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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

Experiment 4.Fertilization outcomes for males inseminating either two females, one on each of two consecutive days, or one female on one day (control). Each dot is the egg fertilization outcome for one male subject. ** p < 0.005 compared with Control group.
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pone.0131786.g006: Experiment 4.Fertilization outcomes for males inseminating either two females, one on each of two consecutive days, or one female on one day (control). Each dot is the egg fertilization outcome for one male subject. ** p < 0.005 compared with Control group.

Mentions: Eight males in the Two Females group and one male in the Control group failed to inseminate one or both of their assigned females, leaving 17 in the Two Females group and 24 in the Control group. There were eight eggs with an early embryonic death out of over 300 eggs total, which were not counted as successfully fertilized eggs. Fig 6 shows the fertilization outcomes for the two groups of males. While the proportions of zeros were not significantly different (3/17 and 6/24 for the Two Females and Control groups, respectively, p = 0.71), the median number of fertilized eggs was greater for the Two Females group than the Control group (medians including zeros: 7 and 2, respectively, U = 96, p = 0.0044; medians excluding zeros: 7.5 and 3.5, respectively, U = 33, p = 0.0004).


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

Adkins-Regan E - PLoS ONE (2015)

Experiment 4.Fertilization outcomes for males inseminating either two females, one on each of two consecutive days, or one female on one day (control). Each dot is the egg fertilization outcome for one male subject. ** p < 0.005 compared with Control group.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131786.g006: Experiment 4.Fertilization outcomes for males inseminating either two females, one on each of two consecutive days, or one female on one day (control). Each dot is the egg fertilization outcome for one male subject. ** p < 0.005 compared with Control group.
Mentions: Eight males in the Two Females group and one male in the Control group failed to inseminate one or both of their assigned females, leaving 17 in the Two Females group and 24 in the Control group. There were eight eggs with an early embryonic death out of over 300 eggs total, which were not counted as successfully fertilized eggs. Fig 6 shows the fertilization outcomes for the two groups of males. While the proportions of zeros were not significantly different (3/17 and 6/24 for the Two Females and Control groups, respectively, p = 0.71), the median number of fertilized eggs was greater for the Two Females group than the Control group (medians including zeros: 7 and 2, respectively, U = 96, p = 0.0044; medians excluding zeros: 7.5 and 3.5, respectively, U = 33, p = 0.0004).

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