scholarly journals A global meta-analysis reveals more variable life histories in urban birds compared to their non-urban neighbours

2021 ◽  
Author(s):  
Pablo Capilla-Lasheras ◽  
Megan J Thompson ◽  
Alfredo Sanchez-Tojar ◽  
Yacob Haddou ◽  
Claire J Branston ◽  
...  

Cities pose a major ecological challenge for wildlife worldwide. Phenotypic variation is a pivotal metric to predict evolutionary potential in response to environmental change. Recent work suggests that urban populations might have higher levels of phenotypic variation than non-urban counterparts. This prediction, however, has never been tested across taxa nor over a broad geographical range. Here, we conduct a meta-analysis of the urban avian literature to compare urban versus non-urban means and variances for phenology and reproductive performance. First, we show that urban birds reproduce earlier and have smaller broods than non-urban ones. Second, we demonstrate that urban populations have a more variable phenology than non-urban populations. Our analyses reveal that the latter pattern arises from differences in phenological variation between individuals within breeding seasons, likely because of higher heterogeneity in the urban study areas. These findings suggest that the opportunity for selection on phenology may be stronger in urban bird populations and that the patterns of phenotypic variation in urban and non-urban avian populations may consistently differ.

2001 ◽  
Vol 79 (9) ◽  
pp. 1552-1558 ◽  
Author(s):  
Matthew J Parris

Terrestrial ecology has been largely neglected in the study of amphibian life histories because it is difficult to manipulate most species during the terrestrial stage. I examined the terrestrial performance of Rana blairi, Rana sphenocephala, and four hybrid (two F1 and two advanced generation) genotypes in replicated experimental enclosures to test for differences in traits related to juvenile terrestrial fitness. I produced all genotypes by means of artificial fertilizations using frogs collected from natural populations in central Missouri, and juvenile frogs were obtained from larvae reared in experimental ponds. Following metamorphosis, froglets were raised in single-genotype groups in terrestrial enclosures through the first overwintering. The proportion surviving did not vary among genotypes, but the power to detect significant differences was low. F1 hybrid genotypes BS and SB demonstrated significantly higher growth rates than either parental species or advanced-generation hybrid genotypes. Observation of growth rates of advanced-generation hybrids equal to those of the parental species, and heterosis in F1 hybrids for growth rate, suggests that natural hybridization between R. blairi and R. sphenocephala can produce novel and relatively fit hybrid genotypes. Direct measurement of multiple fitness components for hybrid and parental genotypes is critical for assessing the evolutionary potential of natural hybridization in organisms with complex life cycles.


2020 ◽  
Vol 77 (2) ◽  
pp. 295-313 ◽  
Author(s):  
Joseph Munyandorero

The recruitment compensation metrics, the stock–recruit steepness (h) and compensation ratio (κ), are difficult to estimate, yet they are integral components of contemporary fishery models. To aid in the estimation of κ and h, a hybrid method to construct their prior distributions for a species is developed. The method is hybrid because it integrates (i) a meta-analysis of the relationship between maximum rates of recruit production (α) and asymptotic lengths obtained across fish species of different life histories and (ii) species-specific unfished spawning biomass per recruit (Φ0). This method is applied to five finfish species found off the East Coast of the United States. Uncertainty is introduced by sampling growth parameters, α, and natural mortality and — through Monte Carlo simulations — propagated into Φ0, κ, and h for the Beverton–Holt and Ricker stock–recruit relationships. Descriptive statistics and parameters from probability density functions of the simulated distributions of κ and h are generated. The method developed requires fewer inputs than the reproductive ecology method while likewise allowing the development of species-specific statistics for κ and h. These statistics, rather than their counterparts generated from classical meta-analyses, are better suited for use in fishery models.


1999 ◽  
Vol 77 (8) ◽  
pp. 1314-1321 ◽  
Author(s):  
Toshihiko Saito ◽  
Shigeru Nakano

Relationships between reproductive timing of spawners and timing of hatch and age at maturity of their offspring were examined in fluvial threespine sticklebacks, Gasterosteus aculeatus. Some age 2 and all age 3 females matured in this age-structured population, with only a few females reproducing over two successive breeding seasons. Age 2 females spawned over the relatively long breeding season (March-August), whereas age 3 females spawned mainly early in the season (March-June). Although the standard length of mature age 3 females was greater than that of age 2 females, the back-calculated standard lengths of the former were always shorter than those of the latter at an equivalent age, the most distinct differences being apparent in young of the year. Analysis of daily otolith increments showed that the earlier the young of the year were born, the larger they were at the end of the growing season. As a result of these findings, age 3 females can be expected to produce offspring that will mature at age 2, whereas the offspring of late-spawning age 2 females are more likely to mature at age 3. Therefore, a partial alternation of life histories between generations is thought to occur.


2005 ◽  
Vol 272 (1571) ◽  
pp. 1415-1425 ◽  
Author(s):  
Anne Charmantier ◽  
Dany Garant

An essential requirement to determine a population's potential for evolutionary change is to quantify the amount of genetic variability expressed for traits under selection. Early investigations in laboratory conditions showed that the magnitude of the genetic and environmental components of phenotypic variation can change with environmental conditions. However, there is no consensus as to how the expression of genetic variation is sensitive to different environmental conditions. Recently, the study of quantitative genetics in the wild has been revitalized by new pedigree analyses based on restricted maximum likelihood, resulting in a number of studies investigating these questions in wild populations. Experimental manipulation of environmental quality in the wild, as well as the use of naturally occurring favourable or stressful environments, has broadened the treatment of different taxa and traits. Here, we conduct a meta-analysis on recent studies comparing heritability in favourable versus unfavourable conditions in non-domestic and non-laboratory animals. The results provide evidence for increased heritability in more favourable conditions, significantly so for morphometric traits but not for traits more closely related to fitness. We discuss how these results are explained by underlying changes in variance components, and how they represent a major step in our understanding of evolutionary processes in wild populations. We also show how these trends contrast with the prevailing view resulting mainly from laboratory experiments on Drosophila . Finally, we underline the importance of taking into account the environmental variation in models predicting quantitative trait evolution.


2000 ◽  
Vol 48 (1) ◽  
pp. 21 ◽  
Author(s):  
Hugh A. Ford ◽  
Steve Trémont

Most endemic Australian passerines that have been studied display long breeding seasons, multiple nesting attempts, small clutches, low annual productivity, high longevity and a high incidence of cooperative breeding. We compare the life histories of two large endemic honeyeaters (Meliphagidae) near Armidale, New South Wales. Red wattlebirds, Anthochaera carunculata, have a long breeding season, with many nesting attempts and clutches of two eggs, similar to other honeyeaters whose breeding biology has been studied. Noisy friarbirds, Philemon corniculatus, which are spring and summer visitors to the study area, have shorter breeding seasons, usually making one attempt and have a modal clutch size of three. Both species had incubation and nestling periods of about 16 days. Friarbirds apparently have a laying interval of 24 hours, the same as other honeyeaters, but unlike some other endemic passerines, which have laying intervals of 48 hours. Breeding success did not differ between the species, with young fledging from 32.7% of wattlebird nests and 40.9% of friarbird nests. The reproductive strategy of the noisy friarbird thus differs quantitatively from the apparent norm for other honeyeaters and many other Australian endemic passerines.


Ibis ◽  
2018 ◽  
Vol 160 (3) ◽  
pp. 489-515 ◽  
Author(s):  
Davide Scridel ◽  
Mattia Brambilla ◽  
Kathy Martin ◽  
Aleksi Lehikoinen ◽  
Aaron Iemma ◽  
...  

2018 ◽  
Vol 285 (1876) ◽  
pp. 20172763
Author(s):  
Simon R. Evans ◽  
Dominique Waldvogel ◽  
Nina Vasiljevic ◽  
Erik Postma

Sexual reproduction is inherently interactive, especially in animal species such as humans that exhibit extended pair bonding. Yet we have little knowledge of the role of male characteristics and their evolutionary impact on reproductive behavioural phenotypes, to the extent that biologists typically consider component traits (e.g. reproductive timing) as female-specific. Based on extensive genealogical data detailing the life histories of 6435 human mothers born across four centuries of modern history, we use an animal modelling approach to estimate the indirect genetic effect of men on the reproductive phenotype of their partners. These analyses show that a woman's reproductive timing (age at first birth) is influenced by her partner's genotype. This indirect genetic effect is positively correlated with the direct genetic effect expressed in women, such that total heritable variance in this trait is doubled when heritable partner effects are considered. Our study thus suggests that much of the heritable variation in women's reproductive timing is mediated via partner effects, and that the evolutionary potential of this trait is far greater than previously appreciated.


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