The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Jussi V K Kukkonen - One of the best experts on this subject based on the ideXlab platform.
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effect of sediment type feeding level and Larval density on growth and development of a midge chironomus riparius
Environmental Toxicology and Chemistry, 1999Co-Authors: Tiina Ristola, Jukka Pellinen, Minna Ruokolainen, Auli Kostamo, Jussi V K KukkonenAbstract:A 10-d growth test and an emergence test were performed with Chironomus riparius Meigen in four unpolluted lake sediments (organic carbon content 0.5–57%) using different feeding levels (Tetramin® at 0.03, 0.06, 0.12, or 0.33 mg/Larva/d in the growth test and 0, 0.15, or 0.30 mg/Larva/d in the emergence test) to study how sediment type and feeding level affect Larval growth. To examine effects of Larval density on growth, another growth test was performed using densities of one Larva per 24, 12, 4.8, or 2.4 cm2 and a feeding level of Tetramin at 0.12 mg/Larva/d. Regardless of sediment type, feeding was necessary in the experiments started with first-instar Larvae. The effects of sediment physicochemical characteristics on Larval growth and development could not be totally compensated for by food addition. When fed, Larvae grew best in sandy sediment with low organic carbon content (0.5%). Acceptable survival was achieved with a very low food dose (0.03 mg/Larva/d), but a somewhat higher dose (0.12 mg/Larva/d) is recommended. Increment of feeding accelerated Larval growth and development. Larval growth was correlated to the food dose per individual and to the density of food particles on the sediment surface.
James P Collins - One of the best experts on this subject based on the ideXlab platform.
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individual responses to population size structure the role of size variation in controlling expression of a trophic polyphenism
Oecologia, 1994Co-Authors: Timothy J Maret, James P CollinsAbstract:We investigated how size structure affects development of alternative Larval phenotypes in Arizona tiger salamanders, Ambystoma tigrinum nebulosum, by testing the hypothesis that population size structure per se is a significant component of an individual's environment. Larvae of this subspecies exhibit one of two feeding phenotypes; typical Larvae eat zooplankton and macroinvertebrates and cannibalistic Larvae feed primarily on conspecifics. Previous laboratory experiments showed that Larval density positively affected expression of the cannibalistic phenotype. In this study we tested the hypothesis that size variation among Larvae also serves as a cue triggering development of the cannibalistic phenotype. We report laboratory experiments and field observations showing that both an individual Larva's position in a size distribution and the amount of size vaiation among Larvae serve as cues stimulating development of cannibalistic Larvae. Larval density and population size structure provide a Larva with an indication of the abundance and vulnerability of potential conspecific prey. Size variation among Larvae, in turn, appears to be influenced by Larval density. Thus, a complex relationship exists between Larval density, population size structure, and the frequency of cannibals within a habitat.
Jean Francois Odoux - One of the best experts on this subject based on the ideXlab platform.
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toxicity of dimethoate and fenoxycarb to honey bee brood apis mellifera using a new in vitro standardized feeding method
Pest Management Science, 2007Co-Authors: Pierrick Aupinel, Franck Marolleau, Jean-noël Tasei, Bruno Michaud, Dominique Fortini, Jean Francois OdouxAbstract:A new in vitro method was devised to assess the effects of pesticides on honey bee brood. The method allowed the quantification of doses ingested by Larvae and the assessment of Larval and pupal mortality. Larval mortality in control samples was lower than 10%. Two active substances were tested: dimethoate and fenoxycarb. The LD 50 of dimethoate was 1.9μg Larva -1 48 h after oral exposure of Larvae at day 4. Additional dose-related effects on pupal mortality were noted. After a chronic intoxication, the NOAEC (No Observed Adverse Effect Concentration) for Larval mortality at day 7 was 2.5 mgkg -1 , whereas a NOAEC ofSmgkg -1 was found at day 22 for delayed effects on the reduction of adult emergence. Fenoxycarb applied at day 4 showed no effect on Larvae, whereas emergence of adults was affected at doses higher than 6 ng Larva -1 .
Tiina Ristola - One of the best experts on this subject based on the ideXlab platform.
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effect of sediment type feeding level and Larval density on growth and development of a midge chironomus riparius
Environmental Toxicology and Chemistry, 1999Co-Authors: Tiina Ristola, Jukka Pellinen, Minna Ruokolainen, Auli Kostamo, Jussi V K KukkonenAbstract:A 10-d growth test and an emergence test were performed with Chironomus riparius Meigen in four unpolluted lake sediments (organic carbon content 0.5–57%) using different feeding levels (Tetramin® at 0.03, 0.06, 0.12, or 0.33 mg/Larva/d in the growth test and 0, 0.15, or 0.30 mg/Larva/d in the emergence test) to study how sediment type and feeding level affect Larval growth. To examine effects of Larval density on growth, another growth test was performed using densities of one Larva per 24, 12, 4.8, or 2.4 cm2 and a feeding level of Tetramin at 0.12 mg/Larva/d. Regardless of sediment type, feeding was necessary in the experiments started with first-instar Larvae. The effects of sediment physicochemical characteristics on Larval growth and development could not be totally compensated for by food addition. When fed, Larvae grew best in sandy sediment with low organic carbon content (0.5%). Acceptable survival was achieved with a very low food dose (0.03 mg/Larva/d), but a somewhat higher dose (0.12 mg/Larva/d) is recommended. Increment of feeding accelerated Larval growth and development. Larval growth was correlated to the food dose per individual and to the density of food particles on the sediment surface.
Timothy J Maret - One of the best experts on this subject based on the ideXlab platform.
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individual responses to population size structure the role of size variation in controlling expression of a trophic polyphenism
Oecologia, 1994Co-Authors: Timothy J Maret, James P CollinsAbstract:We investigated how size structure affects development of alternative Larval phenotypes in Arizona tiger salamanders, Ambystoma tigrinum nebulosum, by testing the hypothesis that population size structure per se is a significant component of an individual's environment. Larvae of this subspecies exhibit one of two feeding phenotypes; typical Larvae eat zooplankton and macroinvertebrates and cannibalistic Larvae feed primarily on conspecifics. Previous laboratory experiments showed that Larval density positively affected expression of the cannibalistic phenotype. In this study we tested the hypothesis that size variation among Larvae also serves as a cue triggering development of the cannibalistic phenotype. We report laboratory experiments and field observations showing that both an individual Larva's position in a size distribution and the amount of size vaiation among Larvae serve as cues stimulating development of cannibalistic Larvae. Larval density and population size structure provide a Larva with an indication of the abundance and vulnerability of potential conspecific prey. Size variation among Larvae, in turn, appears to be influenced by Larval density. Thus, a complex relationship exists between Larval density, population size structure, and the frequency of cannibals within a habitat.
