THE EFFECTS OFF CORPUS ALLATUM IMPLANTATION ON THE DEVELOPMENT OF FLIGHT MUSCLES AND FAT BODY IN LOCUSTA MIGRATORIA

Abstract

Implantation of corpora allata early in the fifth instar of female larvae of Locusta migratoria results in a faster development both during the last instar and the adult somatic growth period. The adult locusts attain a significantly higher maximum wet weight. The increase in dry weight, however, is smaller than in control insects. So the high titer of corpus allatum hormone results in a considerably higher water content. In CA‐implanted locusts the growth of the indirect dorsal longitudinal flight muscles is inhibited and the protein content is lower as compared with control specimens. Especially the differentiation of these muscles is strongly inhibited. A hypothesis for a regulation of the indirect flight muscle development by the changing titer of the corpus allatum hormone is proposed. During the second part of the adult period investigated the high titer of the corpus allatum hormone strongly diminishes the growth of the fat body, but the protein content is not altered in comparison with the normal developing fat body. The data reveal that the influence of an induced high titer of corpus allatum hormone on protein metabolism in the flight muscles is different from that in the fat body. ZUSAMMENFASSUNG DIE WIRKUNG VON CORPORA ALLATA‐IMPLANTATION AUF DIE ENTWICKLUNG DER FLUGMUSKELN UND DES FETTKÖRPERS BEI LOCUSTA MIGRATORIA Nach Corpora allata‐Implantation am Anfang des L5 von weiblichen Larven von Locusta migratoria folgt eine schnellere Entwicklung sowohl im letzten Larvenstadium als auch in der adulten somatischen Wachstumsperiode. Die adulten Heuschrecken erreichen ein signifikant höheres Frischgewicht‐Maximum. Die Zunahme des Trockengewichts ist jedoch geringer als bei Kontrollen. Der hohe Titer an Corpus allatum‐Hormon resultiert also in einem beträchtlich höheren Wassergehalt. Der Zuwachs der indirekten dorsalen Flugmuskeln ist in mit Corpora allata implantierten Heuschrecken gehemmt und der Eiweißgehalt ist niedriger als bei Kontrollen. Besonders die Differenzierungsphase der Muskeln ist stark gehemmt. Es wird eine Hypothese über die Regulation der Entwicklung indirekter Flugmuskeln durch den sich ändernden Titer des Corpus allatum‐Hormons aufgestellt. Während des zweiten Teils der untersuchten adulten Periode nimmt das Wachstum des Fettkörpers unter dem Einfluss des hohen Hormontiters ab, aber der Proteingehalt dieses Gewebes ändert sich im Vergleich zu dem sich normal entwickelnden Fettkörper nicht. Diese Daten zeigen, daß der Einfluss eines induzierten hohen Titers an Corpus allatum‐Hormon beim Proteinstoffwechsel in den Flugmuskeln anders ist als im Fettkörper.

Quantitative determination of the juvenile hormones in the haemolymph of Locusta migratoria during normal development and after implantation of corpora allata

“…The latter aspect is studied in view of the fact that implantation of CA in young fifth instar larvae influences the development of the flight muscles, normally taking place during the fifth larval instar and early adult stage. Thus, after implantation of CA, POELS and BEENAKKERS (1969) observed an inhibition of the normal increase in dry weight and protein content of these muscles. This inhibition is accompanied by lower specific activities of enzymes representative of the main metabolic pathways in the flight muscles (VAN DEN HONDEL-FRANKEN et aI., 1980) and with a delay in invagination of tracheoblasts into the muscle libres (VAN DEN HONDEL-FRANKEN and BEENAKKERS, unpublished), irrespective of the fact whether the CA were taken from young fourth instar larvae (larval CA) or from 18 day adult females (adult CA).…”

“…IMPLANTATION of active corpora allata (CA) (JOHNSON and HILL, 1975) early in the fifth larval instar of Locusta migratoriu results in an increase in heart-beat frequency (ROUSSEL, 1969), a change in pigmentation and a disturbance of metamorphosis (JOLY, 1960;STAAL, 196 1;POELS and BEENAKKERS, 1969;BEENAKKERS and VAN DEN BROEK, 1974). Similar effects have also been found upon injection of any of the three naturally occurring insect juvenile hormones (JH's); the activity of JH-I being the most potent (Rou~~EL, 1977).…”

Morphological and functional maturation of a skeletal muscle regulated by juvenile hormone

“…The importance of metamorphosis for flight muscle differentiation and development has been shown by manipulating the levels of JH. Treatment of larval stages with the JH analog methoprene, or implantation of corpora allata, which shortened the length of the larval stadium, caused slowing of muscle growth and inhibited the development of mitochondria and tracheolation in locust (Poels and Beenakkers, 1969;Cotton and Anstee, 1990) and cricket (Novicki, 1989). Chemical allatectomy, however, enhanced flight muscle development and resulted in normal flight muscles of the adultiform (Wang et al, 1993).…”

Hypertrehalosaemic and hyperlipaemic responses to adipokinetic hormone in fifth larval instar locusts, Locusta migratoria

“…The lower specific activity of total phosphorylase in larvae compared to adults (Table 3) not necessarily reflects a corresponding lower enzyme content of the larval fat body. The difference can, at least partly, be explained by the variations in the fat body protein content, which is relatively high in the second half of the last larval instar, but falls sharply during the final moult, and remains low in the first four to five days after the larval-adult ecdysis (Poels and Beenakkers, 1969). Thus, the subsequent increase of the fat body protein content, combined with the fairly constant specific enzyme activity, implies that the amount of total phosphorylase will increase during the adult stage.…”