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Titre :
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Uptake, excretion and respiration of sucrose and amino acids by the pea aphid Acyrthosiphon pisum
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Auteurs :
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J. Rhodes ;
P. Croghan ;
A. Dixon
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Type de document :
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article/chapitre/communication
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Année de publication :
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1996
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Format :
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1269-1276
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Langues:
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= Anglais
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Mots-clés:
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Acyrthosiphon pisum
;
amino acids
;
aphid
;
excretion rate
;
feeding rate
;
respiration
;
sucrose
;
Alimentation artificielle
;
Acide amine
;
Excretion
;
Metabolisme
;
Saccharose
;
Marquage isotopique
;
Miellat
;
Aphididae
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Résumé :
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Ingestion, excretion and respiration in aphids were studied using artificial diets labelled with radioactive sucrose or amino acids. The rate of ingestion of a 25 % w/v sucrose diet was 12.4 nl mg(-1) h(-1) and the honeydew excretion rate was 5.3 nl mg(-1) h(-1), about 43 % of the volume ingested during the same period. The concentration of sugars in the honeydew was equivalent to 0.53 mol l(-1) sucrose and 69 % of the sucrose ingested was assimilated. The amino acid concentration of honeydew was 24.6 mmol l(-1) and 94 % of the ingested amino acids were assimilated. Respiration was measured by collecting respired (CO2)-C-14 using a chamber which allowed the aphids to feed during the experiments on C-14-labelled artificial diets. While feeding on a 25 % w/v sucrose diet, sucrose was respired at the rate of 1.32 x 10(-6) mmol mg(-1) h-l, equivalent to 0.354 mu l O-2 mg(-1) h(-1), which was 14.6 % of the rate of ingestion. There was no evidence that reducing the dietary sucrose concentration from 22 to 11 % w/v had any effect on the rate at which sucrose was respired. Amino acids were respired at a rate of 0.14 x 10(-6) mmol mg(-1) h(-1), which was 6.4 % of the rate of ingestion. Dietary sucrose was oxidised in preference to amino acids.
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Source :
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Journal of Experimental Biology - 0022-0949, vol. 199, n° 6
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