Recent studies of sperm competition have shown that the timing of copulations can be crucial to f... more Recent studies of sperm competition have shown that the timing of copulations can be crucial to fertilization success. For example, in some birds copulations that occur near the time of laying are less likely to fertilize eggs than copulations that occur at other times. Thus, it was surprising to find that in Australian Brush-turkeys (Alectura lathami), most within-pair copulations (61.2%) occurred less than 1 h before laying, typically providing only 25 to 40 min for sperm to reach storage organs before potentially being flushed out by the descending egg. Brush-turkeys incubate their eggs in large mounds constructed by males; females lay an egg every few days and bury it within a chosen mound. Females usually solicited a copulation within 2 to 3 min after arriving at a mound to lay, but some males still forced copulations, particularly during the latter portion of laying visits. The unusual prevalence of copulations before laying probably results from males having little information about or control over female copulation behavior except when females need to lay in a males' mound. The prevalence of forced copulations during the latter part of laying visits may indicate conflict between the sexes over what constitutes adequate "payment" by females for use of a male's incubation mound. Neither sex showed any interest in copulating immediately after an egg was laid. This observation does not support the idea of a "fertilization window" after laying, but instead indicates that copulations at this time are probably ineffective in fertilizing eggs. Females also frequently made nonlaying visits to incubation mounds. The 38.8% of within-pair copulations that occurred during nonlaying visits may have been more likely to fertilize eggs, but the timing of these visits was controlled by females, who were probably less likely to be subject to male control when not laying.
Recent studies of sperm competition have shown that the timing of copulations can be crucial to f... more Recent studies of sperm competition have shown that the timing of copulations can be crucial to fertilization success. For example, in some birds copulations that occur near the time of laying are less likely to fertilize eggs than copulations that occur at other times. Thus, it was surprising to find that in Australian Brush-turkeys (Alectura lathami), most within-pair copulations (61.2%) occurred less than 1 h before laying, typically providing only 25 to 40 min for sperm to reach storage organs before potentially being flushed out by the descending egg. Brush-turkeys incubate their eggs in large mounds constructed by males; females lay an egg every few days and bury it within a chosen mound. Females usually solicited a copulation within 2 to 3 min after arriving at a mound to lay, but some males still forced copulations, particularly during the latter portion of laying visits. The unusual prevalence of copulations before laying probably results from males having little information about or control over female copulation behavior except when females need to lay in a males' mound. The prevalence of forced copulations during the latter part of laying visits may indicate conflict between the sexes over what constitutes adequate payment by females for use of a male's incubation mound. Neither sex showed any interest in copulating immediately after an egg was laid. This observation does not support the idea of a fertilization window after laying, but instead indicates that copulations at this time are probably ineffective in fertilizing eggs. Females also frequently made nonlaying visits to incubation mounds. The 38.8% of within-pair copulations that occurred during nonlaying visits may have been more likely to fertilize eggs, but the timing of these visits was controlled by females, who were probably less likely to be subject to male control when not laying.
AimUnique amongst birds, megapodes (family Megapodiidae) have exchanged the strategy of incubatin... more AimUnique amongst birds, megapodes (family Megapodiidae) have exchanged the strategy of incubating eggs with the warmth of their bodies for incubation behaviours that rely entirely on environmental heat sources. Typically, mound‐builders capture heat released from the decomposition of organic materials, while burrow‐nesters lay their eggs in geothermal or solar‐heated soils. The evolutionary path towards novel incubation behaviours has led to ecological and physiological adaptations unique to megapodes. Here, we present a species tree for all extant megapodes that settles long‐standing debates about megapode evolution: namely, their biogeographical origins and ancestral nesting behaviour.LocationAustralasia.MethodsA time‐calibrated multilocus species tree for all extant megapodes was constructed using *beast. We estimated and compared divergence dates for megapodes obtained from molecular rates, fossils, and a combination of fossils and rates. Using this tree, Bayesian estimation of ancestral nesting behaviour was conducted in BayesTraits and ancestral ranges were estimated in BioGeoBEARS.ResultsRecent dispersal has led to the recolonization of mainland Australia and New Guinea by Megapodius. Bayesian estimation of ancestral states indicates that mound building is the most probable ancestral nesting behaviour in megapodes (posterior probability = 0.75). Burrow nesting was acquired early in the diversification of the family (at least 14 Ma), followed by a single switch back to mound building.Main conclusionsDivergence dates and biogeographical reconstructions strongly suggest that dispersal, and not vicariance, led to the isolation of megapodes in Australasia. We propose that flight‐mediated dispersal to environmentally variable islands is responsible for the behavioural lability in nesting behaviours observed in some Megapodius species today.
hatch, adults face the costly task of caring for young. Though some chicks can walk and feed soon... more hatch, adults face the costly task of caring for young. Though some chicks can walk and feed soon after hatching, most must be brooded, protected from predators, and provided with a social environment; such parental requirements of bird species appear to have strongly influenced their physiology and behaviourl. There are some birds that dif- fer fundamentally from all others by exploiting environmental rather than body heat to incubate their eggs. These birds, the megapodes, were once thought to be primitive relics of a reptilian past2, but their extraordinary habits are almost cer- tainly derived from normal galli- form ground-nesting3. The 19 extant species occur widely among the islands of Southeast Asia, Australia, Papua New Guinea and the western Pacific (Fig. I 1, but several are endangered (Box I). Throughout this diverse region the birds ap- propriate sources of environmental heat by two principal techniques: either by constructing an incu- bation mound of decomposing or- ganic matter, or by burrowing into pre-existing heat sources (such as r; :
Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have... more Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have evolved a markedly different method of incubation. By making use of environmental heat, adult megapodes are emancipated from most of the usual constraints to reproductive success associated with parental care. Consequences of this unique incubation method are evident in all aspects of megapode development and behaviour. Recently, renewed interest in these birds from a number of disciplines has led to significant advances, especially in aspects associated with reproduction. Both eggs and embryos exhibit remarkable adaptations to the physiologically stressful incubation environment. The use of various types of incubation heat may also shape the mating systems of the species involved.
Additional file 5: Table S2. Divergence time estimations (in 10 millions of years) of different g... more Additional file 5: Table S2. Divergence time estimations (in 10 millions of years) of different gene shopping schemes for the 48-taxon dataset.
Additional file 4: Table S1. UCE phylogenomic studies of Galliformes and novel UCEs used in this ... more Additional file 4: Table S1. UCE phylogenomic studies of Galliformes and novel UCEs used in this study.
Additional file 2: Figure S2. ML phylogeny for the Galliformes from the 48-taxon dataset. Estimat... more Additional file 2: Figure S2. ML phylogeny for the Galliformes from the 48-taxon dataset. Estimation was conducted on the 75% complete matrix using RaxML.
Additional file 1: Figure S1. Species tree for the Galliformes from the 135-taxon dataset. Estima... more Additional file 1: Figure S1. Species tree for the Galliformes from the 135-taxon dataset. Estimation was conducted on the 75% complete matrix using SVDquartets.
Additional file 6: Table S3. Divergence time estimations (in 10 millions of years) from the most-... more Additional file 6: Table S3. Divergence time estimations (in 10 millions of years) from the most-tree like partition for the 95% complete of the 48 and 135-taxon datasets.
Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have... more Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have evolved a markedly different method of incubation. By making use of environmental heat, adult megapodes are emancipated from most of the usual constraints to reproductive success associated with parental care. Consequences of this unique incubation method are evident in all aspects of megapode development and behaviour. Recently, renewed interest in these birds from a number of disciplines has led to significant advances, especially in aspects associated with reproduction. Both eggs and embryos exhibit remarkable adaptations to the physiologically stressful incubation environment. The use of various types of incubation heat may also shape the mating systems of the species involved.
Recent studies of sperm competition have shown that the timing of copulations can be crucial to f... more Recent studies of sperm competition have shown that the timing of copulations can be crucial to fertilization success. For example, in some birds copulations that occur near the time of laying are less likely to fertilize eggs than copulations that occur at other times. Thus, it was surprising to find that in Australian Brush-turkeys (Alectura lathami), most within-pair copulations (61.2%) occurred less than 1 h before laying, typically providing only 25 to 40 min for sperm to reach storage organs before potentially being flushed out by the descending egg. Brush-turkeys incubate their eggs in large mounds constructed by males; females lay an egg every few days and bury it within a chosen mound. Females usually solicited a copulation within 2 to 3 min after arriving at a mound to lay, but some males still forced copulations, particularly during the latter portion of laying visits. The unusual prevalence of copulations before laying probably results from males having little information about or control over female copulation behavior except when females need to lay in a males' mound. The prevalence of forced copulations during the latter part of laying visits may indicate conflict between the sexes over what constitutes adequate "payment" by females for use of a male's incubation mound. Neither sex showed any interest in copulating immediately after an egg was laid. This observation does not support the idea of a "fertilization window" after laying, but instead indicates that copulations at this time are probably ineffective in fertilizing eggs. Females also frequently made nonlaying visits to incubation mounds. The 38.8% of within-pair copulations that occurred during nonlaying visits may have been more likely to fertilize eggs, but the timing of these visits was controlled by females, who were probably less likely to be subject to male control when not laying.
Recent studies of sperm competition have shown that the timing of copulations can be crucial to f... more Recent studies of sperm competition have shown that the timing of copulations can be crucial to fertilization success. For example, in some birds copulations that occur near the time of laying are less likely to fertilize eggs than copulations that occur at other times. Thus, it was surprising to find that in Australian Brush-turkeys (Alectura lathami), most within-pair copulations (61.2%) occurred less than 1 h before laying, typically providing only 25 to 40 min for sperm to reach storage organs before potentially being flushed out by the descending egg. Brush-turkeys incubate their eggs in large mounds constructed by males; females lay an egg every few days and bury it within a chosen mound. Females usually solicited a copulation within 2 to 3 min after arriving at a mound to lay, but some males still forced copulations, particularly during the latter portion of laying visits. The unusual prevalence of copulations before laying probably results from males having little information about or control over female copulation behavior except when females need to lay in a males' mound. The prevalence of forced copulations during the latter part of laying visits may indicate conflict between the sexes over what constitutes adequate payment by females for use of a male's incubation mound. Neither sex showed any interest in copulating immediately after an egg was laid. This observation does not support the idea of a fertilization window after laying, but instead indicates that copulations at this time are probably ineffective in fertilizing eggs. Females also frequently made nonlaying visits to incubation mounds. The 38.8% of within-pair copulations that occurred during nonlaying visits may have been more likely to fertilize eggs, but the timing of these visits was controlled by females, who were probably less likely to be subject to male control when not laying.
AimUnique amongst birds, megapodes (family Megapodiidae) have exchanged the strategy of incubatin... more AimUnique amongst birds, megapodes (family Megapodiidae) have exchanged the strategy of incubating eggs with the warmth of their bodies for incubation behaviours that rely entirely on environmental heat sources. Typically, mound‐builders capture heat released from the decomposition of organic materials, while burrow‐nesters lay their eggs in geothermal or solar‐heated soils. The evolutionary path towards novel incubation behaviours has led to ecological and physiological adaptations unique to megapodes. Here, we present a species tree for all extant megapodes that settles long‐standing debates about megapode evolution: namely, their biogeographical origins and ancestral nesting behaviour.LocationAustralasia.MethodsA time‐calibrated multilocus species tree for all extant megapodes was constructed using *beast. We estimated and compared divergence dates for megapodes obtained from molecular rates, fossils, and a combination of fossils and rates. Using this tree, Bayesian estimation of ancestral nesting behaviour was conducted in BayesTraits and ancestral ranges were estimated in BioGeoBEARS.ResultsRecent dispersal has led to the recolonization of mainland Australia and New Guinea by Megapodius. Bayesian estimation of ancestral states indicates that mound building is the most probable ancestral nesting behaviour in megapodes (posterior probability = 0.75). Burrow nesting was acquired early in the diversification of the family (at least 14 Ma), followed by a single switch back to mound building.Main conclusionsDivergence dates and biogeographical reconstructions strongly suggest that dispersal, and not vicariance, led to the isolation of megapodes in Australasia. We propose that flight‐mediated dispersal to environmentally variable islands is responsible for the behavioural lability in nesting behaviours observed in some Megapodius species today.
hatch, adults face the costly task of caring for young. Though some chicks can walk and feed soon... more hatch, adults face the costly task of caring for young. Though some chicks can walk and feed soon after hatching, most must be brooded, protected from predators, and provided with a social environment; such parental requirements of bird species appear to have strongly influenced their physiology and behaviourl. There are some birds that dif- fer fundamentally from all others by exploiting environmental rather than body heat to incubate their eggs. These birds, the megapodes, were once thought to be primitive relics of a reptilian past2, but their extraordinary habits are almost cer- tainly derived from normal galli- form ground-nesting3. The 19 extant species occur widely among the islands of Southeast Asia, Australia, Papua New Guinea and the western Pacific (Fig. I 1, but several are endangered (Box I). Throughout this diverse region the birds ap- propriate sources of environmental heat by two principal techniques: either by constructing an incu- bation mound of decomposing or- ganic matter, or by burrowing into pre-existing heat sources (such as r; :
Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have... more Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have evolved a markedly different method of incubation. By making use of environmental heat, adult megapodes are emancipated from most of the usual constraints to reproductive success associated with parental care. Consequences of this unique incubation method are evident in all aspects of megapode development and behaviour. Recently, renewed interest in these birds from a number of disciplines has led to significant advances, especially in aspects associated with reproduction. Both eggs and embryos exhibit remarkable adaptations to the physiologically stressful incubation environment. The use of various types of incubation heat may also shape the mating systems of the species involved.
Additional file 5: Table S2. Divergence time estimations (in 10 millions of years) of different g... more Additional file 5: Table S2. Divergence time estimations (in 10 millions of years) of different gene shopping schemes for the 48-taxon dataset.
Additional file 4: Table S1. UCE phylogenomic studies of Galliformes and novel UCEs used in this ... more Additional file 4: Table S1. UCE phylogenomic studies of Galliformes and novel UCEs used in this study.
Additional file 2: Figure S2. ML phylogeny for the Galliformes from the 48-taxon dataset. Estimat... more Additional file 2: Figure S2. ML phylogeny for the Galliformes from the 48-taxon dataset. Estimation was conducted on the 75% complete matrix using RaxML.
Additional file 1: Figure S1. Species tree for the Galliformes from the 135-taxon dataset. Estima... more Additional file 1: Figure S1. Species tree for the Galliformes from the 135-taxon dataset. Estimation was conducted on the 75% complete matrix using SVDquartets.
Additional file 6: Table S3. Divergence time estimations (in 10 millions of years) from the most-... more Additional file 6: Table S3. Divergence time estimations (in 10 millions of years) from the most-tree like partition for the 95% complete of the 48 and 135-taxon datasets.
Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have... more Some birds don't incubate their eggs using the warmth of their bodies. The megapodes have evolved a markedly different method of incubation. By making use of environmental heat, adult megapodes are emancipated from most of the usual constraints to reproductive success associated with parental care. Consequences of this unique incubation method are evident in all aspects of megapode development and behaviour. Recently, renewed interest in these birds from a number of disciplines has led to significant advances, especially in aspects associated with reproduction. Both eggs and embryos exhibit remarkable adaptations to the physiologically stressful incubation environment. The use of various types of incubation heat may also shape the mating systems of the species involved.
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