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Observations sur le Poids et la Taille au Cours de la Croissance et de la Métamorphose Chez Pieris Brassicae

Observations sur le Poids et la Taille au Cours de la Croissance et de la Métamorphose Chez... Summary T. Srihari: Observations on the weight and body changes during the growth and metamorphosis of Pieris brassicae. This paper presents the results of observations made on the weight and body changes during the growth and metamorphosis of Pieris brassicae (L). During the course of larval development the total body weight and length change in an “S” shaped curve. The larvae after attaining the maximum weight and length start decreasing their live weight and length till the formation of the pupa. During the pupal period the length remains constant but it reduces slightly in the adults after emergence whereas the weight continues to decrease almost constantly till the end of the pupal period. The adults however after the emergence reduce their weight by about 50 per cent of the pupal weight before the emergence. They do this by freeing themselves from all the remnants of histolytic and dispensable material. They thus reduce their weight to the minimum possible, and enable themselves to utilise less of the energy required for flight. The percentage of dry matter was found to increase in second instar and decrease in third instar, then it continues to increase up to the formation of the pupa where the increase of fat body was found to be in direct correspondance. In the pupal period the percentage of dry matter decreases up to the fourth day and then it increases up to the sixth day and afterwards remains almost constant till the emergence of adults but they increase suddenly up to 34 per cent after the emergence. In the pupal period the per cent decrease of dry matter seems to correspond to pronounced histolysis of the larval tissues and the increase to the pronounced histogenesis of adult tissues. The earlier instars are found to be more efficient in increasing their live weight than the later instars, whereas it is found to be inverse for the length increases. The increase in the live weight and the length of caterpillars roughly follows the exponential equation g = goekt (for explanation see the text) up to the fourth instar but the said increases do not follow this equation in the fifth instar due to the changes occurring for pupation. The growth in length and width of the head of different larval instars follows the exponential equation as well as the Dyar's rule. Just after every larval moulting, the total length and the lengths of mesothorax and the first abdominal segment were found to decrease with a corresponding increase in their widths. After this the length and widths of mesothorax and the first abdominal segment were found to increase continuously up to the last larval day except on the third and fourth days of the last instar, where we found a decrease in the length of the first abdominal segment accompanied by an increase in its width. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Annales de la Société entomologique de France (N S ) Taylor & Francis

Observations sur le Poids et la Taille au Cours de la Croissance et de la Métamorphose Chez Pieris Brassicae

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Publisher
Taylor & Francis
Copyright
© 1972 Société entomologique de France
ISSN
2168-6351
eISSN
0037-9271
DOI
10.1080/21686351.1972.12278106
Publisher site
See Article on Publisher Site

Abstract

Summary T. Srihari: Observations on the weight and body changes during the growth and metamorphosis of Pieris brassicae. This paper presents the results of observations made on the weight and body changes during the growth and metamorphosis of Pieris brassicae (L). During the course of larval development the total body weight and length change in an “S” shaped curve. The larvae after attaining the maximum weight and length start decreasing their live weight and length till the formation of the pupa. During the pupal period the length remains constant but it reduces slightly in the adults after emergence whereas the weight continues to decrease almost constantly till the end of the pupal period. The adults however after the emergence reduce their weight by about 50 per cent of the pupal weight before the emergence. They do this by freeing themselves from all the remnants of histolytic and dispensable material. They thus reduce their weight to the minimum possible, and enable themselves to utilise less of the energy required for flight. The percentage of dry matter was found to increase in second instar and decrease in third instar, then it continues to increase up to the formation of the pupa where the increase of fat body was found to be in direct correspondance. In the pupal period the percentage of dry matter decreases up to the fourth day and then it increases up to the sixth day and afterwards remains almost constant till the emergence of adults but they increase suddenly up to 34 per cent after the emergence. In the pupal period the per cent decrease of dry matter seems to correspond to pronounced histolysis of the larval tissues and the increase to the pronounced histogenesis of adult tissues. The earlier instars are found to be more efficient in increasing their live weight than the later instars, whereas it is found to be inverse for the length increases. The increase in the live weight and the length of caterpillars roughly follows the exponential equation g = goekt (for explanation see the text) up to the fourth instar but the said increases do not follow this equation in the fifth instar due to the changes occurring for pupation. The growth in length and width of the head of different larval instars follows the exponential equation as well as the Dyar's rule. Just after every larval moulting, the total length and the lengths of mesothorax and the first abdominal segment were found to decrease with a corresponding increase in their widths. After this the length and widths of mesothorax and the first abdominal segment were found to increase continuously up to the last larval day except on the third and fourth days of the last instar, where we found a decrease in the length of the first abdominal segment accompanied by an increase in its width.

Journal

Annales de la Société entomologique de France (N S ) – Taylor & Francis

Published: Apr 30, 1972

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