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Báo cáo sinh học: "Evolution underground: shedding light on the diversification of subterranean insects"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Evolution underground: shedding light on the diversification of subterranean insects. | Juan and Emerson Journal of Biology 2010 9 17 http jbiol.eom content 9 3 17 Journal of Biology MINIREVIEW L__ Evolution underground shedding light on the diversification of subterranean insects Carlos Juan 1 and Brent C Emerson2 See research article http www.biomedcentral.com 1471-2148 10 29 Abstract A recent study in BMC Evolutionary Biology has reconstructed the molecular phylogeny of a large Mediterranean cave-dwelling beetle clade revealing an ancient origin and strong geographic structuring. It seems likely that diversification of this clade in the Oligocene was seeded by an ancestor already adapted to subterranean life. Cave organisms have long been considered a model system for testing evolutionary and biogeographic hypotheses because of their isolation simplicity of community structure and specialization. Adaptation to cave environments promotes the regression of functionless unused characters across a broad taxonomic range in concert with evolutionary change in other morphological traits. Change typically involves the degeneration of eyes and loss of pigments while at the same time appendices become elongated intensification of sensory organs occurs and life cycles become modified -a syndrome known as troglomorphy 1 . Modes of speciation and explanations for the geographic distributions of subterranean animals have both been debated see for example 2 3 . Extrinsic environmental factors causing extinction of surface ancestors pre-adapted to the subterranean such as glaciations or aridification are suggested to be a mechanism forcing populations underground. This model is usually invoked in limestone cave systems of continental temperate regions. However among tropical faunas in which surface epigean taxa are often found co-occurring with subterranean sister taxa active colonization of the subterranean habitat is suggested as a more plausible Correspondence cjuan@uib.es department de Biologia Universitat de les Illes Balears 071 22 Palma de Mallorca