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Five species of torrenticolid mites (Acari, Hydrachnidia), collected in the Anzihe and Qingliangfeng national nature reserves, R. P. China, are identified. Three species are described as new to science: Torrenticola pseudosiamis Gu & Guo, sp. nov., T. anziensis Gu & Guo, sp. nov., and Monatractides sichuanensis Gu & Guo, sp. nov. The other two species, M. macrocorpis Gu & Guo, 2019, M. xiaoxiensis Gu & Guo, 2019, are newly reported from Zhejiang Province. Descriptions and illustrations of these species are included.

New data of Torrenticolidae Piersig, 1902 are presented in this paper from Wuyishan National Nature Reserve, P. R. China. Three new species, Torrenticola suptilisrostrum Gu & Guo sp. nov., Torrenticola spinextension Gu & Guo sp. nov. and Torrenticola wuyiensis Gu & Guo sp. nov. are described and illustrated in detail, and one new record for Chinese fauna is given, Torrenticola dentifera Wiles, 1991, which was originally described from Malaysia. In addition, an updated key is provided to all species of Torrenticolidae in China.

The present paper deals with two new species, Atractides (Atractides) bitergumus Zhang & Guo sp. nov. and Atractides (Tympanomegapus) tergumus Zhang & Guo sp. nov., and a new record of a species, Atractides (Atractides) incertus, from Hainan Province, P. R. China. These species are described and illustrated in detail. Article: Atractides (Atractides) bitergumus: Atractides (Tympanomegapus) tergumus: [ABSTRACT FROM AUTHOR]

Insects that depend on microbial mutualists evolved a variety of organs to transport the microsymbionts while dispersing. The ontogeny and variability of such organs is rarely studied, and the microsymbiont's effects on the animal tissue development remain unknown in most cases. Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae or Platypodinae) and their mutualistic fungi are an ideal system to study the animal–fungus interactions. While the interspecific diversity of their fungus transport organ—mycangia—is well‐known, their developmental plasticity has been poorly described. To determine the ontogeny of the mycangium and the influence of the symbiotic fungus on the tissue development, we dissected by hand or scanned with micro‐CT the mycangia in various developmental stages in five Xylosandrus ambrosia beetle species that possess a large, mesonotal mycangium: Xylosandrus amputatus, Xylosandrus compactus, Xylosandrus crassiusculus, Xylosandrus discolor, and Xylosandrus germanus. We processed 181 beetle samples from the United States and China. All five species displayed three stages of the mycangium development: (1) young teneral adults had an empty, deflated and cryptic mycangium without fungal mass; (2) in fully mature adults during dispersal, the pro‐mesonotal membrane was inflated, and most individuals developed a mycangium mostly filled with the symbiont, though size and symmetry varied; and (3) after successful establishment of their new galleries, most females discharged the bulk of the fungal inoculum and deflated the mycangium. Experimental aposymbiotic individuals demonstrated that the pronotal membrane invaginated independently of the presence of the fungus, but the fungus was required for inflation. Mycangia are more dynamic than previously thought, and their morphological changes correspond to the phases of the symbiosis. Importantly, studies of the fungal symbionts or plant pathogen transmission in ambrosia beetles need to consider which developmental stage to sample. We provide illustrations of the different stages, including microphotography of dissections and micro‐CT scans. [ABSTRACT FROM AUTHOR]