タバコ角虫幼虫（Lepidoptera: Sphingidae）の化学感覚器官の発達奇形の発生率に及ぼす個体数密度の影響

The Effects of Population Density on the Incidence of Developmental Deformities in Chemosensory Organs of Tobacco Hornworm Larvae (Lepidoptera: Sphingidae).

• Frank Hanson
• Elizabeth Stanwyck
• Alexander Bohorquez

抄録

我々の研究室で培養したManduca sexta Johanssenの幼虫には、口縁や触角が欠損していたり、変形していたりすることが判明した。これらの発生奇形は混雑した飼育条件によるものであると仮定して，4つの異なる個体密度で幼虫を飼育し，発生率（影響を受けた幼虫の％）と化学受容体奇形の種類を記録した。その結果、これらの奇形の発生率は幼虫の個体密度に正比例することがわかった。上顎と口蓋の奇形が最も多く，次いで触角，咽頭，上顎スタイロニカの順であった。また，幼虫の質量，食物消費量，発育速度などの生活史的特徴は，正常幼虫と奇形幼虫の両方で幼虫密度に反比例していた。本研究では，これらの奇形の原因とメカニズム，および生活史形質の変化について考察した。

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.

© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America.