scholarly journals Reproductive effort and costs of reproduction do not explain female-biased sex ratios in the moss Pseudocalliergon trifarium (Amblystegiaceae)

2006 ◽  
Vol 93 (9) ◽  
pp. 1313-1319 ◽  
Author(s):  
I. Bisang ◽  
J. Ehrlen ◽  
L. Hedenas
Keyword(s):  
Reproductive Effort ◽  
Sex Ratios ◽  
Costs Of Reproduction

Reproductive effort and costs of reproduction in female European ground squirrels

Oecologia ◽  
1999 ◽  
Vol 121 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Susanne Huber ◽  
Eva Millesi ◽  
Manfred Walzl ◽  
John Dittami ◽  
Walter Arnold
Keyword(s):  
Reproductive Effort ◽  
Ground Squirrels ◽  
Costs Of Reproduction

Female and male costs of reproduction must be equal in dioecious Cape plant genus Leucadendron (Proteaceae)

2019 ◽  
Vol 67 (7) ◽  
pp. 517
Author(s):  
Jeremy J. Midgley ◽  
Adam G. West ◽  
Michael D. Cramer
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Output ◽  
Sex Ratios ◽  
Reproductive Allocation ◽  
Costs Of Reproduction ◽  
Male And Female

The Cape Leucadendron genus is dioecious, with extreme vegetative dimorphism displayed in some species – females having much larger leaves and fewer branches than males – whereas other species are monomorphic. Leucadendron is ecologically diverse, with some species with canopy stored seeds (serotiny) and others with soil stored seeds. These features mean that the Cape Leucadendron is an ideal genus to study the costs of reproduction for the different sexes in plants, and to determine whether vegetative dimorphism could be due to unequal costs. Here we use the unique aspects of the fire-prone Cape environment in which leucadendrons occur to show that the costs of sex must be equal between the sexes. Leucadendron populations are single aged because they only recruit after fires that kill all adults. Therefore, because the sexes have the same lifespans, they must have the same lifetime extent of vegetative versus reproductive allocation. Also, ecologically similar hermaphrodite Proteaceae co-exist with dioecious taxa. To co-occur, dioecious and hermaphrodite taxa must have the same mean post-fire fitness. This implies that dioecious females must have double the reproductive output that a co-occurring hermaphrodite has. This is only possible if the costs of reproduction are the same for the sexes and that the sexes use the same resources for reproduction. Finally, because males and female co-occur, they must be competitively equivalent to maintain natal sex ratios. These three factors suggest male and female allocate equivalently and therefore that vegetative sexual dimorphism is unlikely to be due to differences in allocation.

scholarly journals Determinants of biased sex ratios and inter-sex costs of reproduction in dioecious tropical forest trees

2007 ◽  
Vol 94 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Simon A. Queenborough ◽  
David F. R. P. Burslem ◽  
Nancy C. Garwood ◽  
Renato Valencia
Keyword(s):  
Tropical Forest ◽  
Sex Ratios ◽  
Forest Trees ◽  
Costs Of Reproduction

Older conservatives: reproduction in female Alpine chamois (Rupicapra rupicapra) is increasingly risk-averse with age

2016 ◽  
Vol 94 (5) ◽  
pp. 311-321 ◽  
Author(s):  
A. Morin ◽  
M. Rughetti ◽  
S. Rioux-Paquette ◽  
M. Festa-Bianchet
Keyword(s):  
Reproductive Success ◽  
Reproductive Effort ◽  
Risk Averse ◽  
Costs Of Reproduction ◽  
Rupicapra Rupicapra ◽  
Terminal Investment ◽  
Age Dependent ◽  
Alpine Chamois ◽  
Old Females ◽  
Investment Hypothesis

In long-lived mammals, costs of reproduction may vary with age. The terminal investment hypothesis predicts greater reproductive effort as females approach the end of their life expectancy. We monitored 97 individually marked female Alpine chamois (Rupicapra rupicapra (L., 1758)) between 2007 and 2013 to determine how age-specific reproduction affected body mass and subsequent reproductive success. We captured and weighed females between April and August and monitored reproductive success from April to October through mother–kid associations. Reproductive success was strongly age-dependent and peaked at 70% for prime-aged females (4–7 years). Reproductive senescence began at 8 years, earlier than reported by other studies of ungulates. There was no clear evidence of reproductive costs in any age class. Reproductive success was very heterogeneous for old females, suggesting variability in the onset of senescence. Old females were less likely to reproduce in poor years despite being heavier than prime-aged females, suggesting reproductive restraint in late life rather than terminal investment. Female mass remained stable from May to August with no effect of lactation. Our results suggest that chamois reproductive strategy becomes increasingly conservative with age, resulting in no detectable costs of reproduction.

scholarly journals Androgen Elevation Accelerates Reproductive Senescence in Three-Spined Stickleback

2021 ◽  
Vol 9 ◽  
Author(s):  
Mirre J. P. Simons ◽  
Marion Sebire ◽  
Simon Verhulst ◽  
Ton G. G. Groothuis
Keyword(s):  
Vitamin E ◽  
Reproductive Effort ◽  
Negative Relationship ◽  
Life History Evolution ◽  
Reproductive Capacity ◽  
Costs Of Reproduction ◽  
Iris Color ◽  
Future Reproduction ◽  
Reproductive Activities ◽  
Breeding Coloration

Costs of reproduction shape the life-history evolution of investment in current and future reproduction and thereby aging. Androgens have been proposed to regulate the physiology governing these investments. Furthermore, androgens are hypothesized to play a central role in carotenoid-dependent sexual signaling, regulating how much carotenoids are diverted to ornamentation and away from somatic maintenance, increasing oxidative stress, and accelerating aging. We investigated these relationships in male three-spined stickleback in which we elevated 11-ketotestosterone and supplied vitamin E, an antioxidant, in a 2 × 2 design. Androgen elevation shortened the time stickleback maintained reproductive activities. We suspect that this effect is caused by 11-ketotestosterone stimulating investment in current reproduction, but we detected no evidence for this in our measurements of reproductive effort: nest building, body composition, and breeding coloration. Carotenoid-dependent coloration was even slightly decreased by 11-ketotestosterone elevation and was left unaffected by vitamin E. Red coloration correlated with life expectancy and reproductive capacity in a quadratic manner, suggesting overinvestment of the individuals exhibiting the reddest bellies. In contrast, blue iris color showed a negative relationship with survival, suggesting physiological costs of producing this aspect of nuptial coloration. In conclusion, our results support the hypothesis that androgens regulate investment in current versus future reproduction, yet the precise mechanisms remain elusive. The quadratic relationships between sexual signal expression and aspects of quality have wider consequences for how we view sexual selection on ornamentation and its relationship with aging.

scholarly journals Equality between the sexes in plants for costs of reproduction; evidence from the dioecious Cape genus Leucadendron (Proteaceae)

2017 ◽  
Author(s):  
Jeremy J. Midgley ◽  
Adam G. West ◽  
Michael D. Cramer
Keyword(s):  
Life History ◽  
Fire Ecology ◽  
Sex Ratios ◽  
Costs Of Reproduction ◽  
Male And Female ◽  
Reproductive Synchrony ◽  
Male Function ◽  
Female Function ◽  
Mating Opportunities ◽  
Dimorphic Species

AbstractIt has been argued that sexual allocation is greater for female function than male function in plants in general and specifically for the large dioecious Cape genus Leucadendron. Here, we use new interpretations of published information to support the hypothesis of equality between sexes in this genus. The explanations are based on the fire ecology of the Cape that results in reproductive synchrony, reproductive doubling and competitive symmetry. Firstly, strict post-fire seedling establishment of the reseeder life-history in the Cape results in single-aged populations. Consequently, the reproductive and vegetative schedules of males must synchronously track that of females. This implies equal allocation to sex. Secondly, after fires, dioecious females have double the seedling to adult ratio of co-occurring hermaphrodites. This indicates that being liberated from male function allows females access to resources that double their fitness compared to hermaphrodites. Therefore, male and female costs of reproduction are equal in hermaphrodites. Thirdly, competitive symmetry must occur because males and female plants will frequently encounter each other as close near neighbours. Competitive asymmetry would both reduce mating opportunities and skew local sex ratios. The evidence to date is for 1:1 sex ratios in small plots and this indicates competitive symmetry and a lack of dimorphic niches. Finally, vegetatively dimorphic species must also allocate equally to sex, or else sexual asynchrony, lack of reproductive doubling or competitive asymmetry will occur.

Reproductive Effort Tactics: Balancing Pre- and Postbreeding Costs of Reproduction

Oikos ◽  
1995 ◽  
Vol 74 (1) ◽  
pp. 35 ◽  
Author(s):  
K. Ingemar Jönsson ◽  
Juha Tuomi ◽  
Johannes Järemo ◽  
K. Ingemar Jonsson ◽  
Johannes Jaremo
Keyword(s):  
Reproductive Effort ◽  
Costs Of Reproduction

scholarly journals Costs of reproduction in a long-lived bird: large clutch size is associated with low survival in the presence of a highly virulent disease

2009 ◽  
Vol 5 (2) ◽  
pp. 278-281 ◽  
Author(s):  
Sébastien Descamps ◽  
H. Grant Gilchrist ◽  
Joël Bêty ◽  
E. Isabel Buttler ◽  
Mark R Forbes
Keyword(s):  
Clutch Size ◽  
Reproductive Effort ◽  
The Arctic ◽  
Somateria Mollissima ◽  
Costs Of Reproduction ◽  
Fitness Costs ◽  
Lower Survival ◽  
Large Clutch ◽  
Avian Cholera ◽  
Highly Virulent

Fitness costs of reproduction are expected to be more pronounced when the environmental conditions deteriorate. We took advantage of a natural experiment to investigate the costs of reproduction among common eiders ( Somateria mollissima ) nesting at a site in the Arctic, where an avian cholera epizootic appeared at different magnitudes. We tested the predictions that larger reproductive effort (clutch size) is associated with lower survival or breeding probability the following year, and that this relationship was more pronounced under heightened exposure to the disease. Our results indicate that large clutch sizes were associated with lower survival of female eider ducks, but only when there was heightened exposure to avian cholera, as indexed by eider mortality on site. No cost was observed when cholera was absent or when lesser exposure was evident. This supports the hypothesis that fitness costs of high reproductive effort are higher under unfavourable conditions such as a disease epizootic, and further indicates that being a conservative breeder can increase survival probability, given the presence of a highly virulent disease.

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