ENDOCRINE CONTROL OVER CASTE DIFFERENTIATION IN A MYRMICINE ANT

Author(s):  
M.V. Brian
1975 ◽  
Vol 53 (11) ◽  
pp. 1701-1708 ◽  
Author(s):  
Chih-Ming Yin ◽  
Cedric Gillott

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.


1975 ◽  
Vol 53 (11) ◽  
pp. 1690-1700 ◽  
Author(s):  
Chih-Ming Yin ◽  
Cedric Gillott

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.


1965 ◽  
Vol 49 (3_Suppl) ◽  
pp. S202
Author(s):  
L. Ph. Bengtsson ◽  
G. W. Theobald

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.


EvoDevo ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alice Laciny

AbstractAs social insects, ants represent extremely interaction-rich biological systems shaped by tightly integrated social structures and constant mutual exchange with a multitude of internal and external environmental factors. Due to this high level of ecological interconnection, ant colonies can harbour a diverse array of parasites and pathogens, many of which are known to interfere with the delicate processes of ontogeny and caste differentiation and induce phenotypic changes in their hosts. Despite their often striking nature, parasite-induced changes to host development and morphology have hitherto been largely overlooked in the context of ecological evolutionary developmental biology (EcoEvoDevo). Parasitogenic morphologies in ants can, however, serve as “natural experiments” that may shed light on mechanisms and pathways relevant to host development, plasticity or robustness under environmental perturbations, colony-level effects and caste evolution. By assessing case studies of parasites causing morphological changes in their ant hosts, from the eighteenth century to current research, this review article presents a first overview of relevant host and parasite taxa. Hypotheses about the underlying developmental and evolutionary mechanisms, and open questions for further research are discussed. This will contribute towards highlighting the importance of parasites of social insects for both biological theory and empirical research and facilitate future interdisciplinary work at the interface of myrmecology, parasitology, and the EcoEvoDevo framework.


2010 ◽  
Vol 277 (1690) ◽  
pp. 1953-1961 ◽  
Author(s):  
Satoshi Miyazaki ◽  
Takahiro Murakami ◽  
Takuya Kubo ◽  
Noriko Azuma ◽  
Seigo Higashi ◽  
...  

1951 ◽  
Vol 109 (1) ◽  
pp. 41-69 ◽  
Author(s):  
Joseph D. Feldman

Science ◽  
1957 ◽  
Vol 126 (3281) ◽  
pp. 1002-1005 ◽  
Author(s):  
M. W. Noall ◽  
T. R. Riggs ◽  
L. M. Walker ◽  
H. N. Christensen
Keyword(s):  

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