Flower heliotropism of Anemone rivularis (Ranunculaceae) in the Himalayas: effects on floral temperature and reproductive fitness

2010 ◽  
pp. 121-132
Author(s):  
Shu Zhang ◽  
Hong-Lian Ai ◽  
Wen-Bin Yu ◽  
Hong Wang ◽  
De-Zhu Li
Keyword(s):  
Reproductive Fitness

Inbreeding reduces reproductive fitness

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Natural Selection ◽  
Inbreeding Depression ◽  
Reproductive Fitness ◽  
Heterozygote Advantage ◽  
Small Populations ◽  
Population Bottlenecks ◽  
Risk Of Extinction ◽  
Survival And Reproduction

The harmful impacts of inbreeding are generally greater in species that naturally outbreed compared to those in inbreeding species, greater in stressful than benign environments, greater for fitness than peripheral traits, and greater for total fitness compared to its individual components. Inbreeding reduces survival and reproduction (i.e., it causes inbreeding depression), and thereby increases the risk of extinction. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Natural selection may remove (purge) the alleles that cause inbreeding depression, especially following inbreeding or population bottlenecks, but it has limited effects in small populations and usually does not completely eliminate inbreeding depression. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have higher ploidies.

Cytogenetic Observations in Infertile Men Working with Insecticidal Compounds

1978 ◽  
Vol 27 ◽  
pp. 51-56 ◽  
Author(s):  
Fiorella Shabtai ◽  
Shlomo Bichacho ◽  
Isaac Halbrecht
Keyword(s):  
Y Chromosome ◽  
Male Fertility ◽  
Reproductive Fitness ◽  
Negative Influence ◽  
Chromosomal Breakage ◽  
Infertile Men ◽  
Chemically Induced ◽  
The Individual ◽  
Chromosomal Variants ◽  
Insecticidal Compounds

The negative influence of some insecticides on male fertility has been noted. We report our cytogenetic observations on a group of infertile insecticide workers. Increased chromosomal breakage was a constant finding and the Y chromosome was especially damaged. This may account for impaired spermatogenesis. Furthermore, the involvement of heterochromatic chromosomal variants both in the individual susceptibility to the chemically induced damage and in the reproductive fitness is emphasized.

Reproductive fitness and pathogenicity of selected Radopholus populations on two banana cultivars

1996 ◽  
Vol 45 (2) ◽  
pp. 1-9 ◽  
Author(s):  
M. L. HAHN ◽  
J.‐L. SARAH ◽  
M. BOISSEAU ◽  
N. J. VINES ◽  
D. J. WRIGHT ◽  
...  
Keyword(s):  
Reproductive Fitness

scholarly journals Genome size correlates with reproductive fitness in seed beetles

2015 ◽  
Vol 282 (1815) ◽  
pp. 20151421 ◽  
Author(s):  
Göran Arnqvist ◽  
Ahmed Sayadi ◽  
Elina Immonen ◽  
Cosima Hotzy ◽  
Daniel Rankin ◽  
...  
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Genome Size ◽  
Evolutionary Biology ◽  
Large Scale ◽  
Life History Traits ◽  
Single Species ◽  
Reproductive Fitness ◽  
Correlated Evolution ◽  
Seed Beetles

The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the ‘ C -value paradox’. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4–5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.

Epoxidation of juvenile hormone was a key innovation improving insect reproductive fitness

2021 ◽  
Vol 118 (45) ◽  
pp. e2109381118
Author(s):  
Marcela Nouzova ◽  
Marten J. Edwards ◽  
Veronika Michalkova ◽  
Cesar E. Ramirez ◽  
Marnie Ruiz ◽  
...  
Keyword(s):  
Life Cycle ◽  
Juvenile Hormone ◽  
Reproductive Performance ◽  
Reproductive Fitness ◽  
Fitness Cost ◽  
Evolutionary Significance ◽  
Methyl Farnesoate ◽  
Entire Life ◽  
Entire Life Cycle ◽  
Key Innovation

Methyl farnesoate (MF) plays hormonal regulatory roles in crustaceans. An epoxidated form of MF, known as juvenile hormone (JH), controls metamorphosis and stimulates reproduction in insects. To address the evolutionary significance of MF epoxidation, we generated mosquitoes completely lacking either of the two enzymes that catalyze the last steps of MF/JH biosynthesis and epoxidation, respectively: the JH acid methyltransferase (JHAMT) and the P450 epoxidase CYP15 (EPOX). jhamt−/− larvae lacking both MF and JH died at the onset of metamorphosis. Strikingly, epox−/− mutants, which synthesized MF but no JH, completed the entire life cycle. While epox−/− adults were fertile, the reproductive performance of both sexes was dramatically reduced. Our results suggest that although MF can substitute for the absence of JH in mosquitoes, it is with a significant fitness cost. We propose that MF can fulfill most roles of JH, but its epoxidation to JH was a key innovation providing insects with a reproductive advantage.

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