We know much of how social insects recognize nestmates. We know that social insects use a chemical code composed of epicuticular hydrocarbons, we know that branched hydrocarbons may convey more information than unbranched ones; we know that hydrocarbon quantity matters. However, we still often do not know how the code works. Facultative social parasites, such as the free-living social wasps Polistes nimphus, overmark the host colony odor with their own and therefore change host colony odors. We used nest usurpation between P. nimphus and P. dominulus as a means to alter colony odor and identify the hydrocarbons important in the nestmate recognition code. The colony odor in these two species is very similar because the two species have chemical signature that differ only in their relative proportions of hydrocarbons. In usurped nests, we tested how host workers responded to alien conspecific wasps and to alien P. nimphus wasps. Behavioral and chemical analyses showed that facultative social parasites altered the host colony odors by making small changes in the relative proportions of four branched hydrocarbons and an alkene. These small changes had a large effect on how workers responded to aliens. Host workers were tolerant towards any alien P. nimphus wasp as if they were unable to distinguish their individual odor variations. However, host workers were not tolerant towards conspecific alien wasps, indicating that they were still able to discriminate conspecific aliens. These results document that some hydrocarbons may play key roles in wasp recognition codes and that the variation in the relative proportions of hydrocarbons is an important property in the recognition code.
Nestmate recognition code: Variation in relative proportions of hydrocarbons may open social wasp colonies to aliens
LORENZI, Maria Cristina;
2012-01-01
Abstract
We know much of how social insects recognize nestmates. We know that social insects use a chemical code composed of epicuticular hydrocarbons, we know that branched hydrocarbons may convey more information than unbranched ones; we know that hydrocarbon quantity matters. However, we still often do not know how the code works. Facultative social parasites, such as the free-living social wasps Polistes nimphus, overmark the host colony odor with their own and therefore change host colony odors. We used nest usurpation between P. nimphus and P. dominulus as a means to alter colony odor and identify the hydrocarbons important in the nestmate recognition code. The colony odor in these two species is very similar because the two species have chemical signature that differ only in their relative proportions of hydrocarbons. In usurped nests, we tested how host workers responded to alien conspecific wasps and to alien P. nimphus wasps. Behavioral and chemical analyses showed that facultative social parasites altered the host colony odors by making small changes in the relative proportions of four branched hydrocarbons and an alkene. These small changes had a large effect on how workers responded to aliens. Host workers were tolerant towards any alien P. nimphus wasp as if they were unable to distinguish their individual odor variations. However, host workers were not tolerant towards conspecific alien wasps, indicating that they were still able to discriminate conspecific aliens. These results document that some hydrocarbons may play key roles in wasp recognition codes and that the variation in the relative proportions of hydrocarbons is an important property in the recognition code.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.