Darinka Blies



Caterpillar assemblages on Hedyosmum shrubs along an elevational gradient in a tropical mountain forest in south Ecuador

The larval stages of Lepidoptera on shrubs of the genus Hedyosmum spp. (Chloranthaceae) were investigated in a tropical mountain forest in southern Ecuador in an area around the Podocarpus National Park. Caterpillar communities were surveyed at three elevational levels (1000, 2000 and 3000 m a.s.l.) in 2012 (January-April; September-October) via standardized visual search and branch beating. I collected a total of 70 herbivorous and 90 non-herbivorous caterpillar specimens from 82 shrub individuals representing five different Hedyosmum species. All caterpillars were presented with different foliage and epiphylls to clarify host affiliations. Caterpillars were sorted into 86 operational taxonomic units (OTUs) through an integra-tive taxonomy approach, based on mtDNA barcode sequences and digital photographs of collected caterpillars. Only representatives of four families of Lepidoptera were found, i.e. Geometridae, Noctuidae, Erebidae and Psychidae. Community and feeding guild structure was compared among the different elevations, and abundance and species richness was analyzed separately for each feeding guild. Species turnover between elevation levels was very high. Only four species occurred in more than one elevation. Abundance of herbivorous caterpillars was influenced by elevation, plant species and available leaf biomass of plant individuals. For non-herbivores, the vegetation in the direct surroundings of the focal shrubs, their location in the forest and their leaf biomass were more important than altitude and plant species identity. The fraction of singleton species was 66%. Species richness indicated a mid-elevation peak. The majority (13 species, 67% of individuals) of herbivorous taxa belonged to the Geometridae genus Eois. The observations contribute to a better understanding of diversity and abundance patterns of moths derived from light trapping studies, especially with regard to the speciose genus Eois.

Keywords: Caterpillar communities, host plant affiliation, Chloranthaceae, species richness, altitudinal gradient

Diploma Thesis in Cooperation with University Trier (Germany), Applied Biogeography (Angewandte Biogeographie)

Co-supervisors: Prof. Dr. Thomas Schmitt, Univ.-Prof. Mag. Dr. Konrad Fiedler