Endocrine control of caste differentiation in Zootermopsis angusticollis Hagen (Isoptera)

1975 ◽  
Vol 53 (11) ◽  
pp. 1701-1708 ◽  
Author(s):  
Chih-Ming Yin ◽  
Cedric Gillott
Keyword(s):  
Juvenile Hormone ◽  
Methyl Ether ◽  
Caste Differentiation ◽  
Corpus Allatum ◽  
Endocrine Control ◽  
Reproductive Differentiation ◽  
Zootermopsis Angusticollis ◽  
Supplementary Reproductives

The effect of injection of Röller's juvenile hormone (JH) or farnesyl methyl ether (FME) on differentiation of supplementary reproductives and presoldiers of Zootermopsis angusticollis has been studied. Early in the stadium (that is, during the competence period) Röller's JH and FME inhibit differentiation. When injected after the competence period the substances do not alter the rate of supplementary reproductive differentiation in orphaned colonies but enhance presoldier differentiation in soldierless colonies provided that there is a sufficient number of supplementary reproductives present.A modified version of Lüscher's (1960) hypothesis for the endocrine control of caste differentiation is proposed. It is suggested that all the developmental possibilities that exist in the termite colony can be explained on the basis of a single corpus allatum hormone produced in different quantities and at different times within the stadium.

Endocrine activity during caste differentiation in Zootermopsis angusticollis Hagen (Isoptera): a morphometric and autoradiographic study

1975 ◽  
Vol 53 (11) ◽  
pp. 1690-1700 ◽  
Author(s):  
Chih-Ming Yin ◽  
Cedric Gillott
Keyword(s):  
Autoradiographic Study ◽  
Neurosecretory Cells ◽  
Caste Differentiation ◽  
Corpora Allata ◽  
Synthetic Activity ◽  
Cell Diameter ◽  
Endocrine Control ◽  
Endocrine Activity ◽  
Zootermopsis Angusticollis ◽  
Primary Reproductives

The diameters of the median neurosecretory cells (MNC) and their nuclei, and the volumes of the corpora cardiaca (CC) and corpora allata (CA) were measured in termites (Zootermopsis angusticollis) of differing age, sex, and caste. The synthetic activities of the MNC and CA were estimated autoradiographically.No significant differences in the diameters of the MNC and their nuclei were observed between insects of differing age, sex, and caste, with the exception of primary reproductives whose MNC are significantly larger than those of larvae of the same instar. The six types of MNC distinguishable histologically differ in their nuclear diameter : cell diameter ratios and in their rates of [3H]uridine and [3H]cystine incorporation.The volumes and (or) synthetic activities of the CA change markedly during the differentiation of reproductives and soldiers. The CA of recently molted primary and supplementary reproductives are several times larger than those of larvae and nymphs of the previous instar, yet their synthetic activity remains low. In contrast, the CA of presoldiers and soldiers are only slightly larger than those of previous instar larvae, but show high synthetic activity. The data are discussed in terms of the endocrine control of caste differentiation.

Hormone Balance and the Control of Metamorphosis in Rhodnius Prolixus (Hemiptera)

1952 ◽  
Vol 29 (4) ◽  
pp. 620-631
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Juvenile Hormone ◽  
Corpus Allatum ◽  
Corpora Allata ◽  
Stage Larva ◽  
Mature Adults ◽  
Hormone Balance ◽  
Low Concentrations ◽  
Moulting Cycle ◽  
Increased Activity ◽  
Reduced Activity

A technique is described by which the intact larva of Rhodnius can be transfused with blood from another larva without interfering with ecdysis. If the 4th-stage larva receives blood from a 3rd-stage larva it develops characters little different from those of the 4th instar. This is attributed to the 3rd-stage larva producing juvenile hormone at a higher concentration. If the 4th-stage larva at 24 hr. after feeding receives blood from another 4th-stage larva at 8 days after feeding it develops characters intermediate between those of the 4th and 5th instars. This is attributed to the juvenile hormone being introduced too early in the moulting cycle. The hormone balance is upset by abnormal temperatures. The 4th-stage larva will not moult at a temperature of 36° C. although the larvae can survive up to about 40° C. At temperatures a little below 36° C. moulting is somewhat delayed and the characters developed are slightly ‘adultoid’ (prothetely). This is attributed to slightly reduced activity of the corpus allatum. At temperatures below 20° C. moulting is greatly delayed and the characters developed are slightly ‘juvenile’ (metathetely). This is attributed to relatively increased activity of the corpus allatum. Low concentrations of oxygen (less than 5 %) have an effect similar to that of high temperature. If 5th-stage larvae of Rhodnius receive implants of corpora allata from mature adults of Periplaneta they develop into 6th-stage larvae and many of these subsequently into 7th-stage larvae. The ‘juvenile hormone’ appears to be the same in the two insects. No evidence could be obtained for the persistence of juvenile hormone in the blood from one instar of Rhodnius to the next. The hypothesis of an active elimination of juvenile hormone by the corpus allatum at the time of metamorphosis remains therefore unproven.

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