Senescence and Sexual Selection in a Pelagic Copepod

Ceballos, Sara; Kiørboe, Thomas

doi:10.1371/journal.pone.0018870

Cited by 45 publications

(56 citation statements)

References 61 publications

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“…For instance, adult Pseudocalanus males have a natural lifespan one-fourth that of females (Pertsova & Kosobokova 1996) and adult Oithona davisae male longevity is half of that of the female (Ceballos & Kiørboe 2011). These findings could explain, at least in part, the commonly observed female-skewed sex ratios of species of these genera in situ.…”

Section: Differential Stage Duration Of Juveniles and Differential Admentioning

confidence: 99%

No evidence of predation causing female-biased sex ratios in marine pelagic copepods

Gusmão¹,

McKinnon²,

Richardson³

2013

Mar. Ecol. Prog. Ser.

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Although sex ratios close to unity are expected in dioecious species, biased sex ratios are common in nature. It is essential to understand causes of skewed sex ratios in situ, as they can lead to mate limitation and have implications for the success of natural populations. Femaleskewed sex ratios are commonly observed in copepods in situ. Here we discuss the challenges of copepod sex ratio research and provide a critical review of factors determining copepod sex ratios, focusing on 2 main objectives. The first is a critique of the male predation theory, which is currently the main process thought to be responsible for female-skewed sex ratios. It assumes that males have higher mortality because of increased vulnerability to predation during their search for mates. We show that there is little support for the male predation theory, that sex ratios skewed toward females occur in the absence of predation, that sex ratios are not related to predation pressure, and that where sex-skewed predation does occur, it is biased toward females. Our second objective is to suggest alternative hypotheses regarding the determination of sex ratios. We demonstrate that environmental factors, environmental sex determination and sex change have strong effects on copepod sex ratios, and suggest that differential physiological longevity of males and females may be more important in determining sex ratios than previously thought. We suggest that copepod sex ratios are the result of a mixture of factors.

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Section: Differential Stage Duration Of Juveniles and Differential Admentioning

confidence: 99%

No evidence of predation causing female-biased sex ratios in marine pelagic copepods

Gusmão¹,

McKinnon²,

Richardson³

2013

Mar. Ecol. Prog. Ser.

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“…While information about male mating rates are rare, the few which have been reported show that males are able to produce and deploy more than one spermatophore per day (Ceballos and Kiørboe 2011;Ceballos et al, unpublished data;Ianora et al 1999), whereas females do not need to be remated for several days or never during their lifetime (i.e., Ceballos and Kiørboe 2011;Hylstofte and Kiørboe 2011;Wilson and Parrish 1971). Therefore, especially at high population densities, females of all species are predicted to be choosy.…”

Section: General Pointsmentioning

confidence: 99%

Optimal mate choice patterns in pelagic copepods

2012

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The importance of sexual selection for the evolution, dynamics and adaptation of organisms is well known for many species. However, the topic is rarely studied in marine plankton, the basis of the marine food web. Copepods show behaviors that suggest the existence of sexually selected traits, and recent laboratory experiments identified some selected morphological traits. Here, we use a 'life history-based' model of sex roles to determine the optimal choosiness behavior of male and female copepods for important copepod traits. Copepod females are predicted to be choosy at population densities typically occurring during the main breeding season, whereas males are not. The main drivers of this pattern are population density and the difference in non-receptive periods between males and females. This suggests that male reproductive traits have evolved mainly due to mate competition. The model can easily be parameterized for other planktonic organisms, and be used to plan experiments about sexual selection.

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“…In contrast, we know little about the genes that influence age-related functional declines in life history or physiological traits that may in turn affect age-specific mortality and limit life span (Burger and Promislow 2006;Charmantier et al 2006;Leips et al 2006;Lesser et al 2006;Nussey et al 2008a). Functional decline in such traits with age can reduce fitness in natural environments (Dudycha and Tessier 1999;Wilson et al 2007;Bowler and Terblanche 2008;Nussey et al 2008b;Wilson et al 2008;Blomquist 2010;Ceballos and Kiørboe 2011) and for humans influences the quality of life in older individuals. As such, knowledge of the genes that influence age-related deterioration in functional traits is important for understanding the genetic basis of evolutionary fitness as well as general aspects of health in the aging organism.…”

mentioning

confidence: 99%

Age-Specific Variation in Immune Response inDrosophila melanogasterHas a Genetic Basis

et al. 2012

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Immunosenescence, the age-related decline in immune system function, is a general hallmark of aging. While much is known about the cellular and physiological changes that accompany immunosenescence, we know little about the genetic influences on this phenomenon. In this study we combined age-specific measurements of bacterial clearance ability following infection with whole-genome measurements of the transcriptional response to infection and wounding to identify genes that contribute to the natural variation in immunosenescence, using Drosophila melanogaster as a model system. Twenty inbred lines derived from nature were measured for their ability to clear an Escherichia coli infection at 1 and 4 weeks of age. We used microarrays to simultaneously determine genome-wide expression profiles in infected and wounded flies at each age for 12 of these lines. Lines exhibited significant genetically based variation in bacterial clearance at both ages; however, the genetic basis of this variation changed dramatically with age. Variation in gene expression was significantly correlated with bacterial clearance ability only in the older age group. At 4 weeks of age variation in the expression of 247 genes following infection was associated with genetic variation in bacterial clearance. Functional annotation analyses implicate genes involved in energy metabolism including those in the insulin signaling/TOR pathway as having significant associations with bacterial clearance in older individuals. Given the evolutionary conservation of the genes involved in energy metabolism, our results could have important implications for understanding immunosenescence in other organisms, including humans.

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Senescence and Sexual Selection in a Pelagic Copepod

Cited by 45 publications

References 61 publications

No evidence of predation causing female-biased sex ratios in marine pelagic copepods

No evidence of predation causing female-biased sex ratios in marine pelagic copepods

Optimal mate choice patterns in pelagic copepods

Age-Specific Variation in Immune Response inDrosophila melanogasterHas a Genetic Basis

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