FACTORS AFFECTING CORPORA ALLATA ACTIVITY IN THE ADULT LADY BEETLE <i>COCCINELLA SEPTEMPUNCTATA</i> L.

Guan, Xuechen; Wang, Zongshun

doi:10.1111/j.1744-7917.1995.tb00023.x

Cited by 1 publication

(4 citation statements)

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“…It is difficult to understand why JH synthesis was lowest at the rearing temperature of the animals. In most insect species, including M. sexta (Kramer & Law, 1980) and C. septempunctata (Guan & Chen, 1986), JH synthesis was rather constant for several hours of incubation. However, a quite different time course of JH synthesis was seen in S. cynthia ricini.…”

Section: Discussionmentioning

confidence: 99%

“…In this assay, medium TC199 was first chosen as an optimal medium for the desert locust Schistocerca gregaria , then used for other insect species (Guan & Chen, 1986, Weaver et al, 1980, including Lepidoptera, M. sexta (Kramer & Law, 1980) and the corn earworm, Heliothis armigera (Guan et al, 1995). In this study, we used medium TC199 for the RCA in S. cynthia ricini.…”

Section: Discussionmentioning

confidence: 99%

“…The suggested incubation conditions for CA of the beetle C. septempunctata (Guan & Chen, 1986) were at first used for incubation of CA from newly emerged female adult S. cynthia ricini. Corpora cardiaca-corpora allata complexes (CC-CA) were dissected under a saline solution (0.111 g/l NaCl, 3.355 g/l KCl, 0.555 g/l CaCl2, and 5.083 g/l MgCb, pH 6.5), and placed into medium TC199 (Gibco).…”

Section: Jh Synthesis In Vitro By Camentioning

confidence: 99%

“…This means that the Ca2+ concentration in the medium will also affect JH synthesis (reviewed by Rachinsky & Tobe, 1996). Using the suggested incubation conditions for CA of the beetle Coccinella septempunctata (Guan & Chen, 1986), it was found that the rate of JH synthesis in vitro by CA from newly emerged female adult Eri silkworm Samia cynthia ricini was extremely low. In this paper, we present the most suitable incubation conditions for CA from S. cynthia ricini, the time course of JH synthesis and release, as well as a dose-response curve for methionine (Met).…”

Section: Introductionmentioning

confidence: 99%

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Developmental changes in the ability to synthesize juvenile hormone in vitro by corpora allata from the Eri silkworm, Samia cynthia ricini (Lepidoptera: Saturniidae)

Sheng¹,

Jiang²,

Cao³

2002

Eur. J. Entomol.

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Abstract. A radiochemical assay (RCA) has been used for the measurement ofjuvenile hormone (JH) synthesis in vitro by corpora allata (CA) from the Eri silkworm, Samia cynthia ricini. Using CA from newly emerged female adults for the bioassay, the most suitable incubation conditions were determined. A high rate of JH synthesis was found in medium TC199 at pH 6.5, 30°C and 4 mM Ca2+. The time course of JH synthesis showed a steady decrease during the first 6 hours of incubation.Under optimal incubation conditions, CA from the 4th and 5th larval instars, pupae and adults were used for measuring JH syn thesis in vitro. The highest rates of JH synthesis were found on the 1st day of both larval stages, and then JH synthesis decreased steadily during the following two days of each instar. From the 4th day of the 5th larval instar to the 2nd day after pupation, CA could still synthesize small amounts of JH. However, from the 3rd day of the pupal stage to 12 hours before adult emergence, no JH release was observed. About 6 hours before emergence, CA of both female and male pharate adults regained the ability to synthe size JH. JH synthesis increased to a maximum shortly after emergence and then decreased again during the following two days. During this period, JH synthesis in vitro by CA from females was always higher than that of males. This is the first report on JH syn thesis in vitro by CA from both female and male pharate adults and adults of a lepidopteran species, where the adults do not feed, are relatively short-lived, mate only once, and ovarian maturation and vitellogenesis are completed before emergence.

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Section: Discussionmentioning

confidence: 99%