Life history of the newly discovered Japanese tree sap mite, Hericia sanukiensis (Acari, Astigmata, Algophagidae)

摘要

Hericia sanukiensis (Acari, Algophagidae) is a species of tree sap mite which has been newly discovered in the sap flux of oak trees (Quercus acutissima). In this study, we have clarified the life history of H. sanukiensis at the onset of sap exudation in spring, overwintering deutonymphs molt to tritonymphs as their molting is exacerbated by the sugar contained in the tree sap, and develop to adulthood and reproduce. The mite colony develops as long as the sap continues to exude during the spring and summer. In this period, most of the protonymphs develop into tritonymphs directly bypassing the deutonymphal stage completely. Facultative deutonymphs which arise in the summer season are phoretic morphs. They attach to coleopteran insects, especially of the family Nitidulidae, as carriers by which to disperse. In autumn (when sap exudation terminates), most of the protonymphs molt to non-phoretic deutonymphs. In winter (without sap exudation), the mite colony is composed only of non-phoretic deutonymphs.