Cultures of Manduca sexta Johanssen in our laboratory were found to have larvae with missing or deformed mouthparts or antennae. Hypothesizing that these developmental deformities were caused by crowded rearing conditions, we reared larvae in four different population densities and recorded the incidence (% of larvae affected) and types of chemoreceptor deformities. Results showed that the incidence of these deformities was directly proportional to larval population density. Deformities of the maxilla and palp were the most frequent, followed by those of the antenna, epipharynx and maxillary styloconica. Life history traits of larval mass, food consumption, and rate of development were inversely related to larval density for both normal and deformed larvae. We discuss possible causes and mechanisms of these deformities and of changes to life history traits.

中文翻译：

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人口密度对烟草天蛾幼虫（鳞翅目：天蛾科）化学感觉器官发育畸形发生率的影响。

曼杜卡六sex文化在我们的实验室中，约翰森发现幼虫的口器或触角缺失或变形。假设这些发育畸形是由拥挤的饲养条件引起的，我们以四种不同的种群密度饲养了幼虫，并记录了化学感受器畸形的发生率（受影响的幼虫百分比）和类型。结果表明，这些畸形的发生与幼虫种群密度成正比。上颌和触诊的畸形最常见，其次是触角，上咽和上颌的棘突。幼虫的生活史特征，食物消耗和发育速度与正常和变形幼虫的幼虫密度成反比。我们讨论了这些畸形以及生活史特征变化的可能原因和机制。