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HPLC sugar analysis reveals the nutritional state and the feeding history of parasitoids

Steppuhn, A. and Wäckers, F.L. (2004) HPLC sugar analysis reveals the nutritional state and the feeding history of parasitoids. Functional Ecology, 18, 812-819. ISSN 0269-8463.

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Official URL: http://dx.doi.org/10.1111/j.0269-8463.2004.00920.x

Abstract

1. Adult parasitoids depend on sugar-rich foods such as nectar and honeydew to meet their energy requirements. Many laboratory studies have established fitness benefits of sugar feeding for parasitoids. 2. Nevertheless, we know little about the nutritional ecology of parasitoids in the field, chiefly because of the limited specificity of methods applicable for field studies. 3. Here we use high-performance liquid chromatography (HPLC) analysis to study the sugar profile of Cotesia glomerata L. and Microplitis mediator Haliday relative to feeding-treatment. We identify the overall sugar level and the ratio of glucose to fructose as two parameters that in combination unambiguously characterize an individual's nutritional state and feeding history. 4. Unfed parasitoids contained low total sugar levels and glucose levels that typically exceeded fructose levels more than five-fold. Parasitoids with constant access to sucrose had high overall sugar levels with a balanced glucosefructose ratio. 5. The marked shift of the glucosefructose ratio after feeding was still evident in C. glomerata individuals whose total sugar content had decreased to unfed levels after 3 days of starvation. This makes it possible to distinguish between unfed individuals and those that did feed several days ago. 6. In addition to revealing past feeding events, HPLC analysis also enables the identification and quantification of a wide spectrum of sugars present in each specimen. When food sources contain specific sugars this can provide additional information about the type of sugar source consumed. 7. HPLC analyses revealed that trehalose, considered to be the 'insect haemolymph sugar', is not present in the two species investigated here. 8. Overall, HPLC sugar analysis provides a powerful tool to investigate energy status, feeding history and nutritional physiology of field-collected parasitoids. [KEYWORDS: carbohydrate ; Cotesia glomerata ; fructose ; glucose ; haemolymph sugar ; honeydew ; Microplitis mediator ; nectar ; nutrient state ; signature sugar ; trehalose]

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:11583
Deposited On:23 Nov 2011 01:00
Last Modified:31 Mar 2014 10:43

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