# Faunal and Ecological Analysis of Gamasid Mites (Acari: Mesostigmata) Associated with Small Mammals in Yunnan Province, Southwest China

## TL;DR

This study explores the diversity and ecology of mites linked to small mammals in Yunnan, China, revealing high species diversity and potential zoonotic disease risks.

## Contribution

The study provides a comprehensive faunal and ecological analysis of gamasid mites in Yunnan, identifying patterns of host specificity and environmental influence.

## Key findings

- Most mite species showed low host specificity, being found on more than 10 host species.
- Mountainous and outdoor habitats had higher mite diversity compared to flatland and indoor environments.
- Thirteen vector mite species with low host specificity were identified, potentially increasing zoonotic disease transmission risks.

## Abstract

Gamasid mites are a large group of arthropods, and some of them can serve as vectors or potential vectors of some zoonotic diseases. Yunnan Province of southwest China is an important focus of many zoonotic diseases, with a complicated topography and high biodiversity. The field investigations conducted in 40 survey sites of Yunnan covered five zoogeographical microregions (I, II, III, IV, V). The mites collected from rodents and other sympatric small mammals (hosts) were identified to species level under a microscope, and a series of statistical methods and visualization models were used. Collected from 18,063 hosts, 141,501 mites were identified as 167 species, showing a high level of species diversity. Most mite species showed low host specificity, being found on more than 10 host species. The mite community diversity in the mountainous landscape and outdoor habitat was obviously higher than that in the flatland landscape and indoor habitat, with obvious environmental heterogeneity. The coexistence of 13 vector mite species with low host specificity may increase the potential risk of zoonoses’ transmission. Some mite species showed high similarity in host selection with high niche overlaps. The mite faunae in microregions IV and V showed the highest similarity, which is associated with the specific locality, topography, and climate types in different microregions. Some mite species showed a tendency to choose the same hosts, with a positive correlation. The expected total number of mite species in Yunnan was estimated to be 203 species, 36 species more than actually identified 167 species.

Gamasid mites (Acari: Mesostigmata) are ecologically diverse arthropods, many of which act as vectors for zoonotic diseases such as rickettsial pox and hemorrhagic fever with renal syndrome. This study investigates the faunal and ecological patterns of gamasid mites across five zoogeographic microregions in Yunnan Province, China, a biodiversity hotspot with complex topography. From 1990 to 2022, 18,063 small mammal hosts (primarily rodents) were surveyed, yielding 167 mite species (141,501 specimens). The key findings include the following: (1) Low host specificity: most mite species parasitized >10 host species, with Laelaps nuttalli, L. echidninus, Dipolaelaps anourosorecis, L. guizhouensis, L. turkestanicus, and L. chini dominating (>76.59% abundance). (2) Environmental heterogeneity: mountainous and outdoor habitats exhibited higher mite diversity than flatland/indoor environments. (3) Zoonotic risks: thirteen vector species with low host specificity were identified, potentially amplifying disease transmission. (4) Ecological niche dynamics: high niche overlaps (e.g., Laelaps guizhouensis vs. L. xingyiensis: Oik = 0.997) and positive interspecific correlations (e.g., L. echidninus vs. L. nuttalli: R = 0.97, p < 0.01) suggest co-occurrence trends on shared hosts. (5) Biogeographic patterns: mite communities were clustered distinctly by microregion, with the highest similarity being obtained between western/southern plateaus (IV and V) and unique diversity in the Hengduan Mountains (I). (6) Chao 1 estimation predicted 203 total mite species in Yunnan, 36 of which were undetected in the current sampling. These results highlight the interplay of biogeography, host ecology, and environmental factors in shaping mite distributions, with implications for zoonotic disease surveillance in biodiverse regions.