Hindawi Publishing Corporation Psyche Volume 2013, Article ID 601073, 5 pages http://dx.doi.org/10.1155/2013/601073 Research Article The Tergal Gland Secretion of the Two Rare Myrmecophilous Species Zyras collaris and Z. haworthi (Coleoptera: Staphylinidae) and the Effect on Lasius fuliginosus Michael Stoeffler, Lea Boettinger, Till Tolasch, and Johannes L. M. Steidle Universit¨ at Hohenheim, Institut f¨ ur Zoologie, Fachgebiet Tier¨ okologie 220c, Garbenstr. 30, 70593 Stuttgart, Germany Correspondence should be addressed to Michael Stoefer; m.stoefer@t-online.de Received 25 January 2013; Accepted 9 March 2013 Academic Editor: Jean-Paul Lachaud Copyright © 2013 Michael Stoefer et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te beetle species Zyras collaris and Z. haworthi belong to the rove beetle tribe Myrmedoniini (Staphylinidae: Aleocharinae), which comprises many myrmecophilous species. Due to their rareness, it is unknown how the two species interact with their host ants. GC-MS analyses revealed that both species release -pinene, -pinene, myrcene and limonene from their defensive tergal glands. Tis composition of tergal gland secretion is unique within the subfamily Aleocharinae. In biotests, Lasius fuliginosus ants showed increased antennation towards flter paper balls treated with mixtures of these substances in natural concentrations. Because these monoterpenes are also present in some aphid species which are attended by ants, we hypothesize that Zyras beetles mimic the presence of aphids and thereby achieve acceptance by their host ants. 1. Introduction Te rove beetles tribe Myrmedoniini (Staphylinidae: Aleo- charinae) contains many myrmecophilous species. In Central Europe, it comprises the myrmecophilous genera Lomechusa and Lomechusoides, Zyras, Myrmoecia, and Pella, as well as the nonmyrmecophilous species Drusilla canaliculata Fabri- cius, 1787. Myrmoecia and Pella were formerly considered subgenera of Zyras but, meanwhile, have been elevated to genus rank [1–3], which is also supported by molecular data [4, 5]. Lomechusa and Lomechusoides are textbook examples for the integration of myrmecophiles in ant nests by the use of appeasement glands on their abdomen [6]. Diferent strat- egies are used by Pella species to escape from aggressions by their host ant Lasius fuliginosus (Latreille, 1798). While the Japanese species P. comes (Sharp, 1874) mimics the cuticular hydrocarbon (CHC) pattern of its host ant to be accepted [7], P. laticollis (M¨ arkel, 1845) employs a specifc appeasing behaviour [8]. Pella cognata (M¨ arkel, 1842), P. funesta (Gravenhorst, 1806), and P. humeralis (Gravenhorst, 1802) repel ants by the use of their abdominal tergal gland. Tis tergal gland is only found within the Aleocharinae and is used by most species of the subfamily as defensive gland against aggressors [9]. In P. funesta and P. humeralis, the gland secretion specifcally contains sulcatone, a panic alarm inducing pheromone of L. fuliginosus. By the release of this compound, beetles create an “ant free space” [8, 10]. In contrast to these species, only little is known on the biology of Zyras species, and it is unclear how they achieve acceptance by ants. For Z. collaris (Paykull, 1789) and Z. haworthi (Stephens, 1835), this is mainly due to their rarity. For South-West Germany, only 18 and 10 records exist from 1950 to 2000 for Z. collaris and Z. haworthi, respectively [11]. Our own collection eforts between 2001 and 2011 resulted in approximately 1200 specimens of diferent Pella species, but only one for each of the two Zyras species. Here we report for the frst time on the composition of the tergal gland secretion of Z. collaris and Z. haworthi and its potential role for the interaction with its putative host ant L.