The host-seeking and feeding activities of a new generation of Amblyomma testudinarium nymphs (Acari : Ixodidae) in summer observed under experimental conditions

Abstract

The host-seeking (the vertical activity in plastic cylinders) and feeding activities (the rate of engorgement) of a new generation of Amblyomma testudinarium nymphs that were placed outdoors from the engorged larval stage were observed under experimental conditions from July to October 2002. The vertical activity of the nymphs (molted outdoors in late June 2002) in plastic cylinders placed outdoors was low from July to early September, but abruptly increased from mid- September. The rate of engorgement of the nymphs observed using rabbits under laboratory conditions (25degreeC, 16L-8D photoperiod) was low in July and August; however, it significantly increased in September and October. These results suggest that the host-seeking and feeding activities of the new generation of A. testudinarium nymphs are suppressed in the summer. Since the host-feeding activity of the nymphs was observed in a laboratory maintained at 25degreeC, the suppression did not appear to be a simple quiescence caused by temperature. However, it is not clear whether the suppression is due to diapause.