Geographically close populations of the same species can be genetically more similar between each other than distant populations, as they may have been founded by colonists from the same source population and may have a higher gene flow. Polistes biglumis is a species of social wasps that has a patchy geographic distribution in mountains of South Europe. In some geographical areas populations are quite close, whereas in others they are more distant. As many social insects, P. biglumis wasps use cuticular hydrocarbons (CHCs) to discriminate between nestmates and non-nestmates. CHCs form the colony odor that varies largely among colonies, and this is important in order to prevent colony exploitation by conspecific and heterospecific intruders. In this study we investigated if the colony odor varies between populations as a function of their geographical distance. We studied 14 populations spread along western and central Italian Alps, for a total of 50 nests; we extracted CHCs from foundresses and analyzed their chemical composition using a gas-chromatograph. We found no significant correlation between chemical distances and geographical distances. This finding suggests that local conditions (among them biotic and abiotic factors) are more likely to influence variations in colony odor than geographic distance. Identifying these factors and disentangling their contribution in the differentiation of colony odor is one of the most stimulating challenges for future studies.
Geographic differences in the chemical profiles of a social wasp
BONELLI, MARIAELENA;LORENZI, Maria Cristina
2012-01-01
Abstract
Geographically close populations of the same species can be genetically more similar between each other than distant populations, as they may have been founded by colonists from the same source population and may have a higher gene flow. Polistes biglumis is a species of social wasps that has a patchy geographic distribution in mountains of South Europe. In some geographical areas populations are quite close, whereas in others they are more distant. As many social insects, P. biglumis wasps use cuticular hydrocarbons (CHCs) to discriminate between nestmates and non-nestmates. CHCs form the colony odor that varies largely among colonies, and this is important in order to prevent colony exploitation by conspecific and heterospecific intruders. In this study we investigated if the colony odor varies between populations as a function of their geographical distance. We studied 14 populations spread along western and central Italian Alps, for a total of 50 nests; we extracted CHCs from foundresses and analyzed their chemical composition using a gas-chromatograph. We found no significant correlation between chemical distances and geographical distances. This finding suggests that local conditions (among them biotic and abiotic factors) are more likely to influence variations in colony odor than geographic distance. Identifying these factors and disentangling their contribution in the differentiation of colony odor is one of the most stimulating challenges for future studies.
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