title: The global distribution of diet breadth in insect herbivores.
abstract: Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of the most common and consequential ecological associations on the planet. However, uncertainty persists regarding fundamental features of herbivore diet breadth, including its relationship to latitude and plant species richness. Here, we use a global dataset to investigate host range for over 7,500 insect herbivore species covering a wide taxonomic breadth and interacting with more than 2,000 species of plants in 165 families. We ask whether relatively specialized and generalized herbivores represent a dichotomy rather than a continuum from few to many host families and species attacked and whether diet breadth changes with increasing plant species richness toward the tropics. Across geographic regions and taxonomic subsets of the data, we find that the distribution of diet breadth is fit well by a discrete, truncated Pareto power law characterized by the predominance of specialized herbivores and a long, thin tail of more generalized species. Both the taxonomic and phylogenetic distributions of diet breadth shift globally with latitude, consistent with a higher frequency of specialized insects in tropical regions. We also find that more diverse lineages of plants support assemblages of relatively more specialized herbivores and that the global distribution of plant diversity contributes to but does not fully explain the latitudinal gradient in insect herbivore specialization.
authors.affiliation: Department of Biology, Program in Ecology, Evolution and Conservation Biology and mforister@unr.edu ricklefs@umsl.edu.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Forister
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Science, 370 05 Ceske Budejovice, Czech Republic; New Guinea Binatang Research Center, Madang, Papua New Guinea;
authors.forename: Vojtech
authors.initials: V
authors.lastname: Novotny
authors.affiliation: Department of Mathematics and Statistics, University of Nevada, Reno, NV 89557;
authors.forename: Anna K
authors.initials: AK
authors.lastname: Panorska
authors.affiliation: New Guinea Binatang Research Center, Madang, Papua New Guinea; Department of Biology, University of Papua New Guinea, Port Moresby, Papua New Guinea;
authors.forename: Leontine
authors.initials: L
authors.lastname: Baje
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Panama;
authors.forename: Yves
authors.initials: Y
authors.lastname: Basset
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Science, 370 05 Ceske Budejovice, Czech Republic;
authors.forename: Philip T
authors.initials: PT
authors.lastname: Butterill
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Science, 370 05 Ceske Budejovice, Czech Republic;
authors.forename: Lukas
authors.initials: L
authors.lastname: Cizek
authors.affiliation: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Panama; Department of Biology, University of Utah, Salt Lake City, UT 84112-0840;
authors.forename: Phyllis D
authors.initials: PD
authors.lastname: Coley
authors.affiliation: New Guinea Binatang Research Center, Madang, Papua New Guinea; Environmental Futures Research Institute, Griffith University, Queensland 4111, Australia;
authors.forename: Francesca
authors.initials: F
authors.lastname: Dem
authors.affiliation: Departamento de Zoologia, Universidade de Brasília, Brasília, Distrito Federal, Brazil, 70 910-900;
authors.forename: Ivone R
authors.initials: IR
authors.lastname: Diniz
authors.affiliation: Department of Biology, University of Ostrava, 710 00 Ostrava, Czech Republic;
authors.forename: Pavel
authors.initials: P
authors.lastname: Drozd
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA 70118;
authors.forename: Mark
authors.initials: M
authors.lastname: Fox
authors.affiliation: Department of Biology, Program in Ecology, Evolution and Conservation Biology and.
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Glassmire
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA 70118;
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hazen
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Science, 370 05 Ceske Budejovice, Czech Republic; Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;
authors.forename: Jan
authors.initials: J
authors.lastname: Hrcek
authors.affiliation: Department of Biology, Program in Ecology, Evolution and Conservation Biology and.
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Jahner
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Science, 370 05 Ceske Budejovice, Czech Republic;
authors.forename: Ondrej
authors.initials: O
authors.lastname: Kaman
authors.affiliation: Department of Mathematics and Statistics, University of Nevada, Reno, NV 89557;
authors.forename: Tomasz J
authors.initials: TJ
authors.lastname: Kozubowski
authors.affiliation: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Panama; Department of Biology, University of Utah, Salt Lake City, UT 84112-0840;
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kursar
authors.affiliation: Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;
authors.forename: Owen T
authors.initials: OT
authors.lastname: Lewis
authors.affiliation: Department of Biological Sciences, George Washington University, Washington, DC 20052;
authors.forename: John
authors.initials: J
authors.lastname: Lill
authors.affiliation: Department of Biology and Whitney R. Harris World Ecology Center, University of Missouri-St. Louis, St. Louis, MO 63121;
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Marquis
authors.affiliation: National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012;
authors.forename: Scott E
authors.initials: SE
authors.lastname: Miller
authors.affiliation: Departamento de Zoologia, Universidade de Brasília, Brasília, Distrito Federal, Brazil, 70 910-900;
authors.forename: Helena C
authors.initials: HC
authors.lastname: Morais
authors.affiliation: Department of Biology, Chiba University, Chiba 263-8522, Japan;
authors.forename: Masashi
authors.initials: M
authors.lastname: Murakami
authors.affiliation: J. F. Blumenbach Institute of Zoology and Anthropology, Göttingen University, 37073 Göttingen, Germany;
authors.forename: Herbert
authors.initials: H
authors.lastname: Nickel
authors.affiliation: Department of Biology, Program in Ecology, Evolution and Conservation Biology and.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Pardikes
authors.affiliation: Department of Biology and Whitney R. Harris World Ecology Center, University of Missouri-St. Louis, St. Louis, MO 63121; mforister@unr.edu ricklefs@umsl.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Ricklefs
authors.affiliation: Department of Biology, Wesleyan University, Middletown, CT 06459;
authors.forename: Michael S
authors.initials: MS
authors.lastname: Singer
authors.affiliation: Department of Biology, Program in Ecology, Evolution and Conservation Biology and.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Smilanich
authors.affiliation: Department of Biological Sciences, Wright State University, Dayton, OH 45435; Sección Invertebrados, Museo Ecuatoriano de Ciencias Naturales, Quito, Ecuador;
authors.forename: John O
authors.initials: JO
authors.lastname: Stireman
authors.affiliation: Sección Invertebrados, Museo Ecuatoriano de Ciencias Naturales, Quito, Ecuador;
authors.forename: Santiago
authors.initials: S
authors.lastname: Villamarín-Cortez
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Science, 370 05 Ceske Budejovice, Czech Republic;
authors.forename: Stepan
authors.initials: S
authors.lastname: Vodka
authors.affiliation: Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Science, 370 05 Ceske Budejovice, Czech Republic;
authors.forename: Martin
authors.initials: M
authors.lastname: Volf
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269;
authors.forename: David L
authors.initials: DL
authors.lastname: Wagner
authors.affiliation: Sección Invertebrados, Museo Ecuatoriano de Ciencias Naturales, Quito, Ecuador; Department of Biology, Colorado Mesa University, Grand Junction, CO 81507; and.
authors.forename: Thomas
authors.initials: T
authors.lastname: Walla
authors.affiliation: Bell Museum and Department of Plant Biology, University of Minnesota, St. Paul, MN 55108-1095.
authors.forename: George D
authors.initials: GD
authors.lastname: Weiblen
authors.affiliation: Department of Biology, Program in Ecology, Evolution and Conservation Biology and Sección Invertebrados, Museo Ecuatoriano de Ciencias Naturales, Quito, Ecuador;
authors.forename: Lee A
authors.initials: LA
authors.lastname: Dyer
mesh_terms: D000818:Animals; D044822:Biodiversity; D004032:Diet; D017753:Ecosystem; D060434:Herbivory / Q000502:physiology*; D058507:Host Specificity; D007313:Insecta / Q000145:classification / Q000502:physiology*; D007915:Lepidoptera / Q000145:classification / Q000502:physiology; D008954:Models, Biological; D010802:Phylogeny
keywords: Pareto distribution; host range; latitudinal gradient; niche width; specialization