Queen fertility, egg marking and colony size in the ant Camponotus floridanus
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In ant societies, workers do not usually reproduce but gain indirect fitness benefits from raising related offspring produced by the queen. One of the preconditions of this worker self-restraint is sufficient fertility of the queen. The queen is, therefore, expected to signal her fertility. In Camponotus floridanus, workers can recognize the presence of a highly fertile queen via her eggs, which are marked with the queen's specific hydrocarbon profile. If information on fertility is encoded in the hydrocarbon profile of eggs, we expect workers to be able to differentiate between eggs from highly and weakly fertile queens. We found that workers discriminate between these eggs solely on the basis of their hydrocarbon profiles which differ both qualitatively and quantitatively. This pattern is further supported by the similarity of the egg profiles of workers and weakly fertile queens and the similar treatment of both kinds of eggs. Profiles of queen eggs correspond to the cuticular hydrocarbon profiles of the respective queens. Changes in the cuticular profiles are associated with the size of the colony the queen originates from and her current egg-laying rate. However, partial correlation analysis indicates that only colony size predicts the cuticular profile. Colony size is a buffered indicator of queen fertility as it is a consequence of queen productivity within a certain period of time, whereas daily egg-laying rate varies due to cyclical oviposition. We conclude that surface hydrocarbons of eggs and the cuticular profiles of queens both signal queen fertility, suggesting a major role of fertility signals in the regulation of reproduction in social insects.
KeywordsQueen signal Honest signaling Pheromone Cuticular hydrocarbons Worker policing Conflict Formicidae
We thank Thibaud Monnin, Christian Peeters, Kazuki Tsuji, a referee, and especially Lotta Sundström for providing helpful comments on the manuscript; we also thank the German Science Foundation (SFB 554 TP C3), the European Union (INSECTS, Integrated Studies of the Economy of Insect Societies, HPRN-CT-2000-00052), and Aventis (travel grant to AE) for funding. The Social Insect Working Group of the Santa Fe Institute provided insightful discussions.
- Aitchison J (1986) The statistical analysis of compositional data: monographs in statistics and applied probability. Chapman & Hall, LondonGoogle Scholar
- Bourke AFG, Franks NR (1995) Social evolution in ants. Princeton University Press, PrincetonGoogle Scholar
- Choe JC (1988) Worker reproduction and social evolution in ants (Hymenoptera: Formicidae). In: Trager JC (ed) Advances in myrmecology. E.J. Brill, Leiden, pp 163–187Google Scholar
- Foster KR, Ratnieks FLW (2001) Convergent evolution of worker policing by egg eating in the honeybee and common wasp. Proc R Soc Lond B 268:169–174Google Scholar
- Hölldobler B, Wilson EO (1983) Queen control in colonies of weaver ants (Hymenoptera: Formicidae). Ann Entomol Soc Am 76:235–238Google Scholar
- Hölldobler B, Wilson EO (1990) The ants. Harvard University Press, Cambridge, MAGoogle Scholar
- Maynard Smith J, Szathmary E (1995) The major transitions in evolution. W.H. Freeman and Company, New York OxfordGoogle Scholar
- Schal C, Sevala VL, Young HP, Bachmann JA (1998) Sites of synthesis and transport pathways of insect hydrocarbons: cuticle and ovary as target tissues. Am Zool 38:382–393Google Scholar
- Seeley TD (1985) Honeybee ecology. Princeton University Press, Princeton, NJGoogle Scholar
- Siegel S, Castellan NJ Jr (1988) Nonparametric statistics for behavioral sciences. McGraw-Hill Book Co., New YorkGoogle Scholar