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Hétérogénéité de la Croissance Larvaire Chez Pyrgomorpha Conica [Orth. Acrididae]

Hétérogénéité de la Croissance Larvaire Chez Pyrgomorpha Conica [Orth. Acrididae] SUMMARY R. Abou-Elela: Heterogenity of nymphal growth in Pyrgomorpha conica [Orth. Acrididae] The species studied (from Salins d'Hyères, Var, France) shows variation in the instar number: the males pass through six or seven, the females pass through six, seven or eight instars. This result has been obtained by studying the growth of the female external genitalia, that of the wing rudiments and after measuring the length of the hind femur. This study was facilitated by the existence of eye stripes. We should mention here that the number of these stripes is related to the instar numbers, i. e. the total number of stripes in the adult indicates the total number of instars. The morphology of the female genitalia is important for distinguishing the instars and their changes during the development are shown. The growth of the antenna occurs by successive divisions: the number of segments added at each moult varies from nil to six. The instar in which the reversal of the wing rudiments occurs, varies according to the modality of growth: during the moult from the IVth to Vth instar, Vth to VIth or from VIth to VIIth in the females passing through six, seven or eight instars respectively. In the male it occurs during the IVth to Vth instars or Vth to VIth for individuals passing through six or seven instars respectively. The length of the hind femur is used as an indication for the total body length. According to this size, hatchings obtained can be allocated to five distributions, each being associated with a different modality of growth. The growth showing an extra instar, associated with a slower rate of growth, is originally derived from the distribution of small hind femur. The rate of growth of the femur shows a rang from 1.136 to 1.415 in the females and from 1.181 to 1.319 in the males; it appears that the extra instar is associated with a low rate of femur increase. The mean rate of femur increase in both sexes is not far from 1.26. This increase is higher in the females than in the males, and higher for individuals with lower number of instars than for others. The larvae which are initially smaller than the average give rise to adults which are significantly larger than the average. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Annales de la Société entomologique de France (N S ) Taylor & Francis

Hétérogénéité de la Croissance Larvaire Chez Pyrgomorpha Conica [Orth. Acrididae]

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Publisher
Taylor & Francis
Copyright
© 1971 Société entomologique de France
ISSN
2168-6351
eISSN
0037-9271
DOI
10.1080/21686351.1971.12278032
Publisher site
See Article on Publisher Site

Abstract

SUMMARY R. Abou-Elela: Heterogenity of nymphal growth in Pyrgomorpha conica [Orth. Acrididae] The species studied (from Salins d'Hyères, Var, France) shows variation in the instar number: the males pass through six or seven, the females pass through six, seven or eight instars. This result has been obtained by studying the growth of the female external genitalia, that of the wing rudiments and after measuring the length of the hind femur. This study was facilitated by the existence of eye stripes. We should mention here that the number of these stripes is related to the instar numbers, i. e. the total number of stripes in the adult indicates the total number of instars. The morphology of the female genitalia is important for distinguishing the instars and their changes during the development are shown. The growth of the antenna occurs by successive divisions: the number of segments added at each moult varies from nil to six. The instar in which the reversal of the wing rudiments occurs, varies according to the modality of growth: during the moult from the IVth to Vth instar, Vth to VIth or from VIth to VIIth in the females passing through six, seven or eight instars respectively. In the male it occurs during the IVth to Vth instars or Vth to VIth for individuals passing through six or seven instars respectively. The length of the hind femur is used as an indication for the total body length. According to this size, hatchings obtained can be allocated to five distributions, each being associated with a different modality of growth. The growth showing an extra instar, associated with a slower rate of growth, is originally derived from the distribution of small hind femur. The rate of growth of the femur shows a rang from 1.136 to 1.415 in the females and from 1.181 to 1.319 in the males; it appears that the extra instar is associated with a low rate of femur increase. The mean rate of femur increase in both sexes is not far from 1.26. This increase is higher in the females than in the males, and higher for individuals with lower number of instars than for others. The larvae which are initially smaller than the average give rise to adults which are significantly larger than the average.

Journal

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

Published: Jan 31, 1971

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