Journal of Chemical Ecology

, Volume 20, Issue 11, pp 2901–2915

Interactions betweenAlloxysta brevis (Hymenoptera, Cynipoidea, Alloxystidae) and honeydew-collecting ants: How an aphid hyperparasitoid overcomes ant aggression by chemical defense


  • Wolfgang Völkl
    • Lehrstuhl für Tierökologie IUniversitÄt Bayreuth
  • Gerhard Hübner
    • Lehrstuhl für Tierökologie IUniversitÄt Bayreuth
  • Konrad Dettner
    • Lehrstuhl für Tierökologie IIUniversitÄt Bayreuth

DOI: 10.1007/BF02098397

Cite this article as:
Völkl, W., Hübner, G. & Dettner, K. J Chem Ecol (1994) 20: 2901. doi:10.1007/BF02098397


Foraging females of the aphid hyperparasitoidAlloxysta brevis were attacked by honeydew-collecting workers of the antLasius niger at the first encounter. However, ants abandoned their attacks quickly, and foragingA. brevis remained unmolested for a subsequent time interval of approximately 5 min, which is long enough for the hyperparasitoid to oviposit successfully. Furthermore, freshly killed intactA. brevis were disregarded by ants, while decapitated specimens were readily removed. We present evidence thatA. brevis females release a mandibular gland secretion, which contains 6-methyl-5-hepten-2-one, actinidin, and unidentified iridoids, in response to an ant attack. This secretion functions both as a measure of self-defense if the female is seized by an ant worker and as a repellent, which prevents ant attacks during subsequent encounters. This is the first evidence for chemical defense in a hymenopterous parasitoid. It enablesA. brevis females to hyperparasitize ant-attended aphids that constitute a major proportion of their hosts and significantly reduces mortality by ectohyperparasitoids.

Key words

HymenopteraAlloxystidaehyperparasitoidsantsFormicidaeinteractionsaggressionchemical defense6-methyl-5-hepten-2-oneactinidinbiological significance

Copyright information

© Plenum Publishing Corporation 1994