REU: Genetic Coordination of Insect Life Histories

所有生物都具有影响其生存和繁殖能力的特性。任何性状都不能脱离整个有机体而孤立存在；然而，一个物种或种群的整个生命周期策略是由一些相互作用的特征和一些不相互作用的特征组成的，这也是事实。布拉德肖博士提出，昆虫的生命周期是由基因协调的特征（策略）组成的，这些特征（策略）本身可能是基因协调的。他还认为昆虫生命周期的两个基本组成部分是：(1)在有利条件下的直接发育和(2)在不利条件下的休眠或迁徙。此外，布拉德肖博士还预测，在某些情况下，这些基本组成部分本身应该相互协调，或者自由地独立进化。为了验证这些预测，布拉德肖博士将研究一种蚊子的生命周期特征的协调性，这种蚊子只在一种从墨西哥湾到加拿大中北部的紫色肉食性猪笼草充满水的叶子中生长。猪笼草蚊子可能是在最后一个冰河时代之后从南美入侵北美的，并从南向北进化。在研究这种蚊子的过程中，布拉德肖博士正在研究一种热带蚊子在美国温带地区的入侵和适应。热带黄热病蚊子目前在我们的墨西哥湾沿岸各州出现，亚洲虎蚊最近入侵了美国南部和东部，这种蚊子可以携带登革热和脑炎病毒。因此，这项研究的结果将对热带蚊子成功传播到我国北部气候的限制或机会产生直接影响。

All organisms possess traits that affect their ability to survive and reproduce. No trait exists in isolation from the whole organism; it is also true, however, that the overall life- cycle strategy of a species or population is comprised of some traits that interact and some that do not. Dr. Bradshaw has proposed that insect life cycles are composed of genetically coordinated traits (tactics) that may themselves be genetically coordinated. He has also argued that the two fundamental components of an insect's life cycle are (1) direct development under favorable conditions and (2) dormancy or migration under unfavorable conditions. Further, Dr. Bradshaw has predicted situations under which these fundamental components should, themselves, be coordinated or free to evolve independently. To test these predictions, Dr. Bradshaw will examine the coordination of life-cycle traits in a mosquito that develops only within the water-filled leaves of the carnivorous purple pitcher plant from the Gulf of Mexico to north-central Canada. The pitcher-plant mosquito has invaded North America from South America, probably after the last ice age, and has evolved from south to north. In studying this mosquito, Dr. Bradshaw is examining the invasion and adaptation of a tropical mosquito into the temperate zone of the United States. The tropical yellow- fever mosquito presently is established in our Gulf Coast States and the Asian tiger mosquito, that can carry dengue fever and encephalitis viruses, has recently invaded southern and eastern United States. The results of this research will thus have direct implications on the constraints or opportunities that tropical mosquitoes may have in successfully spreading to more northern climates in our country.