Dissertation Research: Heterochrony in Insects: Phylogeny and Evolution of Acoustic Characters in the True Crickets (Orthoptera: Grylloidea)

论文研究：昆虫的异时性：真蟋蟀（直翅目：蟋蟀总科）的系统发育和声学特征的进化

• 批准号: 0073187
• 负责人: Naomi Pierce
• 金额: $ 1万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-15 至 2002-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0073187&HistoricalAwards=false
• 关键词: Dissertation; Research; Heterochrony; Insects; Phylogeny

0073187Shaw and Jost Crickets have always interested biologists for their calling songs used incourtship. In most species, male crickets produce a song which is heard and recognized by potential female mates. There are thousands of cricket species worldwide, each of which has a unique type of song. Previous studies have looked for ecological or adaptive reasons that cricket calling songs are so diverse. However, few evolutionary studies have looked at cricket song from a morphological perspective, by examining the structures which produce and receive the sounds. In crickets, these acoustic structures are specialized front wings in males, and hearing organs on the front legs of both sexes. These structures are extremely diverse in crickets (there are ca. 3,500 described species in the world), but in many species are completely absent. Developmental studies have found that acoustic body parts are strictly adult structures which do not appear until the final life stage. In addition, many other structures -- such as hind flight wings, eyes, antennae, and genitalia -- are often reduced or absent in non-acoustic cricket species. The simplest way that many adult traits could be reduced or absent in a species is by changing the timing of overall growth. In other words, many non-acoustic cricket species may simply be morphologically immature forms of closely related acoustic species. This project will test the hypothesis that morphological diversity in acoustic structures can be explained by changes in the timing of growth and metamorphosis, a process known as heterochrony. Graduate student Manda Jost, with guidance from faculty adviser Dr. Kerry Shaw, is studying the phylogenetic relationships of exemplar species of crickets and their acoustic evolution. The first step to testing the heterochrony hypothesis will be a broad, detailed survey of cricket morphology for hundreds of species. A diverse sample of species will then be selected from regions around the world, and a phylogeny will be produced using DNA sequence from the mitochondrial gene CO-I. Statistical and comparative tests will then determine whether morphological "maturity" of acoustic structures is significantly correlated with the "maturity" of other morphological structures which are functionally unrelated. Demonstrating that many functionally unrelated traits show simultaneous change would support the hypothesis that these traits are all under control of a basic growth schedule. This idea is not an alternative to ecological or adaptive hypotheses, but provides a physical mechanism which could produce the diversity we observe. This study will result in the most detailed phylogeny to date of the crickets, while using new ideas and methods to study the diversity of cricket acoustic characters.

0073187肖和约斯特蟋蟀一直对它们在求爱时的叫声感兴趣。 在大多数物种中，雄性蟋蟀会发出一种歌声，让潜在的雌性配偶听到并识别。 世界上有成千上万种蟋蟀，每种都有独特的歌声。之前的研究已经寻找了蟋蟀叫声如此多样化的生态或适应性原因。然而，很少有进化研究从形态学的角度，通过检查产生和接收声音的结构来研究蟋蟀的歌声。 在蟋蟀中，这些声学结构是雄性的专门前翅，以及两性前腿上的听觉器官。 这些结构在蟋蟀中是非常多样的（有ca。世界上有3，500种被描述的物种），但在许多物种中完全不存在。发育研究发现，声学身体部位是严格意义上的成人结构，直到生命的最后阶段才出现。此外，许多其他结构-如后翅，眼睛，触角和生殖器-在非声学蟋蟀物种中往往减少或缺失。 一个物种中许多成年特征可能减少或缺失的最简单方法是改变整体生长的时间。换句话说，许多非声学蟋蟀物种可能只是形态上不成熟的形式密切相关的声学物种。这个项目将测试这一假设，即声学结构的形态多样性可以通过生长和变态的时间变化来解释，这一过程被称为异时性。 研究生Manda Jost在导师Kerry Shaw博士的指导下，正在研究蟋蟀的典型物种及其声学进化的系统发育关系。检验异时性假说的第一步将是对数百种蟋蟀形态进行广泛而详细的调查。 然后将从世界各地选择不同的物种样本，并使用线粒体基因CO-I的DNA序列产生一个同源基因。 然后，统计和比较测试将确定声学结构的形态“成熟度”是否与功能上不相关的其他形态结构的“成熟度”显著相关。证明许多功能上不相关的性状同时发生变化将支持这些性状都受基本生长时间表控制的假设。 这个想法不是生态或适应性假设的替代方案，但提供了一种物理机制，可以产生我们观察到的多样性。这项研究将导致最详细的蟋蟀迄今为止，同时使用新的思路和方法来研究蟋蟀声学特征的多样性。