Tick predation by the pseudoscorpion Megachernes ryugadensis (Pseudoscorpiones: Chernetidae), associated with small mammals in Japan

Ticks are obligate blood feeders that parasitize a variety of vertebrates and can be serious pests for these animals. Due to public concerns about the risk of chemical controls, there is a high demand for biological control agents to reduce tick populations and the spread of tick-borne diseases. In this study, we observed tick predation by the pseudoscorpion Megachernes ryugadensis in a laboratory for the first time. Adult and tritonymphal M. ryugadensis were collected in the field during phoresis on Japanese wood mice and transferred to a Petri dish. These pseudoscorpions preyed on larval Haemaphysalis ticks and nymphal and adult Haemaphysalis megaspinosa. Most pseudoscorpions fed on two to three larval ticks on the first day following tick transfer. There were no significant differences between male and female pseudoscorpions in the numbers of larval ticks consumed or the numbers of days required to consume all ticks. Although there was no significant difference between the numbers of days to consume nymphal and adult male ticks, male pseudoscorpions consumed adult female ticks significantly faster than did female pseudoscorpions. Although the sample sizes in this study were small, the tritonymphal pseudoscorpion displayed similar trends in the predation of larval and nymphal ticks. Further study is required to obtain detailed information on the life history traits of the tick and pseudoscorpion and the impacts of the tick on small rodents and their nest fauna to determine the role of M. ryugadensis as a natural enemy of ticks.