Being a parasitoid of parasites: host finding in the tick wasp Ixodiphagus hookeri by odours from mammals |
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Authors: | Jana Collatz Andrea Fuhrmann Philipp Selzer Rainer M Oehme Kathrin Hartelt Peter Kimmig Torsten Meiners Ute Mackenstedt Johannes LM Steidle |
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Institution: | 1. Animal Ecology 220c, Institute of Zoology, University of Hohenheim, Stuttgart, Germany;2. State Health Office Baden‐Wuerttemberg, Stuttgart, Germany;3. Parasitology 220b, Institute for Zoology, University of Hohenheim, Stuttgart, Germany;4. Institute for Applied Zoology/Animal Ecology, Free University of Berlin, Berlin, Germany |
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Abstract: | The parasitic wasp Ixodiphagus hookeri Howard (Hymenoptera: Encyrtidae) parasitizes larvae and nymphs of a number of tick species worldwide. Ticks themselves are parasitic on vertebrate hosts. To study the specificity and reliability of vertebrate odours used by I. hookeri for host location, we conducted bioassays in a four‐chamber olfactometer. Wasps were arrested by carbon dioxide and by odours from roe deer faeces and odours from hair of roe deer and wild boar. Odours from faeces of cattle, rabbit, and field mouse as well as odours from hair of cattle and field mouse had no effect. Odours from faeces of the host tick species Ixodes ricinus L. (Acari: Ixodidae) were attractive only up to a distance of 1 cm. Thus, I. hookeri reacts to general (carbon dioxide) and specific vertebrate odours from wild boar and deer. Examination of freshly shot specimens demonstrates that deer and wild boars are infested with a sufficient number of tick nymphs to tap the full reproductive potential of an I. hookeri female, which makes cues from these mammal species reliable. These results indicate that I. hookeri locates its hosts using specific and reliable mammal odours and that ticks are parasitized on their vertebrate hosts. The implications of this host‐finding strategy and its benefits for the parasitoid are discussed. |
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Keywords: | Parasitic wasp Ixodes ricinus roe deer wild boar Hunterellus hookeri Hymenoptera Encyrtidae Acari Ixodidae |
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