OU model-fitting - constraint or measurement error?
Samantha Price
Evolutionary Quantitative Genetics
Workshop July 14th 2022 Virtual
Body size and reproductive rate have a strong positive relationship in terrestrial mammals
Whales
Bats
Body size and reproductive rate have a weak relationship with low R2 in whales and dolphins
PIC | Adult body length | |||
Trait | df | Slope | t-value
| r-squared
|
Weaning age | 21 | 0.20 | 1.70
| 0.08 |
Gestation length | 28 | 0.09 | 0.09+ | 0.07 |
Age at sexual maturity | 25 | 0.34 | 1.78+ | 0.08 |
Inter-birth interval | 21 | 0.23 | 1.36
| 0.04 |
+ p-value 0.1>0.05
Body size and reproductive rate fit very different evolutionary models in whales and dolphins (best fit worst fit)�
| Traits | BM | OU1 | OU suborder | OU family |
Size-related traits | Adult female body mass |
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Adult female length mass |
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Reproductive traits | Gestation length |
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Inter-birth interval |
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Age at sexual maturity |
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Weaning age |
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Reproductive characters appear to be under strong selective constraint(s) across Cetacea and are only weakly related to size
BUT body mass estimates are fairly reliable from whaling data or beached individuals while reproductive characteristics are really hard to estimate for most cetaceans, as they are not easily tracked or kept in captivity. This measurement error would cause OU to be best-fitting model and reduce the relationship between size and reproductive rate.