Outstanding ant diversity in large old tropical trees along the Andean Amazon gradient: insights from the Life on Trees program.

XXVII Simpósio de Mirmecologia: An International Ant Meeting 11/02/2025–11/06/2025, Recife, Brasil https://www.even3.com.br/mirmeco2025/ Subject area: Population/Community/Ecosystem Ecology, Conservation Biology and Bioindication Format: oral presentation Outstanding ant diversity in large old tropical trees along the Andean Amazon gradient: insights from the Life on Trees program Maurice Leponce1; Fernando Fernández2; Esperidião A. Santos Neto3; Jochen Drescher4; Jürgen Schmidl5; Yves Basset6; Jhon Cesar Neita7; Claire Villemant8, Ángela Aristizabal-Botero1, Jacques H.C. Delabie3 1 - Royal Belgian Institute of Natural Sciences, Belgium; 2 - Universidad Nacional de Colombia, Colombia; 3- Centro de Pesquisas do Cacau – CEPEC, Brasil; 4- Göttingen University, Germany; 5- Universität Erlangen-Nürnberg, Germany ; 6- Smithsonian Tropical Research Institute, Panama; 7- Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Colombia; 8- Muséum national d’Histoire naturelle, France E-mail: (presenting author): mleponce@naturalsciences.be Most ant biodiversity studies focus on forest-scale patterns and ground-dwelling species, leaving the structure of ant assemblages at the scale of individual trees largely unexplored. As part of the Life on Trees (LOT) program (www.lifeontrees.org), we investigated eukaryote diversity using 36 standardized above-ground sampling methods targeting all microhabitats within single large trees (doi: 10.3389/ffgc.2024.1425492). Fieldwork was conducted in the Andes-Amazon biodiversity hotspot (Peru and Colombia) on three large trees located at increasing elevations: a Dussia tessmannii (Fabaceae, 50 m tall, 400 m asl), a Brosimum utile (Moraceae, 40 m, 850 m asl), and a Ficus americana (Moraceae, 32 m, 2400 m asl) growing over a Beilschmiedia latifolia (Lauraceae). Most arboreal-dwelling ants were caught by fogging, Berlese extraction, baits, deadwood inspection, and interception traps. Samples were collected by professional climbers throughout all tree zones. Preliminary results reveal exceptionally high species richness at the mid-elevation site, with over 131 species from 8 subfamilies and 40 genera. The lowland Amazonian tree hosted 112 species (8 subfamilies, 34 genera), while the high-elevation Andean tree supported only 12 species (8 subfamilies, 3 genera). Our findings underscore the value of tree-level intensive sampling for uncovering vertical and elevational patterns in ant assemblages. They highlight the role of large old trees as biodiversity hotspots and the conservation priority of mid-elevation transitional forests increasingly impacted by deforestation.