R. G. Gillespie

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George Gaylord Simpson famously postulated that much of life's diversity originated as adaptive radiations-more or less simultaneous divergences of numerous lines from a single ancestral adaptive type. However, identifying adaptive radiations has proven difficult due to a lack of broad-scale comparative datasets. Here, we use phylogenetic comparative data(More)
Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a(More)
Spiders of the recently described linyphiid genus Orsonwelles (Araneae, Linyphiidae) are one of the most conspicuous groups of terrestrial arthropods of Hawaiian native forests. There are 13 known Orsonwelles species, and all are single- island endemics. This radiation provides an excellent example of insular gigantism. We reconstructed the cladistic(More)
Genetic color variation provides a tangible link between the external phenotype of an organism and its underlying genetic determination and thus furnishes a tractable system with which to explore fundamental evolutionary phenomena. Here we examine the basis of color variation in spiders and its evolutionary and ecological implications. Reversible color(More)
Evolutionary ecologists are increasingly combining phylogenetic data with distributional and ecological data to assess how and why communities of species differ from random expectations for evolutionary and ecological relatedness. Of particular interest have been the roles of environmental filtering and competitive interactions, or alternatively neutral(More)
Islands have traditionally been considered to be any relatively small body of land completely surrounded by water. However, their primary biological characteristic, an extended period of isolation from a source of colonists, is common also to many situations on continents. Accordingly, theories and predictions developed for true islands have been applied to(More)
The family Theridiidae is one of the most diverse assemblages of spiders, from both a morphological and ecological point of view. The family includes some of the very few cases of sociality reported in spiders, in addition to bizarre foraging behaviors such as kleptoparasitism and araneophagy, and highly diverse web architecture. Theridiids are one of the(More)
Todd A. Blackledge*, Jonathan A. Coddington and Rosemary G. Gillespie University of California – Berkeley, Environmental Science, Policy and Management, Division of Insect Biology, 201 Wellman Hall, Berkeley, CA 94720-3112, USA National Museum of Natural History NHB 105, Smithsonian Institution, Washington, DC, 20560-0105, USA *Correspondence and present(More)
Aim The composition of species in any given island community may directly reflect the processes of immigration such that species on a more remote island comprise a nested subset of those on the nearest less remote land mass. Alternatively, new species can arise on islands by less frequent colonization but subsequent evolutionary differentiation. In the(More)