The Aegean archipelago, which has a mostly continental origin, provides a
‘natural laboratory’ to explore the effects of dispersal limitation on population and
community structure. This thesis investigated the phylogeographic, genetic diversity
and species richness patterns of the darkling beetles (Coleoptera: Tenebrionidae) of
the central Aegean islands. Sampling was conducted on 30 islands and the
corresponding coasts of Greece and Turkey and several individuals per taxon and
locality were sequenced for mitochondrial and nuclear markers. The generated
sequence data were used to: reconstruct phylogenies, calculate population genetic
parameters, apply DNA-based species delineation methods, estimate substitution rates
and assess macroecological patterns. The results show that many of the existing
taxonomic names do not reflect the genetic diversification processes in the
archipelago. The majority of the morphological species are split into several
geographically confined clades, recognised as ‘independently coalescing entities’.
Habitat preference and wing development were identified as two major factors
affecting phylogeographic structure, genetic diversity and macroecological patterns.
Differences in dispersal propensity were observed between psammophilic taxa
inhabiting ephemeral coastal sandy habitats and geophilic taxa associated with
presumably stable compact-soil habitats. The widespread geophilic lineages were
found to be deeply subdivided along the biogeographic barrier of the ‘mid-Aegean
trench’, and the age of this geological event was used as a calibration point to estimate
substitution rates and reassess the ‘standard' insect mitochondrial molecular clock. A
positive species – genetic diversity correlation was recorded, driven primarily by
island sizes and geographic distances, while certain macroecological regularities such
as the species – area curve and the distance – decay of similarity relationship could be
described at both species and haplotype level. This study demonstrated how
palaeogeography, contemporary geography and habitat persistence interact with
stochastic processes at population and community level to shape the observed
diversity patterns of the Aegean tenebrionid fauna
