Testing for non-adaptive radiations in European spring snails

• Applicants: Dr. Martin Brändle; Professor Dr. Thomas Wilke
• Subject Area: Evolution and Systematics of Plants and Fungi
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 27030111

Recently, there has been an increased interest in the study of radiations. However, whereas one form of radiation ¿ adaptive radiation ¿ has been studied extensively, another form ¿ non-adaptive radiation ¿ is discussed controversially and poorly understood. In fact, the concept of non-adaptive radiation (i.e., diversification not accompanied by adaptation into various niches and resulting in a group of allopatric species) is rejected by some workers. Although specific and testable criteria have been proposed for this radiation, they have never been tested in a comprehensive and rigorous statistical fashion, partly because many radiations in continental animal groups (particularly in Europe) have been largely affected by human impact. A possible exception is the European spring snail genus Bythinella; a large monophyletic group with several proposed radiations that is distributed throughout the continent, yet only little affected by human impact. Moreover, its presumed lack of morphological and niche differentiation makes it an ideal candidate for studying non-adaptive radiations. Based on extensive morphological, genetic, and ecological data, the goals of the current projects are to identify radiations, to test the previously proposed criteria for nonadaptive radiation and to test for potential gradual differences between adaptive and nonadaptive radiations.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1127: Radiations - Origins of Biological Diversity
• Participating Person: Professor Dr. Christian Albrecht