Reproductive Behavior of Polyphemus Limulus

每年春天，大批马蹄蟹会迁徙到大西洋沿岸的海滩。雌性与雄性交配后，埋在沙子里产卵，雄性在外面受精。单身的雄性聚集在筑巢的配偶周围，有证据表明它们也会给卵子受精。提出的实地研究将描述该物种不寻常的生殖行为。通过DNA指纹鉴定，将确定有伴雄性和无伴雄性所生后代的比例。描述性观察、标记种群的测量和实验操作将量化筑巢和交配行为，以及种群之间的差异。limus是独一无二的。剑肢动物是唯一现存的节肢动物，具有原始的体外受精模式和水中自由游动的精子。对它们繁殖的研究将有助于深入了解现代节肢动物的祖先。此外，尽管limus是地球上研究得最好的物种之一，但人们对它们的繁殖知之甚少。这项实地研究将为它们生物学的其他方面的研究提供有价值的背景，并将利用它们的优势。最后，由于它们的同步，半月繁殖和外部受精，limus交配显示出与爆炸性繁殖的两栖动物的深刻相似之处。因此，对limus的研究可能为交配系统进化理论提供一个独立的检验。

Every spring large numbers of horseshoe crabs migrate to beaches along the Atlantic coast. Females, with males attached, bury in the sand, laying eggs which the male fertilizes externally. Unattached males aggregate around nesting pairs and evidence suggests that they also fertilize eggs. The proposed field study will characterize the unusual reproductive behavior of this species. The proportion of offspring fathered by attached and unattached males will be determined using DNA fingerprinting. Descriptive observations, measurements of marked populations and experimental manipulations will quantify nesting and mating behavior, and differences between populations. Limulus is unique. The Xiphosurida are the only extant arthropods with the primitive pattern of external fertilization and aquatic, free-swimming sperm. A study of their breeding will provide insight into the ancestors of modern arthropods. Furthermore, although Limulus is one of the best-studied species on the planet, little is known about their reproduction. This field study will provide a valuable context for, and will take advantage of, research on other aspects of their biology. Finally, because of their synchronized, semi-lunar breeding and external fertilization, Limulus mating shows profound similarities to explosively breeding amphibians. Therefore, the study of Limulus may provide an independent test of theories on the evolution of mating systems.