scholarly journals Females increase current reproductive effort when future access to males is uncertain

2008 ◽  
Vol 4 (2) ◽  
pp. 224-227 ◽  
Author(s):  
Katja U Heubel ◽  
Kai Lindström ◽  
Hanna Kokko

Trade-offs between current and future reproduction shape life histories of organisms, e.g. increased mortality selects for earlier reproductive effort, and mate limitation has been shown to shape male life histories. Here, we show that female life histories respond adaptively to mate limitation. Female common gobies ( Pomatoschistus microps ) respond to a female-biased operational sex ratio by strongly increasing the size of their first clutch. The plastic response is predicted by a model that assumes that females use the current competitive situation to predict future difficulties of securing a mating. Because female clutch size decisions are much more closely linked to population dynamics than male life-history traits, plastic responses to mate-finding limitations may be an underappreciated force in population dynamics.

1988 ◽  
Vol 66 (8) ◽  
pp. 1906-1912 ◽  
Author(s):  
Todd W. Arnold

Recently, Zammuto (R. M. Zammuto. 1986. Can. J. Zool. 64: 2739–2749) suggested that North American game birds exhibited survival–fecundity trade-offs consistent with the "cost of reproduction" hypothesis. However, there were four serious problems with the data and the analyses that Zammuto used: (i) the species chosen for analysis ("game birds") showed little taxonomic or ecological uniformity, (ii) the measures of future reproductive value (maximum longevity) were severely biased by unequal sample sizes of band recoveries, (iii) the measures of current reproductive effort (clutch sizes) were inappropriate given that most of the birds analyzed produce self-feeding precocial offspring, and (iv) the statistical units used in the majority of analyses (species) were not statistically independent with respect to higher level taxonomy. After correcting these problems, I found little evidence of survival–fecundity trade-offs among precocial game birds, and I attribute most of the explainable variation in life-history traits of these birds to allometry, phylogeny, and geography.


Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.


Ecology ◽  
2011 ◽  
Vol 92 (8) ◽  
pp. 1658-1671 ◽  
Author(s):  
David A. Miller ◽  
William R. Clark ◽  
Stevan J. Arnold ◽  
Anne M. Bronikowski

2012 ◽  
Vol 90 (6) ◽  
pp. 714-721 ◽  
Author(s):  
J.J. Bowden ◽  
C.M. Buddle

We studied populations of three tundra-dwelling wolf spider (Lycosidae) species to determine reproductive trait relationships and developmental timing in the Arctic. We collected 451 Pardosa lapponica (Thorell, 1872), 176 Pardosa sodalis Holm, 1970, and 117 Pardosa moesta Banks, 1892 during summer 2008. We used log-likelihood ratio tests and multiple linear regressions to determine the best predictors of fecundity and relative reproductive effort. Female body size best explained the variation in fecundity and body condition was the best predictor for relative reproductive effort. We tested for a trade-off between the allocation of resources to individual eggs and the number of eggs produced (fecundity) within each species using linear regression. There was variation in detectable egg size and number trade-offs among sites and these may be related to local variation in resource allocation linked to density-related biotic or abiotic factors. These findings contribute to knowledge about the fitness of arctic wolf spiders in the region of study and are particularly relevant in light of the effects that climate changes are predicted to have on the arctic fauna.


Behaviour ◽  
2011 ◽  
Vol 148 (2) ◽  
pp. 247-264 ◽  
Author(s):  
Masanori Kohda ◽  
Nobuhiro Ohnishi ◽  
Noboru Okuda ◽  
Tomohiro Takeyama ◽  
Omar Myint

AbstractFilial cannibalism, eating one's own viable offspring, is accepted as an adaptive response to trade-offs between current and future reproduction. Theoretical models predict that high mate availability may induce more filial cannibalism, but this prediction is rarely tested. To examine this prediction, we performed laboratory experiments using the nest breeding goby Rhinogobius flumineus. Subject males were allowed to mate with a gravid female and care for the broods. A separate gravid female housed in a small cage (stimulus-female) was shown to the subject males at one of three different points during the brood cycle: prior to spawning, within 1 day after spawning and 1 week after spawning. Empty cages were shown as a control. Males that were shown the stimulus-female before spawning cannibalised more eggs than control males. In contrast, males that were shown the stimulus-females after spawning cannibalised as few eggs as control males did. Additionally, males that were shown the stimulus-female prior to spawning did not court females more intensively than other males. Thus, we suggest that the presence of an additional mate, rather than energy expenditure associated with courtship directed toward an additional mate, can facilitate males to cannibalise their eggs.


Author(s):  
Jeffrey A. Hutchings

Life histories describe how genotypes schedule their reproductive effort throughout life in response to factors that affect their survival and fecundity. Life histories are solutions that selection has produced to solve the problem of how to persist in a given environment. These solutions differ tremendously within and among species. Some organisms mature within months of attaining life, others within decades; some produce few, large offspring as opposed to numerous, small offspring; some reproduce many times throughout their lives while others die after reproducing just once. The exponential pace of life-history research provides an opportune time to engage and re-engage new generations of students and researchers on the fundamentals and applications of life-history theory. Chapters 1 through 4 describe the fundamentals of life-history theory. Chapters 5 through 8 focus on the evolution of life-history traits. Chapters 9 and 10 summarize how life-history theory and prediction has been applied within the contexts of conservation and sustainable exploitation. This primer offers an effective means of rendering the topic accessible to readers from a broad range of academic experience and research expertise.


1985 ◽  
Vol 55 (2) ◽  
pp. 141-166 ◽  
Author(s):  
T. P. Hughes ◽  
J. B. C. Jackson

2007 ◽  
Vol 362 (1488) ◽  
pp. 2187-2189 ◽  
Author(s):  
Alex D Rogers ◽  
Eugene J Murphy ◽  
Nadine M Johnston ◽  
Andrew Clarke

The Antarctic biota has evolved over the last 100 million years in increasingly isolated and cold conditions. As a result, Antarctic species, from micro-organisms to vertebrates, have adapted to life at extremely low temperatures, including changes in the genome, physiology and ecological traits such as life history. Coupled with cycles of glaciation that have promoted speciation in the Antarctic, this has led to a unique biota in terms of biogeography, patterns of species distribution and endemism. Specialization in the Antarctic biota has led to trade-offs in many ecologically important functions and Antarctic species may have a limited capacity to adapt to present climate change. These include the direct effects of changes in environmental parameters and indirect effects of increased competition and predation resulting from altered life histories of Antarctic species and the impacts of invasive species. Ultimately, climate change may alter the responses of Antarctic ecosystems to harvesting from humans. The unique adaptations of Antarctic species mean that they provide unique models of molecular evolution in natural populations. The simplicity of Antarctic communities, especially from terrestrial systems, makes them ideal to investigate the ecological implications of climate change, which are difficult to identify in more complex systems.


2010 ◽  
Vol 23 (4) ◽  
pp. 829-839 ◽  
Author(s):  
S. N. GERSHMAN ◽  
C. A. BARNETT ◽  
A. M. PETTINGER ◽  
C. B. WEDDLE ◽  
J. HUNT ◽  
...  

2018 ◽  
Vol 89 (1) ◽  
pp. e01329 ◽  
Author(s):  
William L. Kendall ◽  
Seth Stapleton ◽  
Gary C. White ◽  
James I. Richardson ◽  
Kristen N. Pearson ◽  
...  

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