RELATION BETWEEN OVARIAN MATURATION AND ACTIVITY OF THE CORPORA ALLATA IN SEASONAL FORMS OF THE BUTTERFLY, POLYGONIA C-AUREUM L.

In summer form adults of Polygonia c-aureum, the ovary develops soon after emergence and eggs mature a few days later. However, in autumn form adults, having been kept in laboratory conditions, only several mature eggs are found about four weeks after emergence. The allatectomy during the larval period prevents egg maturation in adults of both forms. When the corpora allata from the summer form of both sexes are transplanted into allatectomized adults of the autumn or summer form, the ovary develops as in the case of summer form adults. But the corpora allata of both sexes of the autumn form are not effective in inducing the ovarian maturation. Environmental factors, especially day-length and temperature during the larval period, may act through the neuroendocrine system to induce the activity of the corpora allata in the adult life.     

FACTORS AFFECTING CORPORA ALLATA ACTIVITY IN THE ADULT LADY BEETLE COCCINELLA SEPTEMPUNCTATA L.

Abstract Corpora allata are the defined site of juvenile hormone (JH) biosynthesis in reproductive adult insects and their activity is regulated by intrinsic and extrinsic factors. In the adult lady beetle Coccinella septempunctata , it has been well established that the development of ovaries is controlled by JH (Guan 1987). The present study aims at the elucidation of the influence of some factors regulating reproduction of the lady beetle. They include topical application of JH analogues, presence of neuropeptides in the extract from the brain, as well as the development of ovary and type of food on CA activity. JH synthesis in CA is monitored with radiochemical assay and immunoelectrophoresis.     

SEASONAL VARIATIONS IN THE PROPORTIONS OF SUBERIZED AND UNSUBERIZED ROOTS OF TREES IN RELATION TO THE ABSORPTION OF WATER

Growing root tips usually constituted less than 1 per cent and mycorrhizal roots less than 6 per cent of the total root surface under a 34-year-old pine stand. Growing root tips usually constituted less than 1 per cent of the total root surface under a yellow poplar stand, although one sample taken in May contained 9 per cent of unsuberized roots. The water permeability of various types of roots was measured under a pressure gradient of 31 cm of mercury. It differed widely among individual roots, ranging from an average of 6.6. mm³/cm²/hr for suberized pine roots 1.33 mm in diameter, to 36.6 mm³ for suberized pine roots 3 mm in diameter, and 178 mm³/ cm²/hr for unsuberized roots grown in water culture. Water intake through a group of unsuberized roots grown in soil averaged 37.4 mm³/cm²/hr. The permeability of yellow poplar roots varied even more, ranging from essentially zero to 30,000 mm³/cm²/hr. It is concluded that the major part of water absorption in pine occurs through suberized roots, some through mycorrhizal roots, and relatively little through growing root tips. Likewise, in yellow-poplar most of the water probably enters through suberized roots. Further study is needed of the role of suberized roots in water and salt absorption.     

THE EFFECT OF CORPORA ALLATA ON SEXUAL BEHAVIOUR AND “ADULT DIAPAUSE” IN MALES OF THE RED LOCUST

Males of the red locust, Nomadacris septemfasciata, allatectomized 3–11 days after the moult to the adult stage did not exhibit any sexual behaviour and remained in a state comparable to adult diapause, while all the sham-allatectomized controls exhibited distinct sexual behaviour. Implantations of four pairs of active corpora allata (originating from sexually mature males of Locusta migratoria migratorioides) into the allatectomized males of the red locust led to sexual behaviour; in contrast, all those allatectomized males in which shamimplantations (appropriate surgical treatment without actual implantation of corpora allata) were performed remained in adult diapause showing no sexual behaviour.Comparison of the results with other data revealed that in some species of Acridids the corpora allata completely control (in a direct or indirect manner) male sexual behaviour, while in other species of the same family this control is either incomplete or perhaps does not exist at all. The presence or absence of a complete endocrine control of male sexual behaviour may perhaps be correlated with the fact that the species involved has or has not the ability to undergo a state of adult diapause.

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Zusammenfassung Männchen der Roten Heuschrecke, Nomadacris septemfasciata, die 3–11 Tage nach der Häutung zur Imago allatektomiert worden waren, zeigten keinerlei sexuelle Aktivität und verharrten in einem der Adult-Diapause vergleichbaren Zustand, während alle scheinallatektomierten Kontrolltiere ausgeprägtes Sexualverhalten aufwiesen. Implantationen von 4 Paar Corpora allata (aus geschlechtsreifen Männchen von Locusta migratoria migratorioides stammend) in allatektomierte Männchen der Roten Heuschrecke führten zu Sexualverhalten; im Gegensatz dazu verharrten alle diejenigen allatektomierten Männchen, bei welchen Schein-Implantationen durchgeführt wurden (entsprechende operative Behandlung ohne Implantation von Corpora allata) in Adult-Diapause und zeigten keine sexuelle Aktivität.Vergleich der Ergebnisse mit anderen Daten lassen erkennen, daß bei einigen Acridier-Arten die Corpora allata das männliche Sexualverhalten (auf direkte oder indirekte Weise) beeinflussen, während dieser Einfluß bei anderen Arten der gleichen Familie entweder unvollständig ist oder überhaupt nicht auftritt. Vorkommen oder Fehlen einer vollständigen endokrinen Kontrolle des männlichen Sexualverhaltens mag vielleicht von dem Umstand abhängen, ob die betreffende Art die Fähigkeit hat, ein Stadium adulter Diapause zu durchlaufen oder nicht.

     

PRESENCE OF 1-METHYLADENINE IN SEA URCHIN GONAD AND ITS RELATION TO OOCYTE MATURATION

A water extract of sea urchin ovary was found to induce maturation of starfish oocytes in vitro . The presence of the active substance was demonstrated in ovaries of the sea urchins, Pseudocentrotus depressus, Anthocidaris crassispina and Hemicentrotus pulcherrimus , and the sand dollars, Clypeaster japonicus and Peronella japonica . The active substance was also contained in the testes of these echinoids. That the content of this substance increases during the reproductive season was demonstrated with Anthocidaris gonads. The active substance present in ovary or testis of the sea urchins was successfully extracted with 85% ethanol and purified with gel-filtrations on Sephadex G-15 columns after washing with chloroform and ether. The purified active substances were the same and were identified as 1-1-methyladenine by thin layer chromatography. 1-Methyladenine was found to be effective in inducing oocyte maturation in Anthocidaris crassispina in vitro . Therefore, 1-methyladenine seems to play an important role in oocyte maturation in echinoids as well as in asteroids.