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Male coercive mating in externally fertilizing species: male coercion, female reluctance and explanation for female acceptance.

Matsumoto Y, Takegaki T - Sci Rep (2016)

Bottom Line: Most males that used small, tight nests acquired new eggs but with experimentally enlarged nests, 90% of the males without eggs failed to confine the females.In the nests where the first eggs were deposited in the early period, subsequent matings with other females were more likely to occur, whereas in the late period, most parental care of the eggs failed without additional matings.The females that spawned in the late period may have been compelled to accept male coercive mating due to time constraints.

View Article: PubMed Central - PubMed

Affiliation: Center for Coastal Fisheries and Aquaculture, Tohoku National Fisheries Research Institute, Fisheries Research Agency, Iwate, Japan.

ABSTRACT
Male coercive mating exerts a strong evolutionary pressure on mating-related traits of both sexes. However, it is extremely rare in externally fertilizing species probably because the male mating behaviour is incomplete until females release their eggs. Here we showed that males of the externally fertilizing fish Rhabdoblennius nitidus coercively confine females to the nests until spawning, and investigated why females accept male coercive mating. The females entered the males' nests following male courtship displays, but they usually tried to escape when there were no eggs because males tended to cannibalize all the eggs when there were few. Most males that used small, tight nests acquired new eggs but with experimentally enlarged nests, 90% of the males without eggs failed to confine the females. Spawning tended to occur during the early/late spawning period in nests with no eggs (i.e. male coercive mating). In the nests where the first eggs were deposited in the early period, subsequent matings with other females were more likely to occur, whereas in the late period, most parental care of the eggs failed without additional matings. The females that spawned in the late period may have been compelled to accept male coercive mating due to time constraints.

No MeSH data available.


(a) Mean (±95% confidence level) proportion of nests with no eggs in the study area at the start and end of the spawning time period (n = 30). (b) The frequency of female visits to nests with no eggs (solid line), and the frequency of spawning in the nests with no eggs by females that had initially visited another nest with other females (shaded bar, n = 11; also see Fig. 2e) and by females that had visited the same nests with no females (open bar, n = 11; also see Fig. 2g) during the spawning time period.
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f3: (a) Mean (±95% confidence level) proportion of nests with no eggs in the study area at the start and end of the spawning time period (n = 30). (b) The frequency of female visits to nests with no eggs (solid line), and the frequency of spawning in the nests with no eggs by females that had initially visited another nest with other females (shaded bar, n = 11; also see Fig. 2e) and by females that had visited the same nests with no females (open bar, n = 11; also see Fig. 2g) during the spawning time period.

Mentions: The frequencies of female visits and subsequent spawning in eggless nests were relatively high during the early and late spawning periods (Fig. 3b), although eggless nests were present throughout the spawning time period (Fig. 3a). In the cases of spawning in the eggless nests, the occurrence of additional mating by other females decreased (likelihood-ratio test, χ2 = 19.80, p < 0.001; Fig. 4a) and failure rate of parental care increased (χ2 = 12.03, p < 0.0001; Fig. 4b) as the remaining spawning period in the day decreased. The additional mating (eggs) following spawning in eggless nests decreased the failure rate of parental care (likelihood-ratio test, χ2 = 13.72, p < 0.0001; Fig. 2). Even without additional mating, spawning in nests that already contained eggs resulted in a relatively low failure rate of parental care (38%: 5/13), which was equivalent to that in the eggless nests with additional mating (23%: 3/13; Fisher’s exact test, p > 0.05).


Male coercive mating in externally fertilizing species: male coercion, female reluctance and explanation for female acceptance.

Matsumoto Y, Takegaki T - Sci Rep (2016)

(a) Mean (±95% confidence level) proportion of nests with no eggs in the study area at the start and end of the spawning time period (n = 30). (b) The frequency of female visits to nests with no eggs (solid line), and the frequency of spawning in the nests with no eggs by females that had initially visited another nest with other females (shaded bar, n = 11; also see Fig. 2e) and by females that had visited the same nests with no females (open bar, n = 11; also see Fig. 2g) during the spawning time period.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834473&req=5

f3: (a) Mean (±95% confidence level) proportion of nests with no eggs in the study area at the start and end of the spawning time period (n = 30). (b) The frequency of female visits to nests with no eggs (solid line), and the frequency of spawning in the nests with no eggs by females that had initially visited another nest with other females (shaded bar, n = 11; also see Fig. 2e) and by females that had visited the same nests with no females (open bar, n = 11; also see Fig. 2g) during the spawning time period.
Mentions: The frequencies of female visits and subsequent spawning in eggless nests were relatively high during the early and late spawning periods (Fig. 3b), although eggless nests were present throughout the spawning time period (Fig. 3a). In the cases of spawning in the eggless nests, the occurrence of additional mating by other females decreased (likelihood-ratio test, χ2 = 19.80, p < 0.001; Fig. 4a) and failure rate of parental care increased (χ2 = 12.03, p < 0.0001; Fig. 4b) as the remaining spawning period in the day decreased. The additional mating (eggs) following spawning in eggless nests decreased the failure rate of parental care (likelihood-ratio test, χ2 = 13.72, p < 0.0001; Fig. 2). Even without additional mating, spawning in nests that already contained eggs resulted in a relatively low failure rate of parental care (38%: 5/13), which was equivalent to that in the eggless nests with additional mating (23%: 3/13; Fisher’s exact test, p > 0.05).

Bottom Line: Most males that used small, tight nests acquired new eggs but with experimentally enlarged nests, 90% of the males without eggs failed to confine the females.In the nests where the first eggs were deposited in the early period, subsequent matings with other females were more likely to occur, whereas in the late period, most parental care of the eggs failed without additional matings.The females that spawned in the late period may have been compelled to accept male coercive mating due to time constraints.

View Article: PubMed Central - PubMed

Affiliation: Center for Coastal Fisheries and Aquaculture, Tohoku National Fisheries Research Institute, Fisheries Research Agency, Iwate, Japan.

ABSTRACT
Male coercive mating exerts a strong evolutionary pressure on mating-related traits of both sexes. However, it is extremely rare in externally fertilizing species probably because the male mating behaviour is incomplete until females release their eggs. Here we showed that males of the externally fertilizing fish Rhabdoblennius nitidus coercively confine females to the nests until spawning, and investigated why females accept male coercive mating. The females entered the males' nests following male courtship displays, but they usually tried to escape when there were no eggs because males tended to cannibalize all the eggs when there were few. Most males that used small, tight nests acquired new eggs but with experimentally enlarged nests, 90% of the males without eggs failed to confine the females. Spawning tended to occur during the early/late spawning period in nests with no eggs (i.e. male coercive mating). In the nests where the first eggs were deposited in the early period, subsequent matings with other females were more likely to occur, whereas in the late period, most parental care of the eggs failed without additional matings. The females that spawned in the late period may have been compelled to accept male coercive mating due to time constraints.

No MeSH data available.