Journal of Chemical Ecology (2010) 36, 1180-1188

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J. Gross, A. Eben, I. Müller and A. Wensing (2010)
A well protected intruder: The effective antimicrobial defence of the invasive Multicolored Ladybird "Harmonia axyridis".
Journal of Chemical Ecology 36, 1180-1188
Abstract: The harlequin ladybird Harmonia axyridis

(Coleoptera: Coccinellidae) is a polyphagous predatory beetle native to Central and Eastern Asia. Since 2007 it has established all over Central Europe. In order to elucidate which defense strategy is responsible for its high resistance to diseases, we tested hemolymph as well as eleven main components of the headspace of H. axyridis for antimicrobial activity against Gram-positive (Bacillus subtilis, B. thuringiensis ssp. tenebrionis, Micrococcus luteus) and Gram-negative bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae). While three of the volatile compounds weakly reduced the growth of microorganisms, hemolymph of adults and larvae of H. axyridis strongly inhibited the growth of Gram-positive and Gram-negative bacteria as well as yeast. Furthermore, we compared the antimicrobial activity in the hemolymph of H. axyridis and Coccinella septempunctata. Antimicrobial activity in H. axyridis was about a thousand times higher compared to hemolymph from C. septempunctata. In contrast to C. septempunctata, the antimicrobial activity in H. axyridis was present without prior challenge. Minimal inhibitory concentration (MIC) of the hemolymph of H. axyridis was lowest against E. coli and yeast followed by B. subtilis, and was highest against entomopathogenic B. thuringiensis ssp. tenebrionidae. Furthermore, MIC values of the hemolymph obtained from live beetles were significantly lower than from frozen insects. This suggests that the active antimicrobial compound is affected by freezing and subsequent thawing of the beetles. Potential implications of our findings for the competitive advantages of H. axyridis over C. septempunctata are discussed.
(The abstract has been supplied by the author or ISPI and is excluded from the Creative Commons licence.)

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Harmonia axyridis	fruit crops, grapes	Germany