Rank and epicuticular hydrocarbons in different populations of the paper wasp Polistes dominulus (Christ) (Hymenoptera, Vespidae)

Several studies of social insects have shown that epicuticular hydrocarbons are involved in recognition. The hypothesis is that the animals can use differences in chemical composition to acquire information about conspecific status (sex, colony, reproductive status or caste recognition). In this study, we searched for differences between the epicuticular profiles of alpha and beta co-foundresses in Polistes dominulus (Christ) colonies from three separate localities. Our aim was to identify specific compounds or sets of compounds which could be general indexes of foundress rank position in an associative foundation. We found quantitative and qualitative differences in the epicuticular profile among the three populations. The compounds that differentiate between alpha foundresses and their subordinates in the two neighbouring localities were not the same as in the third population. However, in all localities the alpha foundresses of each associative foundation presented a higher proportion of heavy compounds than their respective subordinates. Chemical differences related to rank position may be a fertility signal and are probably caused by physiological and behavioural characteristics, although it is not yet certain if they are actually used by the wasps.