scholarly journals Genetic variation and covariation of susceptibility to parasitoids in the aphid Myzus persicae : no evidence for trade-offs

2008 ◽  
Vol 275 (1638) ◽  
pp. 1089-1094 ◽  
Author(s):  
Simone von Burg ◽  
Julia Ferrari ◽  
Christine B Müller ◽  
Christoph Vorburger
Keyword(s):  
Genetic Variation ◽  
Myzus Persicae ◽  
Diaeretiella Rapae ◽  
Mortality Factor ◽  
General Mechanism ◽  
Clonal Variation ◽  
Heritable Variation ◽  
Trade Offs ◽  
Rate Of Increase ◽  
Strong Negative Selection

Parasitoids are an important mortality factor for insects. Susceptibility to parasitoids should thus be under strong negative selection. Nevertheless, ample genetic variation for susceptibility to parasitoids is commonly observed in natural populations, suggesting that trade-offs may constrain the evolution of reduced susceptibility. This can be studied by assessing genetic variation for susceptibility and its covariation with other components of fitness. In a set of 17 clones of the peach potato aphid, Myzus persicae , for which good estimates of heritable variation for life-history traits were available, we found significant clonal variation for susceptibility to two of their common parasitoids: Aphidius colemani and Diaeretiella rapae . One clone, the only one harbouring a facultative endosymbiotic bacterium, Regiella insecticola , was entirely resistant to both parasitoids. Susceptibilities to the two parasitoids exhibited a positive genetic correlation close to unity, implying a general mechanism of defence. However, the susceptibility to parasitoids was uncorrelated to the clones' fecundity or rate of increase, providing no evidence for costs of the ability to resist parasitoids.

scholarly journals Genetic variation and covariation of aphid life-history traits across unrelated host plants

2008 ◽  
Vol 98 (6) ◽  
pp. 543-553 ◽  
Author(s):  
C. Vorburger ◽  
N. Ramsauer
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Host Plants ◽  
Life History Theory ◽  
Life History Traits ◽  
Genetic Correlations ◽  
Covariance Structure ◽  
Clonal Variation ◽  
Common Lambsquarters ◽  
Trade Offs

AbstractA central paradigm of life-history theory is the existence of resource mediated trade-offs among different traits that contribute to fitness, yet observations inconsistent with this tenet are not uncommon. We previously found a clonal population of the aphid Myzus persicae to exhibit positive genetic correlations among major components of fitness, resulting in strong heritable fitness differences on a common host. This raises the question of how this genetic variation is maintained. One hypothesis states that variation for resource acquisition on different hosts may override variation for allocation, predicting strong fitness differences within hosts as a rule, but changes in fitness hierarchies across hosts due to trade-offs. Therefore, we carried out a life-table experiment with 17 clones of M. persicae, reared on three unrelated host plants: radish, common lambsquarters and black nightshade. We estimated the broad-sense heritabilities of six life-history traits on each host, the genetic correlations among traits within hosts, and the genetic correlations among traits on different hosts (cross-environment genetic correlations). The three plants represented radically different environments with strong effects on performance of M. persicae, yet we detected little evidence for trade-offs. Fitness components were positively correlated within hosts but also between the two more benign hosts (radish and lambsquarters), as well as between those and another host tested earlier. The comparison with the most stressful host, nightshade, was hampered by low survival. Survival on nightshade also exhibited genetic variation but was unrelated to fitness on other hosts. Acknowledging that the number of environments was necessarily limited in a quantitative genetic experiment, we suggest that the rather consistent fitness hierarchies across very different plants provided little evidence to support the idea that the clonal variation for life-history traits and their covariance structure are maintained by strong genotype×environment interactions with respect to hosts. Alternative explanations are discussed.

scholarly journals Parasitism rate of Myzus persicae (Sulzer) by Diaeretiella rapae (McIntosh) in the presence of an alternative, resistant host

2018 ◽  
Vol 62 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Samira Evangelista Ferreira ◽  
Marcus Vinicius Sampaio ◽  
Reinaldo Silva de Oliveira ◽  
Heraldo Luís de Vasconcelos
Keyword(s):  
Myzus Persicae ◽  
Diaeretiella Rapae ◽  
Parasitism Rate

scholarly journals Host-Plant Variations Affect the Biotic Potential, Survival, and Population Projection of Myzus persicae (Hemiptera: Aphididae)

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 375
Author(s):  
Muhammad Yasir Ali ◽  
Tayyaba Naseem ◽  
Muhammad Arshad ◽  
Ijaz Ashraf ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Myzus Persicae ◽  
Growth Parameters ◽  
Population Projection ◽  
Chili Pepper ◽  
Intrinsic Rate Of Increase ◽  
Economic Damage ◽  
Pepper Plant ◽  
Net Reproductive Rate ◽  
Rate Of Increase ◽  
Wide Range

The green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae), a polyphagous insect pest is a major threat to a wide range of crops worldwide. Aiming to evaluate the life history traits of M. persicae, feeding on different host plants, we used five vegetables: cabbage, Brassica oleracea (Brassicaceae); chinese cabbage, B. rapa (Brassicaceae); chili pepper, Capsicum annum (Solanaceae); crown daisy, Chrysanthemum coronarium (Asteraceae); and eggplant, Solanum melongena (Solanaceae). TWOSEX-MSchart software was used for the statistical analysis about the age-stage, two-sex life table theory. The highest fecundity (69.65 individuals) rate of M. persicae, intrinsic rate of increase (r = 0.425 d−1), finite rate of increase (λ = 1.531 d−1), net reproductive rate (R0 = 69.65 offspring), and shortest mean generation time (T = 9.964 d) were recorded on the chili pepper plant. Whereas, lower fitness occurred on cabbage. The findings attained from population growth parameters indicate that chili pepper is the most susceptible plant, while cabbage is resistant to aphids. Population projection results also supported this statement, as the final total population size on cabbage was significantly lower than other plants. The reported information would be useful for devising integrated pest management programs, particularly those involving M. persicae. This information also suggests the adaptability of M. persicae causing economic damage to these vegetable cultivars.

Variation during growth of twin cattle

1967 ◽  
Vol 9 (1) ◽  
pp. 35-60 ◽  
Author(s):  
C. S. Taylor ◽  
Jean Craig
Keyword(s):  
Genetic Variation ◽  
Body Part ◽  
Body Measurements ◽  
Body Parts ◽  
Genetic Variances ◽  
Average Value ◽  
Coefficients Of Variation ◽  
Rate Of Increase ◽  
Early Maturing ◽  
Degree Of Maturity

Phenotypic variances within pairs of monozygotic and dizygotic twin heifers and also genetic variances and heritabilities were calculated for 12 linear body measurements at a sequence of eight ages up to two years old. The 60 pairs of fraternal and 60 pairs of identical twins used were reared as part of a larger uniformity trial in which feeding was effectively ad libitum throughout.Size differences between members of DZ twin pairs were found to be approximately normally distributed with about the same variance for all breeds and crosses. The variance within DZ pairs increased strongly with age, with a marked increase between 9 and 12 months of age and with most body measurements showing a broadly similar trend. On a logarithmic scale DZ variances increased roughly linearly with degree of maturity and at about the same rate in each body measurement. Coefficients of variation within DZ pairs corrected for measuring error had an average value of 2%. They did not change greatly with age, and were roughly the same for most body measurements although width measurements tended to be more variable than average.Coefficients of variation within MZ pairs had a corresponding overall average of 1·4%; they declined rapidly with age from 2·0% to 1·1%, were roughly the same for all body measurements, but at early ages tended to be greater in late than in early maturing body parts. However, they showed no association with the earliness of maturing of a body part provided variation was measured at the same degree of maturity for each body part.Genetic variation increased rapidly with age in all body measurements. The rate of increase with age was greater for late than for early maturing parts. The rate of increase with degree of maturity, however, was about the same for all body measurements. Coefficients of genetic variation increased slowly with age; they had an average value of 1·6%.Estimates of heritability are given at a sequence of eight ages for each of 12 body measurements. They increased strongly with age from 0·14 on average at three months of age to 0·67 on average at two years of age. At any fixed age, early maturing body parts tended to have higher heritabilities than later maturing body parts. However, if heritability was measured at the same degree of maturity in each body part, early and late maturing parts had about equal heritabilities.The present results are compared with those obtained from twin cattle studies in New Zealand, Sweden and Wisconsin, U.S.A.Inferences from twins about genetic variances and heritabilities for unrelated animals are discussed.

scholarly journals Substrate-Specific Effects of Natural Genetic Variation on Proteasome Activity

2021 ◽  
Author(s):  
Mahlon Collins ◽  
Randi R. Avery ◽  
Frank W Albert
Keyword(s):  
Genetic Variation ◽  
Protein Degradation ◽  
Dynamic Control ◽  
Cellular Protein ◽  
Proteasome Activity ◽  
Heritable Variation ◽  
Natural Genetic Variation ◽  
Specific Effects ◽  
Regulatory Particle

The bulk of targeted cellular protein degradation is performed by the proteasome, a multi-subunit complex consisting of the 19S regulatory particle, which binds, unfolds, and translocates substrate proteins, and the 20S core particle, which degrades them. Protein homeostasis requires precise, dynamic control of proteasome activity. To what extent genetic variation creates differences in proteasome activity is almost entirely unknown. Using the ubiquitin-independent degrons of the ornithine decarboxylase and Rpn4 proteins, we developed reporters that provide high-throughput, quantitative measurements of proteasome activity in vivo in genetically diverse cell populations. We used these reporters to characterize the genetic basis of variation in proteasome activity in the yeast Saccharomyces cerevisiae. We found that proteasome activity is a complex, polygenic trait, shaped by variation throughout the genome. Genetic influences on proteasome activity were predominantly substrate-specific, suggesting that they primarily affect the function or activity of the 19S regulatory particle. Our results demonstrate that individual genetic differences create heritable variation in proteasome activity and suggest that genetic effects on proteasomal protein degradation may be an important source of variation in cellular and organismal traits.

scholarly journals Effects of cis-Jasmone Treatment of Brassicas on Interactions With Myzus persicae Aphids and Their Parasitoid Diaeretiella rapae

2021 ◽  
Vol 12 ◽  
Author(s):  
Jamin Ali ◽  
Anca D. Covaci ◽  
Joe M. Roberts ◽  
Islam S. Sobhy ◽  
William D. J. Kirk ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Myzus Persicae ◽  
Methyl Salicylate ◽  
Plant Defence ◽  
Diaeretiella Rapae ◽  
Methyl Isothiocyanate ◽  
Volatile Emission ◽  
Brassica Crops ◽  
Wide Range ◽  
Promising Treatment

There is a need to develop new ways of protecting plants against aphid attack. Here, we investigated the effect of a plant defence activator, cis-jasmone (CJ), in a range of cultivars of Brassica napus, Brassica rapa and Brassica oleracea. Plants were sprayed with cis-jasmone or blank formulation and then tested with peach potato aphids (Myzus persicae Sulzer) (Hemiptera: Aphididae) and their parasitoid Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae). CJ treated plants had significantly lower aphid settlement than control plants in a settlement bioassay. Conversely, in a foraging bioassay, D. rapae parasitoids spent a significantly longer time foraging on CJ treated plants. Our results reveal that CJ treatment makes plants less attractive to and less suitable for M. persicae but more attractive to D. rapae in a range of brassica cultivars. It is likely that these effects are due to changes in volatile emission indicating activation of defence and presence of conspecific competitors to aphids but presence of prey to parasitoids. Increases in volatile emission were found in CJ induced plants but varied with genotype. Among the synthetic volatile compounds that were induced in the headspace of CJ treated brassica cultivars, methyl isothiocyanate, methyl salicylate and cis-jasmone were most repellent to aphids. These results build on earlier studies in Arabidopsis and show that tritrophic interactions are influenced by CJ in a wide range of brassica germplasm. The implication is that CJ is a promising treatment that could be used in brassica crops as part of an integrated pest management system.

Life history trade-offs at a single locus maintain sexually selected genetic variation

Nature ◽  
2013 ◽  
Vol 502 (7469) ◽  
pp. 93-95 ◽  
Author(s):  
Susan E. Johnston ◽  
Jacob Gratten ◽  
Camillo Berenos ◽  
Jill G. Pilkington ◽  
Tim H. Clutton-Brock ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Single Locus ◽  
Trade Offs

scholarly journals Genetic Variation Explains Changes in Susceptibility in a Naïve Host Against an Invasive Forest Pathogen: The Case of Alder and the Phytophthora alni Complex

2020 ◽  
Vol 110 (2) ◽  
pp. 517-525 ◽  
Author(s):  
Miguel A. Redondo ◽  
Jan Stenlid ◽  
Jonàs Oliva
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Transmission Rate ◽  
Alternative Hypothesis ◽  
Simulated Data ◽  
Alnus Glutinosa ◽  
Heritable Variation ◽  
Narrow Sense Heritability ◽  
Black Alder

Predicting whether naïve tree populations have the potential to adapt to exotic pathogens is necessary owing to the increasing rate of invasions. Adaptation may occur as a result of natural selection when heritable variation in terms of susceptibility exists in the naïve population. We searched for signs of selection on black alder (Alnus glutinosa) stands growing on riverbanks invaded by two pathogens differing in aggressiveness, namely, Phytophthora uniformis (PU) and Phytophthora × alni (PA). We compared the survival and heritability measures from 72 families originating from six invaded and uninvaded (naïve) sites by performing in vitro inoculations. The results from the inoculations were used to assess the relative contribution of host genetic variation on natural selection. We found putative signs of natural selection on alder exerted by PU but not by PA. For PU, we found a higher survival in families originating from invaded sites compared with uninvaded sites. The narrow sense heritability of susceptibility to PU of uninvaded populations was significantly higher than to PA. Simulated data supported the role of heritable genetic variation on natural selection and discarded a high aggressiveness of PA decreasing the transmission rate as an alternative hypothesis for a slow natural selection. Our findings expand on previous attempts of using heritability as a predictor for the likelihood of natural adaptation of naïve tree populations to invasive pathogens. Measures of genetic variation can be useful for risk assessment purposes or when managing Phytophthora invasions.

scholarly journals The evolution of Daphnia pulex in a temporally varying environment

1998 ◽  
Vol 72 (1) ◽  
pp. 25-37 ◽  
Author(s):  
SAMUEL M. SCHEINER ◽  
LEV Yu YAMPOLSKY
Keyword(s):  
Genetic Variation ◽  
Temperature Change ◽  
Local Population ◽  
Daphnia Pulex ◽  
Selection Response ◽  
Clonal Variation ◽  
Offspring Size ◽  
Malthusian Parameter ◽  
Offspring Number ◽  
Variable Environments

We investigated three aspects of adaptation to variable environments in Daphnia pulex (Cladocera: Crustacea): (1) effects of temporal variation on the evolution of phenotypic plasticity ; (2) plasticity in sexual versus asexual lineages; (3) maintenance of genetic variation in variable environments. We performed a 72-day quasi-natural selection experiment comparing three patterns of variation: constant temperatures, varying but predictable temperature change, and unpredictable temperature change. All populations were begun with an identical array of 34 clones. During selection clonal variation declined in all populations and different patterns of environmental variation had little effect on amounts of genetic variation. Sexual and asexual lineages differed in size and growth rate, but did not differ in amounts of plasticity or in adaptation to variable environments. The primary target of selection was the Malthusian parameter (r) and life history traits of development time, offspring size and offspring number. The heritability of plasticity was generally lower than trait heritability. Because of this difference, the selection response on the mean of the traits overwhelmed the selection response on plasticity. Lower heritabilities of plasticity are very typical, suggesting that our results will be typical of responses to selection in nature. Our results suggest that selection will act mostly on trait means within environments and that plasticity will evolve often as a correlated trait. Because selection on plasticity is based on its across-deme, global fitness, this process will usually be slow. Comparative studies need to shift from closely related, local population differences to those of more distantly related populations or even different species.

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