Transcriptomic Analysis Reveals Insect Hormone Biosynthesis Pathway Involved in Desynchronized Development Phenomenon in Hybridized Sibling Species of Tea Geometrids (<i>Ectropis grisescens</i> and <i>Ectropis obliqua</i>)

• Main Authors: Zhibo Wang, Jiahe Bai, Yongjian Liu, Hong Li, Shuai Zhan, Qiang Xiao
• Format: Article
• Language: English
• Published: MDPI AG 2019-11-01
• Series: Insects
• Subjects: sibling tea geometrid; hybridization generation; desynchronized development; transcriptome analysis; juvenile hormone; moulting hormone
• Online Access: https://www.mdpi.com/2075-4450/10/11/381

<i>Ectropis grisescens</i> and <i>Ectropis obliqua</i> are sibling species of tea-chewing pests. An investigation of the distribution of tea geometrids was implemented for enhancing controlling efficiency. <i>E. grisescens</i> is distributed across a wider range of tea-producing areas than <i>Ectropis obliqua</i> in China with sympatric distribution found in some areas. In order to explore reproductive isolation mechanisms in co-occurrence areas, hybridization experiments were carried out. Results showed they can mate but produce infertile hybrids. During experiments, the desynchronized development phenomenon was found in the hybridized generation of sibling tea geometrids. Furthermore, transcriptome analysis of those individuals of fast-growing and slow-growing morphs revealed that the insect hormone biosynthesis pathway was enriched in two unsynchronized development groups of hybrid offspring. More importantly, some genes regulating the synthesis of moulting hormone showed significantly up-regulated expression in fast-growing groups. Above all, metabolism of the juvenile hormone and synthesis of the ecdysone pathway were found to be crucially involved in the desynchronized development phenomenon. This research finding contributes to a better understanding of the mechanisms of insect development and reproductive isolation of two sibling species.