Reproductive capacity of the grey pine aphid and allocation response of Scots pine seedlings across temperature gradients: a test of hypotheses predicting outcomes of global warming

2004 ◽  
Vol 34 (1) ◽  
pp. 94-102 ◽  
Author(s):  
Jarmo K Holopainen ◽  
Pirjo Kainulainen
Keyword(s):  
Intrinsic Rate ◽  
Resin Acids ◽  
Reproductive Capacity ◽  
Population Increase ◽  
Total Phenolic ◽  
Nymphal Stage ◽  
Pine Seedlings ◽  
Test Of Hypotheses ◽  
Nitrogen Ratio ◽  
Phenolic Concentration

The effects of the expected increase in growing season temperature on the performance of the aphid Schizolachnus pineti (Fabricius) (Homoptera: Lachnidae) and on the nutritional quality of its host plant (Pinus sylvestris L.) were studied under a daytime temperature range of 20–28 °C, with nighttime temperature that was either fixed at 12 °C or 8 °C below the daytime temperature. Fecundity had a curvilinear response, with an optimum at 24 or 26 °C, which is 4 to 6 °C above the local mean daytime temperatures. Longevity of nymphal stage was negatively and linearly correlated (r2 = 0.967) with daytime temperature. Intrinsic rate of population increase (rm) and relative growth rate were significantly higher at 26 °C than at 20 °C. Fecundity and rm were negatively correlated with total phenolic concentration in needles. Temperature affected concentrations of some individual resin acids in needles and stems, while concentrations of monoterpenes, total phenolics, starch, and total nitrogen in needles were not affected by temperature. Seedlings grown at 24 °C achieved the greatest biomass. Results support the protein competition hypothesis, which predicts no changes in the concentration of plant phenolics with small temperature increases. However, at 26 °C the low starch/nitrogen ratio and low total phenolic concentration may partly explain increased fecundity of aphids.

scholarly journals LIFE AND FERTILITY TABLES OF Pineus boerneri ANNAND (HEMIPTERA: ADELGIDAE) ON Pinus spp. (PINACEAE)

FLORESTA ◽  
2016 ◽  
Vol 46 (2) ◽  
pp. 251
Author(s):  
Josiane Teresinha Cardoso ◽  
Sonia Maria Noemberg Lazzari
Keyword(s):  
Intrinsic Rate ◽  
Pinus Elliottii ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Reproductive Capacity ◽  
Nymphal Stage ◽  
Net Reproductive Rate ◽  
Rate Of Increase ◽  
Significant Difference ◽  
Pinus Spp

Biological parameters of Pineus boerneri were evaluated in laboratory using seedlings of Pinus taeda and Pinus elliottii. The nymphs were observed along their development. The total life cycle was not significantly different on P. taeda and P. elliottii, being, respectively, 69 and 65 days. The same trend was observed for mean fecundity, being about 40 eggs/female on P. taeda and 53 on P. elliottii. However, when daily mean fecundity was considered, the difference was significant, being 1.3 eggs/female/day on P. taeda and 1.8 on P. elliottii. The nymphal mortality was greater on P. taeda (50%) than on P. elliottii (28%). These results reflected on life expectancy which was higher on P. elliottii for the nymphal stage, but for the adult stage there was no significant difference between both host plants. The intrinsic rate of natural increase and the finite rate of increase were similar, indicating that P. boerneri shows the same reproductive capacity on both hosts, despite the net reproductive rate being much greater on P. elliottii (23.8 eggs/female) than on P. taeda (15.4). The highest nymphal survival and reproductive rates on P. elliottii indicate that this host plant is more suitable for the development of P. boerneri.

Plant Resistance in Some Modern Soybean Varieties May Favor Population Growth and Modify the Stylet Penetration of Bemisia tabaci (Hemiptera: Aleyrodidae)

2021 ◽  
Author(s):  
Mauricélia F Almeida ◽  
Clébson S Tavares ◽  
Euires O Araújo ◽  
Marcelo C Picanço ◽  
Eugênio E Oliveira ◽  
...  
Keyword(s):  
Population Growth ◽  
Bemisia Tabaci ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Genetically Engineered ◽  
Population Increase ◽  
Net Reproductive Rate ◽  
Bt Toxin ◽  
Demographic Performance

Abstract Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R0) 100% higher and intrinsic rate of population increase (rm) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties.

scholarly journals Effect of Addition of Fennel (Foeniculum vulgare L.) on the Quality of Protein Bread

2017 ◽  
Vol 71 (6) ◽  
pp. 509-514 ◽  
Author(s):  
Bouchra Sayed-Ahmad ◽  
Evita Straumīte ◽  
Mārtiņš Šabovics ◽  
Zanda Krūma ◽  
Othmane Merah ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Oil Extraction ◽  
Added Value ◽  
Total Phenolic ◽  
Bread Making ◽  
Foeniculum Vulgare ◽  
Phenolic Concentration

Abstract Fennel (Foeniculum vulgare L.) is an aromatic plant belonging to Apiaceae family widely cultivated elsewhere for its strongly flavoured leaves and seeds. Fennel seeds are of particular interest as a rich source of both vegetable and essential oils with high amounts of valuable components. However, residual cakes after oil extraction were typically considered as byproducts, in the present framework, the potential added value of these cakes was studied. The aim of this study was to investigate the effect of addition of fennel cake and seeds to protein bread quality. In the current research, a single-screw extruder, which is a solvent-free technique, was used for fennel seed oil extraction. For the protein bread making, fennel seed and cake flour in concentrations from 1 to 6% were used. Moisture, colour L*a*b*, hardness, total phenolic concentration, DPPH radical scavenging activity, and nutritional value of protein bread were determined. The addition of fennel cake and seeds had significant (p < 0.05) effect on bread crumb colour and hardness attribute, whereby the bread became darker and harder in texture than the control. Moreover, higher antioxidant activity and total phenolic concentration were observed for both protein breads enriched with fennel cake and seed flour. The overall results showed that addition of fennel cake and seed had beneficial effects on phenolic concentration, antioxidant activity and quality of protein bread. This result suggests also that added value of fennel seeds oil by-products could be increased by their utilisation in bread production.

scholarly journals Physico-Chemical Indices, Iso-alpha-Acid, Phenolic Contents and Antioxidant Activity of Commercial Beers

2013 ◽  
Vol 2 (4) ◽  
pp. 107 ◽  
Author(s):  
Antonietta Baiano ◽  
Carmela Terracone
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Content ◽  
Principal Component ◽  
Titratable Acidity ◽  
Great Variability ◽  
Total Phenolic ◽  
Gluten Free ◽  
Phenolic Contents ◽  
Physico Chemical ◽  
Phenolic Concentration

<p>The effects of brewing style on physicochemical indices, iso-a-acids and antioxidant contents of commercial beers were investigated. A great variability was highlighted for all the considered parameters (sugar and alcohol contents, density, pH, titratable acidity, iso-a-acids, phenolic content, antioxidant activity). The beers having the highest iso-a-acids contents were Guinness Special Export Stout (which also showed the highest phenolic content), Chimay Pères Trappistes Triple, and Greene King IPA whereas the lowest values were detected in Cuveè De Ranke, Heineken Premium Quality Lager, and Riedenburger Brauhaus gluten free. The latter also had the lowest phenolic concentration. The antioxidant activity values strictly correlated with the total phenolic content but not with the iso-?-acid amount. The Principal Component Analysis failed in distinguishing beers based on their declared type/styles. This was a predictable result since the beer styles don’t represent a compositional classification but they are rather used to indicate commercial types.</p>

Potential Rates of Increase of a Harbour Porpoise (Phocoena phocoena) Population Subjected to Incidental Mortality in Commercial Fisheries

1991 ◽  
Vol 48 (12) ◽  
pp. 2429-2435 ◽  
Author(s):  
Thomas H. Woodley ◽  
Andrew J. Read
Keyword(s):  
Gulf Of Maine ◽  
Intrinsic Rate ◽  
Frequency Equation ◽  
Harbour Porpoise ◽  
Population Increase ◽  
Intrinsic Rate Of Increase ◽  
Natural Mortality ◽  
Phocoena Phocoena ◽  
Rate Of Increase ◽  
Incidental Mortality

We estimated the potential intrinsic rate of increase (r) of the harbour porpoise (Phocoena phocoena) population in the Bay of Fundy and Gulf of Maine using empirical data on reproductive rates (mx) and several hypothetical survival (Ix) schedules. Schedules of Ix, to maximum ages of 12 and 15 yr, were calculated from two potential natural mortality (nx) schedules combined with several schedules of incidental mortality (hx) estimates. The most realistic results were obtained when nx of non-calves were calculated from Caugley's (1966. Ecology 47: 906–918) smoothed age-frequency equation for Himalayan thar (Hemitragus jemlahicus) and applied in conjunction with a range of calf natural mortality estimates, this model indicates that harbour porpoises have a limited capacity for population increase, and populations are unlikely to sustain even moderate levels of incidental mortality (4% of the population per year). Extending the maximum age used in the models from 12 to 15 yr does little to increase estimates of r for the harbour porpoise population, and hence their susceptibility to incidental mortality.

scholarly journals Comparison of Field Population Growths of Three Cereal Aphid Species on Winter Wheat

2011 ◽  
Vol 39 (No. 2) ◽  
pp. 61-64 ◽  
Author(s):  
V. Jarošík ◽  
A. Honěk ◽  
A. Tichopád
Keyword(s):  
Winter Wheat ◽  
Rhopalosiphum Padi ◽  
Intrinsic Rate ◽  
Aphid Species ◽  
Population Increase ◽  
Intrinsic Rate Of Increase ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Aphid Density ◽  
Rate Of Increase

Population growths of three aphid species colonising winter wheat stands, Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae, were analysed by regression method. The calculations were based on counts in 268 winter wheat plots at 3 or 7 day intervals over 10 (leaves) or 6 (ears) years. The population dynamics of a particular species differed widely between years. Density independent exponential growth of the population was most common, but its rate differed significantly between species, and for S. avenae also between populations on leaves and ears, on which the populations grew fastest. Field estimates of the intrinsic rate of increase derived from the exponential growths ranged between 0.010&ndash;0.026 in M. dirhodum, 0.0071&ndash;0.011 in R. padi, and between 0.00078&ndash;0.0061 and 0.0015&ndash;0.13 in S. avenae on leaves and ears, respectively. In the populations with the most vigorous population growth, S. avenae on ears and M. dirhodum on leaves, the rate of population increase significantly decreased with increasing aphid density. &nbsp;

scholarly journals Biology of Bemisia tuberculata Bondar (Aleyrodidae) and parasitism by Encarsia porteri (Mercet, 1928) (Hymenoptera, Aphelinidae) on cassava plants

2012 ◽  
Vol 72 (4) ◽  
pp. 903-907 ◽  
Author(s):  
NN. Andrade Filho ◽  
AR. Roel ◽  
AM. Penteado-Dias ◽  
RB. Costa
Keyword(s):  
Adult Stage ◽  
Egg Laying ◽  
Reproductive Capacity ◽  
Experimental Unit ◽  
Nymphal Stage ◽  
Mato Grosso ◽  
Cassava Leaves ◽  
Stage Of Development ◽  
Average Size ◽  
Mato Grosso Do Sul

The whitefly Bemisia tuberculata has caused serious damage to cassava producing areas in the state of Mato Grosso do Sul. However, little is known about the biological characteristics of this species. The objective of this study was therefore, to monitor the development of this species bred on cassava plants under controlled greenhouse conditions, and to determine its most vulnerable stages and its reproductive capacity, as well as measuring the length and width each stage of development. To obtain these data, adult individuals were kept in voile traps on cassava leaves of five different plants, totalling ten leaves. After 24 hours the leaves were removed from the traps thus making each egg-laden leaf an experimental unit. The lowest mortality rate was record in the last nymphal stage ('pupae) compared with the other development stages. The highest mortality occurred in the nymphs at the 2nd and 3rd instars. Each female laid an average of 6.3 eggs in 24 hours. Thirteen days after egg laying, every one of the nymphs was fixed on the leaves of cassava plants. From the egg laying stage up until the adult stage, the process took 26 days. The proportion of females was 73.5%. The average size of the B. tuberculata egg was 163.22 µm in length and 72.39 µm in width and the "pupae" is 915.82 µm in length and 628.71 µm in width. The measurements of males were 797.16 µm in length and 200.81 µm in width and the length females 916.12 µm in length and 338.99 µm in width. The parasitoid Encarsia porteri (Mercet, 1928) (Hymenoptera, Aphelinidae) was found in the insect stock culture.

scholarly journals Maximum intrinsic rate of population increase in sharks, rays, and chimaeras: the importance of survival to maturity

2016 ◽  
Vol 73 (8) ◽  
pp. 1159-1163 ◽  
Author(s):  
Sebastián A. Pardo ◽  
Holly K. Kindsvater ◽  
John D. Reynolds ◽  
Nicholas K. Dulvy
Keyword(s):  
Life Span ◽  
Reproductive Output ◽  
Extinction Risk ◽  
Intrinsic Rate ◽  
Population Increase ◽  
Age At Maturity ◽  
Average Life ◽  
Demographic Parameter ◽  
Average Life Span

The maximum intrinsic rate of population increase (rmax) is a commonly estimated demographic parameter used in assessments of extinction risk. In teleosts, rmax can be calculated using an estimate of spawners per spawner, but for chondrichthyans, most studies have used annual reproductive output (b) instead. This is problematic as it effectively assumes all juveniles survive to maturity. Here, we propose an updated rmax equation that uses a simple mortality estimator that also accounts for survival to maturity: the reciprocal of average life-span. For 94 chondrichthyans, we now estimate that rmax values are on average 10% lower than previously published. Our updated rmax estimates are lower than previously published for species that mature later relative to maximum age and those with high annual fecundity. The most extreme discrepancies in rmax values occur in species with low age at maturity and low annual reproductive output. Our results indicate that chondrichthyans that mature relatively later in life, and to a lesser extent those that are highly fecund, are less resilient to fishing than previously thought.

Plausible bounds for maximum rate of increase in magpie geese (Anseranas semipalmata): implications for harvest

2005 ◽  
Vol 32 (5) ◽  
pp. 465 ◽  
Author(s):  
Barry W. Brook ◽  
Peter J. Whitehead
Keyword(s):  
Intrinsic Rate ◽  
Maximum Sustainable Yield ◽  
Management Policy ◽  
Population Increase ◽  
Sustainable Harvest ◽  
Precautionary Approach ◽  
Conservation Implications ◽  
Rate Of Increase ◽  
Prior Estimate ◽  
Over Exploitation

We used improved information on fecundity and credible estimates of survival to define the plausible bounds of maximum intrinsic rate of population increase (r m) in magpie geese and explored the management and conservation implications, given current estimates of off-take. We considered previous estimates of r m (0.78, based on time-series analysis of aerial count data) and the corresponding predicted maximum sustainable harvest rates (30–39% per annum) to be excessive, thereby risking poor management decisions. In contrast, our estimate of the maximum plausible range of r m (0.11–0.28) is substantially lower than the previous estimate, and suggests maximum harvest rates of no more than 5–14% of total population size per annum. We consider that it would be unwise to adopt the prior estimate of r m for management policy because it would risk over-exploitation. Our results embody a more precautionary approach to assessing maximum sustainable yield for magpie geese in northern Australia, and are not confounded by migration. The move from a simple empirical model to a partially mechanistic one reflects a significant improvement in understanding, but must nevertheless be viewed as part of an ongoing process of model refinement and testing.

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