ESJ58 一般講演（口頭発表） E2-05

Juvenile hormone guides the worker development in the termite Nasutitermes takasagoensis

*¹Bourguignon T.,¹ Gotoh H., ¹Miura T.

Juvenile hormone (JH) has particularly attracted the curiosity of researchers for its preponderant role in many biological processes such as development, reproduction and behavior. In termites, JH determines the caste developmental fates during postembryonic development. For example, a high JH titer during a sensitive period preceding the worker molt induces presoldier differentiation, while individuals proceeding to reproductive molt are characterized by a low JH titer. These mechanisms have been well studied in a few lower termite species but have never been investigated in higher termites, which generally have a more constrained developmental pathway. Here, we investigated the JH titer in the neuter line of Nasutitermes takasagoensis in order to determine whether there are differences among worker instars; and whether JH plays a role in the strict male origin of soldiers. We found that minor workers, from which all soldiers originate in N. takasagoensis, tend to have higher JH titer than other worker instars, while major workers generally have lower titer. This suggests that when JH titer rises in the colony, minor workers are the first to reach the threshold for the presoldier molt, and thereby the only colony member to molt into soldiers. We will present the results of further analyses to confirm our hypothesis.