The spatial analysis of biological interactions: morphological variation responding to the co‐occurrence of competitors and resources

Rosa Daniela Tovilla‐Sierra,Héctor T Arita,Leonel Herrera‐Alsina,Rafael Bribiesca

doi:10.1111/jav.02223

Rosa Daniela Tovilla‐Sierra, Héctor T Arita + Show 2 more

Open Access

https://doi.org/10.1111/jav.02223

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Abstract

By sharing geographic space, species are forced to interact with one another and the contribution of this process to evolutionary and ecological patterns of individual species is not fully understood. At the same time, species turnover makes that species composition varies from one area to another, so the analysis of biological interaction cannot be uncoupled from the spatial context. This is particularly important for clades that show high degree of specialization such as hummingbirds, where any variation in biotic pressures might lead to changes in morphology. Here, we describe the influence of biological interactions on the morphology of Hylocharis leucotis by simultaneously considering potential competition and diet resources. We characterized the extent of local potential competition and local available floral resources by correlating two measurements of hummingbird diversity, floral resources and the size of morphological space of H. leucotis along its geographic distribution. We found that H. leucotis shows an important morphological variability across its range and two groups can be recognized. Surprisingly, morphological variation is not always linked to local hummingbird richness or the phylogenetic similarity of. Only in the southern part of its distribution, H. leucotis is morphologically more variable in those communities where it coexist with closely related hummingbird species. We also found that morphological variation in H. leucotis is independent from the availability of floral resources. Our results suggest that abiotic factors might be responsible for morphological differences across populations in Hylocharis leucotis being biological interactions of minor importance.

Highlights

Species occurrence in local assemblages is determined by the joint influence of environment and biological interactions and their relative contribution is matter of debate (Diamond 1975, Sanderson et al 2009, Harmon and Harrison 2015, Rabosky and Hurlbert 2015)
We found with the ANOVA analysis, that eight variables for males and seven variables for females have significant differences across the 41 operational geographical units (OGUs) (Table 1, Fig. 4a–b), suggesting that there is an important variation in the morphological space of H. leucotis and pointing towards a larger size in specimens collected in the northern part of its geographical distribution
We found that there is an important morphological variation of H. leucotis across its geographic distribution and, intriguingly, this variation is not associated in general with neither diet diversity nor potential competition experienced by H. leucotis at local communities

Summary

Introduction

Species occurrence in local assemblages is determined by the joint influence of environment and biological interactions and their relative contribution is matter of debate (Diamond 1975, Sanderson et al 2009, Harmon and Harrison 2015, Rabosky and Hurlbert 2015). Dispersal might play an important role in community assembly as species distributions at continental scales are cohesive (but see Herrera-Alsina et al 2018). From this perspective, the occurrence of species in a site is determined by the combined effect of evolutionary processes such as speciation and extinction, environmental conditions, interactions between species and rates of range expansion (Wiens and Donoghue 2004, Field et al 2009)

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