Mitteilungen der deutschen Gesellschaft für allgemeine und angewandte Entomologie (2001) 13, 433-436

Michael Henn, Reinhard Schopf, Frank Fleischmann and Wolfgang Oßwald (2001)
Einfluss von CO₂ und N auf die Nahrungsqualität der Buche (Fagus sylvatica) für den Schwammspinner (Lymantria dispar; Lymantriidae, Lepidoptera)
[Effect of CO₂- and N-mediated alteration of the nutritional quality of beech leaves on the performance of a herbivorous insect (Lymantria dispar; Lepidoptera, Lymantriidae)]
Mitteilungen der deutschen Gesellschaft für allgemeine und angewandte Entomologie 13, 433-436
Abstract: The study evaluated how plant phytochemical responses to enriched atmospheric CO₂ are effected by soil nitrogen availability and how these chemical changes, in turn, alter the performance of a folivorous insect. Beech (Fagus sylvatica) seedlings were grown from germination in ambient (AC) or elevated (EC) CO₂ (700 ppm) in combination with normal nitrogen (NN, 370 mg/m² applied as Hoagland standard solution once a month) or high (EN) nitrogen availability (= NN four fold enhanced). The effect of these growing conditions of the trees on the performance of the defoliator Lymantria dispar was studied two years after initiating the tree cultivation. Beech leaves exhibited significantly increased concentrations of proteins in AC-EN. Moreover starch as well as glucose and fructose were enriched in EC and EC-NN, respectively, whereas the amounts of total phenolics remained nearly unaffected. Larvae consumed significant higher amounts of foliage (RCR) on untreated beech trees (AC-NN) compared to those under EC-EN. The opposite was true for the food processing (ECI). Lowest efficacy to convert consumed food to body substance was observed under AC-NN and highest when the larvae were kept on seedlings grown under EC-NN. These opposite effects resulted in the fact that the growth rate (RGR) of the gypsy moth larvae remained unaffected. The results indicate that the gypsy moth larvae are able to change their ECI and RCR in order to obtain a specific growth rate. Beech seedlings grown under the mentioned CO₂/N treatments and inoculated with Phytophthora citricola were found to affect L.dispar performance. Larvae fed leaves of inoculated trees grown in EC-EN suffered high mortality and exhibited less weight gain.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: German)
Database assignments for author(s): Wolfgang Oßwald, Michael W. Henn

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Lymantria dispar	Beech (Fagus)