Innate immune system still works at diapause, a physiological state of dormancy in insects

► Two major types of cells are present in the body fluid isolated from the thoracic region of a diapausing pupa. ► Phagocytosis and encapsulation by these cells were observed when latex beads as foreign targets were microinjected into a pupa. ► Such behavior by these cells was still observed even when pupae were continuously chilled at 4 °C. ► Innate cellular reactions can work in diapausing insects in a dormant state.