Hexamerin-based regulation of juvenile hormone-dependent gene expression underlies phenotypic plasticity in a social insect

Area of Science:

• * Insect developmental biology
• * Molecular endocrinology
• * Social insect caste determination

Background:

• * Termite worker development involves temporal regulation of juvenile hormone (JH).
• * Hexamarins are known to reduce JH efficacy, maintaining high worker proportions for colony fitness.
• * The precise role of hexamarins in JH-dependent gene expression requires further investigation.

Purpose of the Study:

• * To investigate the influence of hexamarins on JH-dependent gene expression in *Reticulitermes* termite workers.
• * To elucidate the molecular mechanisms by which hexamarins modulate JH signaling pathways.

Main Methods:

• * RNA interference (RNAi) was used to silence hexamerin expression in termite workers.
• * Gene expression levels of 17 morphogenesis-associated genes were quantified.
• * Gene expression profiles were compared between hexamerin-silenced workers, untreated workers, and JH-treated workers.

Main Results:

• * Silencing hexamarins significantly affected the expression of 15 out of 17 tested morphogenesis-associated genes.
• * A significant correlation was observed between hexamerin silencing and JH-treatment effects on gene expression.
• * No correlation was found between hexamerin silencing and colony-release effects.

Conclusions:

• * Hexamarins play a crucial role in modulating JH availability and limiting its impact on termite caste polyphenism.
• * These findings support the hypothesis that hexamarins are key regulators within JH-responsive genomic networks.
• * Further research is needed to understand the interplay of JH, colony, and environmental cues in termite development.