Get access

Beta diversity at multiple hierarchical levels: explaining the high diversity of scarab beetles in tropical montane forests

Authors

  • Alejandra García-López,

    Corresponding author
    1. Centro Iberoamericano de la Biodiversidad (CIBIO), Universidad de Alicante, Carretera de San Vicente del Raspeig s/n 03690 San Vicente del Raspeig, Alicante, Spain
    2. Department of Entomology, Natural History Museum, London, UK
    • Correspondence: Centro Iberoamericano de la Biodiversidad (CIBIO), Universidad de Alicante, Carretera de San Vicente del Raspeig s/n 03690 San Vicente del Raspeig, Alicante, Spain.

      E-mail: alejandra.garcia@ua.es

    Search for more papers by this author
  • Estefanía Micó,

    1. Centro Iberoamericano de la Biodiversidad (CIBIO), Universidad de Alicante, Carretera de San Vicente del Raspeig s/n 03690 San Vicente del Raspeig, Alicante, Spain
    Search for more papers by this author
  • Cesc Múrria,

    1. Department of Entomology, Natural History Museum, London, UK
    Search for more papers by this author
  • Eduardo Galante,

    1. Centro Iberoamericano de la Biodiversidad (CIBIO), Universidad de Alicante, Carretera de San Vicente del Raspeig s/n 03690 San Vicente del Raspeig, Alicante, Spain
    Search for more papers by this author
  • Alfried P. Vogler

    1. Department of Entomology, Natural History Museum, London, UK
    2. Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, UK
    Search for more papers by this author

Abstract

Aim

High gamma diversity in tropical montane forests may be ascribed to high geographical turnover of community composition, resulting from population isolation that leads to speciation. We studied the evolutionary processes responsible for diversity and turnover in assemblages of tropical scarab beetles (Scarabaeidae) by assessing DNA sequence variation at multiple hierarchical levels.

Location

A 300-km transect across six montane forests (900–1100 m) in Costa Rica.

Methods

Assemblages of Scarabaeidae (subfamilies Dynastinae, Rutelinae, Melolonthinae) including 118 morphospecies and > 500 individuals were sequenced for the cox1 gene to establish species limits with a mixed Yule–coalescent method. A species-level phylogenetic tree was constructed from cox1 and rrnL genes. Total diversity and turnover among assemblages were then assessed at three hierarchical levels: haplotypes, species and higher clades.

Results

DNA-based analyses showed high turnover among communities at all hierarchical levels. Turnover was highest at the haplotype level (community similarity 0.02–0.12) and decreased with each step of the hierarchy (species: 0.21–0.46; clades: 0.41–0.43). Both compositional and phylogenetic similarities of communities were geographically structured, but turnover was not correlated with distance among forests. When three major clades were investigated separately, communities of Dynastinae showed consistently higher alpha diversity, larger species ranges and lower turnover than Rutelinae and Melolonthinae.

Main conclusions

Scarab communities of montane forests show evidence of evolutionary persistence of communities in relative isolation, presumably tracking suitable habitats elevationally to accommodate climatic changes. Patterns of diversity on all hierarchical levels seem to be determined by restricted dispersal, and differences in Dynastinae could be explained by their greater dispersal ability. Community-wide DNA sequencing across multiple lineages and hierarchical levels reveals the evolutionary processes that led to high beta diversity in tropical montane forests through time.

Ancillary