Journal of Insect Behavior, Vol. 19, No. 2, March 2006 ( C  2006) DOI: 10.1007/s10905-006-9018-3 The Immediate Source of the Oviposition-Deterring Pheromone Produced by Larvae of Adalia bipunctata (L.) (Coleoptera, Coccinellidae) E. Laubertie, 1 X. Martini, 1 C. Cadena, 2 M. Treilhou, 2 A. F. G. Dixon, 3 and J.-L. Hemptinne 1,4 Revised October 28, 2005; accepted December 6, 2005 Published online: June 7, 2006 As is the case for other insects ovipositing on or in resources that are limited in time and/or space, the two-spot ladybird beetle, Adalia bipunctata (L.) pro- duces an oviposition-deterring pheromone (ODP), which is produced by the larval stages. Foraging larvae touch the substrate with their tarsi and the anal disk on the tenth abdominal segment. The aim of this paper was to determine whether the ODP produced by larvae was deposited by the tarsi or the anal disk. Fourth instar larvae either had their anal disk and tarsi, or anal disk, or tarsi coated with a water-soluble mounting medium. Larvae so treated were allowed to walk on filter paper that was subsequently presented to gravid fe- males. The tracks of larvae that had both their tarsi and anal disk masked did not inhibit oviposition. However, the tracks of larvae that had only their tarsi masked significantly inhibited oviposition but those of larvae that had only their anal disk masked did not. It is concluded that the ODP is deposited on the substrate by the anal disk on the tenth abdominal segment of larvae. KEY WORDS: oviposition-deterring pheromone; larvae; anal disk; tarsi; coccinellidae. 1 UMR CNRS/UPS/ENFA 5174 “Evolution et diversit ´ e biologique,” Ecole nationale de For- mation agronomique, BP 22687, F-31326, Castanet-Tolosan Cedex, France. 2 Unit ´ e propre “Signaux biologiques et m ´ etabolites secondaires,” Ecole nationale de Forma- tion agronomique, BP 22687, F-31326, Castanet-Tolosan Cedex, France. 3 School of Biological Sciences, University of East Anglia, Norwich, UK. 4 To whom correspondence should be addressed at Ecole nationale de Formation agronomique, BP 22687, F-31326, Castanet-Tolosan Cedex, France; e-mail: jean-louis. hemptinne@educagri.fr. 231 0892-7553/06/0300-0231/1 C  2006 Springer Science+Business Media, Inc.