title: Downregulation of the evolutionary capacitor Hsp90 is mediated by social cues.
abstract: The relationship between robustness and evolvability is a long-standing question in evolution. Heat shock protein 90 (HSP90), a molecular chaperone, has been identified as a potential capacitor for evolution, since it allows for the accumulation and release of cryptic genetic variation, and also for the regulation of novel genetic variation through transposon activity. However, to date, it is unknown whether Hsp90 expression is regulated upon demand (i.e. when the release of cryptic genetic variation is most needed). Here, we show that Hsp90 has reduced transcription under conditions where the mobilization of genetic variation could be advantageous. We designed a situation that indicates a stressful environment but avoids the direct effects of stress, by placing untreated (focal) red flour beetles, Tribolium castaneum, into groups together with wounded conspecifics, and found a consistent reduction in expression of two Hsp90 genes (Hsp83 and Hsp90) in focal beetles. We moreover observed a social transfer of immunity in this non-eusocial insect: there was increased activity of the phenoloxidase enzyme and downregulation of the immune regulator, imd. Our study poses the exciting question of whether evolvability might be regulated through the use of information derived from the social environment.
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, Münster 48149, Germany.
authors.forename: Robert
authors.identifier: http://orcid.org/0000-0002-9716-6650
authors.initials: R
authors.lastname: Peuß
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, Münster 48149, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Eggert
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, Münster 48149, Germany.
authors.forename: Sophie A O
authors.identifier: http://orcid.org/0000-0002-5561-9543
authors.initials: SA
authors.lastname: Armitage
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, Münster 48149, Germany joachim.kurtz@uni-muenster.de.
authors.forename: Joachim
authors.identifier: http://orcid.org/0000-0002-7258-459X
authors.initials: J
authors.lastname: Kurtz
mesh_terms: D000818:Animals; D003463:Cues; D015536:Down-Regulation; D005260:Female; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000378:metabolism; D012919:Social Behavior; D014231:Tribolium / Q000201:enzymology / Q000235:genetics / Q000502:physiology*
chemical_list: D018841:HSP90 Heat-Shock Proteins; D019476:Insect Proteins; D014442:Monophenol Monooxygenase
keywords: Hsp90; Tribolium castaneum; canalization; heat shock proteins; immune defence; stress