggest that sperm cooperation is a potential evolutionary response to sperm competition. Sperm cooperation may enhance the performance of the ejaculate increasing a male's chance to outcompete rival males in competition for fertilisation. Whether and how sperm cooperation may evolve is the focal point of this review. The relative importance of haploid and diploid gene expression for the evolution of sperm cooperation and the potential conflict of interest between (i) haploid sperm and diploid male and (ii) among sibling sperm, since sibling sperm only share an average of 50% of their genes in a diploid organism, are discussed. Furthermore, sperm cooperation is defined and the literature for empirical evidence of sperm cooperation is reviewed in light of the author's definitions.

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Cryptic preference for MHC-dissimilar females in male red junglefowl, Gallus gallus

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2008.1549 ◽

2008 ◽

Vol 276 (1659) ◽

pp. 1083-1092 ◽

Cited By ~ 60

Author(s):

Mark A.F Gillingham ◽

David S Richardson ◽

Hanne Løvlie ◽

Anna Moynihan ◽

Kirsty Worley ◽

...

Keyword(s):

Major Histocompatibility Complex ◽

Function Theory ◽

Gallus Gallus ◽

Fertilization Success ◽

Gene Complex ◽

Male And Female ◽

Offspring Fitness ◽

Histocompatibility Complex ◽

Red Junglefowl ◽

Mhc Alleles

An increasing number of studies test the idea that females increase offspring fitness by biasing fertilization in favour of genetically compatible partners; however, few have investigated or controlled for corresponding preferences in males. Here, we experimentally test whether male red junglefowl, Gallus gallus , prefer genetically compatible females, measured by similarity at the major histocompatibility complex (MHC), a key gene complex in vertebrate immune function. Theory predicts that because some degree of MHC heterozygosity favours viability, individuals should prefer partners that carry MHC alleles different from their own. While male fowl showed no preference when simultaneously presented with an MHC-similar and an MHC-dissimilar female, they showed a ‘cryptic’ preference, by allocating more sperm to the most MHC-dissimilar of two sequentially presented females. These results provide the first experimental evidence that males might respond to the MHC similarity of a female through differential ejaculate expenditure. By revealing that cryptic male behaviours may bias fertilization success in favour of genetically compatible partners, this study demonstrates the need to experimentally disentangle male and female effects when studying preferences for genetically compatible partners.

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The Next Step: Disentangling the Role of Plant-Soil Feedbacks in Plant Performance and Species Coexistence Under Natural Conditions

10.3389/978-2-88966-023-0 ◽

2020 ◽

Keyword(s):

Species Coexistence ◽

Plant Performance ◽

Natural Conditions ◽

Plant Soil

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Population Control (Review Article)

The Pakistan Development Review ◽

10.30541/v1i3pp.89-98 ◽

1961 ◽

Vol 1 (3) ◽

pp. 89-98

Author(s):

Karol J. Krotki

Keyword(s):

Population Control ◽

Review Article ◽

Small Enterprise ◽

Opportunity Costs ◽

Relative Importance ◽

Factual Information ◽

Undue Influence ◽

Clear Cut ◽

Economic Considerations

Discussions about the role of small enterprise in economic development tend to remain inconclusive partly because of the difficulty of assessing the relative importance of economic and non-economic objectives and partly because of the dearth of factual information on which to base an economic calculus. It is probably true, moreover, that, because of a lack of general agreement as to the economic case for or against small enterprise, non-economic considerations, including some merely romantic attitudes toward smallness and bigness, tend to exert an undue influence on public policies. There may, of course, be no clear-cut economic case. And noneconomic considerations should and will inevitably weigh significantly in policy decisions. If, however, some of the economic questions could be settled by more and better knowledge, these decisions could more accurately reflect the opportunity costs of pursuing non-economic objectives.

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