scholarly journals Effect of NaCl-Stressed Bt Cotton on the Feeding Behaviors and Nutritional Parameters of Helicoverpa armigera

2018 ◽  
Author(s):  
Jun-Yu Luo ◽  
Shuai Zhang ◽  
Xiang-Zhen Zhu ◽  
Ji-Chao Ji ◽  
Kai-Xin Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Feeding Behavior ◽  
Relative Growth Rate ◽  
Nacl Stress ◽  
Bt Cotton ◽  
Insecticidal Proteins ◽  
Relative Growth ◽  
Cotton Variety ◽  
Nutritional Parameters ◽  
Helicoverpa Armígera

AbstractSaline-alkali soil is an arable land resource on which transgenic Bt cotton has been planted on a large scale in accordance with food security strategies, but there are concerns about the insecticidal effects of Bt cotton on target insect pests. In this study, a Bacillus thuringiensis (Bt) cotton variety, GK19, and its nontransgenic parent variety, Simian-3, were used as experimental materials to study the effect of the expression of exogenous insecticidal proteins in Bt cotton under NaCl stress on the feeding behavior and nutritional parameters of Helicoverpa armigera. The results showed that the expression of exogenous insecticidal proteins in GK19 was significantly inhibited under NaCl stress. However, on GK19 Bt cotton, the feeding, crawling, resting and spinning down of the 5th instar H. armigera larvae, as well as the food consumption and feces amount of these larvae, did not markedly differ under different NaCl concentrations. In contrast, the mean relative growth rate (MRGR), relative growth rate (RGR), approximate digestibility (AD), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) of the larvae decreased markedly in response to NaCl stress. Under the same concentration of NaCl, the nutritional parameters of the bollworm larvae on GK19 Bt cotton or Simian-3 nontransgenic cotton were different. However, the interaction between salt stress and cotton variety had no significant effect on the feeding behavior or nutritional parameters of H. armigera larvae. These results may provide a scientific basis for determining the effect of exogenous insecticidal protein expression in Bt cotton under NaCl stress on H. armigera and can therefore be useful for the effective application of Bt cotton in saline-alkali soils to prevent and control H. armigera.

scholarly journals Moving to Keep Fit: Feeding Behavior and Movement of Helicoverpa armigera (Lepidoptera: Noctuidae) on Artificial Diet With Different Protein: Carbohydrate Ratios

2019 ◽  
Vol 19 (5) ◽  
Author(s):  
Peng Wang ◽  
Michael J Furlong ◽  
Thomas K Walsh ◽  
Myron P Zalucki
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Helicoverpa Armigera ◽  
Artificial Diet ◽  
Pest Species ◽  
Relative Growth ◽  
First Instar ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Third Instar Larvae

Abstract Insect herbivores can modify their foraging behavior to obtain a balanced food intake, and they tend to move between food sources with different nutrient values. We investigated this movement in early instar larvae of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) using a putative optimal artificial diet (OP) and high protein (HP) and high carbohydrate (HC) artificial diets based on protein (p) and carbohydrate (c) ratios. Larvae were allowed to choose between the same kind of diet cubes (effectively no-choice), or diet cubes with different p: c ratios. In no-choice tests, we found that first instar larvae remained longest on OP diet and spent the least time on HC diet, while third instar larvae remained longest on HC diet and spent least time on OP diet. First instar larvae moved the most when provided with HC diet, while third instar larvae moved most when provided with OP diet. However, both stages moved the least when allowed to choose between diet cubes with different p: c ratios. The relative growth rate decreased when larvae increased their movement, but this influence was not evident when larvae fed on HC diet. Larvae that fed only on HC diet had the highest relative growth rate, followed by larvae with access to all diets simultaneously, indicating a behavior to mix nutrient intake. We relate these findings to behavior of this major pest species under field conditions.

scholarly journals Seed mass effects on germination and growth of diverse European Scots pine populations

1994 ◽  
Vol 24 (2) ◽  
pp. 306-320 ◽  
Author(s):  
P.B. Reich ◽  
J. Oleksyn ◽  
M.G. Tjoelker
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Scots Pine ◽  
Field Experiments ◽  
Seed Mass ◽  
Growing Season ◽  
Turkish Population ◽  
Dry Mass ◽  
Relative Growth ◽  
Mass Effects

Seedlings of 24 European Scots pine (Pinussylvestris L.) populations were grown in controlled environment chambers under simulated photoperiodic conditions of 50 and 60°N latitude to evaluate the effect of seed mass on germination and seedling growth characteristics. Seeds of each population were classified into 1-mg mass classes, and the four classes per population with the highest frequencies were used. Photoperiod had minimal influence on seed mass effects. Overall, seed mass was positively related to the number of cotyledons and hypocotyl height. Populations differed significantly in seed mass effect on biomass. In northern populations (55–61°N), dry mass at the end of the first growing season was little affected by seed mass. However, dry mass in 9 of 15 central populations (54–48°N) and all southern (<45°N) populations correlated positively with seed mass. Relative growth rate was not related to seed mass within or across populations, and thus early growth is largely determined by seed mass. Relative growth rate also did not differ among populations, except for a geographically isolated Turkish population with the highest seed mass and lowest relative growth rate. After one growing season, height was positively correlated (r2 > 0.6) with seed mass in 15 populations. To check the duration of seed mass effects, height growth of 1- to 7-year-old field experiments established with the same seed lots were compared. Seed mass effects on height were strongest for 1-year-old seedlings and declined or disappeared by the age of 5–7 years among central and southern populations, but remained stable over that time in northern populations.

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