MatthiasSchleuningBiodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft fuer Naturforschung

Maria AlejandraMaglianesiBiodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft fuer Naturforschung

B.BluthgenKatrinBoehning-GaeseBiodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft fuer Naturforschung

M.BluthgenAuthor2015-03-27Ecological communities are organized in complex ecological networks. Trait-based analyses of the structure of these networks in highly diversified species assemblages are crucial for improving our understanding of the ecological and evolutionary processes causing specialization in mutualistic networks. In this study, we assessed the importance of morphological traits for structuring plant-hummingbird networks in Neotropical forests by using a novel combination of quantitative analytical approaches. We recorded the visitation of hummingbirds to plant species over an entire year at three different elevations in Costa Rica and constructed quantitative networks based on interaction frequencies. Three morphological traits were measured in hummingbirds (bill length, bill curvature, and body mass) and plants (corolla length, curvature, and volume). We tested the effects of avian morphological traits and abundance on ecological specialization of hummingbird species. All three morphological traits of hummingbirds were positively associated with ecological specialization, especially bill curvature. We tested whether interaction strength in the networks was associated with the degree of trait matching between corresponding pairs of morphological traits in plant and hummingbird species and explore whether this was related to resource handling times by hummingbird species. We found strong and significant associations between interaction strength and the degree of trait matching. Moreover, the degree of trait matching, particularly between bill and corolla length, was associated with the handling time of nectar resources by hummingbirds. Our findings show that bill morphology structures tropical plant-hummingbird networks and patterns of interactions are closely associated with morphological matches between plant and bird species and the efficiency of hummingbirds' resource use. These results are consistent with the findings of seminal studies in plant-hummingbird systems from the neotropics. We conclude that trait-based analyses of quantitative networks contribute to a better mechanistic understanding of the causes of specialization in ecological networks and could be valuable for studying processes of complementary trait evolution in highly diversified species assemblages.biotic interactionscosta ricafourth-corner analysishummingbirdsmutualistic networksneotropical forestoptimal foragingpollinationspecializationtrait complementaritytrochilidaeObtain permission from data set owner(s)The study was conducted in northeastern Costa Rica within the forest of the La Selva Braulio Carrillo corridor on the Caribbean slope of the Cordillera Central. This area extends from La Selva Biological Station to the Braulio Carrillo National Park. Our study sites included three tropical forest types located at different elevations: wet forest (50 m) in LS, pre-montane forest (1000 m), and lower montane wet forest (2000 m) in the park (Holdridge 1967). All sites were located in old-growth forest. Canopy heights were; 30-40 m at LS, 30-35 m at 1000 m, and 20 m at 2000 m (Hartshorn and Peralta 1988). Mean annual temperature ranges from 258C in the lowlands to 148C in the highlands, while mean annual precipitation ranges from 4300 mm in the lowlands to 2200 mm in the highlands (data provided by the Tropical Ecology Assessment and Monitoring network [TEAM], Volcan Barba, Costa Rica; Blake and Loiselle 2000). The dry season lasts from January to April, and the wettest months are July and October-November.-84.0167-84.116710.433310.18332011-05-012012-04-30TrochilidaeHummingbird speciesMatthiasSchleuningBiodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft fuer Naturforschung

Matthias.Schleuning@senckenberg.deMaria AlejandraMaglianesiBiodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft fuer Naturforschung

KatrinBoehning-GaeseBiodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft fuer Naturforschung

During the period of sampling, we collected data on abundances and morphological traits of flower resources and hummingbirds and on plant-hummingbird interactions across seven sampling periods per site, each lasting for about 10 days.

attached_fileNot authorized to access resourceOtherattached_fileNot authorized to access resourceOtherattached_fileNot authorized to access resourceOther timeseries The study was conducted from May to September 2011 and from December 2011 to April 2012. During the period of sampling, we collected data across seven sampling periods per site, each lasting for about 10 days. monthly