title: Intraspecific Signals Inducing Aggregation in Periplaneta americana (Insecta: Dictyoptera).
abstract: Chemical communication is necessary to induce aggregation and to maintain the cohesion of aggregates in Periplaneta americana (L.) cockroaches. We aimed to identify the chemical message inducing aggregation in this species. Two types of bioassays were used-binary choice tests in Petri dishes and tests in Y-olfactometer. Papers conditioned by direct contact of conspecifics induce aggregation when proposed in binary choice tests and were attractive in a Y-olfactometer. The identification of the molecules present on these conditioned papers indicated that dichloromethane extracts contained mainly cuticular hydrocarbons whereas methanol extracts contained more volatile molecules. Only a mixture of extracts in both solvents induced aggregation. High concentrations of cuticular hydrocarbons are necessary to induce aggregation when presented alone. When presented with volatile molecules present in methanol extracts, low concentrations of cuticular hydrocarbons are sufficient to induce aggregation if they are presented in contact. Among volatile molecules collected on filter paper, a mixture of three compounds-hexadecanoic acid, pentadecanoic acid, and pentaethylene glycol-induced aggregation. Our results provide evidence that aggregation processes in P. americana relies on a dual mechanism: attraction over long distances by three volatile molecules and maintenance on site by contact with cuticular hydrocarbons.
authors: Faculté des Sciences de Gafsa, Université de Gafsa, Campus Zarroug, 2112 Gafsa, Tunisia. imensaid@gmx.fr.
authors: Saïd
authors: S
authors: Imen
authors: Unité de Spectrométrie de Masse Structurale et Protéomique, Institut Pasteur, 75015 Paris, France.
authors: Malosse
authors: M
authors: Christian
authors: Laboratoire d'éthologie animale et humaine, Université de Rennes I Campus de Beaulieu, 35042 Rennes Cedex, France.
authors: Durier
authors: D
authors: Virginie
authors: Laboratoire d'éthologie animale et humaine, Université de Rennes I Campus de Beaulieu, 35042 Rennes Cedex, France.
authors: Rivault
authors: R
authors: Colette
mesh_terms: D000818:Animals; D006838:Hydrocarbons / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D010526:Periplaneta / Q000187:drug effects / Q000502:physiology*; D010675:Pheromones / Q000378:metabolism / Q000494:pharmacology*; D012919:Social Behavior
chemical_list: D006838:Hydrocarbons; D010675:Pheromones
keywords: Periplaneta americana; aggregation; behavioral test; cuticular hydrocarbon; volatile fatty acid