Ecological Modelling 258 (2013) 74–81 Contents lists available at SciVerse ScienceDirect Ecological Modelling jo u r n al hom ep age : www.elsevier.com/locate/ecolmodel Interactions at large spatial scale: The case of Centris bees and floral oil producing plants in South America T.C. Giannini a,b,* , C.E. Pinto c,1 , A.L. Acosta a,2 , M. Taniguchi d,3 , A.M. Saraiva e,4 , I. Alves-dos-Santos a,2 a Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, n. 321, 05508-900 São Paulo, São Paulo, Brazil b Universidade Santo Amaro, Rua Professor Enéas de Siqueira Neto, n. 340, 4829-300 São Paulo, São Paulo, Brazil c Faculdade de Filosofia, Ciências e Letras, Universidade de São Paulo, Av. Bandeirantes, n. 3900, 14040-901 Ribeirão Preto, São Paulo, Brazil d Laboratório de Entomologia, Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro s/n., Caixa Postal, 48, 66095-100 Belém, Pará, Brazil e Sistemas Digitais, Escola de Engenharia, Universidade de São Paulo, Av. Prof. Luciano Gualberto, trav. 3, n. 380, 05508-010 São Paulo, São Paulo, Brazil a r t i c l e i n f o Article history: Received 16 October 2012 Received in revised form 25 February 2013 Accepted 27 February 2013 Keywords: Pollinator–plant interaction Distributional range Climate similarity Elaiophore a b s t r a c t Abiotic features and biogeography have been suggested as influencing factors for large-scale species dis- tribution, but little is known about the role of interactions. Aiming to understand how the environmental variables and floral morphology shape the large-scale spatial pattern of species distribution and how this is reflected in the interactions, we analyzed the oil-collecting Centris bee species and the floral oil producing plants in South America. We surveyed the academic literature to build a matrix of interactions and Internet data providers for a dataset of occurrence points of Centris bee species and oil plants with which the bees have been observed. We grouped the interacting bee–plant species according to the two types of floral oil producing gland (epithelial and trichomatic elaiophores) and performed a Cluster Anal- ysis using the averages of climatic and topographic variables to determine the climate similarity among the occurrence areas of each group of bee–plant interacting species. We estimate the significant differ- ences among the climatic conditions in the occurrence areas of the clusters. We identified a distributional pattern of plant–bee interactions that is associated with abiotic factors, especially precipitation, in the occurrence areas. Areas with higher precipitation presented the highest number of species; also, the bee species were associated to plants with epithelial elaiophore and the interactions were more generalized (many partners). In the areas with lower precipitation, we found few species; the interactive plant species include the botanical families that have flowers with trichomatic elaiophores and the interactions were more specialized (few partners). In addition, in these latter areas Centris and their interacting plant are phylogenetically related. The distributional pattern of interactions between Centris bees and floral oil producing plants in South America is related to current ecological processes, mainly precipitation, but also to past evolutionary history. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The geographical distribution of a species can be shaped by four main drivers: abiotic and biotic features, dispersion capabil- ities and biogeography (Hortal et al., 2010). These drivers were * Corresponding author at: Universidade Santo Amaro, Rua Professor Enéas de Siqueira Neto, n. 340, 4829-300 São Paulo, São Paulo, Brazil. Tel.: +55 11 3091 7533/0800 171796; fax: +55 11 3091 7533. E-mail addresses: giannini@usp.br (T.C. Giannini), eduepronto@gmail.com (C.E. Pinto), andreluisacosta@usp.br (A.L. Acosta), marit0210@gmail.com (M. Taniguchi), saraiva@usp.br (A.M. Saraiva), isabelha@usp.br (I. Alves-dos-Santos). 1 Tel.: +55 16 3602 3670. 2 Tel.: +55 11 3091 7533; fax: +55 11 3091 7533. 3 Tel.: +55 91 3204 1000. 4 Tel.: +55 11 3091 9088. supposed to influence the distribution on different geographical scales: abiotic and biogeographic features have significant effects on large-scale processes, and biotic features and dispersion have effects on smaller-scale ones. However, the influence of biotic factors on large-scale distribu- tion has been described in few studies, either because they have not been considered or because data were simply unavailable (Wiens, 2011). For example, a global plant–pollinator (mainly insects) inter- action network analysis demonstrated a more specialized interac- tion pattern (when focal species interact with few partners) toward the tropics and no relationship between richness and altitude or latitude (Trøjelsgaard and Olesen, 2012). Other studies showed that species richness and specialization are positively related when analyzing the global pattern of specialization in bird assem- blages (Belmaker et al., 2012) and in plant-hummingbird networks (Dalsgaard et al., 2011). However, these findings contradict 0304-3800/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ecolmodel.2013.02.032