Project B2

Evolution, biogeography and genetic diversity of insects and their associated gregarine protists

Research areas: Evolution, Biodiversity, Phylogeny, Population Genetics

Principal investigator: Prof. Dr. Reinhard Predel

Project Info

In B02 we study the evolution of insects and their endobiotic protists (gregarines) in the Atacama with a focus on desert specialists such as the hyperdiverse tenebrionid beetles (Tenebrionidae) and silverfish (Zygentoma). Tenebrionid beetles are generally regarded as theinsects best suited for desert colonization and show increasing species diversity with an increasing degree of aridity.

As was shown in phase 1, some silverfish species are in fact evenmore adapted to hyperarid conditions and the remarkable Gondwanan relict Maindronia was identified as the most xerophilic desert animal. A main goal of our subproject is to correlate, on different time scales, the geographical distribution of desert-adapted insects and their co-evolving gregarines with genetic differentiation. The specific adaptation to their hosts, their ability to form cysts as well as their adaptability to extreme conditions make gregarines ideal model organisms for studies of speciation processes and the speed of evolution of host and endobionts and to analyse effects of geological and behavioural separation. This unprecedented dataset will then be correlated with both ancient and present-day biotic and abiotic factors, especially to identify the key conditions that have led to today's diversity and exceptional endemism in the Atacama Desert.

On the younger time scale, we additionally study the colonization of selected transects in the Atacama with population genetic methods for selected species. Extensive data obtained in the first phase on insect distribution and habitat requirements have provided valuable information for hypotheses on survival, speciation and minimum requirements for the existence of animals at the dry limit, which we will test through experimental and/or long-term studies in regions with an increasing aridity level.

For all approaches, the Atacama Desert can be seen as a perfect area for the study of theevolution of life at the dry limit because of habitat fragmentation and the generally low biodiversity. All planned work will benefit greatly from synergies with other subprojects and collaboration with colleagues from Argentina, Peru and Chile.