Phylogeography of caddisflies in the THR
Xi-Ling Deng1,2,3,4,*, Sami
Domisch4, Adrien Favre5, Sonja C.
Jähnig4,6, Paul B. Frandsen3,7,8,
Fengzhi He4,6,9, Deep Narayan
Shah10, Ram Devi Tachamo Shah11,12,
Qinghua Cai13, Steffen U. Pauls1,2,3
1 Senckenberg Research Institute and Natural History
Museum, Frankfurt am Main, Germany
2 Institute of Insect Biotechnology,
Justus-Liebig-University Gießen, Gießen, Germany
3 LOEWE Centre for Translational Biodiversity Genomics
(LOEWE-TBG), Frankfurt am Main, Germany
4 Leibniz Institute of Freshwater Ecology and Inland
Fisheries, Berlin, Germany
5 Regional nature park of the Trient Valley, Salvan,
Switzerland
6 Geography Department, Humboldt-Universität zu
Berlin, Berlin, Germany
7 Department of Plant & Wildlife Sciences, Brigham
Young University, Provo, USA
8 Data Science Lab, Office of the Chief Information
Officer, Smithsonian Institution, Washington, USA
9 Center for Biodiversity Dynamics in a Changing World
(BIOCHANGE) and Section for Ecoinformatics and Biodiversity, Department
of Biology, Aarhus University, Aarhus C, Denmark
10 Central Department of Environmental Science,
Tribhuvan University, Kirtipur, Nepal
11 Aquatic Ecology Centre, School of Science,
Kathmandu University, Dhulikhel, Nepal
12 Department of Life Sciences, School of Science,
Kathmandu University, Dhulikhel, Nepal
13 State Key Laboratory of Freshwater Ecology and
Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences,
Wuhan, China
* Corresponding author-xiling.deng@outlook.com
Abstract
The Tibeto-Himalayan Region is famous for its geography, climatic
influence, and exceptional and immense biodiversity. The
“mountain-geobiodiversity hypothesis (MGH)” explores the interaction
of topography, climate, and biology in the evolution of mountain
biodiversity. We tested this hypothesis in the Himalayas and the
Hengduan Mountains on a group of caddisflies that are endemic to this
region. We investigated one caddisfly species pair from each mountain
respectively, each pair containing one species inhabiting high elevation
and one inhabiting low elevation. We incorporated genomic and ecological
evidence to reveal population structure, demographic history, and
potential habitat range dating back to the last glacial maximum (LGM) of
each species. The results indicated that in both mountains, the
high-elevation species showed strong local differentiation, while the
low-elevation species were shaped by hydro-morphology indicating greater
regional dispersal activity. Results of demographic history and species
distribution modelling supported demographic expansions for all species
during the LGM linked to an increase in potential habitats. Caddisfly
species in the Himalayas generally exhibited an East-West oriented
dispersal. Species from the Hengduan Mountains showed greater
connectivity on the North-South orientation, suggesting that species
have a higher chance to survive in the Hengduan Mountains by bothin-situ displacement (along the elevational gradients) and
long-distance dispersal (along the latitudinal gradients) during
glaciation. Our study demonstrates that historical geodiversity and
climate fluctuations interact and influence the diversification of
caddisflies in the Tibeto-Himalayan Region, thus supporting the MGH.