Microanatomical and microbiological characteristics of the quiescent state of Scutovertex minutus (Acari: Oribatida).

Both adults and juveniles of the oribatid mite Scutovertex minutus (Scutoverticidae) may enter an immobile quiescent state under extreme dry conditions. The microanatomy of the alimentary tract, contents of parenchyma tissue and internal extraintestinal microbial communities were observed in these states. The quiescent state lasted at least 10 days and was generally characterized by an empty gut, guanine deposition and, in adults, by the resorption of spermatids or oocytes and eggs. The homogenate of mites was sterile, without microorganisms. The reverse processes were recorded two hours after remoistening: the mites started to move again and accompanying histological changes were shown.