Beyond chemicals: neglected communication modalities in paper-wasp societies

Social life requires a complex and efficient communication system. Traditionally, chemical communication is considered the most important sensory channel in insects societies. However, in the last decades, visual and substrate-borne vibrational communication have inspired a growing interest. In order to understand if these understudied sensory channels could be used in fundamental aspects of social life, such as nestmate recognition, dominance hierarchies and adult-brood interactions, I used the primitively eusocial paper wasp Polistes dominula, whose features of nest structure and the body coloration pattern are suitable to vibrational and visual communication. The main results of this work are: i) P. dominula wasps can use both visual and chemical signals in nestmate recognition according to the colony social environment; ii) substrate-borne vibrations produced by adult females evoke a measurable behavioral response in larvae, which thus provides evidence that vibrations can play a role as signal; iii) the intensity of vibrations produced by different females in associative foundations is related to individual position in the dominance hierarchy position and, from the physiological point of view, to ovary development, suggesting that such feature could vehicle individual information; iv) finally, the study of vibrations produced by Polistes sulcifer, the obligate social parasite of P. dominula, suggests that the parasite could exploit the vibrational host communication system to get integrated into the host colony. Overall, the results of this work show that communication modalities other than the chemical one can play a crucial role in regulating insect social life.