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Metamorphic changes in posterior region of foregut of Papilio aristolochiae F. (Lepidoptera: Papilionidae)
Int. J. Insect Morphol. & Embryol. 1 (2): 163-168. 1972. Pergamon Press. Printed in Great Britain.
METAMORPHIC CHANGES IN POSTERIOR REGION OF FOREGUT OF PAPILIO ARISTOLOCHIAE F. (LEPIDOPTERA:
PAPILIONIDAE)
O. P. KATHURIA* School of Studies in Zoology, Vikram University, Ujjain (M.P.), India
(Accepted 19 January 1972) Abstract--The ceils of the anterior imaginal ring in Papilio aristolochiae divide mitotically during the early pupal period and increase in number. Some of the cells of the anterior imaginal ring evaginate on the ventral side and form the anlage of ventral oesophageal diverticulum. After the formation of the diverticulum the imaginal ring again becomes divided into anterior and posterior regions, which are the anlagen of the proventriculus and oesophageal valve respectively. The cells of the latter 2 regions remain columnar in the beginning but soon become squamous and folded. The folds of the oesophageal valve form an intussception with the anterior part of the midgut, prior to the imaginal emergence. Index descriptors (in addition to those in title): Ventral oesophageal diverticulum. THE FINDINGS on the metamorphosis of the foregut in insects are contradictory. Deegener (1908) in Malacosoma castransis, Perez (1910) in Calliphora erythrocephala and Gray (1931) in Homaledra sabalella, believed that the anterior imaginal ring formed the posterior region of foregut, including oesophageal diverticulum and oesophageal valve. Thompson (1905) in Culex pipiens, however, showed that the anterior imaginal ring formed only the oesophageal valve, and that the oesophageal diverticula are derived from the oesophageal tissue. According to Risler (1961), in Aedes aegypti, the anterior imaginal ring forms the oesophageal diverticula also. Romoser and Venard (1966, 1967) arrived at a different conclusion. These authors divided the larval oesophageal tissue within the proventriculus into 5 regions and showed that the ventral oesophageal diverticulum and the oesophageal valve are derived from the anterior imaginal ring. In Papilio aristolochiae the anterior imaginal ring forms the ventral oesophageal diverticulum, the proventriculus and the oesophageal valve. This paper presents the development of the proventriculus and the oesophageal valve. The development of the ventral oesophageal diverticulum has been described elsewhere (Bahadur and Kathuria, 1971). M A T E R I A L S AND M E T H O D S The larvae o f P . aristolochiae were collected from the local fields and were supplied daily with fresh leaves of Aristolochia plant. Full grown larvae, when stopped feeding, were separated and allowed to pupate. The pupal period lasts from 12 to 14 days in the field. Pupae of different ages were taken. Dissections were done under stereoscopic binocular * Present address: Department of Zoology, Government Degree College, Jhabua (M.P.), India. 163
164
O.P. KATHURIA
m i c r o s c o p e and tissues were fixed in B o u i n ' s solution. The sections were cut at 6 - 8 / ~ an d stained with H e i d e n h a i n ' s iron h a e m o t o x y l i n or with a modification o f the A z a n m e t h o d ( H u b s c h m a n , 1962). D r a w i n g s have been m a d e with the help o f c a m e r a lucida. OBSERVATIONS The cells o f the a n t e r i o r imaginal ring f o r m 3 adult structures: the ventral oesophageal diverticulum, the proventriculus, and the oesophageal valve during metamorphosis. The d e v e l o p m e n t o f ventral oesophageal diverticulum has been described in detail in an earlier pa pe r (Bahadur and K a t h u r i a , 1971), where we have shown that, some o f the cells o f anterior imaginal ring f o r m the anlage o f ventral oesophageal diverticulum in a 45-hr p u p a ; and
FIG. I. FIG. 2. FIGS. 1-6. L.S. Posterior part of foregut of Papilio aristolochiae. Scale used in Figs. 1-5 is the same as in Fig. 6. FIG. l. 100-hr pupa. FIG. 2. 150-hr pupa. Note folding of anterior region over posterior region denoted by R. A Air CM Ep 1N MG Oe V P Pro R VD
-= = = ------
Abbreviations used in figures anterior region of the imaginal ring anterior imaginal ring circular muscle epithelium intima midgut oesophageal valve posterior region of the imaginal ring proventriculus reflection of the anterior region over posterior region of imaginal ring ventral diverticulum
Metamorphic Changes in Posterior Region of Foregut of Papilio aristolochiae F.
165
that evagination grows further as a result of mitotic activity. The cells of the anterior imaginal ring left after the formation of the anlage of ventral evagination again become divided into anterior and posterior regions in a 10O-hr pupa (Fig. 1). The cells of the latter 2 regions show mitotic activity. The anterior region, which lies immediately behind the ventral evagination, is the anlage of proventriculus. The posterior region, which is the anlage of oesophageal valve, lies anterior to the foregut-midgut junction. In a 150-hr pupa the epithelium of the anterior portion becomes folded upon the anterior margin of the posterior region (Fig. 2) and gradually covers it as the pupa becomes 200-hr old (Fig. 3).
FIG. 3.
FIG. 3. 200-hr pupa. As a result of this folding of the anterior region, the posterior region becomes two-layered. The cells of the anterior region, which appear columnar in the beginning, attain a flattened appearance. Owing to the flattening of the cells, the epithelium also increases in length and becomes folded and projects into the lumen. In contrast to this, the cells of the posterior region, remain columnar, and closely appressed in 152-hr pupa. The luminal surface of the epithelium in this region is smooth. In a 200-hr pupa the luminal surface appears wavy and the cells are still columnar in shape. A thick intima almost fills up the lumen of the posterior region. In a 240-hr old pupa the epithelium in the anterior region is more flattened and is produced into large fingerlike projections (Fig. 4). The cells possess small nuclei and granular cytoplasm. The epithelium of the posterior region also becomes folded and the cells appear cuboidal. The old intima is no longer visible, and a new one is formed. In a 288-hr pupa no further changes are noticeable except that the epithelium in the posterior region also shows smaller projections (Fig. 5). The cells become squamous and the cytoplasm is scanty. The double-layered wall of the posterior region gradually folds posteriorly into the midgut so that an oesophageal valve makes its appearance in the anterior part of the midgut, prior to the imaginal emergence (Fig. 6). A feebly developed
166
O . P . KATHURIA
FIG. 5.
FIG. 4. FIG. 4. 240-hr pupa. FIG. 5. 288-hr pupa.
_J FIG. 6. FIG. 6. 312-hr pupa.
Metamorphic Changes in Posterior Region of Foregut of Papilio aristolochiae F.
167
blood sinus is enclosed between the 2 folds of the oesophageal valve. The lumen of the proventriculus contracts and becomes obliterated by the folded epithelium. The circular muscles lie outside the proventriculus. DISCUSSION Bordas (1911) recognized a region between the oesophageal valve and midgut and considered it as a regenerative region of the peritrophic membrane. Deegener (1908) in Malacosoma and Hufnagel (1918) in Hyponomeuta identified the same region and supported the views of Bordas. They called this region "regenerative region". Perez (1910) regarded it as a persistent embryonic region, which forms certain parts of the imaginal gut. He doubted if any great part was played by the imaginal ring in Lepidoptera during metamorphosis. Henson (1931) called this region "anterior interstitial ring" in Vanassa and concluded that "it plays so little a part in the metamorphosis that it can scarcely be regarded as embryonic region set aside for the production ofimaginal tissue". But in 1946 he probably recognized its importance and wrote " . . . the behaviour of the ring at metamorphosis is most diverse. In Diptera, Lepidoptera and Hymenoptera it is said to form the posterior region of the foregut". G r a y (1931) did not use the term anterior imaginal ring for this embryonic zone of cells but termed it "histoblastic disc". He further showed that the larval cells of the foregut in Homaledra sabalella (Lepidoptera) degenerate completely and most of the posterior region of the adult foregut, consisting of oesophageal diverticulum, proventriculus and the oesophageal valve, is reconstructed by the proliferation of cells of the "histoblastic disc". In P. aristolochiae the anterior imaginal ring divides mitotically and extends forward in the posterior region of the foregut in prepupa and early pupa. These cells later form the oesophageal valve. The metamorphic changes in the foregut as described in this work, have been supported also by the works of Thompson (1905), Risler (1961), Romoser and Venard (1966, 1967), and Ameen (1969).
Acknowledgements--The author wishes to express his gratitude to Dr. J. Bahadur for suggesting this study. Thanks are also due to Dr. H. Swarup, Professor and Head, School of Studies in Zoology, for providing the necessary facilities.
REFERENCES AMEEN, M. U. 1969. Metamorphosis of some of the organ systems in the fly Ptychoptera albimana F. Trans. Roy. EntomoL Soc. London 121 (6): 235-79. BAHADUR,J. and O. P. KAXHURIA.1971. Development of ventral oesophageal diverticulum in Papilio aristolochiae F. (Lepidoptera: Papilionidae). Int. J. Insect Morphol. EmbryoL 1: 21-7. BORDAS, L. 1911. L'appereil digestif et les tubes de Malpighi des larves de 16pidopt~res. Ann. Sci. Natur. (ZooL). 14: 191-273. DEEGENER, P. 1908. Die Entwicklung des Darmkanals der lnsekten w~ihrend der Metamorphose, II. Malacosoma castransis (Lepid.). Zool. Jahrb. Anat. 26: 45-182. GRAY, J. 1931. The post-embryological development of the digestive system in Homaledra saballela Chambers. (Lepidoptera: Cosmopterygidae). Ann. EntomoL Soc. Amer. 24: 45-107. HENSON, H. 1931. The structure and post embryonic development of Vanassa utricae (Lep.) (1). The larval alimentary canal. Quart. J. Miscrosc. Sci. 74: 321-60. HENSON, H. 1946. The theoretical aspects of insect metamorphosis. Biol. Rev. (Cambridge) 21: 1-14. HUBSCHMAN,J. H. 1962. A simplified azan process well suited for crustacean tissue. Stain TechnoL 37: 379-80. HUFNACEL, A. 1918. Recherches histologiques sur la m6tamorphose d'un Lepidopt~r (Hyponomeuta padella L.). Arch. ZooL Exp. Gen. 57: 47-202.
168
O . P . KATHURIA
PEREZ, C. 1910. Recherches histologiques sur la m&amorphose des Muscides (Calliphora erythrocephala Meig.). Arch. Zool. Exp. Gen. 4: 1-274. RISLER, H. 1961. Untersuchungen zur somatischen Reduktion in der Metamorphose des Stechmiickendarms. Biol. Zentralbl. 80: 413-28. ROMOSER, W. S. and C. E. VENARD. 1966. The development of the ventral oesophageal diverticulum in Aedes triseriatus (Diptera: Culicidae). Ann. Entomol. Soc. Amer. 59: 484-89. ROMOSER, W. S. and C. E. VENARD. 1967. Development of the dorsal oesophageal diverticular in Aedes triseriatus (Diptera: Culcidae). Ann. Entomol. Soc. Amer. 60: 617-23. THOMPSON, M. T. 1905. The alimentary canal of the mosquito. Proc. Boston. Soc. Natur. Hist. 32: 145-202.
METAMORPHIC CHANGES IN POSTERIOR REGION OF FOREGUT OF PAPILIO ARISTOLOCHIAE F. (LEPIDOPTERA:
PAPILIONIDAE)
O. P. KATHURIA* School of Studies in Zoology, Vikram University, Ujjain (M.P.), India
(Accepted 19 January 1972) Abstract--The ceils of the anterior imaginal ring in Papilio aristolochiae divide mitotically during the early pupal period and increase in number. Some of the cells of the anterior imaginal ring evaginate on the ventral side and form the anlage of ventral oesophageal diverticulum. After the formation of the diverticulum the imaginal ring again becomes divided into anterior and posterior regions, which are the anlagen of the proventriculus and oesophageal valve respectively. The cells of the latter 2 regions remain columnar in the beginning but soon become squamous and folded. The folds of the oesophageal valve form an intussception with the anterior part of the midgut, prior to the imaginal emergence. Index descriptors (in addition to those in title): Ventral oesophageal diverticulum. THE FINDINGS on the metamorphosis of the foregut in insects are contradictory. Deegener (1908) in Malacosoma castransis, Perez (1910) in Calliphora erythrocephala and Gray (1931) in Homaledra sabalella, believed that the anterior imaginal ring formed the posterior region of foregut, including oesophageal diverticulum and oesophageal valve. Thompson (1905) in Culex pipiens, however, showed that the anterior imaginal ring formed only the oesophageal valve, and that the oesophageal diverticula are derived from the oesophageal tissue. According to Risler (1961), in Aedes aegypti, the anterior imaginal ring forms the oesophageal diverticula also. Romoser and Venard (1966, 1967) arrived at a different conclusion. These authors divided the larval oesophageal tissue within the proventriculus into 5 regions and showed that the ventral oesophageal diverticulum and the oesophageal valve are derived from the anterior imaginal ring. In Papilio aristolochiae the anterior imaginal ring forms the ventral oesophageal diverticulum, the proventriculus and the oesophageal valve. This paper presents the development of the proventriculus and the oesophageal valve. The development of the ventral oesophageal diverticulum has been described elsewhere (Bahadur and Kathuria, 1971). M A T E R I A L S AND M E T H O D S The larvae o f P . aristolochiae were collected from the local fields and were supplied daily with fresh leaves of Aristolochia plant. Full grown larvae, when stopped feeding, were separated and allowed to pupate. The pupal period lasts from 12 to 14 days in the field. Pupae of different ages were taken. Dissections were done under stereoscopic binocular * Present address: Department of Zoology, Government Degree College, Jhabua (M.P.), India. 163
164
O.P. KATHURIA
m i c r o s c o p e and tissues were fixed in B o u i n ' s solution. The sections were cut at 6 - 8 / ~ an d stained with H e i d e n h a i n ' s iron h a e m o t o x y l i n or with a modification o f the A z a n m e t h o d ( H u b s c h m a n , 1962). D r a w i n g s have been m a d e with the help o f c a m e r a lucida. OBSERVATIONS The cells o f the a n t e r i o r imaginal ring f o r m 3 adult structures: the ventral oesophageal diverticulum, the proventriculus, and the oesophageal valve during metamorphosis. The d e v e l o p m e n t o f ventral oesophageal diverticulum has been described in detail in an earlier pa pe r (Bahadur and K a t h u r i a , 1971), where we have shown that, some o f the cells o f anterior imaginal ring f o r m the anlage o f ventral oesophageal diverticulum in a 45-hr p u p a ; and
FIG. I. FIG. 2. FIGS. 1-6. L.S. Posterior part of foregut of Papilio aristolochiae. Scale used in Figs. 1-5 is the same as in Fig. 6. FIG. l. 100-hr pupa. FIG. 2. 150-hr pupa. Note folding of anterior region over posterior region denoted by R. A Air CM Ep 1N MG Oe V P Pro R VD
-= = = ------
Abbreviations used in figures anterior region of the imaginal ring anterior imaginal ring circular muscle epithelium intima midgut oesophageal valve posterior region of the imaginal ring proventriculus reflection of the anterior region over posterior region of imaginal ring ventral diverticulum
Metamorphic Changes in Posterior Region of Foregut of Papilio aristolochiae F.
165
that evagination grows further as a result of mitotic activity. The cells of the anterior imaginal ring left after the formation of the anlage of ventral evagination again become divided into anterior and posterior regions in a 10O-hr pupa (Fig. 1). The cells of the latter 2 regions show mitotic activity. The anterior region, which lies immediately behind the ventral evagination, is the anlage of proventriculus. The posterior region, which is the anlage of oesophageal valve, lies anterior to the foregut-midgut junction. In a 150-hr pupa the epithelium of the anterior portion becomes folded upon the anterior margin of the posterior region (Fig. 2) and gradually covers it as the pupa becomes 200-hr old (Fig. 3).
FIG. 3.
FIG. 3. 200-hr pupa. As a result of this folding of the anterior region, the posterior region becomes two-layered. The cells of the anterior region, which appear columnar in the beginning, attain a flattened appearance. Owing to the flattening of the cells, the epithelium also increases in length and becomes folded and projects into the lumen. In contrast to this, the cells of the posterior region, remain columnar, and closely appressed in 152-hr pupa. The luminal surface of the epithelium in this region is smooth. In a 200-hr pupa the luminal surface appears wavy and the cells are still columnar in shape. A thick intima almost fills up the lumen of the posterior region. In a 240-hr old pupa the epithelium in the anterior region is more flattened and is produced into large fingerlike projections (Fig. 4). The cells possess small nuclei and granular cytoplasm. The epithelium of the posterior region also becomes folded and the cells appear cuboidal. The old intima is no longer visible, and a new one is formed. In a 288-hr pupa no further changes are noticeable except that the epithelium in the posterior region also shows smaller projections (Fig. 5). The cells become squamous and the cytoplasm is scanty. The double-layered wall of the posterior region gradually folds posteriorly into the midgut so that an oesophageal valve makes its appearance in the anterior part of the midgut, prior to the imaginal emergence (Fig. 6). A feebly developed
166
O . P . KATHURIA
FIG. 5.
FIG. 4. FIG. 4. 240-hr pupa. FIG. 5. 288-hr pupa.
_J FIG. 6. FIG. 6. 312-hr pupa.
Metamorphic Changes in Posterior Region of Foregut of Papilio aristolochiae F.
167
blood sinus is enclosed between the 2 folds of the oesophageal valve. The lumen of the proventriculus contracts and becomes obliterated by the folded epithelium. The circular muscles lie outside the proventriculus. DISCUSSION Bordas (1911) recognized a region between the oesophageal valve and midgut and considered it as a regenerative region of the peritrophic membrane. Deegener (1908) in Malacosoma and Hufnagel (1918) in Hyponomeuta identified the same region and supported the views of Bordas. They called this region "regenerative region". Perez (1910) regarded it as a persistent embryonic region, which forms certain parts of the imaginal gut. He doubted if any great part was played by the imaginal ring in Lepidoptera during metamorphosis. Henson (1931) called this region "anterior interstitial ring" in Vanassa and concluded that "it plays so little a part in the metamorphosis that it can scarcely be regarded as embryonic region set aside for the production ofimaginal tissue". But in 1946 he probably recognized its importance and wrote " . . . the behaviour of the ring at metamorphosis is most diverse. In Diptera, Lepidoptera and Hymenoptera it is said to form the posterior region of the foregut". G r a y (1931) did not use the term anterior imaginal ring for this embryonic zone of cells but termed it "histoblastic disc". He further showed that the larval cells of the foregut in Homaledra sabalella (Lepidoptera) degenerate completely and most of the posterior region of the adult foregut, consisting of oesophageal diverticulum, proventriculus and the oesophageal valve, is reconstructed by the proliferation of cells of the "histoblastic disc". In P. aristolochiae the anterior imaginal ring divides mitotically and extends forward in the posterior region of the foregut in prepupa and early pupa. These cells later form the oesophageal valve. The metamorphic changes in the foregut as described in this work, have been supported also by the works of Thompson (1905), Risler (1961), Romoser and Venard (1966, 1967), and Ameen (1969).
Acknowledgements--The author wishes to express his gratitude to Dr. J. Bahadur for suggesting this study. Thanks are also due to Dr. H. Swarup, Professor and Head, School of Studies in Zoology, for providing the necessary facilities.
REFERENCES AMEEN, M. U. 1969. Metamorphosis of some of the organ systems in the fly Ptychoptera albimana F. Trans. Roy. EntomoL Soc. London 121 (6): 235-79. BAHADUR,J. and O. P. KAXHURIA.1971. Development of ventral oesophageal diverticulum in Papilio aristolochiae F. (Lepidoptera: Papilionidae). Int. J. Insect Morphol. EmbryoL 1: 21-7. BORDAS, L. 1911. L'appereil digestif et les tubes de Malpighi des larves de 16pidopt~res. Ann. Sci. Natur. (ZooL). 14: 191-273. DEEGENER, P. 1908. Die Entwicklung des Darmkanals der lnsekten w~ihrend der Metamorphose, II. Malacosoma castransis (Lepid.). Zool. Jahrb. Anat. 26: 45-182. GRAY, J. 1931. The post-embryological development of the digestive system in Homaledra saballela Chambers. (Lepidoptera: Cosmopterygidae). Ann. EntomoL Soc. Amer. 24: 45-107. HENSON, H. 1931. The structure and post embryonic development of Vanassa utricae (Lep.) (1). The larval alimentary canal. Quart. J. Miscrosc. Sci. 74: 321-60. HENSON, H. 1946. The theoretical aspects of insect metamorphosis. Biol. Rev. (Cambridge) 21: 1-14. HUBSCHMAN,J. H. 1962. A simplified azan process well suited for crustacean tissue. Stain TechnoL 37: 379-80. HUFNACEL, A. 1918. Recherches histologiques sur la m6tamorphose d'un Lepidopt~r (Hyponomeuta padella L.). Arch. ZooL Exp. Gen. 57: 47-202.
168
O . P . KATHURIA
PEREZ, C. 1910. Recherches histologiques sur la m&amorphose des Muscides (Calliphora erythrocephala Meig.). Arch. Zool. Exp. Gen. 4: 1-274. RISLER, H. 1961. Untersuchungen zur somatischen Reduktion in der Metamorphose des Stechmiickendarms. Biol. Zentralbl. 80: 413-28. ROMOSER, W. S. and C. E. VENARD. 1966. The development of the ventral oesophageal diverticulum in Aedes triseriatus (Diptera: Culicidae). Ann. Entomol. Soc. Amer. 59: 484-89. ROMOSER, W. S. and C. E. VENARD. 1967. Development of the dorsal oesophageal diverticular in Aedes triseriatus (Diptera: Culcidae). Ann. Entomol. Soc. Amer. 60: 617-23. THOMPSON, M. T. 1905. The alimentary canal of the mosquito. Proc. Boston. Soc. Natur. Hist. 32: 145-202.