The U.S. Fish and Wildlife Service (FWS) has declared that one of North America's best known butterflies, the monarch, might be in trouble. But the agency put off protecting the insect under the federal Endangered Species Act, which may give researchers time to resolve a long-standing debate over how best to gauge the health of monarch populations. In recent months, dueling preprints and publications have intensified the debate. In one camp: researchers who have documented drastic declines in the number of monarchs in Mexico and other areas where some butterflies spend the winter. They believe the species needs even more immediate help, particularly by protecting and expanding the milkweed-filled meadows where its larvae feed. In another: scientists who have tallied the surveys of butterflies in areas they occupy during the warmer months and have concluded there is less cause for alarm.

美国鱼类和野生动物服务局（FWS）宣布，北美最著名的蝴蝶之一君主可能会遇到麻烦。但是该机构根据联邦《濒危物种法》推迟了对昆虫的保护，该法案可能使研究人员有时间解决关于如何最好地评估君主种群健康的长期争论。近几个月来，预印本和出版物的争执加剧了争论。在一个集中营中：研究人员记录了墨西哥和其他蝴蝶过冬的其他地区的君主人数急剧下降的情况。他们认为该物种需要更紧急的帮助，特别是通过保护和扩大其幼虫为食的马利筋牧场。在另一个：