title: Chemical disguise of myrmecophilous cockroaches and its implications for understanding nestmate recognition mechanisms in leaf-cutting ants.
abstract: Cockroaches of the genus Attaphila regularly occur in leaf-cutting ant colonies. The ants farm a fungus that the cockroaches also appear to feed on. Cockroaches disperse between colonies horizontally (via foraging trails) and vertically (attached to queens on their mating flights). We analysed the chemical strategies used by the cockroaches to integrate into colonies of Atta colombica and Acromyrmex octospinosus. Analysing cockroaches from nests of two host species further allowed us to test the hypothesis that nestmate recognition is based on an asymmetric mechanism. Specifically, we test the U-present nestmate recognition model, which assumes that detection of undesirable cues (non-nestmate specific substances) leads to strong rejection of the cue-bearers, while absence of desirable cues (nestmate-specific substances) does not necessarily trigger aggression.
  
  
  
  We found that nests of Atta and Acromyrmex contained cockroaches of two different and not yet described Attaphila species. The cockroaches share the cuticular chemical substances of their specific host species and copy their host nest's colony-specific cuticular profile. Indeed, the cockroaches are accepted by nestmate but attacked by non-nestmate ant workers. Cockroaches from Acromyrmex colonies bear a lower concentration of cuticular substances and are less likely to be attacked by non-nestmate ants than cockroaches from Atta colonies.
  
  
  
  Nest-specific recognition of Attaphila cockroaches by host workers in combination with nest-specific cuticular chemical profiles suggest that the cockroaches mimic their host's recognition labels, either by synthesizing nest-specific substances or by substance transfer from ants. Our finding that the cockroach species with lower concentration of cuticular substances receives less aggression by both host species fully supports the U-present nestmate recognition model. Leaf-cutting ant nestmate recognition is thus asymmetric, responding more strongly to differences than to similarities.
authors: Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark. volker.nehring@biologie.uni-freiburg.de.|Department for Ecology and Evolution, Biology I, Freiburg University, Hauptstr. 1, 79104, Freiburg, Germany. volker.nehring@biologie.uni-freiburg.de.
authors: Volker
authors: 0000-0002-0494-1428
authors: V
authors: Nehring
authors: Centro di Servizi di Spettrometria di Massa (CISM), University of Florence, Florence, Italy.|Dipartimento di Biologia, University of Florence, Florence, Italy.
authors: Francesca R
authors: FR
authors: Dani
authors: Centro di Servizi di Spettrometria di Massa (CISM), University of Florence, Florence, Italy.|Dipartimento di Scienza del Suolo e Nutrizione della Pianta, University of Florence, Florence, Italy.
authors: Luca
authors: L
authors: Calamai
authors: Department for Ecology and Evolution, Biology I, Freiburg University, Hauptstr. 1, 79104, Freiburg, Germany.|Centro di Servizi di Spettrometria di Massa (CISM), University of Florence, Florence, Italy.
authors: Stefano
authors: S
authors: Turillazzi
authors: Zoologische Staatssammlung München, Munich, Germany.
authors: Horst
authors: H
authors: Bohn
authors: Senckenberg Naturhistorische Sammlungen Dresden, Dresden, Germany.
authors: Klaus-Dieter
authors: KD
authors: Klass
authors: Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark.|Laboratoire d'Ethologie Expérimentale et Comparée (LEEC), Université Paris 13, Sorbonne Paris Cité, Villetaneuse, France.
authors: Patrizia
authors: P
authors: d'Ettorre
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D003058:Cockroaches / Q000502:physiology*; D005247:Feeding Behavior; D009425:Nesting Behavior; D018515:Plant Leaves / Q000737:chemistry* / Q000469:parasitology
keywords: Acromyrmex; Atta; Attaphila; Camouflage; Cuticular hydrocarbons; Leaf-cutting ants; Mimicry; Myrmecophily; Nestmate recognition