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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 2.Representative fertilization patterns in the eggs laid by four females (one female per row of eggs) on days 2–10 of the laying sequence following a mating and single insemination on day 0. Black ovals are fertilized eggs (those containing an embryo); white ovals are unfertilized eggs. The day 1 egg is never fertilized (it was ovulated before mating occurred) and day 11 is almost never fertilized (see Fig 3). The second row has a fertilization gap on day 2 and a laying gap on day 4. The third row has a fertilization gap on day 5. The fourth row (no fertilized eggs) was the outcome in 44% of the trials.
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pone.0131786.g002: Experiment 2.Representative fertilization patterns in the eggs laid by four females (one female per row of eggs) on days 2–10 of the laying sequence following a mating and single insemination on day 0. Black ovals are fertilized eggs (those containing an embryo); white ovals are unfertilized eggs. The day 1 egg is never fertilized (it was ovulated before mating occurred) and day 11 is almost never fertilized (see Fig 3). The second row has a fertilization gap on day 2 and a laying gap on day 4. The third row has a fertilization gap on day 5. The fourth row (no fertilized eggs) was the outcome in 44% of the trials.

Mentions: Hypothesis 2: sperm release is triggered by oviposition and fertilizes the ovum ovulated shortly after oviposition. If there is no egg laid, sperm will not be released and the next ovum will not get fertilized. The prediction is that the next egg following a day without an egg (a laying gap- see Fig 2) will have a lower probability of being fertilized. Alternatively, as with Hypothesis 1 the last fertilized egg day might occur later.


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

Adkins-Regan E - PLoS ONE (2015)

Experiment 2.Representative fertilization patterns in the eggs laid by four females (one female per row of eggs) on days 2–10 of the laying sequence following a mating and single insemination on day 0. Black ovals are fertilized eggs (those containing an embryo); white ovals are unfertilized eggs. The day 1 egg is never fertilized (it was ovulated before mating occurred) and day 11 is almost never fertilized (see Fig 3). The second row has a fertilization gap on day 2 and a laying gap on day 4. The third row has a fertilization gap on day 5. The fourth row (no fertilized eggs) was the outcome in 44% of the trials.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131786.g002: Experiment 2.Representative fertilization patterns in the eggs laid by four females (one female per row of eggs) on days 2–10 of the laying sequence following a mating and single insemination on day 0. Black ovals are fertilized eggs (those containing an embryo); white ovals are unfertilized eggs. The day 1 egg is never fertilized (it was ovulated before mating occurred) and day 11 is almost never fertilized (see Fig 3). The second row has a fertilization gap on day 2 and a laying gap on day 4. The third row has a fertilization gap on day 5. The fourth row (no fertilized eggs) was the outcome in 44% of the trials.
Mentions: Hypothesis 2: sperm release is triggered by oviposition and fertilizes the ovum ovulated shortly after oviposition. If there is no egg laid, sperm will not be released and the next ovum will not get fertilized. The prediction is that the next egg following a day without an egg (a laying gap- see Fig 2) will have a lower probability of being fertilized. Alternatively, as with Hypothesis 1 the last fertilized egg day might occur later.

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