Effect on mandibular length of juvenile hormones and regulation of soldier differentiation in the termite Reticulitermes speratus (Isoptera: Rhinotermitidae)

To understand the relationship between juvenile hormone (JH) titers and morphogenetic changes associated with soldier differentiation of the termite Reticulitermes speratus, mandibular length (length between apex and first teeth) of presoldiers induced by various concentrations of JH III (0–320 μg per dish) was measured. Presoldiers were observed when treated with more than 20 μg JH III. Both left and right mandibular lengths were significantly different among differentiated presoldiers treated with different concentrations of JH III. Concentration-dependent effects on mandibular lengths were observed: higher JH III concentrations (160 and 320 μg) caused differentiation in presoldiers with longer mandibles, and lower concentrations (40 and 80 μg) caused differentiation in presoldiers with shorter mandibles. These results suggest that morphogenetic changes specific to soldiers are influenced by JH titers (endogenous JH+applied JH III) in workers. Live soldiers could inhibit presoldier differentiation in R. speratus workers. Interestingly, mandibular lengths of presoldiers induced by JH III were influenced by soldier presence, which could influence morphological changes, probably by regulation of JH titers in workers, as recently shown in the termite Coptotermes formosanus.

[1]  K. Maekawa,et al.  Soldier Differentiation and Larval Juvenile Hormone Sensitivity in an Incipient Colony of the Damp-Wood Termite Zootermopsis nevadensis (Isoptera, Termopsidae) , 2008 .

[2]  A. Zera.  Endocrine analysis in evolutionary‐developmental studies of insect polymorphism: hormone manipulation versus direct measurement of hormonal regulators , 2007, Evolution & development.

[3]  R. Hanus,et al.  Juvenile hormone III, hydroprene and a juvenogen as soldier caste differentiation regulators in three Reticulitermes species: potential of juvenile hormone analogues in termite control. , 2006, Pest management science.

[4]  X. Zhou,et al.  Social exploitation of hexamerin: RNAi reveals a major caste-regulatory factor in termites. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[5]  R. Laine,et al.  Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Soldiers Regulate Juvenile Hormone Levels and Caste Differentiation in Workers , 2005 .

[6]  A. Raina,et al.  Regulation of juvenile hormone titers by soldiers in the Formosan subterranean termite, Coptotermes formosanus. , 2005, Journal of insect physiology.

[7]  K. Hartfelder.  3.13 – Endocrine Control of Insect Polyphenism , 2005 .

[8]  A. Raina,et al.  Juvenile hormone III titers and regulation of soldier caste in coptotermes formosanus (Isoptera: Rhinotermitidae). , 2004, Journal of insect physiology.

[9]  B. Pittendrigh,et al.  Caste differentiation responses of two sympatric Reticulitermes termite species to juvenile hormone homologs and synthetic juvenoids in two laboratory assays , 2003, Insectes Sociaux.

[10]  D. J. Wright,et al.  The life cycle of Reticulitermes spp (Isoptera: Rhinotermitidae): what do we know? , 2003, Bulletin of entomological research.

[11]  A. Raina,et al.  Factors regulating caste differentiation in the Formosan subterraneantermite with emphasis on soldier formation , 2003 .

[12]  T. Miura,et al.  Morphometric changes during soldier differentiation of the damp-wood termite Hodotermopsis japonica (Isoptera, Termopsidae) , 2002, Insectes Sociaux.

[13]  K. Hartfelder.  Insect juvenile hormone: from "status quo" to high society. , 2000, Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas.

[14]  Yves Roisin,et al.  Diversity and evolution of caste patterns , 2000 .

[15]  C. Everaerts,et al.  Effects of juvenile hormone analogues upon soldier differentiation in the termite Reticulitermes santonensis (Rhinotermitidae, Heterotermitinae) , 1993, Journal of morphology.

[16]  G. Prestwich,et al.  Changes in morphogenetic hormone titers in isolated workers of the termite Reticulitermes flavipes (Kollar). , 1993, General and comparative endocrinology.

[17]  Tadao Matsumoto,et al.  Juvenile Hormone Analogue,S-31183,Causes a High Level Induction of Presoldier Differentiation in the Japanese Damp-Wood Termite , 1993 .

[18]  Y. Takematsu.  Biometrical Study on the Development of the Castes in Reticulitermes speratus (Isoptera, Rhinotermitidae) , 1992 .

[19]  C. Bordereau,et al.  Soldier formation regulated by a primer pheromone from the soldier frontal gland in a higher termite, Nasutitermes lujae. , 1984, Proceedings of the National Academy of Sciences of the United States of America.

[20]  M. Haverty.  The proportion of soldiers in termite colonies , 1977 .

[21]  C. Gillott,et al.  Endocrine control of caste differentiation in Zootermopsis angusticollis Hagen (Isoptera) , 1975 .

[22]  F. M. Weesner.  2 – External Anatomy , 1969 .

[23]  V B WIGGLESWORTH,et al.  INSECT HORMONES. , 1965, Endeavour.