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Hit or Miss: Fertilization Outcomes of Natural Inseminations by Japanese Quail.

Adkins-Regan E - PLoS ONE (2015)

Bottom Line: Variation in fertilization success underlies sexual selection, yet mating does not guarantee fertilization.Both sexes gained similar numbers of fertilized eggs by mating with a second partner the next day, but males, unlike females in a previous study, did not gain by having two females to mate with at the same time.Even double inseminations often failed to fertilize any eggs, and multiple matings would be needed for an entire clutch to be fertilized with high certainty.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology and Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, United States of America.

ABSTRACT
Variation in fertilization success underlies sexual selection, yet mating does not guarantee fertilization. The relationship between natural inseminations and fertilization success is essential for understanding sexual selection, yet that relationship and its underlying mechanisms are poorly understood in sperm-storing vertebrates such as birds. Here the relationship is analyzed in mating trials using Japanese quail (Coturnix japonica), which show striking variation in the fertilizing success of inseminations. Failures of males' inseminations to fertilize eggs were mainly due to failures prior to sperm-egg contact. Fertilization probabilities on any given day were unrelated to whether the female had laid an egg the previous day, arguing against stimulation of sperm release from sperm storage tubules by the events of the daily egg-laying cycle. Instead, an unfertilized egg laid between two fertilized eggs predicted a longer sperm storage interval. Both sexes gained similar numbers of fertilized eggs by mating with a second partner the next day, but males, unlike females in a previous study, did not gain by having two females to mate with at the same time. Instead, they were both behaviorally and sperm limited, whereas females gain by mating twice in quick succession. Even double inseminations often failed to fertilize any eggs, and multiple matings would be needed for an entire clutch to be fertilized with high certainty. Paradoxically, this low and probabilistic fertilization success co-occurs with other notable characteristics of male quail suggestive of past sexual selection for increased success, including vigorous copulatory behavior, forced copulations, foamy secretion aiding in sperm competition, large testes and unusual sperm morphology.

No MeSH data available.


Related in: MedlinePlus

Fertilization outcomes for Experiments 3 (female subjects, F) and 4 (male subjects, M) summarized to show the sex comparison in reproductive success gains from a second mating with insemination.The M– 2F and F– 2M birds mated with a second opposite-sex bird on the next day; the M– 1F and F– 1M birds are the controls in the experiments that mated once on one day. The box plots show the median, lower and upper quartiles and range. Both sexes gained from the second mating on average, but some subjects still had zero success (see text and Figs 5 and 6).
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pone.0131786.g007: Fertilization outcomes for Experiments 3 (female subjects, F) and 4 (male subjects, M) summarized to show the sex comparison in reproductive success gains from a second mating with insemination.The M– 2F and F– 2M birds mated with a second opposite-sex bird on the next day; the M– 1F and F– 1M birds are the controls in the experiments that mated once on one day. The box plots show the median, lower and upper quartiles and range. Both sexes gained from the second mating on average, but some subjects still had zero success (see text and Figs 5 and 6).

Mentions: Fig 7 summarizes the fertilization outcomes for Experiments 3 and 4 so that the gains from a second mating can be compared between male and female subjects mating with a different partner on the second day. The median numbers fertilized increased from 2 to 7 for males and 0 to 4 for females. Because of the shapes of the distributions, it is not possible to compare these gains quantitatively, nor does a change in median from 2 to 7 mean that males gained more than three times the success. Nonetheless, it is clear that on average both sexes gained substantial additional reproductive success while still failing to produce a single fertilized egg in some cases.


Hit or Miss: Fertilization Outcomes of Natural Inseminations by Japanese Quail.

Adkins-Regan E - PLoS ONE (2015)

Fertilization outcomes for Experiments 3 (female subjects, F) and 4 (male subjects, M) summarized to show the sex comparison in reproductive success gains from a second mating with insemination.The M– 2F and F– 2M birds mated with a second opposite-sex bird on the next day; the M– 1F and F– 1M birds are the controls in the experiments that mated once on one day. The box plots show the median, lower and upper quartiles and range. Both sexes gained from the second mating on average, but some subjects still had zero success (see text and Figs 5 and 6).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519265&req=5

pone.0131786.g007: Fertilization outcomes for Experiments 3 (female subjects, F) and 4 (male subjects, M) summarized to show the sex comparison in reproductive success gains from a second mating with insemination.The M– 2F and F– 2M birds mated with a second opposite-sex bird on the next day; the M– 1F and F– 1M birds are the controls in the experiments that mated once on one day. The box plots show the median, lower and upper quartiles and range. Both sexes gained from the second mating on average, but some subjects still had zero success (see text and Figs 5 and 6).
Mentions: Fig 7 summarizes the fertilization outcomes for Experiments 3 and 4 so that the gains from a second mating can be compared between male and female subjects mating with a different partner on the second day. The median numbers fertilized increased from 2 to 7 for males and 0 to 4 for females. Because of the shapes of the distributions, it is not possible to compare these gains quantitatively, nor does a change in median from 2 to 7 mean that males gained more than three times the success. Nonetheless, it is clear that on average both sexes gained substantial additional reproductive success while still failing to produce a single fertilized egg in some cases.

Bottom Line: Variation in fertilization success underlies sexual selection, yet mating does not guarantee fertilization.Both sexes gained similar numbers of fertilized eggs by mating with a second partner the next day, but males, unlike females in a previous study, did not gain by having two females to mate with at the same time.Even double inseminations often failed to fertilize any eggs, and multiple matings would be needed for an entire clutch to be fertilized with high certainty.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology and Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, United States of America.

ABSTRACT
Variation in fertilization success underlies sexual selection, yet mating does not guarantee fertilization. The relationship between natural inseminations and fertilization success is essential for understanding sexual selection, yet that relationship and its underlying mechanisms are poorly understood in sperm-storing vertebrates such as birds. Here the relationship is analyzed in mating trials using Japanese quail (Coturnix japonica), which show striking variation in the fertilizing success of inseminations. Failures of males' inseminations to fertilize eggs were mainly due to failures prior to sperm-egg contact. Fertilization probabilities on any given day were unrelated to whether the female had laid an egg the previous day, arguing against stimulation of sperm release from sperm storage tubules by the events of the daily egg-laying cycle. Instead, an unfertilized egg laid between two fertilized eggs predicted a longer sperm storage interval. Both sexes gained similar numbers of fertilized eggs by mating with a second partner the next day, but males, unlike females in a previous study, did not gain by having two females to mate with at the same time. Instead, they were both behaviorally and sperm limited, whereas females gain by mating twice in quick succession. Even double inseminations often failed to fertilize any eggs, and multiple matings would be needed for an entire clutch to be fertilized with high certainty. Paradoxically, this low and probabilistic fertilization success co-occurs with other notable characteristics of male quail suggestive of past sexual selection for increased success, including vigorous copulatory behavior, forced copulations, foamy secretion aiding in sperm competition, large testes and unusual sperm morphology.

No MeSH data available.


Related in: MedlinePlus