Brighter-colored paper wasps (Polistes dominula) have larger poison glands Vidal-Cordero, J. Manuel Moreno Rueda, Gregorio López-Orta, Antonio Marfil-Daza, Carlos Ros-Santaella, José L. Ortiz-Sánchez, F. Javier Paper wasp Poison glands Aposematic coloration Warning signals Introduction Aposematism is a defense system against predators consisting of the toxicity warning using conspicuous coloration. If the toxin production and aposematic coloration is costly, only individuals in good physical condition could simultaneously produce abundant poison and striking coloration. In such cases, the aposematic coloration not only indicates that the animal is toxic, but also the toxicity level of individuals. The costs associated with the production of aposematic coloration would ensure that individuals honestly indicate their toxicity levels. In the present study, we examine the hypothesis that a positive correlation exists between the brightness of warning coloration and toxicity level using as a model the paper wasp (Polistes dominula). Results We collected wasps from 30 different nests and photographed them to measure the brightness of warning coloration in the abdomen. We also measured the volume of the poison gland, as well as the length, and the width of the abdomen. The results show a positive relationship between brightness and poison-gland size, which remained positive even after controlling for the body size and abdomen width. Conclusion The results suggest that the coloration pattern of these wasps is a true sign of toxicity level: wasps with brighter colors are more poisonous (they have larger poison glands). 2014-06-25T12:49:32Z 2014-06-25T12:49:32Z 2012 journal article Vidal-Cordero, J.M.; et al. Brighter-colored paper wasps (Polistes dominula) have larger poison glands. Frontiers in Zoology, 9: 20 (2012). [http://hdl.handle.net/10481/32369] 1742-9994 http://hdl.handle.net/10481/32369 10.1186/1742-9994-9-20 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Biomed Central