Costs of Reproduction and Success of Manipulated Broods Under Varying Food Conditions in Tengmalm's Owl

10.2307/5109 ◽  
1988 ◽  
Vol 57 (3) ◽  
pp. 1027 ◽  
Author(s):  
Erkki Korpimaki





Author(s):  
Katherine Paugh

The abolition of the Atlantic slave trade by the British government in 1807 was prompted by a confluence of geopolitical developments and concerns about reproduction. Shifts in the Atlantic world sugar economy had led to a glut on the British sugar market, and boosting production was therefore less of an economic concern than safeguarding reproduction. After 1807, demographic and financial calculations regarding the future of the plantation system intensified with the institution of a registry system designed to track slave populations. By 1823, British politicians, both abolitionists and West Indian planters, agreed to further radical reform: they hoped that encouraging Christian marital mores would finally bring about economically beneficial population growth. Acts legalizing Afro-Caribbean marriage were subsequently passed throughout the Caribbean. The outcome of this new emphasis on family life was ironic: as slavery gave way to wage labor, the costs of reproduction were shifted to Afro-Caribbean parents.



Primates ◽  
2021 ◽  
Author(s):  
Goro Hanya ◽  
Miki Matsubara ◽  
Shuhei Hayaishi ◽  
Koichiro Zamma ◽  
Shinichi Yoshihiro ◽  
...  


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Louise C Archer ◽  
Stephen A Hutton ◽  
Luke Harman ◽  
W Russell Poole ◽  
Patrick Gargan ◽  
...  

Abstract Metabolic rates vary hugely within and between populations, yet we know relatively little about factors causing intraspecific variation. Since metabolic rate determines the energetic cost of life, uncovering these sources of variation is important to understand and forecast responses to environmental change. Moreover, few studies have examined factors causing intraspecific variation in metabolic flexibility. We explore how extrinsic environmental conditions and intrinsic factors contribute to variation in metabolic traits in brown trout, an iconic and polymorphic species that is threatened across much of its native range. We measured metabolic traits in offspring from two wild populations that naturally show life-history variation in migratory tactics (one anadromous, i.e. sea-migratory, one non-anadromous) that we reared under either optimal food or experimental conditions of long-term food restriction (lasting between 7 and 17 months). Both populations showed decreased standard metabolic rates (SMR—baseline energy requirements) under low food conditions. The anadromous population had higher maximum metabolic rate (MMR) than the non-anadromous population, and marginally higher SMR. The MMR difference was greater than SMR and consequently aerobic scope (AS) was higher in the anadromous population. MMR and AS were both higher in males than females. The anadromous population also had higher AS under low food compared to optimal food conditions, consistent with population-specific effects of food restriction on AS. Our results suggest different components of metabolic rate can vary in their response to environmental conditions, and according to intrinsic (population-background/sex) effects. Populations might further differ in their flexibility of metabolic traits, potentially due to intrinsic factors related to life history (e.g. migratory tactics). More comparisons of populations/individuals with divergent life histories will help to reveal this. Overall, our study suggests that incorporating an understanding of metabolic trait variation and flexibility and linking this to life history and demography will improve our ability to conserve populations experiencing global change.



2007 ◽  
Vol 363 (1490) ◽  
pp. 375-398 ◽  
Author(s):  
John R Speakman

Life-history trade-offs between components of fitness arise because reproduction entails both gains and costs. Costs of reproduction can be divided into ecological and physiological costs. The latter have been rarely studied yet are probably a dominant component of the effect. A deeper understanding of life-history evolution will only come about once these physiological costs are better understood. Physiological costs may be direct or indirect. Direct costs include the energy and nutrient demands of the reproductive event, and the morphological changes that are necessary to facilitate achieving these demands. Indirect costs may be optional ‘compensatory costs’ whereby the animal chooses to reduce investment in some other aspect of its physiology to maximize the input of resource to reproduction. Such costs may be distinguished from consequential costs that are an inescapable consequence of the reproductive event. In small mammals, the direct costs of reproduction involve increased energy, protein and calcium demands during pregnancy, but most particularly during lactation. Organ remodelling is necessary to achieve the high demands of lactation and involves growth of the alimentary tract and associated organs such as the liver and pancreas. Compensatory indirect costs include reductions in thermogenesis, immune function and physical activity. Obligatory consequential costs include hyperthermia, bone loss, disruption of sleep patterns and oxidative stress. This is unlikely to be a complete list. Our knowledge of these physiological costs is currently at best described as rudimentary. For some, we do not even know whether they are compensatory or obligatory. For almost all of them, we have no idea of exact mechanisms or how these costs translate into fitness trade-offs.



1994 ◽  
Vol 9 (8) ◽  
pp. 304-307 ◽  
Author(s):  
K.I. Jösson ◽  
J. Tuomi


Oecologia ◽  
1999 ◽  
Vol 121 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Susanne Huber ◽  
Eva Millesi ◽  
Manfred Walzl ◽  
John Dittami ◽  
Walter Arnold




1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.



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