Regulation of the corpora allata in the black mutant of Manduca sexta

Kramer, Steven J.; Kalish, Fred

doi:10.1016/0022-1910(84)90132-x

Cited by 11 publications

(7 citation statements)

References 15 publications

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“…For example, the black larval mutant of M. sexta is caused by a recessive gene (bl-) that is sex-linked (Safranek & Riddiford 1975;Franks & Lampert 1993). Animals homozygous for this gene are 37 per cent smaller in size, have a 20 per cent lower growth rate and, apparently, have lower titers of JH than wild-type individuals (Safranek & Riddiford 1975;Kramer & Kalish 1984;Orth & Goodman 1995). It is possible that the black mutants are smaller because they have a smaller critical weight and a shorter ICG than the wild types owing to decreased titers of JH and premature cessation of JH secretion (Stillwell et al 2010).…”

Section: Discussionmentioning

confidence: 99%

A developmental perspective on the evolution of sexual size dimorphism of a moth

Stillwell

Davidowitz

2010

Proc. R. Soc. B.

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Males and females of almost all organisms exhibit sexual differences in body size, a phenomenon called sexual size dimorphism (SSD). How the sexes evolve to be different sizes, despite sharing the same genes that control growth and development, and hence a common genetic architecture, has remained elusive. Here, we show that the genetic architecture (heritabilities and genetic correlations) of the physiological mechanism that regulates size during the last stage of larval development of a moth, differs between the sexes, and thus probably facilitates, rather than hinders, the evolution of SSD. We further show that the endocrine system plays a critical role in generating SSD. Our results demonstrate that knowledge of the genetic architecture underlying the physiological process during development that ultimately produces SSD in adults can elucidate how males and females of organisms evolve to be of different sizes.

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Section: Discussionmentioning

confidence: 99%

A developmental perspective on the evolution of sexual size dimorphism of a moth

Stillwell

Davidowitz

2010

Proc. R. Soc. B.

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“…The bl gene is sex-linked and the effect on larval pigmentation is recessive (62, 105). Subsequent studies have shown that the bl − mutation causes an overall decrease in JH synthesis, resulting in low titers of JH during much of larval life (77, 92, 105). The bl − mutation also apparently causes a greater sensitivity of the CA to inhibitory factors circulating in the hemolymph (69, 77).…”

Section: Phenotypic Plasticity In Body Size In Insectsmentioning

confidence: 99%

“…Subsequent studies have shown that the bl − mutation causes an overall decrease in JH synthesis, resulting in low titers of JH during much of larval life (77, 92, 105). The bl − mutation also apparently causes a greater sensitivity of the CA to inhibitory factors circulating in the hemolymph (69, 77). Thus, the bl gene appears to affect the titer of JH via regulatory control of its secretion, possibly by means of an allatostatic (inhibitory) hormone (140).…”

Section: Phenotypic Plasticity In Body Size In Insectsmentioning

confidence: 99%

“…These two factors (ICG and the critical weight) may have a direct connection to the diminished JH titer of the mutant such that when JH titers are low the mutant will take less time to clear JH from the hemolymph, producing a shortened ICG in mutant larvae. A lower critical weight could be due to the increased sensitivity of the CA to inhibitory factors (69, 77), which could cause a premature cessation of JH secretion. These insights offer a promising glimpse into how genetic and physiological mechanisms may regulate SSD in insects, but studies that address SSD per se are needed to fully understand the mechanisms by which SSD is produced.…”

Section: Phenotypic Plasticity In Body Size In Insectsmentioning

confidence: 99%

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Sex Differences in Phenotypic Plasticity Affect Variation in Sexual Size Dimorphism in Insects: From Physiology to Evolution

Stillwell

Blanckenhorn

Teder

et al. 2010

Annu. Rev. Entomol.

372

410

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Males and females of nearly all animals differ in their body size, a phenomenon called sexual size dimorphism (SSD). The degree and direction of SSD vary considerably among taxa, including among populations within species. A considerable amount of this variation is due to sex differences in body size plasticity. We examine how variation in these sex differences is generated by exploring sex differences in plasticity in growth rate and development time and the physiological regulation of these differences (e.g., sex differences in regulation by the endocrine system). We explore adaptive hypotheses proposed to explain sex differences in plasticity, including those that predict that plasticity will be lowest for traits under strong selection (adaptive canalization) or greatest for traits under strong directional selection (condition dependence), but few studies have tested these hypotheses. Studies that combine proximate and ultimate mechanisms offer great promise for understanding variation in SSD and sex differences in body size plasticity in insects.

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“…Riddiford (1985, 1988) later showed that JH reduces the activities of dopa decarboxylase and cuticular phenoloxidase in treated bl larvae, thereby reducing or blocking cuticular melanization. Lower JH synthetic activity of the corpora allata (Kramer and Kalish, 1984) in combination with a shorter JH half-life (Fain and Riddiford, 1975) suggests that fourth stadium bl larvae have a lower JH titer than do wild-type larvae.…”

Section: Introductionmentioning

confidence: 99%

Juvenile hormone regulation of hemolymph juvenile hormone binding protein in the black strain of the tobacco hornworm, Manduca sexta

Orth

Goodman

1995

Arch Insect Biochem Physiol

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Numerous studies have demonstrated regulation of specific lepidopteran proteins by pharmacological doses of insect juvenile hormone (JH). In this study, topical application of a 1 pg dose of JH I to fourth stadium larvae of the black (61) mutant strain of the tobacco hornworm, Manduca sexra, induced a 50% increase in the titer of hemolymph juvenile hormone binding protein (hJHBP).Radioimmunoassay confirmed that JH titers were lower in bl larvae than in wild-type larvae at the time of JH treatment. Enzyme immunoassay analysis of hJHBP titers demonstrated that regulation by JH I was dose-dependent at doses up to 10 pg and that the response was saturated above 100 pg. Western blotting and equilibrium dialysis confirmed these results and demonstrated that hJHBP from bl larvae had the same molecular mass and displayed the same affinity for JH I as hJHBP isolated from wild-type larvae. Time course studies showed that regulation was complex: 12 h after JH I treatment, hJHBP titers were twofold lower in treated than in control bl larvae, while 44 h after treatment they were twofold higher. JH I regulation of hJHBP titers in bl larvae was independent of changes in total hemolymph protein. o 1995 WiIey-Liss, Inc.

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Regulation of the corpora allata in the black mutant of Manduca sexta

Cited by 11 publications

References 15 publications

A developmental perspective on the evolution of sexual size dimorphism of a moth

A developmental perspective on the evolution of sexual size dimorphism of a moth

Sex Differences in Phenotypic Plasticity Affect Variation in Sexual Size Dimorphism in Insects: From Physiology to Evolution

Juvenile hormone regulation of hemolymph juvenile hormone binding protein in the black strain of the tobacco hornworm, Manduca sexta

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