Skip to main content
ARS Home » Research » Publications at this Location » Publication #157591
Title: JUVENILE HORMONE III TITERS AND REGULATION OF SOLDIER CASTE IN COPTOTERMES FORMOSANUS

Author
item Park, Yong
item Raina, Ashok

Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2004
Publication Date: 6/14/2004
Citation: Park, Y.I., Raina, A.K. 2004. Juvenile hormone III titers and regulation of soldier caste in Coptotermes formosanus. Journal of Insect Physiology. 50:561-566.

Interpretive Summary: Formosan termite is a subterranean species that is composed of different castes; young and matured workers, soldier, and adult. A specific hormone is known to play a key role in the formation of different castes. However, there is no information available on how various termite castes regulate their hormone titers in the field. It is important to understand the mechanism of soldier formation for developing efficient methods to control the termite colony. We report for the first time that juvenile hormone III is specific to the Formosan subterranean termite. JH III and its analog methoprene, can promote caste differentiation from workers to soldiers. However, feedback mechanism by soldiers regulates additional soldier formation. Changes of hormonal titers showed how workers were influenced by soldiers in experimental groups and how the hormone analog regulated the formation of soldier caste. The information will be useful for termite researchers to better understand the hormonal control of caste differentiation in termites with emphasis on soldier formation.

Technical Abstract: Juvenile hormone (JH) is an important growth hormone in insects that has also been implicated in caste determination in termites. Gas chromatography-mass spectrometry was used to establish that the JH in the Formosan subterranean termite (FST), Coptotermes formosanus Shiraki, is JH III. JH III titers were measured in workers, pre-soldiers, and soldiers of the FST from samples collected from the field. The average amounts of JH III in workers and soldiers were 41 and 78 pg respectively, however, a pre-soldier contained a significantly higher amount of 1600 pg. As expected, treatment of workers with a JH-analog (JHA), methoprene, triggered rapid formation of pre-soldiers. However, these pre-soldiers had a very low JH III titer (166 pg). It appears that the application of JHA while inducing pre-soldier formation does not increase the endogenous JH III titer. The titer however increased as the pre-soldiers aged and before transforming into soldiers.