REU/LTER: Insect Fossils and Late Quaternary Environments of Western Texas

在过去的二十年里，对西南沙漠晚第四纪环境的认识得到了极大的扩展，这主要是由于对包鼠丘的古植物学研究的引入。Van Devender（1985）在过去4万年中对德克萨斯州西部奇瓦瓦沙漠地区进行了古生态重建，记录了威斯康星冰期期间和之后植被对环境变化的一系列反应。Van Devender制作了一系列110种昆虫化石组合，以供详细研究。在这项研究中，这些组合将被用来检验关于过去昆虫区系组合的现代类似物的假设，昆虫对环境变化的相对响应率与植被的相对响应率，以及现代奇瓦瓦沙漠昆虫区系的起源。此外，还将研究叠鼠丘昆虫化石的分类学，收集现代昆虫的生境和分布资料。以活鼠为实验对象，测试它们对各种大型甲虫的接受程度和偏好。昆虫化石样本涵盖了与古植物学记录相同的时间跨度，并来自相同的midden样本。它提供逐点逐样的古植物数据和放射性碳年表，以便与昆虫化石数据进行对比。

Knowledge of Late Quaternary environments of the desert southwest has expanded greatly in the past twenty years, due mostly to the introduction of paleobotanical studies of packrat middens. Paleoecological reconstructions of the Chihuahuan Desert regions of western Texas have been developed by Van Devender (1985) for the past 40,000 years, documenting a series of vegetational responses to environmental changes during and after the Wisconsin Glaciation. Van Devender has made a series of 110 insect fossil assemblages available for detailed investigation. In this research, these assemblages will be used to test hypotheses concerning modern analogs for past insect faunal assemblages, the relative rate of insect response to environmental change in comparison to that of the vegetation, and the origins of the modern Chihuahuan Desert insect fauna. In addition, the taphonomy of insect fossils in packrat middens will be examined and modern insect habitat and distribution data will be collected. Experiments on live-trapped packrats will test their acceptance and/or preference for various large-sized beetle species. The insect fossil samples cover the same time span as the paleobotanical record, and derive from the same midden samples. This provides site-by-site and sample-by-sample paleobotanical data and radiocarbon chronologies for correlation with insect fossil data.