Strategic sperm allocation under parasitic sex-ratio distortion

Dunn, Alison M.; Andrews, Tara Lee; Ingrey, Hannah; Riley, J.E.; Wedell, Nina

doi:10.1098/rsbl.2005.0402

Cited by 35 publications

(23 citation statements)

References 18 publications

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“…Although females of gammarid amphipods are sexually receptive for only a brief period of the molt cycle, males are considered available for mating during most of their molt cycle [51]. The G. pulex male has limited numbers of spermatozoa in its gonads, which has been estimated at 10,000 gametes per testis [52], which is in the same range reported for G. duebeni [53]. Lemaître et al [52] found substantial sperm allocation to each reproductive event but also a relatively fast replenishment.…”

Section: Spermatogenesis In Amphipodssupporting

confidence: 64%

“…Depletion of G. pulex spermatozoa from copulation had no impact on male reproduction, because males could engage in precopula within a few hours of a previous copulation [52]. In contrast, G. duebeni males were shown to have reduced sperm counts after three consecutive matings that resulted in decreased female fecundity [53]. Lower sperm counts have been reported in intersex males of the intertidal amphipod E. marinus [54].…”

Section: Spermatogenesis In Amphipodsmentioning

confidence: 98%

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Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

Hyne¹

2011

Enviro Toxic and Chemistry

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Abstract-The reproductive biology of amphipods is reviewed to update the knowledge of the male and female reproductive processes of oogenesis and spermatogenesis as well as the endocrine systems of amphipods with the aim of advancing studies of reproductive toxicology. The ovarian and reproduction cycles of female gammaridean amphipods are closely correlated with the molt cycle, which is under direct control by the steroid hormone 20-hydroxyecdysone. The ability of males to copulate and subsequently for females to ovulate is restricted to the early postmolt period of the females. New developments in our understanding of the molt cycle and the endocrine regulatory pathways for reproduction using genomics techniques on other crustacean species are also discussed. The arthropod sterol ponasterone A or xenobiotics such as the fungicide fenarimol have been shown to elicit endocrine disruption in some crustaceans by acting as an agonist for 20-hydroxyecdysone at the ecdysone receptor or by inhibiting the synthesis of 20-hydroxyecdysone, respectively, resulting in disruption of molting and reproduction. Recent studies suggest that cadmium can inhibit secondary vitellogenesis in amphipods. Experimental approaches for examining the metabolic pathways associated with ecdysteroid hormonal signaling or metabolism, exoskeleton maintenance and molting, and the regulation of vitellogenin in amphipods are discussed. This information should aid in the identification of useful biomarkers for reproductive toxicity. Environ. Toxicol. Chem.

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Section: Spermatogenesis In Amphipodssupporting

confidence: 64%

Section: Spermatogenesis In Amphipodsmentioning

confidence: 98%

Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

Hyne¹

2011

Enviro Toxic and Chemistry

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“…This is consistent with the action of selection to partition ejaculates to enable a greater mating rate in males. Further, in Gammarus duebeni, males are sperm-limited and allocate larger ejaculates to females that do not carry feminizing symbionts (Dunn et al 2006). Although this may be the expression of a historic preference for high-quality females, it is also consistent with adaptive preferences evolved to counter the problem of feminization.…”

Section: Alteration In Mating System/reproductive Ecologymentioning

confidence: 71%

Reproductive Parasitism: Maternally Inherited Symbionts in a Biparental World

Hurst

Frost

2015

Cold Spring Harb Perspect Biol

131

146

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Most species of insect, and many other plants and animals, carry maternally heritable microorganisms-viruses, bacteria, unicellular eukaryotes, and fungi that pass from a female host to her progeny. Maternal inheritance establishes a correlation between the fitness of symbiont and host female, which can select for the symbiont to contribute to host fitness. Nevertheless, its lack of transmission through male hosts places the symbiont in conflict with biparentally inherited nuclear genes. In this review, we first examine how this conflict is manifest in selection to promote the production and survival of infected female hosts and gametes. We then examine how the distorted population sex ratios that they produce may affect host reproductive ecology, and thus the intensity of other conflicts associated with sexual reproduction. Finally, we examine evolved host responses to symbiont manipulation. We argue that the unusual intensity of symbiont-host conflict generates extreme selection pressures that can drive changes in sex-determination systems, the basic pathway through which males and females are constructed.

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“…Similarly, male G. duebeni shrimps in populations harbouring feminizing microsporidia (Nosema granulosis) provide fewer sperm to feminized males. This is advantageous for males as they are severely sperm limited and feminized males have lower fecundity than uninfected females (Dunn et al 2006). …”

Section: Pre-copulatory Choice In Relation To Sgesmentioning

confidence: 97%

Selfish genetic elements and sexual selection: their impact on male fertility

Price

Wedell

2007

Genetica

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Females of many species mate with more than one male (polyandry), yet the adaptive significance of polyandry is poorly understood. One hypothesis to explain the widespread occurrence of multiple mating is that it may allow females to utilize post-copulatory mechanisms to reduce the risk of fertilizing their eggs with sperm from incompatible males. Selfish genetic elements (SGEs) are ubiquitous in eukaryotes, frequent sources of reproductive incompatibilities, and associated with fitness costs. However, their impact on sexual selection is largely unexplored. In this review we examine the link between SGEs, male fertility and sperm competitive ability. We show there is widespread evidence that SGEs are associated with reduced fertility in both animals and plants, and present some recent data showing that males carrying SGEs have reduced paternity in sperm competition. We also discuss possible reasons why male gametes are particularly vulnerable to the selfish actions of SGEs. The widespread reduction in male fertility caused by SGEs implies polyandry may be a successful female strategy to bias paternity against SGE-carrying males.

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Strategic sperm allocation under parasitic sex-ratio distortion

Cited by 35 publications

References 18 publications

Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

Reproductive Parasitism: Maternally Inherited Symbionts in a Biparental World

Selfish genetic elements and sexual selection: their impact on male fertility

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