The evolution of phally polymorphism in Bulinus truncatus (Gastropoda, Planorbidae): the cost of male function analysed through life-history traits and sex allocation

Oecologia ◽  
1996 ◽  
Vol 106 (4) ◽  
pp. 464-469 ◽  
Author(s):  
Claudie Doums ◽  
Philippe Jarne
2006 ◽  
Vol 27 (3) ◽  
pp. 365-375 ◽  
Author(s):  
Delfi Sanuy ◽  
Christoph Leskovar ◽  
Neus Oromi ◽  
Ulrich Sinsch

AbstractDemographic life history traits were investigated in three Bufo calamita populations in Germany (Rhineland-Palatinate: Urmitz, 50°N; 1998-2000) and Spain (Catalonia: Balaguer, Mas de Melons, 41°N; 2004). We used skeletochronology to estimate the age as number of lines of arrested growth in breeding adults collected during the spring breeding period (all localities) and during the summer breeding period (only Urmitz). A data set including the variables sex, age and size of 185 males and of 87 females was analyzed with respect to seven life history traits (age and size at maturity of the youngest first breeders, age variation in first breeders, longevity, potential reproductive lifespan, median lifespan, age-size relationship). Spring and summer cohorts at the German locality differed with respect to longevity and potential reproductive lifespan by one year in favour of the early breeders. The potential consequences on fitness and stability of cohorts are discussed. Latitudinal variation of life history traits was mainly limited to female natterjacks in which along a south-north gradient longevity and potential reproductive lifespan increased while size decreased. These results and a review of published information on natterjack demography suggest that lifetime number of offspring seem to be optimized by locally different trade-offs: large female size at the cost of longevity in southern populations and increased longevity at the cost of size in northern ones.


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.


2016 ◽  
Vol 3 (10) ◽  
pp. 160202 ◽  
Author(s):  
Pablo Brosset ◽  
Josep Lloret ◽  
Marta Muñoz ◽  
Christian Fauvel ◽  
Elisabeth Van Beveren ◽  
...  

Limited resources in the environment prevent individuals from simultaneously maximizing all life-history traits, resulting in trade-offs. In particular, the cost of reproduction is well known to negatively affect energy investment in growth and maintenance. Here, we investigated these trade-offs during contrasting periods of high versus low fish size and body condition (before/after 2008) in the Gulf of Lions. Female reproductive allocation and performance in anchovy ( Engraulis encrasicolus ) and sardine ( Sardina pilchardus ) were examined based on morphometric historical data from the 1970s and from 2003 to 2015. Additionally, potential maternal effects on egg quantity and quality were examined in 2014/2015. After 2008, the gonadosomatic index increased for sardine and remained steady for anchovy, while a strong decline in mean length at first maturity indicated earlier maturation for both species. Regarding maternal effects, for both species egg quantity was positively linked to fish size but not to fish lipid reserves, while the egg quality was positively related to lipid reserves. Atresia prevalence and intensity were rather low regardless of fish condition and size. Finally, estimations of total annual numbers of eggs spawned indicated a sharp decrease for sardine since 2008 but a slight increase for anchovy during the last 5 years. This study revealed a biased allocation towards reproduction in small pelagic fish when confronted with a really low body condition. This highlights that fish can maintain high reproductive investment potentially at the cost of other traits which might explain the present disappearance of old and large individuals in the Gulf of Lions.


2012 ◽  
Vol 90 (9) ◽  
pp. 1072-1085 ◽  
Author(s):  
Marco Festa-Bianchet

Life-history trade-offs are well known in female mammals, but have seldom been quantified for males in polygynous species. I compared age-specific mass, weapon size, survival, and reproductive success of males in eight species of ungulates, and found weak interspecific correlations among life-history traits. Young males tended to have higher reproductive success in rapidly-growing than in slow-growing species, and in species where horns or antlers reached near-asymptotic size over the first few years of life. There was no clear interspecific trade-off between early reproduction and early survival. Reproductive senescence was evident in most species. Generation length, calculated as the mean age of fathers, was negatively correlated with the reproductive success of young males and positively with life expectancy of 3-year-olds, but not with early mortality. The main determinant of male reproductive success in polygynous ungulates is the ability to prevail against competing males. Consequently, the number and age structure of competitors should strongly affect an individual’s ability to reproduce, making classic trade-offs among life-history traits very context-dependent. Most fitness costs of reproduction in male ungulates likely arise from energy expenditure and injuries sustained while attempting to mate. Individual costs may be weakly correlated with fitness returns.


2008 ◽  
Vol 4 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Alexandra L Basolo

Understanding life-history evolution requires knowledge about genetic interactions, physiological mechanisms and the nature of selection. For platyfish, Xiphophorus maculatus , extensive information is available about genetic and physiological mechanisms influencing life-history traits. In particular, alleles at the pituitary locus have large and antagonistic effects on age and size at sexual maturation. To examine how predation affects the evolution of these antagonistic traits, I examined pituitary allele evolution in experimental populations differing in predation risk. A smaller size, earlier maturation allele increased in frequency when predators were absent, while a larger size, later maturation allele increased in frequency when predators were present. Thus, predation favours alleles for larger size, at the cost of later maturation and reproduction. These findings are interesting for several reasons. First, predation is often predicted to favour early reproduction at smaller sizes. Second, few studies have shown how selection acts on alleles that affect age and size at sexual maturation. Finally, many studies assume that trade-offs between these life-history traits result from antagonistic pleiotropy, with alleles that positively affect one trait negatively affecting another, yet this is rarely known. This study unequivocally demonstrates that genetically based trade-offs affect life-history evolution in platyfish.


2007 ◽  
Vol 57 (2) ◽  
pp. 137-195 ◽  
Author(s):  
Thierry Backeljau ◽  
Kurt Jordaens ◽  
Lobke Dillen

AbstractThere are approximately 20 000 pulmonate gastropod species that are all hermaphroditic and (with a few exceptions) can act in both (i.e., male and female) sexual roles. Life history traits such as growth (rate), age at first reproduction, fecundity, fertility, future survival and offspring survival are highly variable within pulmonate species, even among individuals of the same population. Here, we review some aspects of reproduction (availability of partners, size-dependent sex allocation, courtship, (multiple) mating, sperm longevity/viability, social facilitation), breeding system (self-fertilisation, outcrossing or mixed) and parasitism that may influence an individual's reproductive success and therefore account for part of the intraspecific variation in life history traits. A literature study showed that fecundity, fertility and/or growth are significantly affected by: i) the mating group size through changes in interference competition (e.g., crowding), breeding system and sex allocation; ii) individual body size with larger individuals producing more eggs than smaller individuals; iii) mating whereby female fitness may be positively or negatively affected; iv) social facilitation whereby female fitness is positively affected by the presence of conspecifics; v) the breeding system including the phenomena of inbreeding and outbreeding depression; and vi) parasites that may suppress or stimulate reproduction, especially egg-laying, in parasitised individuals. Moreover, multiple mating and multiple paternity seem very common in pulmonates. Interestingly, several of the above-mentioned aspects seem to interact or even act synergetically. Although many aspects of life history variation in pulmonate gastropods are still poorly understood which makes it difficult to draw general conclusions, pulmonates offer ample opportunities to study the evolution of major topics in evolution and life history strategies. Indeed, there is a growing number of basommatophoran and stylommatophoran model species, experimental setups and molecular, histological and histochemical techniques that are used to test current hypothesis on sex allocation, sexual selection (sexual conflict, sperm competition or cryptic female choice), the evolution of breeding systems and host-parasite interactions which will yield much information for the study of life history strategies as well.


2020 ◽  
Vol 650 ◽  
pp. 7-18 ◽  
Author(s):  
HW Fennie ◽  
S Sponaugle ◽  
EA Daly ◽  
RD Brodeur

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.


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