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Keywords:

  • Hymenoptera;
  • parasitoid;
  • C. rubecula;
  • foraging behaviour;
  • specialist;
  • synomones;
  • infochemical use;
  • tritrophic interactions;
  • olfaction

Abstract

The role of volatile stimuli in the long-range host-searching behaviour of the specialist parasitoid Cotesia rubecula Marshall (Hymenoptera: Braconidae) was studied. Components from the plant-host-complex Brussels sprouts (Brassica oleracea L. var. gemmifera (DC.) Schulz. cv. ‘Titurel’)-Pieris rapae L. (Lepidoptera: Pieridae) were compared for their attractiveness in dual choice tests in a windtunnel. Stimuli from cabbage plants that were mechanically damaged or damaged by P. rapae caterpillars were more attractive to this parasitoid species than stimuli emitted by the host larvae or their faeces. Parasitoids preferred leaves from the plant-host-complex over artificially damaged leaves. Undamaged cabbage plants were the least attractive to the foraging females. These results indicate that in-flight searching behaviour of C. rubecula is guided by plant-derived information and that for this specialist species more reliable and specific host-derived cues play a minor role at longer distances.