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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 3.Number of fertilized eggs laid by females inseminated by the same male on each of two consecutive days, a different male on each of two consecutive days, or one male on one day (control). Each dot is one female’s egg fertilization outcome. * p < 0.05 compared with the Control group.
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pone.0131786.g005: Experiment 3.Number of fertilized eggs laid by females inseminated by the same male on each of two consecutive days, a different male on each of two consecutive days, or one male on one day (control). Each dot is one female’s egg fertilization outcome. * p < 0.05 compared with the Control group.

Mentions: Fig 5 shows the fertilization outcomes for the three groups. Even with two inseminations on consecutive days, some females did not lay any fertilized eggs (19% in the Same Male group and 24% in the Different Male group did not) and there were also many unfertilized eggs in the sequences with at least one fertilized egg. Nonetheless, both groups produced more fertilized eggs than the Control group (Same Male vs. Control: Mann-Whitney U = 74, p = 0.026; Different Male vs. Control: U = 75, p = 0.016) (Fig 5). The gain from two inseminations rather than one was mainly in the probability that there would be at least one fertilized egg, rather than in the number of eggs fertilized if any were fertilized. The proportions of zeros were significantly different in both two-mating groups compared to the control group (Same Male vs. Control: Fisher’s exact test p = 0.013; Different Male vs. Control: p = 0.037). The median numbers of fertilized eggs in sequences with at least one fertilized egg, on the other hand, did not differ significantly between two-mating and one-mating groups (medians 4, 5 and 4 for Same Male, Different Male and Control groups, respectively; both Mann-Whitney U > 0.3) (see Fig 5).


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

Adkins-Regan E - PLoS ONE (2015)

Experiment 3.Number of fertilized eggs laid by females inseminated by the same male on each of two consecutive days, a different male on each of two consecutive days, or one male on one day (control). Each dot is one female’s egg fertilization outcome. * p < 0.05 compared with the Control group.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131786.g005: Experiment 3.Number of fertilized eggs laid by females inseminated by the same male on each of two consecutive days, a different male on each of two consecutive days, or one male on one day (control). Each dot is one female’s egg fertilization outcome. * p < 0.05 compared with the Control group.
Mentions: Fig 5 shows the fertilization outcomes for the three groups. Even with two inseminations on consecutive days, some females did not lay any fertilized eggs (19% in the Same Male group and 24% in the Different Male group did not) and there were also many unfertilized eggs in the sequences with at least one fertilized egg. Nonetheless, both groups produced more fertilized eggs than the Control group (Same Male vs. Control: Mann-Whitney U = 74, p = 0.026; Different Male vs. Control: U = 75, p = 0.016) (Fig 5). The gain from two inseminations rather than one was mainly in the probability that there would be at least one fertilized egg, rather than in the number of eggs fertilized if any were fertilized. The proportions of zeros were significantly different in both two-mating groups compared to the control group (Same Male vs. Control: Fisher’s exact test p = 0.013; Different Male vs. Control: p = 0.037). The median numbers of fertilized eggs in sequences with at least one fertilized egg, on the other hand, did not differ significantly between two-mating and one-mating groups (medians 4, 5 and 4 for Same Male, Different Male and Control groups, respectively; both Mann-Whitney U > 0.3) (see Fig 5).

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