The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Karen M. Clancy - One of the best experts on this subject based on the ideXlab platform.
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response of western spruce budworm lepidoptera tortricidae to increased nitrogen in Artificial Diets
Environmental Entomology, 1992Co-Authors: Karen M. ClancyAbstract:The western spruce budworm, Choristoneura occidentalis Freeman, was used to test the hypothesis that insect herbivore performance is dependent on dietary nitrogen in a positively linear or convex manner. Artificial Diets with seven levels of N were tested both with or without mineral supplements to determine if minerals had important effects on the budworm's response to N. A three-generation bioassay quantified survival rates for all life stages and pupal weights for insects reared on Diets with 1.2–7.6% N dry mass. Data were used to estimate population growth over three generations by determining the number of F1 F2, and F3 offspring produced (i.e., fitness). The budworm's response to increased dietary N was neither positively linear nor convex. Larvae reared on Diets with very high (3.9 and 7.6%) concentrations of N, compared with N levels in Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, foliage, had good survival and reproduction, whereas larvae on Diets with N levels near foliage quantities (1.2–3.0%) had very poor performance, with the exception that performance was good on the mineral-limited 1.2% N diet. The addition of minerals to the Diets had important effects on responses to N, implicating an interaction between N and minerals. Regression analysis of data on estimated population growth on the 14 Diets tested indicated that the ratio of Zn to N was the best predictor of budworm fitness, not the actual N content of the diet. The response to Zn/N ratios was concave, implying proportions ≤0.00085 or ≥0.00282 had positive effects on fitness, whereas ratios from 0.001 to 0.0025 had negative effects. It was hypothesized that host plant N determines the amount of food ingested, which in tum affects the amounts of other nutrients consumed. Thus, a proper balance of many different nutrients appears to be the most important factor in the nutritional ecology of insect herbivores.
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western spruce budworm response to different moisture levels in Artificial Diets
Forest Ecology and Management, 1991Co-Authors: Karen M. ClancyAbstract:Western spruce budworm (Choristoneura occidentalis Freeman) performance (survival, larval development time, and pupal biomass) was evaluated for three consecutive generations on Artificial Diets with four moisture levels: 72%, 76%, 84%, and 88% moisture, for three levels of nitrogen: 1.2%, 1.9%, and 3.9% N dry biomass. Budworm performance was generally negatively associated with food moisture content, rather than positively associated as reported by others. Furthermore, increased moisture in the Artificial Diets did not improve the efficiency with which the budworm could utilize the nitrogen in the Diets. Budworm survival, pupal biomass, and development time were best on Diets with low N and low water or high N and low water. Water appeared simply to be acting as a diluent in these experiments. For the western spruce budworm the importance of plant water and N as key nutrients for predicting herbivore performance may not be direct cause-and-effect but, rather, to be related to other factors that are linked to these characteristics in plant tissues. Water is not likely to be a critically limiting nutrient when budworm larvae feed on the new, current-year needles of their conifer hosts. The higher moisture levels tested, 84% and 88%, did not improve larval performance; thus, the budworm's enhanced growth on early-season, new foliage may not be directly associated with the higher moisture content of new, expanding needles, but is probably related to other factors linked to plant water content.
Thomas H. Carefoot - One of the best experts on this subject based on the ideXlab platform.
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Artificial Diets in sea urchin culture effects of dietary protein level and other additives on egg quality larval morphometrics and larval survival in the green sea urchin strongylocentrotus droebachiensis
Canadian Journal of Zoology, 1995Co-Authors: Marja De Jongwestman, B. E. March, Peiyuan Qian, Thomas H. CarefootAbstract:The effect of Artificial Diets on the size and energy content of eggs and morphometry, survival, and metamorphic success of larvae was investigated in the green sea urchin, Strongylocentrotus droebachiensis, from the standpoint of developing a good broodstock diet for culturists. Groups of sea urchins were fed eight Diets over a period of 9 months, then five of these dietary groups were selected for detailed larval-growth studies. The Artificial Diets differed in protein content and in various additives including mannitol, algin, cholesterol, and β-carotene; a diet of air-dried kelp was also included. Egg-energy content was highest on a high-protein diet with cholesterol and β-carotene additives, and the largest eggs so far recorded for the species (2.39 mm3 × 10−3) were produced on a high-protein diet with cholesterol additive. Larval survival to metamorphosis was >92% for all Diets save for kelp (<5%). Kelp-fed adults also produced poorly metamorphosing larvae (<2%), suggesting that air-drying causes ch...
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The effect of different nutrient formulations in Artificial Diets on gonad growth in the sea urchin Strongylocentrotus droebachiensis
Canadian Journal of Zoology, 1995Co-Authors: M. De Jong-westman, B. E. March, Thomas H. CarefootAbstract:Several Artificial Diets were tested for their ability to promote growth of gonads in the green sea urchin, Strongylocentrotus droebachiensis, over a 9-month period. Survival and test growth were also monitored, as were gonad lipid levels and water content (at the middle and end of the reproductive cycle only). The Artificial Diets differed in amount of protein and in the presence of various additives such as mannitol, algin, cholesterol, and β-carotene; a diet of air-dried kelp (Nereocystis luetkeana) was included for comparison. Survival was > 95% for all Diets save a low-protein one (82% survival). Test diameters showed no significant change over time or among dietary treatments. All high-protein formulations produced significantly higher gonad indices than low-protein ones. Addition of β-carotene to the high-protein formulation significantly increased gonad growth relative to all other Diets; this was especially noticeable in December, at the time of best market quality for the roe. Lipid levels were ...
Craig A Abel - One of the best experts on this subject based on the ideXlab platform.
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response of heliothis virescens lepidoptera noctuidae strains to bacillus thuringiensis cry1ac incorporated into different insect Artificial Diets
Journal of Economic Entomology, 2009Co-Authors: Carlos A Blanco, Fred Gould, Paulina Vegaaquino, Juan Luis Juratfuentes, Omaththage P Perera, Craig A AbelAbstract:ABSTRACT Susceptibility to the Cry1Ac toxin from Bacillus thuringiensis in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is usually measured by performing bioassays under laboratory conditions. Accurate comparison of Cry1Ac susceptibility among H. virescens samples conducted in different places is challenged by several important methodological aspects, especially if different insect Artificial Diets are used to perform bioassays. In this study, we compared Cry1Ac susceptibility of four different-origin H. virescens colonies when challenged with this toxin incorporated into four different insect Artificial Diets. Our data show that Cry1Ac susceptibility was lower in all the H. virescens colonies for one of the commercial Diets (Bio-Serv). Bio-Serv diet was one of the least significantly consumed Diets by larvae of the four different colonies, which indicates that insects encountered less Cry1Ac toxin due to lower consumption of diet. Larvae fed Bio-Serv diet also seemed to display slo...
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response of heliothis virescens lepidoptera noctuidae strains to bacillus thuringiensis cry1ac incorporated into different insect Artificial Diets
Journal of Economic Entomology, 2009Co-Authors: Carlos A Blanco, Fred Gould, Paulina Vegaaquino, Juan Luis Juratfuentes, Omaththage P Perera, Craig A AbelAbstract:Susceptibility to the Cry1Ac toxin from Bacillus thuringiensis in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is usually measured by performing bioassays under laboratory conditions. Accurate comparison of Cry1Ac susceptibility among H. virescens samples conducted in different places is challenged by several important methodological aspects, especially if different insect Artificial Diets are used to perform bioassays. In this study, we compared Cry1Ac susceptibility of four different-origin H. virescens colonies when challenged with this toxin incorporated into four different insect Artificial Diets. Our data show that Cry1Ac susceptibility was lower in all the H. virescens colonies for one of the commercial Diets (Bio-Serv). Bio-Serv diet was one of the least significantly consumed Diets by larvae of the four different colonies, which indicates that insects encountered less Cry1Ac toxin due to lower consumption of diet. Larvae fed Bio-Serv diet also seemed to display slower Cry1Ac toxin activation compared with larvae fed any of the other three Diets tested. In contrast, a wheat germ-soybean diet (ARS) was one of the most consumed Diets by the four H. virescens colonies. The increased consumption of ARS diet probably led to the high level of Cry1Ac susceptibility observed in all the H. virescens colonies. Our data highlight the importance of using common Diets and use a standard tobacco budworm colony when comparing Cry1Ac susceptibility between diverse H. virescens strains or across time.
B. E. March - One of the best experts on this subject based on the ideXlab platform.
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Artificial Diets in sea urchin culture effects of dietary protein level and other additives on egg quality larval morphometrics and larval survival in the green sea urchin strongylocentrotus droebachiensis
Canadian Journal of Zoology, 1995Co-Authors: Marja De Jongwestman, B. E. March, Peiyuan Qian, Thomas H. CarefootAbstract:The effect of Artificial Diets on the size and energy content of eggs and morphometry, survival, and metamorphic success of larvae was investigated in the green sea urchin, Strongylocentrotus droebachiensis, from the standpoint of developing a good broodstock diet for culturists. Groups of sea urchins were fed eight Diets over a period of 9 months, then five of these dietary groups were selected for detailed larval-growth studies. The Artificial Diets differed in protein content and in various additives including mannitol, algin, cholesterol, and β-carotene; a diet of air-dried kelp was also included. Egg-energy content was highest on a high-protein diet with cholesterol and β-carotene additives, and the largest eggs so far recorded for the species (2.39 mm3 × 10−3) were produced on a high-protein diet with cholesterol additive. Larval survival to metamorphosis was >92% for all Diets save for kelp (<5%). Kelp-fed adults also produced poorly metamorphosing larvae (<2%), suggesting that air-drying causes ch...
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The effect of different nutrient formulations in Artificial Diets on gonad growth in the sea urchin Strongylocentrotus droebachiensis
Canadian Journal of Zoology, 1995Co-Authors: M. De Jong-westman, B. E. March, Thomas H. CarefootAbstract:Several Artificial Diets were tested for their ability to promote growth of gonads in the green sea urchin, Strongylocentrotus droebachiensis, over a 9-month period. Survival and test growth were also monitored, as were gonad lipid levels and water content (at the middle and end of the reproductive cycle only). The Artificial Diets differed in amount of protein and in the presence of various additives such as mannitol, algin, cholesterol, and β-carotene; a diet of air-dried kelp (Nereocystis luetkeana) was included for comparison. Survival was > 95% for all Diets save a low-protein one (82% survival). Test diameters showed no significant change over time or among dietary treatments. All high-protein formulations produced significantly higher gonad indices than low-protein ones. Addition of β-carotene to the high-protein formulation significantly increased gonad growth relative to all other Diets; this was especially noticeable in December, at the time of best market quality for the roe. Lipid levels were ...
Carlos A Blanco - One of the best experts on this subject based on the ideXlab platform.
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response of heliothis virescens lepidoptera noctuidae strains to bacillus thuringiensis cry1ac incorporated into different insect Artificial Diets
Journal of Economic Entomology, 2009Co-Authors: Carlos A Blanco, Fred Gould, Paulina Vegaaquino, Juan Luis Juratfuentes, Omaththage P Perera, Craig A AbelAbstract:ABSTRACT Susceptibility to the Cry1Ac toxin from Bacillus thuringiensis in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is usually measured by performing bioassays under laboratory conditions. Accurate comparison of Cry1Ac susceptibility among H. virescens samples conducted in different places is challenged by several important methodological aspects, especially if different insect Artificial Diets are used to perform bioassays. In this study, we compared Cry1Ac susceptibility of four different-origin H. virescens colonies when challenged with this toxin incorporated into four different insect Artificial Diets. Our data show that Cry1Ac susceptibility was lower in all the H. virescens colonies for one of the commercial Diets (Bio-Serv). Bio-Serv diet was one of the least significantly consumed Diets by larvae of the four different colonies, which indicates that insects encountered less Cry1Ac toxin due to lower consumption of diet. Larvae fed Bio-Serv diet also seemed to display slo...
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response of heliothis virescens lepidoptera noctuidae strains to bacillus thuringiensis cry1ac incorporated into different insect Artificial Diets
Journal of Economic Entomology, 2009Co-Authors: Carlos A Blanco, Fred Gould, Paulina Vegaaquino, Juan Luis Juratfuentes, Omaththage P Perera, Craig A AbelAbstract:Susceptibility to the Cry1Ac toxin from Bacillus thuringiensis in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is usually measured by performing bioassays under laboratory conditions. Accurate comparison of Cry1Ac susceptibility among H. virescens samples conducted in different places is challenged by several important methodological aspects, especially if different insect Artificial Diets are used to perform bioassays. In this study, we compared Cry1Ac susceptibility of four different-origin H. virescens colonies when challenged with this toxin incorporated into four different insect Artificial Diets. Our data show that Cry1Ac susceptibility was lower in all the H. virescens colonies for one of the commercial Diets (Bio-Serv). Bio-Serv diet was one of the least significantly consumed Diets by larvae of the four different colonies, which indicates that insects encountered less Cry1Ac toxin due to lower consumption of diet. Larvae fed Bio-Serv diet also seemed to display slower Cry1Ac toxin activation compared with larvae fed any of the other three Diets tested. In contrast, a wheat germ-soybean diet (ARS) was one of the most consumed Diets by the four H. virescens colonies. The increased consumption of ARS diet probably led to the high level of Cry1Ac susceptibility observed in all the H. virescens colonies. Our data highlight the importance of using common Diets and use a standard tobacco budworm colony when comparing Cry1Ac susceptibility between diverse H. virescens strains or across time.
