Systematics and ecology of Adhaesozetes polyphyllos sp.nov. (Acari: Oribatida: Licneremaeoidea), a leaf-inhabiting mite from Australian rainforests

Abstract

We present the first study of the systematics, ecology, and biogeography of an arboreal oribatid mite from Australia, describe all stages of Adhaesozetes polyphyllos sp.nov., propose new diagnoses for its genus and family, and present a character analysis demonstrating that the family Adhaesozetidae is a member of the Licneremaeoidea. Certain character states, especially the expanded tarsal pulvilli, are interpreted as adaptations to arboreal life. Adhaesozetes polyphyllos grazes on epiphyllic fungi and prefers leaves with smooth surfaces or with closely appressed hairs. It inhabits at least 51 species of trees, shrubs, vines, and ferns in pockets of rainforest in eastern Australia. It is often the most abundant leaf-inhabiting oribatid mite in the cool- to warm-temperate rainforests of Tasmania and Victoria, and inhabits montane subtropical to tropical rainforests at least as far north as Mount Lewis (16°32′S). It appears to be absent from lowland subtropical to tropical rainforests, which suggests an ancient relationship with the Antarctic elements of the Australian flora. Populations are bisexual, with females representing an average of 55% of the adult population. At Wilson's Promontory, populations increase from late winter to midsummer, but all stages are present throughout the year. Females use their ovipositors to lay eggs in protected sites (e.g., insect damage or leaf domatia), often within the cast skins of immature mites.