Sexual Selection, Male Quality and Swimming Performance

2010 ◽  
pp. 249-268 ◽  
Author(s):  
Astrid Kodric-Brown
Keyword(s):  
Sexual Selection ◽  
Swimming Performance ◽  
Male Quality

scholarly journals Male mate choice, male quality, and the potential for sexual selection on female traits under polygyny

Evolution ◽  
2016 ◽  
Vol 71 (1) ◽  
pp. 174-183 ◽  
Author(s):  
Courtney L. Fitzpatrick ◽  
Maria R. Servedio
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Male Mate Choice ◽  
Male Quality ◽  
Male Mate

scholarly journals Collective sperm movements in Peromyscus mice are shaped by phylogenetic history and post-copulatory sexual selection

2020 ◽  
Author(s):  
Kristin A. Hook ◽  
W. David Weber ◽  
Heidi S. Fisher
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Reproductive Tract ◽  
Swimming Performance ◽  
Aggregate Size ◽  
Female Reproductive Tract ◽  
Testis Size ◽  
Limited Evidence ◽  
Closely Related Species ◽  
Sperm Migration

AbstractIn some species, sperm form motile, coordinated groups as they migrate through the female reproductive tract. Collective sperm migration is posited to have evolved to improve sperm swimming performance, and thus may be beneficial in a competitive context, but limited evidence supports this theory. Here we investigate sperm aggregation across closely-related species of Peromyscus mice that naturally vary by mating system. We find that phylogenetic history predicts the likelihood that sperm will aggregate but that variation in aggregate size negatively associates with relative testis size, suggesting that sperm competition has a stabilizing effect on this trait. Moreover, we show that sperm aggregation is not kinematically beneficial for all species, and we hypothesize that swimming performance is dependent on the orientation and composition of sperm groups. To test this, we compared sperm from the two sister-species that aggregate most frequently and find that sperm of the species that evolved under intense sperm competition forms aggregates with efficient geometry more frequently than sperm from its monogamous congener. Together, our results are consistent with the hypothesis that sperm aggregation evolved to improve motility in a competitive context; however, when monogamy evolved secondarily, relaxed sexual selection allowed for less efficient strategies to persist.

scholarly journals Imperfect synchrony in animal displays: why does it occur and what is the true role of leadership?

2021 ◽  
Vol 376 (1835) ◽  
pp. 20200339
Author(s):  
Daniela M. Perez ◽  
Cristian L. Klunk ◽  
Sabrina B. L. Araujo
Keyword(s):  
Sexual Selection ◽  
Fiddler Crab ◽  
Theoretical Explanation ◽  
Behavioural Ecology ◽  
Male Quality ◽  
Male Size ◽  
Theme Issue ◽  
Stable Strategy ◽  
The Brain

Synchrony can be defined as the precise coordination between independent individuals, and this behaviour is more enigmatic when it is imperfect. The traditional theoretical explanation for imperfect synchronous courtship is that it arises as a by-product of the competition between males to broadcast leading signals to attract female attention. This competition is considered an evolutionary stable strategy maintained through sexual selection. However, previous studies have revealed that leading signals are not honest indicators of male quality. We studied imperfect courtship synchrony in fiddler crabs to mainly test whether (i) signal leadership and rate are defined by male quality and (ii) signal leadership generates synchrony. Fiddler crab males wave their enlarged claws during courtship, and females prefer leading males—displaying ahead of their neighbour(s). We filmed groups of waving males in the field to detect how often individuals were leaders and if they engaged in synchrony. Overall, we found that courtship effort is not directly related to male size, a general proxy for quality. Contrary to the long-standing assumption, we also revealed that leadership is not directly related to group synchrony, but faster wave rate correlates with both leadership and synchrony. This article is part of the theme issue ‘Synchrony and rhythm interaction: from the brain to behavioural ecology’.

Song characters as reliable indicators of male reproductive quality in the Savannah Sparrow (Passerculus sandwichensis)

2020 ◽  
Vol 98 (1) ◽  
pp. 32-38
Author(s):  
Ha-Cheol Sung ◽  
Paul Handford
Keyword(s):  
Sexual Selection ◽  
Reproductive Performance ◽  
Territory Size ◽  
Male Mating ◽  
Combined Effects ◽  
Male Quality ◽  
Passerculus Sandwichensis ◽  
Song Variation ◽  
Savannah Sparrow ◽  
Savannah Sparrows

Bird song may provide female birds with signals of male quality. To investigate this potential for sexual selection via female choice, we assessed the relationships between male song variation and male mating and reproductive success of the Savannah Sparrow (Passerculus sandwichensis (J.F. Gmelin, 1789)) over 3 years (2001–2003) in a population of Savannah Sparrows near London, Ontario, Canada. We measured song rate, as well as temporal and frequency attributes of song structure, as possible predictors of male quality, and then related these measures to attributes of male reproductive performance (mating and breeding success and territory size of males). We found significant correlations between male reproductive performance and several song features, such that the combined effects of two trill sections could potentially play an important role: males possessing such songs arrived and paired earlier and had higher fledging success. The results suggested that the trill segments of the song may signal important aspects of male quality. Possible reasons for significant roles of such songs in open-habitat birds are discussed.

Strong sexual selection despite spatial constraints on extrapair paternity

2020 ◽  
Vol 31 (3) ◽  
pp. 618-626 ◽  
Author(s):  
Emily R A Cramer ◽  
Emma I Greig ◽  
Sara A Kaiser
Keyword(s):  
Sexual Selection ◽  
Male Quality ◽  
Spatial Constraints ◽  
Selection Gradient ◽  
Extrapair Paternity ◽  
Female Preferences ◽  
Bateman Gradient ◽  
Socially Monogamous ◽  
Individual Potential ◽  
The Impact

Abstract Extrapair paternity should contribute to sexual selection by increasing the number of potential mates available to each individual. Potential copulation partners are, however, limited by their proximity. Spatial constraints may therefore reduce the impact of extrapair paternity on sexual selection. We tested the effect of spatial constraints on sexual selection by simulating extrapair copulations for 15 species of socially monogamous songbirds with varying rates of extrapair paternity. We compared four metrics of sexual selection between simulated populations without spatial constraints and populations where extrapair copulations were restricted to first- and second-order neighbors. Counter to predictions, sexual selection as measured by the Bateman gradient (the association between the number of copulation partners and offspring produced) increased under spatial constraints. In these conditions, repeated extrapair copulations between the same individuals led to more offspring per copulation partner. In contrast, spatial constraints did somewhat reduce sexual selection—as measured by the opportunity for selection, s’max, and the selection gradient on male quality—when the association between simulated male quality scores and copulation success (e.g., female preferences or male–male competition) was strong. Sexual selection remained strong overall in those populations even under spatial constraints. Spatial constraints did not substantially reduce sexual selection when the association between male quality and copulation success was moderate or weak. Thus, spatial constraints on extrapair copulations are insufficient to explain the absence of strong selection on male traits in many species.

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