title: The parasitic wasp Cotesia congregata uses multiple mechanisms to control host (Manduca sexta) behaviour.
abstract: Some parasites alter the behaviour of their hosts. The larvae of the parasitic wasp Cotesia congregata develop within the body of the caterpillar Manduca sexta During the initial phase of wasp development, the host's behaviour remains unchanged. However, once the wasps begin to scrape their way out of the caterpillar, the caterpillar host stops feeding and moving spontaneously. We found that the caterpillar also temporarily lost sensation around the exit hole created by each emerging wasp. However, the caterpillars regained responsiveness to nociception in those areas within 1 day. The temporary reduction in skin sensitivity is probably important for wasp survival because it prevents the caterpillar from attacking the emerging wasp larvae with a defensive strike. We also found that expression of plasmatocyte spreading peptide (PSP) and spätzle genes increased in the fat body of the host during wasp emergence. This result supports the hypothesis that the exiting wasps induce a cytokine storm in their host. Injections of PSP suppressed feeding, suggesting that an augmented immune response may play a role in the suppression of host feeding. Injection of wasp larvae culture media into non-parasitized caterpillars reduced feeding, suggesting that substances secreted by the wasp larvae may help alter host behaviour.
authors.affiliation: Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2 sadamo@dal.ca.
authors.forename: Shelley A
authors.identifier: 0000-0002-5973-571X
authors.initials: SA
authors.lastname: Adamo
authors.affiliation: Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2.
authors.forename: Ilya
authors.initials: I
authors.lastname: Kovalko
authors.affiliation: Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2.
authors.forename: Kurtis F
authors.initials: KF
authors.lastname: Turnbull
authors.affiliation: Department of Biology, Acadia University, Wolfville, NS, Canada B4P 2R6.
authors.forename: Russell H
authors.initials: RH
authors.lastname: Easy
authors.affiliation: Department of Biological Sciences, SUNY Binghamton, Binghamton, NY 13902, USA.
authors.forename: Carol I
authors.initials: CI
authors.lastname: Miles
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins; D007814:Larva / Q000254:growth & development* / Q000378:metabolism*; D018402:Manduca / Q000502:physiology*; D059225:Nociception / Q000502:physiology; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D014863:Wasps / Q000502:physiology*
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; C108084:plasmatocyte-spreading peptide 1
keywords: Cytokine; Illness-induced anorexia; Immune gene expression; Numbness; Sickness behaviour