Effects of soybean resistance on variability in life history traits of the higher trophic level parasitoidMeteorus pulchricornis(Hymenoptera: Braconidae)

2016 ◽  
Vol 107 (1) ◽  
pp. 1-8 ◽  
Author(s):  
X. Li ◽  
B. Li ◽  
G. Xing ◽  
L. Meng

AbstractTo extrapolate the influence of plant cultivars varying in resistance levels to hosts on parasitoid life history traits, we estimated variation in parasitoid developmental and reproductive performances as a function of resistance in soybean cultivars, which were randomly chosen from a line of resistant genotypes. Our study showed that the parasitoidMeteorus pulchricornisvaried widely in offspring survival and lifetime fecundity, but varied slightly in development time and adult body size, in response to the soybean cultivars that varied in resistance to the hostSpodoptera litura. Furthermore, the variability in survival and lifetime fecundity was different between attacking the 2nd and the 4th instar host larvae, varying more in survival but less in lifetime fecundity when attacking the 4th than 2nd instar larvae. Our study provides further evidence supporting that plant resistance to herbivorous hosts have variable effects on different life history traits of higher trophic level parasitoids.

2012 ◽  
Vol 8 (3) ◽  
pp. 362-364 ◽  
Author(s):  
Andrew T. Kahn ◽  
Julianne D. Livingston ◽  
Michael D. Jennions

A poor start in life owing to a restricted diet can have readily detectable detrimental consequences for many adult life-history traits. However, some costs such as smaller adult body size are potentially eliminated when individuals modify their development. For example, male mosquitofish ( Gambusia holbrooki ) that have reduced early food intake undergo compensatory growth and delay maturation so that they eventually mature at the same size as males that develop normally. But do subtle effects of a poor start persist? Specifically, does a male's developmental history affect his subsequent attractiveness to females? Females prefer to associate with larger males but, controlling for body length, we show that females spent less time in association with males that underwent compensatory growth than with males that developed normally.


Zoology ◽  
2016 ◽  
Vol 119 (3) ◽  
pp. 216-223 ◽  
Author(s):  
Neus Oromi ◽  
Eudald Pujol-Buxó ◽  
Olatz San Sebastián ◽  
Gustavo A. Llorente ◽  
Mohamed Aït Hammou ◽  
...  

1997 ◽  
Vol 75 (6) ◽  
pp. 954-958 ◽  
Author(s):  
Roger Fons ◽  
Françoise Poitevin ◽  
Josette Catalan ◽  
Henri Croset

Populations of the lesser white-toothed shrew, Crocidura suaveolens (Pallas, 1811), from Corsica show an increase in adult body size associated with a decrease in litter size. The average number of embryos in wild Corsican females is smaller (mean 2.6, n = 62) than in mainland females (mean 4.6, n = 173). A breeding experiment was run for 4 years, yielding three generations. Under standard breeding conditions, the differences between island and mainland populations were maintained and were significant (median litter size was 2 for Corsica and 5 for the mainland). These differences in life-history traits were therefore proved experimentally to be genetically determined. Hypotheses concerning the mechanisms responsible for these differences are discussed.


2017 ◽  
Vol 150 (1) ◽  
pp. 87-99
Author(s):  
Sohini Singha Roy ◽  
Gautam Aditya ◽  
Sujay Ghosh

AbstractAn assessment of the effects of competitive behaviour and sex on seven selected life history traits ofDrosophila melanogasterMeigen (Diptera: Drosophilidae) was made under precisely regulated larval density. Contrary to the conditions of crowding, as considered in many previous studies, the low scale of density enabled assessment of the life history traits at the individual level with higher precision and low variations. The 0-day-old first instars were reared with the relative density of 1,2, 3, and 4 individuals with optimal food until the adults emerged. The life history traits like age at pupation, age at eclosion, adult body weight, adult body length, wing length, and adult survival were used as response variables. Both the density and sex of the competitors were considered as predictors of the life history traits and a stronger effect was evident in the female sex than in males, which is statistically significant. Result also revealed the effect of competitive behaviour was more intense in case of same sex competitors than of opposite sex. In all instances, the life history traits exhibited a trend of decreasing function with the increasing larval rearing density, in compliance with the norms of density-dependent effects on development ofDrosophilaFallén and similar insects.


2017 ◽  
Author(s):  
Aleksandra V. Bezmenova ◽  
Georgii A. Bazykin ◽  
Alexey S. Kondrashov

AbstractNatural selection is possible only because all species produce more offspring than what is needed to maintain the population. Still, the lifetime number of offspring varies widely across species. One can expect natural selection to be stronger in high-fecundity species. We analyzed the prevalence of loss-of-function alleles in 32 metazoan species and have found that, in contrast to this expectation, the strength of negative selection does not correlate with lifetime fecundity, as well as with other life-history traits. Perhaps, higher random mortality in high-fecundity species negates the effect of increased opportunity for selection.


Author(s):  
Walter E. Meshaka ◽  
Thomas K. Pauley ◽  
Danielle F. Wright ◽  
Kelli-Marie Herrick

Museum specimens of five species of fossorial snakes collected in West Virginia during 1930–2000 were examined to determine monthly incidence of capture, adult body sizes, reproductive cycle, and clutch characteristics. Captures occurred over the shortest time in the year in the Eastern Earthsnake (Virginia valeriae valeriae) and Northern Red-bellied Snake (Storeria occipitomaculata occipitomaculata) and were longest in the Northern Brownsnake (S. dekayi dekayi). Male gonadal cycle conformed to the temperate pattern, whereas that of females tended towards a tropical pattern. Incidence of females nearing oviposition or parturition was highest during June–July for all species, and length of their reproductive seasons were generally in keeping with those of northerly populations of the respective species. Mean clutch sizes were largest in the Northern Brownsnake (mean = 20.5) and smallest in the single oviparous snake, the Eastern Wormsnake (mean = 2.8). Adult body sizes were similar to respective populations elsewhere within their ranges. The Mountain Earth Snake (V. pulchra) was the least represented species in this study. A meaningful degree of predictability existed in the life history traits examined in our study as they related to geographic trends of this Allegheny snake assemblage.


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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