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Mechanisms structuring arboreal ant communities along ecological gradients in New Guinea rainforests
PLOWMAN, Nichola Sarah
The thesis explores the community ecology and diversity of tropical ants, with a strong focus on the arboreal ants of Papua New Guinea rainforests. The aim was to investigate the drivers of community structure in these diverse communities, and how these change along the ecological gradients of elevation and forest succession. Using unique datasets from censuses of whole forest plots at low, mid and high elevation forests, the effects of vegetation structure and nest microhabitat use on ant community structure and diversity are compared across elevations. Furthermore, a community study of an understorey ant-plant mutualism was undertaken to explore elevational changes in interaction networks and the costs and benefits of mutualistic interaction. For lowland primary and secondary forest, taxonomic, functional and phylogenetic diversity of arboreal ant communities were quantified. In addition, aspects of the methodology of community functional diversity studies are examined, and suggested improvements to data handling in cases where full datasets are not available are discussed.
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Preferences of the basic components of food by central European speciens of ants.
NOSKOVÁ, Lenka
This thesis has two parts: the first brings an overview of the role of various foods and nutrients in ants, the second presents the results of an experiment focused on preference of the basic components of food by central European species of ants. In the experiment we provided ants with six different baits (water, 1% sodium chlorid, olive oil, 20% amino acid glutamine, artificial honey [10% sucrose + 10% amino acid] and 20% sucrose). Total, 187 of 690 traps were visited by ants. There were 26 recorded species of ants. Preference of four most abundant species differed. F. polyctena attended most of the offered baits, while other species preferred the sugar components. In general, ants preferred artificial honey and sucrose, regardless of the season and habitats. Additional field tests with different bait concentration of salt and sucrose showed the same preferences regardless of bait type and no additive effects of the amino acid in the sucrose baits. The results of the experiment show a surprisingly consistent and strong preference of central European species of ants for sugars.
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Diversity and ecology of arboreal ant communities in a tropical lowland forest
KLIMEŠ, Petr
The thesis focuses on the study of arboreal ant communities in a highly diverse tropical rainforest in Papua New Guinea. In the first study of its kind, whole patches of forest were sampled extensively for ants foraging and nesting in tree trunks and canopies. An extraordinary amount of material collected from 684 felled trees and 260 bait stations in plots of primary and secondary forest was used to study the mechanisms structuring the diversity and species coexistence of this ecologically important insect group at the local scale. The first chapter addresses the question "Why are ant communities more species rich in primary than in secondary forests?" and explores the main environmental traits that influence their diversity in tropical trees. The second chapter compares the community diversity and composition and nesting preferences of ant species between both forest types. The final third chapter introduces a novel method, involving large-scale manipulation of ant communities that could serve as a template for future studies focused on complex tropical food-webs of canopy arthropods and plants. In summary, the results of the thesis highlight the importance of primary vegetation in conserving the diversity of native ant communities and the relevance of nesting microhabitats and their turnover between trees, rather than tree taxonomic diversity, for sustaining the diverse arboreal fauna in tropical forests.
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