Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution.

Arctic Research Centre Aarhus University Ny Munkegade 114 DK 8000 Aarhus C Denmark

Center for Macroecology Evolution and Climate Change Natural History Museum of Denmark University of Copenhagen Universitetsparken 15 København Denmark

Department of Biological Sciences University of Alberta Edmonton T6G 2E9 Alberta Canada

Department of Biology Swarthmore College 500 College Avenue Swarthmore PA 19081 USA

Department of Biology The University of Texas at Arlington Arlington TX 76019 USA

Department of Biology University of Bergen Post Office Box 7800 5020 Bergen Norway

Department of Bioscience Aarhus University Frederiksborgvej 399 DK 4000 Roskilde Denmark

Department of Ecology and Evolutionary Biology University of California Irvine 321 Steinhaus Hall Irvine CA 92697 2525 USA

Department of Ecology University of São Paulo Rua do Matão 321 T 14 CEP 05508 900 São Paulo SP Brazil

Department of Plant Ecology University of Bayreuth 95440 Bayreuth Germany

Department of Zoology Faculty of Science University of South Bohemia Branisovska 1760 37005 Ceske Budejovice Czech Republic

Department of Zoology Institute of Ecology and Earth Sciences University of Tartu EE 51014 Tartu Estonia

Department of Zoology University of Oxford South Parks Road Oxford OX1 3PS UK

Evolutionarily Distinct and Globally Endangered of Existence Conservation Programmes Zoological Society of London Regent's Park London NW1 4RY UK

Insect Ecology Lab Centre of Excellence for Behavioural and Physiological Ecology University of New England NSW Australia 2351 Australia

Institute of Entomology Biology Centre of the Czech Academy of Sciences Branisovska 31 37005 Ceske Budejovice Czech Republic

Institute of Integrative Biology Eidgenössische Technische Hochschule Zürich Universitätstrasse 16 8092 Zurich Switzerland

Institute of Life and Environmental Sciences University of Iceland Sturlugata 7 IS 101 Reykjavik Iceland

Instituto de Ciencias Biológicas Escuela Politécnica Nacional Ladrón de Guevara E11 253 Quito Ecuador

Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla 666303 Yunnan People's Republic of China

Lancaster Environment Centre University of Lancaster Lancaster UK

Makerere University Biological Field Station Post Office Box 409 Fort Portal Uganda

Metapopulation Research Centre Department of Biosciences Post Office Box 65 FI 00014 University of Helsinki Finland

Red de Ecoetología Instituto de Ecología CP 91070 Xalapa Veracruz Mexico

School of Biological Sciences The University of Hong Kong Pok Fu Lam Rd Hong Kong SAR People's Republic of China

Section of Ecology FI 20014 University of Turku Finland

Smithsonian Tropical Research Institute Apartado 0843 03092 Panama City Republic of Panama

Spatial Foodweb Ecology Group Department of Agricultural Sciences Post Office Box 27 FI 00014 University of Helsinki Finland

Spatial Foodweb Ecology Group Department of Ecology Swedish University of Agricultural Sciences Post Office Box 7044 SE 750 07 Uppsala Sweden

State Institution of Education Zditovo High School Zditovo Belarus

The New Guinea Binatang Research Center Post Office Box 604 Madang Papua New Guinea

Town End Lane Lepton Huddersfield HD8 ONA UK

University of Aberdeen Zoology Building Tillydrone Avenue Aberdeen AB24 2TZ UK

University of Ostrava Faculty of Science Department of Biology and Ecology Chittussiho 10 710 00 Slezská Ostrava Czech Republic

Zoological Museum Biodiversity Unit FI 20014 University of Turku Finland

References provided by Crossref.org

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Camera traps unable to determine whether plasticine models of caterpillars reliably measure bird predation

Arthropod Food Webs in the Foreland of a Retreating Greenland Glacier: Integrating Molecular Gut Content Analysis With Structural Equation Modelling

Entomopathogenic Fungi as Mortality Agents in Insect Populations: A Review

Different feeding preferences for macronutrients across seasons and sites indicate temporal and spatial nutrient limitation in the black bog ant

Predators control pests and increase yield across crop types and climates: a meta-analysis

Globally invariant metabolism but density-diversity mismatch in springtails

Metabolome-Wide, Phylogenetically Controlled Comparison Indicates Higher Phenolic Diversity in Tropical Tree Species

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Dryad
10.5061/dryad.j432q