TAILIEUCHUNG - Báo cáo sinh học: "Clocks, cryptochromes and Monarch migrations"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Clocks, cryptochromes and Monarch migrations. | Journal of Biology BioMed Central Minireview Clocks cryptochromes and Monarch migrations Charalambos P Kyriacou Address Department of Genetics University of Leicester Leicester LE1 7RH UK. Email cpk@ Published 18 June 2009 Journal of Biology 2009 8 55 doi jbiol153 The electronic version of this article is the complete one and can be found online at http content 8 6 55 2009 BioMed Central Ltd Abstract The annual migration of the Monarch butterfly Danaus plexippus from eastern North America to central Mexico is one of nature s most inspiring spectacles. Recent studies including one in BMC Biology have begun to dissect the molecular and neurogenetic basis for this most complex behavior. At the approach of fall in the northern United States and southern Canada the Monarch butterfly Danaus plexippus Figure 1 starts to get restless. These butterflies usually represent the third or fourth generation that season each previous generation having lived for around 6-8 weeks. The current generation senses the shorter photoperiod of autumn days and starts to shut down its reproductive system lay down extra layers of fat and in general become more physiologically resistant to environmental stresses such as colder temperatures. This state of diapause precedes one of nature s most glorious sights the annual autumn migration of the Monarch from the northern United States to its overwintering grounds in central Mexico where it settles in oyamel fir trees 1 . This alteration in the Monarch s physiological state in readiness for the arduous 4 000-kilometer journey south includes a three-to fourfold increase in longevity that will carry these individuals through to the following spring in Mexico. At that time they mate lay the fertilized eggs on milkweed Asclepias and the few adults that survive begin their northern journey home. In two or three generations each one laying eggs progressively further north as milkweed starts into new growth the Monarchs .

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