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.

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 Individual variation in phenotypic plasticity of the stress axis

2019 ◽  
Author(s):  
Sarah Guindre-Parker ◽  
Andrew G. Mcadam ◽  
Freya Van Kesteren ◽  
Rupert Palme ◽  
Rudy Boonstra ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Individual Variation ◽  
Local Density ◽  
Reaction Norm ◽  
Tamiasciurus Hudsonicus ◽  
Stress Axis ◽  
Red Squirrels ◽  
Conspecific Density ◽  
North American Red Squirrels ◽  
Future Work

ABSTRACTPhenotypic plasticity—one individual’s capacity for phenotypic variation under different environments—is critical for organisms facing fluctuating conditions within their lifetime. North American red squirrels (Tamiasciurus hudsonicus) experience drastic among-year fluctuations in conspecific density. This shapes juvenile competition over vacant territories and overwinter survival. To help young cope with competition at high densities, mothers can increase offspring growth rates via a glucocorticoid-mediated maternal effect. However, this effect is only adaptive under high densities, and faster growth often comes at a cost to longevity. While experiments have demonstrated that red squirrels can adjust hormones in response to fluctuating density, the degree to which mothers differ in their ability to regulate glucocorticoids across changing densities remains unknown—little is known about within-individual plasticity in endocrine traits relative to among-individual variation. Findings from our reaction norm approach revealed significant individual variation not only in a female red squirrel’s mean endocrine phenotype, but also in endocrine plasticity in response to changes in local density. Future work on the proximate and ultimate drivers of variation in the plasticity of endocrine traits and maternal effects is needed, particularly in free-living animals experiencing fluctuating environments.

Brood size manipulation reveals cost on the size of the second clutch in the earwig Anisolabis maritime

Behaviour ◽  
2021 ◽  
pp. 1-11
Author(s):  
Seizi Suzuki
Keyword(s):  
Reproductive Success ◽  
Parental Care ◽  
Clutch Size ◽  
Maternal Care ◽  
Brood Size ◽  
Trade Off ◽  
Brood Size Manipulation ◽  
Second Clutch ◽  
The Cost

Abstract There may be a trade-off between the duration of parental care and future reproductive success. Traditionally, studies about the cost of parental care have included the removal of the parent. However, producing a secondary clutch after the failure of the first one is a compensatory behaviour that occurs in cases of brood failure. In this study, attempts were made to detect the cost of maternal care in the earwig, Anisolabis maritima (Dermaptera: Anisolabididae) by either extending the period of care or increasing the brood size to prevent compensation through the brood’s success. The results indicated that manipulation did not change the inter-clutch interval, although my previous study revealed shortening of these intervals after the removal of the clutch in this species. In this study, decreased clutch size manipulation increased the size of the following clutch.

Survival and lifetime reproductive success in dispersing and resident red squirrels

1994 ◽  
Vol 34 (3) ◽  
pp. 197-201 ◽  
Author(s):  
Luc Wauters ◽  
Erik Matthysen ◽  
Andr�?A. Dhondt
Keyword(s):  
Reproductive Success ◽  
Lifetime Reproductive Success ◽  
Red Squirrels

Survival and lifetime reproductive success in dispersing and resident red squirrels

1994 ◽  
Vol 34 (3) ◽  
pp. 197-201 ◽  
Author(s):  
Luc Wauters ◽  
Erik Matthysen ◽  
Andr� A. Dhondt
Keyword(s):  
Reproductive Success ◽  
Lifetime Reproductive Success ◽  
Red Squirrels

scholarly journals Effects of maternal care on the lifetime reproductive success of females in a neotropical harvestman

2007 ◽  
Vol 76 (5) ◽  
pp. 937-945 ◽  
Author(s):  
BRUNO A. BUZATTO ◽  
GUSTAVO S. REQUENA ◽  
EDUARDO G. MARTINS ◽  
GLAUCO MACHADO
Keyword(s):  
Reproductive Success ◽  
Maternal Care ◽  
Lifetime Reproductive Success

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.

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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