Co-evolution between ambrosia fungi and abrosia beetles of the genus Xyleborus

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Ambrosia beetles of the genus Xyleborus (Scolytidae) live as larvae and adults in the sapwood of woddy plants. They depend obligatorily on fungi of the genus Ambrosiella (ophiostomatoid fungi) that are disseminated and reared by the beetles for nutrition. The spores of the fungi are stored and tansmitted by the beetles to new host plants within specialized organs associated with essential glandular cells, the mycangia. The symbiotic association between Xyleborus ambrosia beetles and Ambrosiella fungi functioning as a model of co-evolution of insects and fungi will be investigated. An inventory of the hitherto undescribed fungal partners of the ambrosia beetles is essential and to be done by isolation, cultivation, morphological and molecular characterization. Phylogenetic relationships between beetle species will be evaluated using molecular techniques and comparisons of characteristics involved in the symbiotic interaction, especially position and morphology of the mycangia and the composition of secretions produced by the mycangial glands. The response of the ambroisa fungi to the presence of the secretions of host and non-host beetles will be tested experimentally. In a synthesis, these approaches will be used for calculating possible cospeciation events.