Energy allocation to reproduction and maintenance in mountain bluebirds (Sialia currucoides): a food supplementation experiment

1993 ◽  
Vol 71 (12) ◽  
pp. 2352-2357 ◽  
Author(s):  
Patrick F. J. Garcia ◽  
Marilyn S. Merkle ◽  
Robert M. R. Barclay
Keyword(s):  
Reproductive Success ◽  
Food Supplementation ◽  
Lifetime Reproductive Success ◽  
Control Group ◽  
Additional Energy ◽  
Trade Off ◽  
Adult Females ◽  
Sialia Currucoides ◽  
Nestling Period ◽  
Mountain Bluebirds

Mountain bluebirds (Sialia currucoides) were supplemented with food during the nestling period to assess the trade-off between allocation of energy to parental self-maintenance and investment in offspring. Three treatment groups were established, with pairs of birds receiving 0 (control), 9 (small), or 18% (large) of the estimated daily energy requirements of both parents and their brood. Unsupplemented adult females lost an average of 3 g during the nestling period, while both supplemented groups maintained their body mass at approximately 33 g. Adult males in all three groups maintained their mass at approximately 30.5 g. Nestlings in both supplemented groups fledged with heavier masses than did those in the control group. Those receiving the large supplement also grew faster. Food appears to limit the lifetime reproductive success of mountain bluebirds. Adult females allocated additional energy to self-maintenance rather than to increased investment in current offspring. This result was not seen in males. We conclude that our results demonstrate a trade-off between investment in current versus future components of reproductive success.

Instability of Harems of Feral Horses in Relation To Season and Presence of Subordinate Stallions

Behaviour ◽  
1990 ◽  
Vol 112 (3-4) ◽  
pp. 149-161 ◽  
Author(s):  
Elizabeth Franke Stevens
Keyword(s):  
Reproductive Success ◽  
Social Interactions ◽  
Lifetime Reproductive Success ◽  
Late Winter ◽  
Island Population ◽  
Single Male ◽  
Seasonal Differences ◽  
Feral Horses ◽  
Adult Females ◽  
Abundance And Distribution

AbstractMale horses (Equus caballus) defend harems of females (bands) year-round and throughout their lifetimes. A male's lifetime reproductive success depends upon the number of females in his harem. Although harems have previously been reported as remaining stable over many years, during the two years of this study 30 % of the adult females in an island population of feral horses changed harems during late winter. The seasonal differences in harem stability resulted from seasonal differences in the abundance and distribution of food. The spacing between band members was greater and the frequency of social interactions between them was lower in winter than in summer. In addition, the amount of time devoted to grazing increased in winter. These differences are attributed to the lower availability of suitable vegetation duirng winter. Harem stability did not depend on the age of females, the size of the harem, nor the age of the harem stallion, but did depend on the presence of subordinate stallions attached to the band. All of the females that changed bands left single-male bands; multi-male bands were stable throughout the study.

Games Embedded in Life

2020 ◽  
pp. 203-230
Author(s):  
John M. McNamara ◽  
Olof Leimar
Keyword(s):  
Reproductive Success ◽  
Dynamic Games ◽  
Traditional Approach ◽  
Holistic Approach ◽  
Current Situation ◽  
Lifetime Reproductive Success ◽  
Trade Off ◽  
State Dependent ◽  
Mean Lifetime ◽  
Payoff Structure

Many games focus on a part of the life of an organism. The payoff structure of the game then represents how the game affects fitness proxies such as mean lifetime reproductive success, which are concerned with the whole of the life of the organism. However, the traditional approach of specifying payoffs in advance of the analysis of the game can lead to inconsistencies because the rest of the life of an individual is not fixed but depends on what happens in the game. This chapter concerns this issue, identifying situations in which a more holistic approach is needed. A series of models illustrates links between the current situation and a lifetime perspective. When each of two parents must decide whether to care for their common young or desert, the payoff for desertion depends on the solution of the game and cannot be specified in advance. A game in which two males contest for a female illustrates the approach that must be taken if this game can be repeated at a later time. A game in which individuals must possess territories in order to breed is developed that highlights various interdependencies and, by incorporating learning, advances the understanding of owner–intruder interactions. The interdependencies in state-dependent dynamic games are also illustrated with a model in which individuals must trade off the risks of starvation and predation in a situation in which the choice of the best foraging habitat depends on the number of other animals that use that habitat.

scholarly journals Carry-over effects of food supplementation on recruitment and breeding performance of long-lived seabirds

2015 ◽  
Vol 282 (1812) ◽  
pp. 20150762 ◽  
Author(s):  
Simone Vincenzi ◽  
Scott Hatch ◽  
Thomas Merkling ◽  
Alexander S. Kitaysky
Keyword(s):  
Life Cycle ◽  
Reproductive Success ◽  
Conservation Strategy ◽  
Food Supplementation ◽  
Lower Probability ◽  
Lifetime Reproductive Success ◽  
Vital Rates ◽  
Rissa Tridactyla ◽  
Food Conditions ◽  
Carry Over

Supplementation of food to wild animals is extensively applied as a conservation tool to increase local production of young. However, in long-lived migratory animals, the carry-over effects of food supplementation early in life on the subsequent recruitment of individuals into natal populations and their lifetime reproductive success are largely unknown. We examine how experimental food supplementation early in life affects: (i) recruitment as breeders of kittiwakes Rissa tridactyla born in a colony on Middleton Island (Alaska) between 1996 and 2006 ( n = 1629) that bred in the same colony through 2013 ( n = 235); and (ii) breeding success of individuals that have completed their life cycle at the colony ( n = 56). Birds were raised in nests that were either supplemented with food (Fed) or unsupplemented (Unfed). Fledging success was higher in Fed compared with Unfed nests. After accounting for hatching rank, growth and oceanic conditions at fledging, Fed fledglings had a lower probability of recruiting as breeders in the Middleton colony than Unfed birds. The per-nest contribution of breeders was still significantly higher for Fed nests because of their higher productivity. Lifetime reproductive success of a subset of kittiwakes that thus far had completed their life cycle was not affected by the food supplementation during development. Our results cast light on the carry-over effects of early food conditions on the vital rates of long-lived animals and support food supplementation as an effective conservation strategy for long-lived seabirds.

scholarly journals Life history variation is maintained by fitness trade-offs and negative frequency-dependent selection

2018 ◽  
Vol 115 (17) ◽  
pp. 4441-4446 ◽  
Author(s):  
Mark R. Christie ◽  
Gordon G. McNickle ◽  
Rod A. French ◽  
Michael S. Blouin
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Life History Strategies ◽  
Lifetime Reproductive Success ◽  
Life History Variation ◽  
Additional Energy ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Trade Offs ◽  
Negative Frequency Dependent Selection

The maintenance of diverse life history strategies within and among species remains a fundamental question in ecology and evolutionary biology. By using a near-complete 16-year pedigree of 12,579 winter-run steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, we examined the continued maintenance of two life history traits: the number of lifetime spawning events (semelparous vs. iteroparous) and age at first spawning (2–5 years). We found that repeat-spawning fish had more than 2.5 times the lifetime reproductive success of single-spawning fish. However, first-time repeat-spawning fish had significantly lower reproductive success than single-spawning fish of the same age, suggesting that repeat-spawning fish forego early reproduction to devote additional energy to continued survival. For single-spawning fish, we also found evidence for a fitness trade-off for age at spawning: older, larger males had higher reproductive success than younger, smaller males. For females, in contrast, we found that 3-year-old fish had the highest mean lifetime reproductive success despite the observation that 4- and 5-year-old fish were both longer and heavier. This phenomenon was explained by negative frequency-dependent selection: as 4- and 5-year-old fish decreased in frequency on the spawning grounds, their lifetime reproductive success became greater than that of the 3-year-old fish. Using a combination of mathematical and individual-based models parameterized with our empirical estimates, we demonstrate that both fitness trade-offs and negative frequency-dependent selection observed in the empirical data can theoretically maintain the diverse life history strategies found in this population.

scholarly journals Attentive red squirrel mothers have faster-growing pups and higher lifetime reproductive success

2019 ◽  
Author(s):  
Sarah E Westrick ◽  
Ryan W Taylor ◽  
Stan Boutin ◽  
Jeffrey E Lane ◽  
Andrew G McAdam ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Individual Variation ◽  
Maternal Care ◽  
Wild Population ◽  
Lifetime Reproductive Success ◽  
Red Squirrels ◽  
Trade Off ◽  
Offspring Growth ◽  
North American Red Squirrels ◽  
Care Behavior

AbstractParental investment theory predicts that observed levels of parental care afforded to offspring are set by the benefits (to offspring quality and survival) relative to the costs (to parental survival or future reproduction). Although difficult to document in mammals, there is often substantial individual-variation in the amount of parental care within species. We measured the impact of individual variation in maternal care (“attentiveness” towards offspring or maternal motivation) on offspring growth and survival in a wild population of North American red squirrels (Tamiasciurus hudsonicus). We used latency to return to pups following a nest intrusion as a measure of maternal attentiveness to pups. We found this behavior to be repeatable within individuals suggesting this behavior is a personality trait or a “maternal style”. In this population, postnatal growth rate is important for pup overwinter survival. Pups from large litters grew faster if they had a highly attentive mother, indicating that maternal care behavior can mitigate the trade-off between litter size and offspring growth and potentially improve survival of pups. Additionally, more attentive mothers had slightly higher lifetime reproductive success than less attentive mothers. These results highlight important fitness effects of having a highly attentive mother and show that maternal care behavior can alter a fundamental life history trade-off between offspring quantity and quality.Lay SummaryIt pays to be attentive to your pups as a squirrel mom. In a long-term study of a wild population of North American red squirrels, we observed repeatable individual variation in maternal attentiveness towards offspring. Mothers who returned faster to pups following a nest intrusion produced faster growing pups and were able to produce larger fast-growing litters. Over their entire lifetime, attentive mothers also had more offspring recruit into the breeding population.

scholarly journals Parents face quantity–quality trade-offs between reproduction and investment in offspring in Iceland

2016 ◽  
Vol 3 (5) ◽  
pp. 160087 ◽  
Author(s):  
Robert Francis Lynch
Keyword(s):  
Reproductive Success ◽  
Evolutionary Biology ◽  
Fundamental Problem ◽  
Lifetime Reproductive Success ◽  
Trade Off ◽  
Evolutionary Conflict ◽  
Trade Offs ◽  
Fitness Consequences ◽  
Using Data ◽  
Primary Impact

How to optimally allocate time, energy and investment in an effort to maximize one's reproductive success is a fundamental problem faced by all organisms. This effort is complicated when the production of each additional offspring dilutes the total resources available for parental investment. Although a quantity–quality trade-off between producing and investing in offspring has long been assumed in evolutionary biology, testing it directly in humans is difficult, partly owing to the long generation time of our species. Using data from an Icelandic genealogy (Íslendingabók) over two centuries, I address this issue and analyse the quantity–quality trade-off in humans. I demonstrate that the primary impact of parents on the fitness of their children is the result of resources and or investment, but not genes. This effect changes significantly across time, in response to environmental conditions. Overall, increasing reproduction has negative fitness consequences on offspring, such that each additional sibling reduces an individual's average lifespan and lifetime reproductive success. This analysis provides insights into the evolutionary conflict between producing and investing in children while also shedding light on some of the causes of the demographic transition.

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