In animals, the progress and outcome of contests can be influenced by an individual's own condition, their opponent's condition or a combination of the two. The use of chemical information to assess the quality of rivals has been underestimated despite its central role in the regulation of social interactions in many taxa. Here, we studied pairwise contests between founding queens of the ant Lasius niger to investigate whether the decision to engage in agonistic interactions relies on self-assessment or mutual assessment. Queens modulated their aggressive behaviours depending on both their own status and their opponent's status. We found no influence of lipid stores or size on the onset of fights. However, differences in cuticular chemical signatures linked to fertility status accurately predicted the probability of behaving aggressively in pairs. Our study thus suggests that ant queens could rely on mutual assessment via chemical cues to make informed decisions about fight initiation.
The authors declare no competing or financial interests.
K.B. and R.J. conceived the study, K.B. and F.R.P. conducted the experiments. All authors analysed the data, wrote the manuscript and approved the final version.
This research was funded by the Centre National de la Recherche Scientifique (CNRS). K.B. was funded by a PhD grant from the Ministère de l'Education Nationale, de l'Enseignement Supérieur et de la Recherche.
Supplementary information available online at http://jeb.biologists.org/lookup/doi/10.1242/jeb.150375.supplemental
- Received September 26, 2016.
- Accepted December 7, 2016.
- © 2017. Published by The Company of Biologists Ltd