The Effects of Late-Incubation Body Mass on Reproductive Success and Survival of Canvasbacks and Redheads

The Condor ◽  
1995 ◽  
Vol 97 (4) ◽  
pp. 953-962 ◽  
Author(s):  
Todd W. Arnold ◽  
Michael G. Anderson ◽  
Robert B. Emery ◽  
Michael D. Sorenson ◽  
Cristina N. de Sobrino
Keyword(s):  
Reproductive Success ◽  
Body Mass

scholarly journals Nutrient Reserves of Lesser Scaup (Aythya Affinis) During Spring Migration in the Mississippi Flyway: A Test of the Spring Condition Hypothesis

The Auk ◽  
2004 ◽  
Vol 121 (3) ◽  
pp. 917-929 ◽  
Author(s):  
Michael J. Anteau ◽  
Alan D. Afton
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Body Condition ◽  
Female Body ◽  
Population Decline ◽  
Spring Migration ◽  
Aythya Affinis ◽  
Lesser Scaup ◽  
Nutrient Reserves ◽  
Mineral Reserves

AbstractThe continental scaup population (Lesser [Aythya affinis] and Greater [A. marila] combined) has declined markedly since 1978. One hypothesis for the population decline states that reproductive success has decreased because female scaup are arriving on breeding areas in poorer body condition than they did historically (i.e. spring condition hypothesis). We tested one aspect of that hypothesis by comparing body mass and nutrient reserves (lipid, protein, and mineral) of Lesser Scaup at four locations (Louisiana, Illinois, Minnesota, and Manitoba) between the 1980s and 2000s. We found that mean body mass and lipid and mineral reserves of females were 80.0, 52.5, and 3.0 g higher, respectively, in the 2000s than in the 1980s in Louisiana; similarly, body mass and lipid and mineral reserves of males were 108.8, 72.5, and 2.5 g higher, respectively. In Illinois, mean body mass and lipid reserves of females were 88.6 and 56.5 g higher, respectively, in the 2000s than in the 1980s; similarly, body mass and lipid and mineral reserves of males were 80.6, 76.0, and 2.7 g higher, respectively. Mean body mass of females were 58.5 and 58.9 g lower in the 2000s than in the 1980s in Minnesota and Manitoba, respectively; mean body mass of males, similarly, were 40.7 g lower in Minnesota. Mean lipid reserves of females in the 2000s were 28.8 and 27.8 g lower than those in the 1980s in Minnesota and Manitoba, respectively. Mean mineral reserves of females in the 2000s were 3.2 g lower than those in the 1980s in Manitoba. Consequently, females arriving to breed in Manitoba in the 2000s had accumulated lipid reserves for 4.1 fewer eggs and mineral reserves for 0.8 fewer eggs than those arriving to breed there in the 1980s. Accordingly, our results are consistent with the spring condition hypothesis and suggest that female body condition has declined, as reflected by decreases in body mass, lipids, and mineral reserves that could cause reductions in reproductive success and ultimately a population decline.

Body mass influences maternal allocation more than parity status for a long-lived cervid mother

2019 ◽  
Vol 100 (5) ◽  
pp. 1459-1465 ◽  
Author(s):  
Eric S Michel ◽  
Stephen Demarais ◽  
Bronson K Strickland ◽  
Jerrold L Belant ◽  
Larry E Castle
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Litter Size ◽  
Reproductive Value ◽  
Lifetime Reproductive Success ◽  
Reproductive Tactics ◽  
High Quality ◽  
Maternal Body ◽  
Individual Offspring ◽  
Maternal Allocation

Abstract Mothers should balance the risk and reward of allocating resources to offspring to optimize the reproductive value of both offspring and mother while maximizing lifetime reproductive success by producing high-quality litters. The reproductive restraint hypothesis suggests maternal allocation should peak for prime-aged mothers and be less for younger mothers such that body condition is not diminished to a level that would jeopardize their survival or future reproductive events. We assessed if reproductive tactics varied by maternal body mass and parity status in captive female white-tailed deer (Odocoileus virginianus) to determine if prime-aged mothers allocate relatively more resources to reproduction than primiparous mothers. Maternal body mass, not parity status, positively affected maternal allocation, with heavier mothers producing both heavy litters and heavy individual offspring. Conversely, maternal body mass alone did not affect litter size, rather the interaction between maternal body mass and parity status positively affected litter size such that maternal body mass displayed a greater effect on litter size for primiparous than multiparous mothers. Our results suggest that heavy white-tailed deer mothers allocate additional resources to current year reproduction, which may be an adaptation allowing mothers to produce high-quality litters and increase their annual reproductive success because survival to the next reproductive attempt is not certain.

scholarly journals Effects of litter size on pup defence and weaning success of neighbouring bank vole females

2002 ◽  
Vol 80 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Pernilla Jonsson ◽  
Jep Agrell ◽  
Esa Koskela ◽  
Tapio Mappes
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Litter Size ◽  
Bank Vole ◽  
Dominance Rank ◽  
The Other ◽  
Clethrionomys Glareolus ◽  
Bank Voles ◽  
Litter Size Manipulation

Reproductive success of territorial female mammals depends partly on their capability to defend their young from conspecific intruders. However, how this is related to the characteristics of females and their litter sizes is largely unknown. The defence activity of 25 female bank voles (Clethrionomys glareolus) in relation to the number of offspring was studied in a behavioural arena by manipulating litter sizes (–2 pups or +2 pups). Infanticidal male bank voles were used as intruders–predators. Moreover, the weaning success (weaned at least one offspring or none) of 15 pairs of neighbouring females was investigated in a large indoor runway system. In each pair of females, the litter size of one female was reduced (–2 pups) and the litter size of the other enlarged (+2 pups). Defence activity of females increased with the number of offspring and the mother's size. However, weaning success of neighbours was related only to their body mass, and litter-size manipulation did not affect weaning success. Present results indicate that, although bank vole females increase their defence intensity with an increase in the number of pups, the weaning success of neighbouring females may be primarily determined by their size and dominance rank.

Comparative effects of mites and lice on the reproductive success of rock doves (Columba livia)

Parasitology ◽  
1995 ◽  
Vol 110 (2) ◽  
pp. 195-206 ◽  
Author(s):  
D. H. Clayton ◽  
D. M. Tompkins
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Growth Rates ◽  
Columba Livia ◽  
Nestling Growth ◽  
Adult Body Mass ◽  
Evolution Of Virulence ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

SUMMARYWe report experimental data comparing the effects of Mesostigmatid mites and Ischnoceran lice on the reproductive performance of a single group of captive rock doves (Columba livia). Several components of host reproductive success were compared for the two groups, including number of eggs laid, hatching success, nestling growth rates, fledging success, post-fledging body mass and survival. Adult body mass and survival were also compared. There was a dramatic difference in the effects of the mites and lice. The former drove host reproductive success to zero, mainly by agitating adults and causing them to incubate eggs less faithfully. Nestling growth rates and post-fledging survival were also significantly reduced by mites. Lice showed no effect on reproductive success whatsoever, even though the feather damage they cause is known to have energetic consequences (Booth, Clayton & Block, 1993). Neither parasite had a significant effect on adult birds. Although Ischnocera are found on most species of birds, our results for lice constitute the first experimental test of the impact of Ischnocera on avian reproductive success (preliminary report by Clayton & Tompkins, 1994). We discuss reasons for the different effects of mites and lice, including the relationship of horizontal (mites) and vertical (lice) transmission to the evolution of virulence.

Sex differences in immunocompetence differ between two Peromyscus species

1997 ◽  
Vol 273 (2) ◽  
pp. R655-R660 ◽  
Author(s):  
S. L. Klein ◽  
R. J. Nelson
Keyword(s):  
Sex Differences ◽  
Reproductive Success ◽  
Body Mass ◽  
Serum Testosterone ◽  
Cell Mediated Immunity ◽  
Female Reproductive Success ◽  
Proximate Mechanisms ◽  
Peromyscus Californicus ◽  
Monogamous Species ◽  
Cell Mitogen

Males generally exhibit reduced immunocompetence and greater susceptibility to disease than females. The explanations for why males may be more susceptible to disease than females fall into two categories: 1) the proximate mechanisms mediating immunity, such as hormonal mechanisms, and 2) variation in reproductive success between the sexes. The present study examined the extent to which these factors contribute to sex differences in cell-mediated immune function in polygynous Peromyscus maniculatus and monogamous Peromyscus californicus. Prevailing hypotheses suggest that, because variation in male and female reproductive success is greater among polygynous than monogamous species, sex differences in immunocompetence should be greater among polygynous than monogamous species as well. In contrast to these predictions, sex differences in cell-mediated immunity and body mass were only observed among monogamous P. californicus, in which females exhibited higher splenocyte proliferation in response to the T cell mitogen, concanavalin A, and weighed less than male conspecifics. Male P. maniculatus had higher serum testosterone concentrations than male P. californicus, but females of the two species did not differ in circulating estradiol concentrations. Sex steroid concentrations were not correlated with either immunocompetence or body mass; however, large P. californicus males exhibited reduced immune responses. Taken together, these results do not support the hypothesis that sex differences in immunocompetence are more pronounced among polygynous compared with monogamous species. Furthermore, these data suggest that circulating testosterone does not mediate sex differences in immuno-competence or body mass in P. californicus.

scholarly journals A Model for Brain Life History Evolution

2016 ◽  
Author(s):  
Mauricio González-Forero ◽  
Timm Faulwasser ◽  
Laurent Lehmann
Keyword(s):  
Mathematical Modeling ◽  
Life History ◽  
Reproductive Success ◽  
Body Mass ◽  
Life History Evolution ◽  
Brain Evolution ◽  
The Body ◽  
Brain Mass ◽  
History Evolution ◽  
The Brain

AbstractMathematical modeling of brain evolution is scarce, possibly due in part to the difficulty of describing how brain relates to fitness. Yet such modeling is needed to formalize verbal arguments and deepen our understanding of brain evolution. To address this issue, we combine elements of life history and metabolic theories to formulate a metabolically explicit mathematical model for brain life history evolution. We assume that some of the brain’s energetic expense is due to production (learning) and maintenance (memory) of skills (or cognitive abilities, knowledge, information, etc.). We also assume that individuals use skills to extract energy from the environment, and can allocate this energy to grow and maintain the body, including brain and reproductive tissues. Our model can be used to ask what fraction of growth energy should be allocated to the growth of brain and other tissues at each age under various biological settings as a result of natural selection. We apply the model to find uninvadable allocation strategies under a “me-against-nature” setting, namely when overcoming environmentally determined energy-extraction challenges does not involve any interactions with other individuals (possibly except caregivers), and using parameter values for modern humans. The uninvadable strategies yield predictions for brain and body mass throughout ontogeny, as well as for the ages at maturity, adulthood, and brain growth arrest. We find that (1) a me-against-nature setting is enough to generate adult brain and body mass of ancient human scale, (2) large brains are favored by intermediately challenging environments, moderately effective skills, and metabolically expensive memory, and (3) adult skill number is proportional to brain mass when metabolic costs of memory saturate the brain metabolic rate allocated to skills. Overall, our model is a step towards a quantitative theory of brain life history evolution yielding testable quantitative predictions as ecological, demographic, and social factors vary.Author SummaryUnderstanding what promotes the evolution of a given feature is often helped by mathematical modeling. However, mathematical modeling of brain evolution has remained scarce, possibly because of difficulties describing mathematically how the brain relates to reproductive success, which is the currency of evolution. Here we combine elements of two research fields that have previously been successful at detailing how a feature impacts reproductive success (life history theory) and at predicting the individual’s body mass throughout its life without the need to describe in detail the inner workings of the body (metabolic theory). We apply the model to a setting where individuals must extract energy from the environment without interacting with other individuals except caregivers (“me-against-nature”) and parameterize the model with data from humans. In this setting, the model can correctly predict a variety of human features, including large brain sizes. Our model can be used to obtain testable quantitative predictions in terms of brain mass throughout an individual’s life from assumed hypotheses promoting brain evolution, such as harsh environments or plentiful social interactions.

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