Durability of information concerning the presence of a gamergate in Diacamma sp from Japan

In social insects, information on the presence of a queen is known to affect the reproductive behaviour of workers. In the queenless ant Diacamma sp., information of the presence of the gamergate, the functional queen, is transmitted exclusively by direct physical contact between the gamergate and workers. Periodic contacts between the gamergate and each worker are therefore necessary to maintain worker sterility. However, how the difference in the contact interval influences reproductive behaviour of workers is unclear. In the present study, by artificially controlling the exact interval of physical contact between workers with the gamergate, it is shown that the inter-contact interval influences the worker's reproductive condition (i.e. a longer interval leads to more developed ovaries). This system provides a good opportunity to study the mechanisms underling the colony size dependence of individual as well as colony characteristics.