title: Clusters of ant colonies and robust criticality in a tropical agroecosystem.
abstract: Although sometimes difficult to measure at large scales, spatial pattern is important in natural biological spaces as a determinant of key ecological properties such as species diversity, stability, resiliency and others. Here we demonstrate, at a large spatial scale, that a common species of tropical arboreal ant forms clusters of nests through a combination of local satellite colony formation and density-dependent control by natural enemies, mainly a parasitic fly. Cluster sizes fall off as a power law consistent with a so-called robust critical state. This endogenous cluster formation at a critical state is a unique example of an insect population forming a non-random pattern at a large spatial scale. Furthermore, because the species is a keystone of a larger network that contributes to the ecosystem function of pest control, this is an example of how spatial dynamics at a large scale can affect ecosystem service at a local level.
authors.affiliation: Department of Ecology and Evolutionary Biology, Kraus Natural Science Building, University of Michigan, Ann Arbor, Michigan 48109, USA. jvander@umich.edu
authors.forename: John
authors.initials: J
authors.lastname: Vandermeer
authors.forename: Ivette
authors.initials: I
authors.lastname: Perfecto
authors.forename: Stacy M
authors.initials: SM
authors.lastname: Philpott
mesh_terms: D000383:Agriculture; D000818:Animals; D001000:Ants / Q000469:parasitology / Q000502:physiology*; D003069:Coffee / Q000469:parasitology / Q000502:physiology; D017753:Ecosystem; D005260:Female; D008800:Mexico; D010572:Pest Control, Biological; D011156:Population Density; D015996:Survival Rate; D013997:Time Factors; D014197:Trees / Q000469:parasitology / Q000502:physiology; D014329:Tropical Climate
chemical_list: D003069:Coffee