Adult Parasitoids of Honeydew-Producing Insects Prefer Honeydew Sugars to Cover their Energetic Needs.
To meet their carbohydrate requirements, adult parasitoids exploit a broad range of sugar resources, including floral and extrafloral nectar and honeydew. Although honeydew might be the predominant sugar source, especially in agricultural systems, it often is nutritionally inferior to sugar sources like nectar. Given its broad availability, it may be expected that sugar-feeding insects have evolved specialized adaptations to deal with this typically inferior sugar source. This would apply especially to organisms that have a close association with honeydew producers. Here, we hypothesized that parasitoids of honeydew-producing insects should show a pronounced response to sugars, such as fructose, sucrose, melezitose, and trehalose, and to a lesser extent glucose. To test this hypothesis, we investigated sugar consumption, feeding behavior and survival of the aphid parasitoid Aphidius ervi on several sugars (equiweight solutions). Our results show that A. ervi adults consumed typical honeydew sugars (sucrose, fructose, trehalose, and melezitose) the most, while consuming considerably less glucose or melibiose. Rhamnose, which does not occur in aphid honeydew, was not, or was only marginally, consumed. When different sugars were provided at the same time, A. ervi adults preferred sucrose or fructose over glucose or melezitose. Furthermore, pre-exposure to sucrose or fructose significantly reduced subsequent intake of glucose, suggesting an acquired distaste for glucose after being previously exposed to highly preferred sugars such as sucrose and fructose. Altogether, this study shows that A. ervi adults prefer sugars (fructose, melezitose, trehalose, and sucrose) that are overrepresented in aphid honeydew and show a lower preference to one (glucose) that is underrepresented in honeydew.
Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems, KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium.
Marijke
M
Lenaerts
Unité de Biochimie et Biologie Moléculaire, Faculté des Sciences de Tunis,, Université de Tunis El Manar, 2092, Tunis, Tunisia.
Lamis
L
Abid
Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems, KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium.
Caroline
C
Paulussen
Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems, KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium.
Tim
T
Goelen
Biobest, B-2560, Westerlo, Belgium.|Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
Felix
F
Wäckers
Division of Plant Ecology and Systematics, Biology Department, KU Leuven, B-3001, Heverlee, Belgium.
Hans
H
Jacquemyn
Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems, KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium. bart.lievens@kuleuven.be.
Bart
B
Lievens
D000818:Animals; D001042:Aphids / Q000469:parasitology* / Q000502:physiology; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000032:analysis; D004734:Energy Metabolism; D005247:Feeding Behavior; D005260:Female; D008136:Longevity; D008297:Male; D014863:Wasps / Q000502:physiology*
D002241:Carbohydrates
Aphidius ervi; Honeydew; Sugar consumption; Sugar feeding; Survival