scholarly journals Disentangling the determinants of reproductive success in a temperate reef fish, Forsterygion lapillum

2021 ◽  
Author(s):  
◽  
McKenzie Grace Tornquist

<p>Identifying sources of individual variation in reproductive success has been a longstanding challenge for evolutionary ecologists. Reproductive success among individuals can be due to several factors such as competition between conspecifics for nest sites and mating partners, mate choice, or by the physical environment. Reproductive success, particularly among males, can be extremely diverse both within and between species and determining which components contribute to success can be particularly challenging. In this thesis, I investigated patterns and drivers of reproductive success in a temperate marine reef fish, Forsterygion lapillum (the common triplefin). Specifically, I examined how male quality, nest quality, and female choice influence male reproductive success. Additionally, I quantified male reproductive success during the winter and summer of the breeding season to examine the temporal dynamics of breeding success in F. lapillum.   Selection of mates by females can be driven by the quality and behavioural attributes of the male or by the quality of resources offered. In Chapter 2, using field-based observations, combined with a lab-based study, I evaluated the effects of different male traits and nest characteristics on female choice and male reproductive success. Specifically, I observed egg guarding males in the field during the breeding season and recorded their phenotypic traits, behaviours, and nest characteristics. I then examined their influence on 3 different components of male reproductive success (brood size, individual egg size, and mate attraction). Additionally, I conducted dichotomous choice tests in the laboratory to evaluate female preference for different sized males, holding different sized nests. In the field, I did not detect a significant relationship between male mating success and male total length or nest size. Brood size and individual egg size were highly variable among sampled males, however, further factors such as courtship frequency, and the number of interactions with potential predators did not explain any additional variation. The number of agonistic displays performed by egg guarding males was the only factor to influence egg size, however, it had no direct impact on brood size or mate attraction. On the contrary, results from the laboratory experiment suggested that male total length and nest size were important during female choice. Females were attracted to and spawned more frequently with larger males holding larger nests. Additionally, females showed a particular preference towards males that displayed intense courtship behaviours. These results suggest that variation in reproductive success among individuals is not random in the common triplefin (F. lapillum) and may be due to a range of complex factors.  In natural systems, individual variation in mating success is known to be highly dynamic and vary over time. In Chapter 3, I addressed 3 questions related to reproductive success in male common triplefin: 1) Does the operational sex ratio (OSR) and the density of individuals change predictably within the breeding season? 2) Does male reproductive success change within the breeding season? And 3) Does the age and growth rate of successful males change within the breeding season? To address these questions, I sampled a population of F. lapillum during two periods of the breeding season and quantified a set of morphological and physical traits. Furthermore, I reconstructed individual life histories from the otoliths of egg guarding males. My results show that the density of individuals in the population increased during the summer months, but the operational sex ratio (OSR) remained male-biased. Male reproductive success in terms of brood size and average egg size did not fluctuate during the sampling period. However, the size of males and the size of the nest (cobblestone) held by males was significantly larger in summer compared to winter. Interestingly, successful males sampled in the winter had hatched significantly earlier than successful males sampled in the summer, but their average growth rate remained similar. These findings indicate that variation in male traits across the breeding season plays an important role in female mate choice. The mating system and pool of mating individuals in the common triplefin (F. lapillum) is highly dynamic over the year and has the potential to shape the success of individuals.   Overall, this study emphasizes the importance of considering multiple cues and temporal dynamics when disentangling the determinants of individual reproductive success. These findings suggest that male-male competition and female mate choice have a significant influence on male reproductive success. The reproductive ecology of F. lapillum is highly complex and my research has provided valuable insight into its dynamic nature. These results may apply to other species with male parental care and provides an important contribution towards understanding sexual selection and the evolution of mating systems with male parental care.</p>

2021 ◽  
Author(s):  
◽  
McKenzie Grace Tornquist

<p>Identifying sources of individual variation in reproductive success has been a longstanding challenge for evolutionary ecologists. Reproductive success among individuals can be due to several factors such as competition between conspecifics for nest sites and mating partners, mate choice, or by the physical environment. Reproductive success, particularly among males, can be extremely diverse both within and between species and determining which components contribute to success can be particularly challenging. In this thesis, I investigated patterns and drivers of reproductive success in a temperate marine reef fish, Forsterygion lapillum (the common triplefin). Specifically, I examined how male quality, nest quality, and female choice influence male reproductive success. Additionally, I quantified male reproductive success during the winter and summer of the breeding season to examine the temporal dynamics of breeding success in F. lapillum.   Selection of mates by females can be driven by the quality and behavioural attributes of the male or by the quality of resources offered. In Chapter 2, using field-based observations, combined with a lab-based study, I evaluated the effects of different male traits and nest characteristics on female choice and male reproductive success. Specifically, I observed egg guarding males in the field during the breeding season and recorded their phenotypic traits, behaviours, and nest characteristics. I then examined their influence on 3 different components of male reproductive success (brood size, individual egg size, and mate attraction). Additionally, I conducted dichotomous choice tests in the laboratory to evaluate female preference for different sized males, holding different sized nests. In the field, I did not detect a significant relationship between male mating success and male total length or nest size. Brood size and individual egg size were highly variable among sampled males, however, further factors such as courtship frequency, and the number of interactions with potential predators did not explain any additional variation. The number of agonistic displays performed by egg guarding males was the only factor to influence egg size, however, it had no direct impact on brood size or mate attraction. On the contrary, results from the laboratory experiment suggested that male total length and nest size were important during female choice. Females were attracted to and spawned more frequently with larger males holding larger nests. Additionally, females showed a particular preference towards males that displayed intense courtship behaviours. These results suggest that variation in reproductive success among individuals is not random in the common triplefin (F. lapillum) and may be due to a range of complex factors.  In natural systems, individual variation in mating success is known to be highly dynamic and vary over time. In Chapter 3, I addressed 3 questions related to reproductive success in male common triplefin: 1) Does the operational sex ratio (OSR) and the density of individuals change predictably within the breeding season? 2) Does male reproductive success change within the breeding season? And 3) Does the age and growth rate of successful males change within the breeding season? To address these questions, I sampled a population of F. lapillum during two periods of the breeding season and quantified a set of morphological and physical traits. Furthermore, I reconstructed individual life histories from the otoliths of egg guarding males. My results show that the density of individuals in the population increased during the summer months, but the operational sex ratio (OSR) remained male-biased. Male reproductive success in terms of brood size and average egg size did not fluctuate during the sampling period. However, the size of males and the size of the nest (cobblestone) held by males was significantly larger in summer compared to winter. Interestingly, successful males sampled in the winter had hatched significantly earlier than successful males sampled in the summer, but their average growth rate remained similar. These findings indicate that variation in male traits across the breeding season plays an important role in female mate choice. The mating system and pool of mating individuals in the common triplefin (F. lapillum) is highly dynamic over the year and has the potential to shape the success of individuals.   Overall, this study emphasizes the importance of considering multiple cues and temporal dynamics when disentangling the determinants of individual reproductive success. These findings suggest that male-male competition and female mate choice have a significant influence on male reproductive success. The reproductive ecology of F. lapillum is highly complex and my research has provided valuable insight into its dynamic nature. These results may apply to other species with male parental care and provides an important contribution towards understanding sexual selection and the evolution of mating systems with male parental care.</p>


2005 ◽  
Vol 272 (1568) ◽  
pp. 1121-1127 ◽  
Author(s):  
Scott A Tarof ◽  
Peter O Dunn ◽  
Linda A Whittingham

Melanin-based ornaments often function as signals in male–male competition, whereas carotenoid-based ornaments appear to be important in female mate choice. This difference in function is thought to occur because carotenoid pigments are more costly to produce than melanins and are thus more reliable indicators of male quality. We examined the role of melanin- and carotenoid-based ornaments in male–male competition and female choice in the common yellowthroat Geothlypis trichas , a sexually dichromatic passerine. Males display a black facial mask produced by melanin pigmentation and a bright yellow bib (throat, breast and belly) produced by carotenoid pigmentation. In controlled aviary experiments, mask size was the best predictor of both male–male competition and female mate choice, and, therefore, mask size may be regarded as an ornament of dual function. These dual functions may help to maintain the reliability of mask size as an indicator of male quality, despite the potentially low cost of production. The size of the bib was unrelated to male–male competition or female choice, but there was a tendency for females to prefer males with more colourful bibs. We propose that the black mask is important in competition for territories with other males and for attracting females. Our results highlight the need for more studies of the mechanisms of sexual selection in species with ornaments composed of different pigment types.


Behaviour ◽  
1993 ◽  
Vol 124 (1-2) ◽  
pp. 45-56 ◽  
Author(s):  
Steven R. Telford ◽  
J. Mark Dangerfield

AbstractField and laboratory observations of mating behaviour in a population of the tropical millipede Alloporus uncinatus were carried out over one breeding season. Males obtained mates through random encounters and by forming triplet associations with copula pairs. The occurrence of triplet associations in the field was coincident with a highly male biased operational sex ratio. Mate acquisition by males was apparently stochastic and direct physical competition did not occur. In laboratory experiments mating was size-selective probably as a consequence of female choice. We consider the possibility that sperm competition has contributed to the evolution of the mating system in this species.


2017 ◽  
Author(s):  
David Thomas Mellor

The rock-dwelling cichlids of Lake Malawi, the mbuna, are a model system of rapid, sympatric diversification of vertebrates. Though sexual selection has often been invoked to explain their radiation, the best evidence to date suggests that female choice and male-male interactions act to reinforce incipient, allopatric divergence upon secondary contact. First, I expand on the evidence previously gathered on male-male interactions at the inter-population level, by examining within-population behavioral patterns that could explain the diversification of this lineage. Specifically, I measure female preference for conspecific males who are in social isolation and those who are in groups of interacting males. I found that females show preference for males who score higher in male-male contests. In chapter two, I measure the effect of these male-male interactions on female choice and show that these interactions do affect female preference. By controlling the outcome of each male-male interaction, I show that female preference is affected by the male-male contests themselves. In chapter three, I measure the reflectance of brightly colored, territorial males and look for a correlation between color-similarity and level of aggression between two males. Males show more aggression towards similarly colored conspecific rivals than they do towards rivals who are more differently colored. In chapter four, I measure male reproductive success and the chromatic, behavioral, and territorial traits that affect it. Male color does predict reproductive success. Given my desire to integrate scholarship into every aspect of my academic career, I undertake an investigation on students who are at risk for leaving college because of low academic performance. I describe the social and psychological issues affecting the high rate of college attrition and the effects of a small scale class intervention on student retention, GPA, locus of control, and academic self-efficacy.


2020 ◽  
Vol 77 (12) ◽  
pp. 1943-1959
Author(s):  
Douglas L. Larson ◽  
Jacob G. Kimmel ◽  
Joseph J. Riedy ◽  
Jonathan Hegna ◽  
Edward A. Baker ◽  
...  

Intra-annual reproductive investments may not be predictive of male reproductive success because of the effects of intra- and intersexual interactions on sperm depletion. For long-lived iteroparous fish species such as lake sturgeon (Acipenser fulvescens), reproductive effort may affect lifetime reproductive success. Radio frequency identification antennas were placed at the mouth of the Upper Black River, Michigan, and downstream of spawning locations to quantify male migratory and mating behaviors, including upstream migration time (UT), river residence time (RT), number of intra-annual spawning migrations (IM), interannual spawning interval, and operational sex ratio during 2017–2018. Computer assisted sperm analysis was used to quantify sperm quality. RT had a strong negative influence on sperm concentration and with measures of sperm quality. RT and the number of females encountered were positively associated with male reproductive success (number of offspring sired) across years. RT, IM, and UT were negatively associated with sperm quality, indicating sperm depletion is a reliable measure of sexual activity. Results demonstrate trade-offs between benefits and costs associated with current reproductive effort on future reproduction.


2007 ◽  
Vol 85 (2) ◽  
pp. 169-176 ◽  
Author(s):  
D.M. Weber ◽  
J.S. Millar ◽  
B.D. Neff

In many mating systems, females may benefit by selecting a male with high genetic quality in the form of good genes or compatible genes. In bushy-tailed woodrats ( Neotoma cinerea Ord, 1815), previous research has shown that male reproductive success correlates with the mass change of males over the breeding season, indicating that physical body condition may directly influence female choice and hence male reproductive success. We examined male physical condition in relation to reproductive success in the field. Male physical condition was measured as body-mass change over the breeding season, body size, body condition (mass versus size), and anaemia (packed cell volume and mean corpuscular volume). We then conducted trials in the laboratory in which captive females were presented with visual and olfactory cues from two males simultaneously. In the field, males with a low mean corpuscular volume had the highest reproductive success. Captive females also showed a preference for males with low levels of anaemia based on mean corpuscular volume. These results suggest that females are employing a condition-dependent preference.


2021 ◽  
Author(s):  
Seoghyun Kim ◽  
Mevin B. Hooten ◽  
Tanya L. Darden ◽  
Yoichiro Kanno

Abstract Nest construction is an energetically costly behavior displayed by males in many taxa. In some species, males construct nests and co-breed with other males and they may construct multiple nests in a breeding season. However, little is understood about how allocation of effort within and among nests affects male reproductive success. We characterized reproductive effort of male bluehead chub (Nocomis leptocephalus) on nests in an entire breeding season using PIT antennas deployed around nests and linked effort within and among nests to reproductive success, measured by number of offspring assigned genetically to each male, in a small stream in South Carolina, USA. We monitored time spent by a total of 34 males on each of 18 nests during the spawning season in 2017. A Bayesian hierarchical analysis showed that larger males spent more time constructing and maintaining a given nest, and consequently were more reproductively successful than smaller males on the same nest. Combined with aggressive behavior displayed by larger males toward smaller males, this finding suggested that reproductive effort including agonistic interactions within nests was a determinant of reproductive success. In contrast, more males together constructed larger nests, which led to higher reproductive success of members that constructed those nests. Number of nests that male constructed, a measure of effort across nests, was not a predictor of reproductive success, indicating that reproductive success varied among nests due to nest size. Our study showed that male reproductive success was determined by both aggressive and cooperative behaviors in a co-breeding species.


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