SHORT COMMUNICATION Decision rules for egg recognition are related to functional roles and chemical cues in the queenless ant Dinoponera quadriceps Ivelize C. Tannure-Nascimento & Fabio S. Nascimento & José O. Dantas & Ronaldo Zucchi Received: 21 February 2009 / Revised: 26 March 2009 / Accepted: 30 March 2009 / Published online: 7 May 2009 # Springer-Verlag 2009 Abstract The capacity to distinguish colony members from strangers is a key component in social life. In social insects, this extends to the brood and involves discrimina- tion of queen eggs. Chemical substances communicate colony affiliation for both adults and brood; thus, in theory, all colony members should be able to recognize fellow nestmates. In this study, we investigate the ability of Dinoponera quadriceps workers to discriminate nestmate and non-nestmate eggs based on cuticular hydrocarbon composition. We analyzed whether cuticular hydrocarbons present on the eggs provide cues of discrimination. The results show that egg recognition in D. quadriceps is related to both age and the functional role of workers. Brood care workers were able to distinguish nestmate from non- nestmate eggs, while callow and forager workers were unable to do so. Keywords Dinoponera quadriceps . Functional roles . Egg recognition Introduction Recognition is a fundamental feature that permits cooperative groups to obtain benefits through helping. Social insects employ a complex chemical communication system, which mediates most interactions between colony members (Hölldobler and Wilson 1990; Lenoir et al. 2001). The capacity for nestmate recognition enables individuals to protect their colonies against intruders and parasites (Beekman and Oldroyd 2008; Brandt et al. 2005). At the group level, discriminators use available information to distinguish between members and non-members (Dietemann et al. 2003; Couvillon et al. 2007). The importance of cuticular hydrocarbons for intra- colonial communication and individual recognition in social insects is well known (Breed 1998; Vander Meer and Morel 1998; Nunes et al. 2008; Tannure-Nascimento et al. 2008). Recognition odors are determined mostly by genetic factors (Carlin and Hölldobler 1986), but environ- mental origin is also important for the acquisition of colonial cues (Crosland 1988; Obin and Vander Meer 1989). In ants, cuticular hydrocarbon profiles are acquired within 48 h of emergence (Errard 1994), and callow workers are more likely to be accepted into alien colonies than older workers (Stuart 1992). Indeed, the ontogeny of nestmate recognition in ants seems to be related to individual age (Lenoir et al. 1999). For example, in the primitive ant, Ectatomma tuberculatum, adults preferred nestmate larvae over alien conspecific brood when 2– 10 weeks old, a period corresponding to nursing behavior in this species (Féneron and Jaisson 1992). However, workers outside this age group were unable to discriminate larvae (Féneron and Jaisson 1995). Previous studies have shown that workers across Hymenoptera are able to recognize queen-laid from Naturwissenschaften (2009) 96:857–861 DOI 10.1007/s00114-009-0535-8 Electronic supplementary material The online version of this article (doi:10.1007/s00114-009-0535-8) contains supplementary material, which is available to authorized users. I. C. Tannure-Nascimento (*) : F. S. Nascimento (*) : R. Zucchi Departamento de Biologia, FFCLRP, Universidade de São Paulo, 14040-901 Ribeirão Preto, São Paulo, Brazil e-mail: tannure@usp.br e-mail: fabio.nascimento@pq.cnpq.br F. S. Nascimento : J. O. Dantas Departamento de Biologia, CCBS, Universidade Federal de Sergipe, 49100-000 São Cristóvão, Sergipe, Brazil