Nest depth was strongly correlated with female size in coho salmon (Oncorhynchus kisutch). Since ... more Nest depth was strongly correlated with female size in coho salmon (Oncorhynchus kisutch). Since nests of different-sized females are at different depths, they are differentially vulnerable to destruction by floods and to other females competing for the same nest sites.
... like teeth, and deposits of car-tilage along their backs as a shield against attacks. ... to ... more ... like teeth, and deposits of car-tilage along their backs as a shield against attacks. ... to their cryptic coloration and small body size, the sneaking behavioral tactic offers jacks a successful ... With the decision to sneak or fight being reversible, jack and hooknose males can employ ...
Investment theory states that animals should base their parental investment decisions on expected... more Investment theory states that animals should base their parental investment decisions on expected benefits, and not on whether or not past investment will be wasted. Otherwise, they would commit the Concorde fallacy. If reproduction has a cost, however, then past investment and expected benefits are necessarily confounded. Assuming a cost of reproduction, animals will be selected to maximize their remaining lifetime reproductive success, subject to a tradeoff between present and future reproduction (Williams' principle). We extend Williams' principle and develop an experimental design that would allow past investment and expected benefits to be varied independently. This design illustrates the importance of the value of the brood relative to the value of future reproduction.
Our understanding of parental care behavior can be significantly advanced through the application... more Our understanding of parental care behavior can be significantly advanced through the application of Williams's Principle, which states that reproduction has not only a benefit but also a cost to lifetime fitness. My laboratory has formalized Williams's Principle into the relative value theorem and found that its application to fishes, the taxa with the most diverse patterns of parental care, can help to explain which sex provides care and how much. In fishes, it is often the male that provides parental care, not because the male obtains greater benefits from this care, but probably because he pays fewer costs. Fish dynamically adjust their investment into parental care according to the number of offspring in their brood, past investment, genetic relatedness, and alternative mating opportunities, all of which affect the value of current offspring relative to potential future offspring. These results may also help us understand the joy and the challenges of parental care in humans.
Memoirs of the Faculty of Fisheries Hokkaido University, May 1, 1997
and fall. Little growth was observed during the winter, probably because of low water temperature... more and fall. Little growth was observed during the winter, probably because of low water temperature (I-3°C). Growth resumed in the late winter and spring coincident with the parrto-smolt transformation. Migrating smolts were larger than the resident parr and transitional fish. Condition factor was high in the summer, declined during winter, and then increased sharply in the spring. Smolt migrants had reduced condition factor as is characteristic of smolts. Liver glycogen declined during the winter and then increased markedly in the spring in resident fish. Liver glycogen was depleted in smolt migrants. Body lipid levels were highest in the summer, declined in the winter, and then became elevated again in the spring in resident fish. Body lipid levels of migrant smolts were low (1-3%), among the lowest that we have seen in salmon ids. Stomach fullness was correlated with growth and energy storage; it was high in the summer, low in the winter, and then increased sharply in the spring. The pattern of change in body weight, stomach fullness, and body energy storage of resident fish is dynamic during the year. The high anabolic state in the summer contrasts with the low levels of energy in the winter. In the late winter and spring parr begin feeding and resume growth, coincident with body lipid and liver glycogen stores becoming replenished. Both live glycogen and body lipid are depleted in the smolt migrants, which were captured after only one-third of the seaward migration had been completed. This suggests that additional energy to support migration must come from food captured during migration or from stored protein. We speculate that large body size and growth during the parr-smolt transformation are important in building up stored energy as protein to be used to support smolt migration.
Philosophical Transactions of the Royal Society of London Series B Biological Sciences, Apr 1, 1991
This study provides empirical evidence in a wild population for frequency-dependent sexual select... more This study provides empirical evidence in a wild population for frequency-dependent sexual selection between alternative male reproductive strategies. The bluegill sunfish ( Lepomis macrochirus ) has two male reproductive strategies, cuckolder or parental, used by different males to compete in fertilizing the same eggs. As the density of cuckolders in colonies of parental males increases, the average mating success of cuckolders initially peaks but then declines. The cuckolder density at which their success peaks is determined by ecological characteristics of each colony. A theoretical analysis assuming random and omniscient cuckolder distributions among ecologically different colonies shows that cuckolders will fertilize decreasing proportions of eggs, relative to parental males, as cuckolders increase in frequency in the population. This supports evolutionary models that assume negative frequency-dependent selection between the competing strategies. Cuckolder and parental strategies may therefore have evolved as an Evolutionarily Stable State (ESST).
Fleming, LA. and Gross, M.R., 1992. Reproductive behavior of hatchery and wild coho salmon ( Onco... more Fleming, LA. and Gross, M.R., 1992. Reproductive behavior of hatchery and wild coho salmon ( Oncorhynchus kimtch ): does it differ? Aquaculture, 103: 10 I-12 1. We report an experimental study that contrasts the reproductive behavior of wild to hatchery coho salmon (Oncorhynchus kisutch). The hatchery fish had completed four generations of sea-ranching, which involves artificial breeding and juvenile rearing but natural growth to adulthood in the sea. Mature males and females were individually tagged, measured and placed into three experimental arenas in a stream channel. One arena contained isolated pairs of fish, thus providing data on reproductive behavior in the absence of competition. A second arena contained male and female hatchery fish and a third arena contained male and fe:nale wild fish. In the latter two arenas the fish were free to compete among themselves for breeding opportunities. Three variables significantly influenced reproductive behavior and breeding sucess: ( I) competition: (2) body weight: and (3) hatchery versus wild origin. In the absence ofcompetition, both hatchcry and wild fish bred readily. Howcvcr, competition delayed spawning, reduced nest numbers, increased body wounding, increased egg loss through retention and nest superimposition, and increased variance in breeding success. Body weight was an important determinant of success in the competitive environment. Small females were delayed in spawning and experienced greater egg losses, and small males had reduced access to spawning females. As a group, the hatchery fish differed from the wild fish in breeding behavior and potential. Hatchery females had larger egg masses but smaller fecundities than wild females due to their larger egg size. Hatchery males had \zrger testes than wild males, but were less aggressive, exhibited less spawning behavior and were generally less active than wild males. These results imply significant differences in the reproductive potential of hatchery relative to wild fish during competition.
Page 1. 310 Hormonal Regulation of Parental Care Behavior in Nesting Male Bluegills: Do the Effec... more Page 1. 310 Hormonal Regulation of Parental Care Behavior in Nesting Male Bluegills: Do the Effects of Bromocriptine Suggest a Role for Prolactin? Pawel M. Kindlerl,* Janice M. Bahr' Mart R. Gross2 David P. Philipp3,t 1Department ...
In North American sunfishes (Lepomis: Centrarchidae) 8 build nests and provide solitary parental ... more In North American sunfishes (Lepomis: Centrarchidae) 8 build nests and provide solitary parental care for the young. In this paper I provide for bluegill (Lmacrochirus) a detailed account of 4 8 which do not build nests, but steal fertilizations from the nests of other (3 8. I begin by ...
... extinction. In spite of this, the Minister of the Environment declined to recommend the listi... more ... extinction. In spite of this, the Minister of the Environment declined to recommend the listing of Sakinaw and Cultus sockeye under SARA. ... sockeye. Vancouver, BC. Available: http://www.pac.dfo-mpo.gc.ca/sara/SARA%20Report%20FINAL.pdf.
Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but ... more Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but the factors underlying this difference remain an active area of research. We used genetic parentage analysis of alevins produced by experimentally mixed groups of wild and hatchery coho salmon (Oncorhynchus kisutch) to quantify male paternity in spawning hierarchies. We identify factors influencing paternity and revise previously published behavioural estimates of reproductive success for wild and hatchery males. We observed a strong effect of hierarchy size and hierarchy position on paternity: in two-male hierarchies, the first male sired 63% (±29%; s.d.) of the alevins and the second male 37% (±29%); in three-male hierarchies, the first male sired 64% (±26%), the second male 24% (±20%) and the third male 12% (±10%). As previously documented, hatchery males hold inferior positions in spawning hierarchies, but we also discovered that hatchery males had only 55-84% the paternity of wild males when occupying the same position within a spawning hierarchy. This paternity difference may result from inferior performance of hatchery males during sperm competition, female mate choice for wild males, or differential offspring survival. Regardless of its cause, the combination of inferior hierarchical position and inferior success at a position resulted in hatchery males having only half (51%) the reproductive success of wild males.
Transactions of the American Fisheries Society, 1997
Abstract We tested the hypothesis that larger individuals in a temperate fish population emerge f... more Abstract We tested the hypothesis that larger individuals in a temperate fish population emerge from winter in better energetic condition than do smaller individuals. We sampled adult male bluegills Lepomis macrochirus in Lake Opinicon, Ontario, after spring ice break ...
We use elasticity analyses for three sturgeon species, the shortnose sturgeon Acipenser brevirost... more We use elasticity analyses for three sturgeon species, the shortnose sturgeon Acipenser brevirostrum, Atlantic sturgeon A. oxyrinchus, and white sturgeon A. transmontanus, to calculate the potential to increase population growth rate, l, by improving survival and fecundity. Elasticity analysis is a means of assessing changes to l resulting from conserva- tion initiatives. The elasticity of l to survival has a
... 11.6 Hypothetical parental reproductive trade-offs for four different ... The top row shows p... more ... 11.6 Hypothetical parental reproductive trade-offs for four different ... The top row shows present and future reproduction versus reproductive effort; the lower row shows the rates of return oninvestment into present and future reproduction versus reproductive effort. ...
The role of past investment in parental-care behaviour has often been controversial. Some researc... more The role of past investment in parental-care behaviour has often been controversial. Some researchers have argued that organisms basing present investment on past investment are committing the 'Concorde fallacy'. Others have incorporated life history theory to suggest that investing according to past investment is one component of investing according to expected future reproductive success: a parent can use past investment as well as other information, such as brood size, to make its optimal parental-investment decisions. Although parental-investment research is still in its infancy, the incorporation of life history theory suggests that the Concorde fallacy is a misleading concept.
I n the minds of many researchers, sexual variation is understood as being the differences exhibi... more I n the minds of many researchers, sexual variation is understood as being the differences exhibited between males and females. However, during the past two decades we have witnessed the discovery of widespread variation among individuals within the two sexesiJ. Such variation is found in most major taxa and may include significant behavioural, morphological, physiological and life history differences (Table 1). These examples illustrate that, rather than evolution giving rise to a single best male and female phenotype for each species, it has instead resulted in extreme phenotypic diversity. This realization is changing the way biologists view the adaptiveness of organisms. An important evolutionary force in generating individual variation within a sex is social interactions. Current evolutionary studies are attempting to understand how and why social interactions give rise to often elaborate phenotypic Not all members of a sex behave in the same way. Frequency-and statusdependent selection have given rise to many alternative reproductive phenotypes within the sexes. The evolution and proximate control of these alternatives are only beginning to be understood. Although game theory has provided a theoretical framework, the concept of the mixed strategy has not been realized in nature, and alternative strategies are very rare. Recent findings suggest that almost all alternative reproductive phenotypes within the sexes are due to alternative tactics within a conditional strategy, and, as such, while the average fitnesses of the alternative phenotypes are unequal, the strategy is favoured in evolution. Proximate mechanisms that underlie alternative phenotypes may have many similarities with those operating between the sexes.
Nest depth was strongly correlated with female size in coho salmon (Oncorhynchus kisutch). Since ... more Nest depth was strongly correlated with female size in coho salmon (Oncorhynchus kisutch). Since nests of different-sized females are at different depths, they are differentially vulnerable to destruction by floods and to other females competing for the same nest sites.
... like teeth, and deposits of car-tilage along their backs as a shield against attacks. ... to ... more ... like teeth, and deposits of car-tilage along their backs as a shield against attacks. ... to their cryptic coloration and small body size, the sneaking behavioral tactic offers jacks a successful ... With the decision to sneak or fight being reversible, jack and hooknose males can employ ...
Investment theory states that animals should base their parental investment decisions on expected... more Investment theory states that animals should base their parental investment decisions on expected benefits, and not on whether or not past investment will be wasted. Otherwise, they would commit the Concorde fallacy. If reproduction has a cost, however, then past investment and expected benefits are necessarily confounded. Assuming a cost of reproduction, animals will be selected to maximize their remaining lifetime reproductive success, subject to a tradeoff between present and future reproduction (Williams' principle). We extend Williams' principle and develop an experimental design that would allow past investment and expected benefits to be varied independently. This design illustrates the importance of the value of the brood relative to the value of future reproduction.
Our understanding of parental care behavior can be significantly advanced through the application... more Our understanding of parental care behavior can be significantly advanced through the application of Williams's Principle, which states that reproduction has not only a benefit but also a cost to lifetime fitness. My laboratory has formalized Williams's Principle into the relative value theorem and found that its application to fishes, the taxa with the most diverse patterns of parental care, can help to explain which sex provides care and how much. In fishes, it is often the male that provides parental care, not because the male obtains greater benefits from this care, but probably because he pays fewer costs. Fish dynamically adjust their investment into parental care according to the number of offspring in their brood, past investment, genetic relatedness, and alternative mating opportunities, all of which affect the value of current offspring relative to potential future offspring. These results may also help us understand the joy and the challenges of parental care in humans.
Memoirs of the Faculty of Fisheries Hokkaido University, May 1, 1997
and fall. Little growth was observed during the winter, probably because of low water temperature... more and fall. Little growth was observed during the winter, probably because of low water temperature (I-3°C). Growth resumed in the late winter and spring coincident with the parrto-smolt transformation. Migrating smolts were larger than the resident parr and transitional fish. Condition factor was high in the summer, declined during winter, and then increased sharply in the spring. Smolt migrants had reduced condition factor as is characteristic of smolts. Liver glycogen declined during the winter and then increased markedly in the spring in resident fish. Liver glycogen was depleted in smolt migrants. Body lipid levels were highest in the summer, declined in the winter, and then became elevated again in the spring in resident fish. Body lipid levels of migrant smolts were low (1-3%), among the lowest that we have seen in salmon ids. Stomach fullness was correlated with growth and energy storage; it was high in the summer, low in the winter, and then increased sharply in the spring. The pattern of change in body weight, stomach fullness, and body energy storage of resident fish is dynamic during the year. The high anabolic state in the summer contrasts with the low levels of energy in the winter. In the late winter and spring parr begin feeding and resume growth, coincident with body lipid and liver glycogen stores becoming replenished. Both live glycogen and body lipid are depleted in the smolt migrants, which were captured after only one-third of the seaward migration had been completed. This suggests that additional energy to support migration must come from food captured during migration or from stored protein. We speculate that large body size and growth during the parr-smolt transformation are important in building up stored energy as protein to be used to support smolt migration.
Philosophical Transactions of the Royal Society of London Series B Biological Sciences, Apr 1, 1991
This study provides empirical evidence in a wild population for frequency-dependent sexual select... more This study provides empirical evidence in a wild population for frequency-dependent sexual selection between alternative male reproductive strategies. The bluegill sunfish ( Lepomis macrochirus ) has two male reproductive strategies, cuckolder or parental, used by different males to compete in fertilizing the same eggs. As the density of cuckolders in colonies of parental males increases, the average mating success of cuckolders initially peaks but then declines. The cuckolder density at which their success peaks is determined by ecological characteristics of each colony. A theoretical analysis assuming random and omniscient cuckolder distributions among ecologically different colonies shows that cuckolders will fertilize decreasing proportions of eggs, relative to parental males, as cuckolders increase in frequency in the population. This supports evolutionary models that assume negative frequency-dependent selection between the competing strategies. Cuckolder and parental strategies may therefore have evolved as an Evolutionarily Stable State (ESST).
Fleming, LA. and Gross, M.R., 1992. Reproductive behavior of hatchery and wild coho salmon ( Onco... more Fleming, LA. and Gross, M.R., 1992. Reproductive behavior of hatchery and wild coho salmon ( Oncorhynchus kimtch ): does it differ? Aquaculture, 103: 10 I-12 1. We report an experimental study that contrasts the reproductive behavior of wild to hatchery coho salmon (Oncorhynchus kisutch). The hatchery fish had completed four generations of sea-ranching, which involves artificial breeding and juvenile rearing but natural growth to adulthood in the sea. Mature males and females were individually tagged, measured and placed into three experimental arenas in a stream channel. One arena contained isolated pairs of fish, thus providing data on reproductive behavior in the absence of competition. A second arena contained male and female hatchery fish and a third arena contained male and fe:nale wild fish. In the latter two arenas the fish were free to compete among themselves for breeding opportunities. Three variables significantly influenced reproductive behavior and breeding sucess: ( I) competition: (2) body weight: and (3) hatchery versus wild origin. In the absence ofcompetition, both hatchcry and wild fish bred readily. Howcvcr, competition delayed spawning, reduced nest numbers, increased body wounding, increased egg loss through retention and nest superimposition, and increased variance in breeding success. Body weight was an important determinant of success in the competitive environment. Small females were delayed in spawning and experienced greater egg losses, and small males had reduced access to spawning females. As a group, the hatchery fish differed from the wild fish in breeding behavior and potential. Hatchery females had larger egg masses but smaller fecundities than wild females due to their larger egg size. Hatchery males had \zrger testes than wild males, but were less aggressive, exhibited less spawning behavior and were generally less active than wild males. These results imply significant differences in the reproductive potential of hatchery relative to wild fish during competition.
Page 1. 310 Hormonal Regulation of Parental Care Behavior in Nesting Male Bluegills: Do the Effec... more Page 1. 310 Hormonal Regulation of Parental Care Behavior in Nesting Male Bluegills: Do the Effects of Bromocriptine Suggest a Role for Prolactin? Pawel M. Kindlerl,* Janice M. Bahr' Mart R. Gross2 David P. Philipp3,t 1Department ...
In North American sunfishes (Lepomis: Centrarchidae) 8 build nests and provide solitary parental ... more In North American sunfishes (Lepomis: Centrarchidae) 8 build nests and provide solitary parental care for the young. In this paper I provide for bluegill (Lmacrochirus) a detailed account of 4 8 which do not build nests, but steal fertilizations from the nests of other (3 8. I begin by ...
... extinction. In spite of this, the Minister of the Environment declined to recommend the listi... more ... extinction. In spite of this, the Minister of the Environment declined to recommend the listing of Sakinaw and Cultus sockeye under SARA. ... sockeye. Vancouver, BC. Available: http://www.pac.dfo-mpo.gc.ca/sara/SARA%20Report%20FINAL.pdf.
Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but ... more Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but the factors underlying this difference remain an active area of research. We used genetic parentage analysis of alevins produced by experimentally mixed groups of wild and hatchery coho salmon (Oncorhynchus kisutch) to quantify male paternity in spawning hierarchies. We identify factors influencing paternity and revise previously published behavioural estimates of reproductive success for wild and hatchery males. We observed a strong effect of hierarchy size and hierarchy position on paternity: in two-male hierarchies, the first male sired 63% (±29%; s.d.) of the alevins and the second male 37% (±29%); in three-male hierarchies, the first male sired 64% (±26%), the second male 24% (±20%) and the third male 12% (±10%). As previously documented, hatchery males hold inferior positions in spawning hierarchies, but we also discovered that hatchery males had only 55-84% the paternity of wild males when occupying the same position within a spawning hierarchy. This paternity difference may result from inferior performance of hatchery males during sperm competition, female mate choice for wild males, or differential offspring survival. Regardless of its cause, the combination of inferior hierarchical position and inferior success at a position resulted in hatchery males having only half (51%) the reproductive success of wild males.
Transactions of the American Fisheries Society, 1997
Abstract We tested the hypothesis that larger individuals in a temperate fish population emerge f... more Abstract We tested the hypothesis that larger individuals in a temperate fish population emerge from winter in better energetic condition than do smaller individuals. We sampled adult male bluegills Lepomis macrochirus in Lake Opinicon, Ontario, after spring ice break ...
We use elasticity analyses for three sturgeon species, the shortnose sturgeon Acipenser brevirost... more We use elasticity analyses for three sturgeon species, the shortnose sturgeon Acipenser brevirostrum, Atlantic sturgeon A. oxyrinchus, and white sturgeon A. transmontanus, to calculate the potential to increase population growth rate, l, by improving survival and fecundity. Elasticity analysis is a means of assessing changes to l resulting from conserva- tion initiatives. The elasticity of l to survival has a
... 11.6 Hypothetical parental reproductive trade-offs for four different ... The top row shows p... more ... 11.6 Hypothetical parental reproductive trade-offs for four different ... The top row shows present and future reproduction versus reproductive effort; the lower row shows the rates of return oninvestment into present and future reproduction versus reproductive effort. ...
The role of past investment in parental-care behaviour has often been controversial. Some researc... more The role of past investment in parental-care behaviour has often been controversial. Some researchers have argued that organisms basing present investment on past investment are committing the 'Concorde fallacy'. Others have incorporated life history theory to suggest that investing according to past investment is one component of investing according to expected future reproductive success: a parent can use past investment as well as other information, such as brood size, to make its optimal parental-investment decisions. Although parental-investment research is still in its infancy, the incorporation of life history theory suggests that the Concorde fallacy is a misleading concept.
I n the minds of many researchers, sexual variation is understood as being the differences exhibi... more I n the minds of many researchers, sexual variation is understood as being the differences exhibited between males and females. However, during the past two decades we have witnessed the discovery of widespread variation among individuals within the two sexesiJ. Such variation is found in most major taxa and may include significant behavioural, morphological, physiological and life history differences (Table 1). These examples illustrate that, rather than evolution giving rise to a single best male and female phenotype for each species, it has instead resulted in extreme phenotypic diversity. This realization is changing the way biologists view the adaptiveness of organisms. An important evolutionary force in generating individual variation within a sex is social interactions. Current evolutionary studies are attempting to understand how and why social interactions give rise to often elaborate phenotypic Not all members of a sex behave in the same way. Frequency-and statusdependent selection have given rise to many alternative reproductive phenotypes within the sexes. The evolution and proximate control of these alternatives are only beginning to be understood. Although game theory has provided a theoretical framework, the concept of the mixed strategy has not been realized in nature, and alternative strategies are very rare. Recent findings suggest that almost all alternative reproductive phenotypes within the sexes are due to alternative tactics within a conditional strategy, and, as such, while the average fitnesses of the alternative phenotypes are unequal, the strategy is favoured in evolution. Proximate mechanisms that underlie alternative phenotypes may have many similarities with those operating between the sexes.
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