Behavioural responses of <i>Ixodes ricinus</i> nymphs to carbon dioxide and rodent odour

Abstract

Abstract Many haematophagous ectoparasites use carbon dioxide (CO 2 ) and host odour to detect and locate their hosts. The tick Ixodes ricinus (Linnaeus) (Ixodida: Ixodidae) walks only small distances and quests in vegetation until it encounters a host. The differential effects of CO 2 and host odour on the host‐finding behaviour of I. ricinus have, however, never been clarified and hence represent the subject of this study. The effects of CO 2 and odour from bank voles on the activation and attraction of I. ricinus nymphs were analysed in a Y‐tube olfactometer. Carbon dioxide evoked a response in the absence and presence of host odour, but did not attract nymphs. Host odour, however, did not evoke a response but did attract nymphs in the absence and presence of CO 2 . The current results show that CO 2 is an activator, but not an attractant, and that host odour is an attractant, but not an activator, of I. ricinus nymphs, and provide ecological insights into the host‐finding behaviour of I. ricinus .