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Influence of food on lesions induced by nerve severance in the American cockroach
JOURNAL
OF
INVERTEBRATE
Influence
PATHOLOGY
15, 281-283
(1970)
of Food on Lesions Induced by Nerve in the American Cockroach1 DONALD
J. SUTHERLAND
Department of Entomology and Economic Rutgers-The State University, New Brun.swick, Receiued
Severance
August
Zoology, New Jersey
08905
25, 1969
Adult Peripluneta americana (the American cockroach) were subjected to nerve severance and maintained on various diets for 2 months to determine the effect of food type on incidence of crop lesions. Incidence was highest among individuals on lab food and lowest on bread crumbs, which formed a more malleable food bolus. Intermediate incidence was observed among those on banana, a diet which was malleable but apparently consumed in much greater quantity.
INTRODUCTION
Since it was first reported that severance of the recurrent nerve (oesophageal nerve, Willey, 1961) in the cockroach Leucophaea maderae induced “tumors” in organs supplied by this nerve (Scharrer, 1945), other researchers have investigated the phenomenon in this (Matz, 1961; Taylor, 1969) and other speciesof Blattaria (Hema, 1966; Sutherland, 1969). Schlumberger ( 1952)) studying the response to injury in the American cockroach, Periplaneta americanu, and reviewing the effect of nerve severance in L. muderae, opinioned that in the latter case, “hemocytes appeared to figure prominently, suggesting that the epithelial proliferation is hyperplasia accompanying a reaction to injury. The injury may be sought in stasis following nerve section and the resultant accumulation of food and secretions.” This view is supported by studies of similarly induced “tumors,” more appropriately termed lesions, in P. americana, 1 Paper of the Journal Series, New Jersey Agricultural Experiment Station, Rutgers-The State University. This investigation was supported by National Science Foundation Grant No. GB-7446. 281
wherein special attention was given to late stages of development ( Sutherland, 1969). In this species nerve severance at least reduces the flow of food passing the paralyzed proventriculus but does not interrupt the normal feeding rhythm. Consequently, the increase in crop contents stressessome of the insertions of the muscularis which, with subsequent Iocal destruction of epithelium, hemocyte encapsulation, and epithelial regeneration, are destroyed, leaving the muscularis detached in varying degrees. In some instances these processes are modified by epithelial rupture and probable leakage of crop contents into the hemolymph. Recently, it has been suggested that in L. maderae some similar events are involved after nerve severance, although in such studies the intervals may not have been sufficiently extended to allow lesion development to proceed to observable muscle detachment and epithelial repair (Taylor, 1969) . If crop distension by food is one of the most important stimuli for crop lesions, then it follows that the incidence and sites of lesions could be influenced by both the amount and physical type of diet ingested. To determine if this might explain the dif-
282
SUTHERLAND
ferences in the major sites of lesions in P. americana (midgut, Hema, 1966; crop, Sutherland, 1969), a series of experiments has been conducted in which adult P. americana were subjected to nerve lesion and maintained thereafter on various diets ad lib. for 2 months prior to examination for lesions. MATERIALS
AND METHODS
Young adult female and male cockroaches within 2 weeks after the adult molt were used. Nerve severance was performed as previously described ( Sutherland, 1969)) and cockroaches were maintained under a 1ight:dark regimen of 12 hr: 12 hr. Prior to the examination of the crop, the organ was excised, fixed in Carnoy’s solution, and its contents were removed to allow its luminal surfaces to be exposed. Certain diets initially employed, such as fresh apple, potato, or banana, were unsuitable because of rapid drying, decay, and loss of apparent attractiveness. Therefore, diet types were restricted to: (1) pelletized laboratory animal food, which was used in previous experiments and with which crops became distended at the major site of lesions; (2) commercially prepared bread crumbs, which formed a much softer food bolus than 1; and (3) commercially prepared strained banana. It was felt that diets 2 and 3, particularly the latter, were sufficiently malleable to pass more readily through a paralyzed proventriculus.
INCIDENCE
OF
RESULTS AND DISCUSSION
Although food consumption was not measured, it was apparent that diet 3 was very attractive and consumed in such large quantities as to necessitate frequent replenishment. In contrast to treated individuals fed diets 1 or 2, the hindguts of those on diet 3 were full with food. Since the oesophageal nerve does not innervate such posterior portions of the alimentary canal, it is reasoned that large amounts of diet 3 in the hindgut and crop indicate not only the ingestion of large quantities but also at least partial passage through the paralysed proventriculus. Although the crops of over 90% of the treated individuals were full irrespective of diet, those of individuals on diet 1 (laboratory food) generally appeared more distended and their contents so solidly packed as to reduce markedly their possible passage posteriorly. The incidence of crop lesions in young adult females after nerve severance and maintenance for 2 months on various diets is given in Table 1. Incidence was highest in treated groups receiving diet 1 and lowest for diet 2. Lacking knowledge of the possible chemical effect of various foods on lesion formation, it appears lesion incidence is at least dependent on the quantity and/or physical consistency of food. Lesions in all cases were restricted to the crop, and no abnormal changes were observed in the midgut as noted by Hema (1966). In another series with young adult males ( 74 individuals ) , in which incidence
TABLE 1 CROP LESIONS IN FEMALE COCKROACHES MAINTAINED DIETS FOR 2 MONTHS AFTER NERVE SEVERANCE No. l-Lab food NSa Control
Numbers examined Percent with lesions in crop a NS, nerve severance.
39
50
21 0
ON VARIOUS
Diets No. e--Bread Control NS
No. 3-Banana NS Control
20 5
28 19
8 0
27 0
FOOD
AND
LESIONS
INDUCED
of crop lesions of individuals on diets 1 and 3 was 33% and 18%, respectively, approximately 10% of the treated individuals possessed midgut abnormalities. The latter consisted of excessive exfoliation accompanied by hemocyte encapsulation, Therefore, in addition to the influence of consistency and/or quantity of food, sites of lesions may vary with sex in this species. Such sex differences have been reported for L. muderae ( Scharrer, 1949). However, other differences in the incidence and sites of lesions in this latter species (Scharrer, 1945; Matz, 1961) may be due to strain differences or technique differences between researchers. Some differences between species may be due to slight morphological differences. For example, in L. muderae the salivary glands and reservoirs are tightly bound by muscle and connective tissue to the crop (Sutherland and Chillseyzn, 1968), so that crop distension after nerve severance might also be expected to stress physically and induce lesions in the glands and reservoir. Possibly the absence of lesions in BZatteZZu germunica after nerve severance (Johansson and Schreiner, 1966) may be attributed to a combination of all or several factors discussed in this report. ACKNOWLEDGMENT I gratefully Chillseyzn in
acknowledge these studies.
the
aid
of Mrs.
Jean
BY
NERVE
SEVERANCE
283
REFERENCES HEMA,
P.
1966.
Induced
gut tumors in cock(India) 35, 624-626. A. S., AND SCHREINER, B. 1966. Intumors in the German cockroach germanica L. Nature 212, 845.
roaches. Current Sci. JOHANSSON, testinal Blattella MATZ,
G. 1961. Tumeurs experimentales chez Leucophaea muderae F. et Locusta migratoriu L. J. Insect Physiol., 6, 309-313. SCHARRER, B. 1945. Experimental tumors after nerve section in an insect. Proc. Sot. Exptl. Biol. Med. 60, 184-189. SCHARRER, B. 1949. Tumor mortality and sex in Leucophaea maderae. Anat. Record 105, 624-625. SCHLUMBERGER, H. G. 1952. A comparative study of the reaction to injury. I. The cellular response to methylcholanthrene and to talc in the body cavity of the cockroach (Periplaneta americanu). A.M.A. Arch. Pathol. 54, 98-113. SUTHERLAND, D. J. 1969. Nerve severance and tumor induction in Peripluneta americana (L.). In “Neoplasmisms and Related Disorders of Invertebrate and lower Vertebrate Animals” (C. J. Dawe and J. C. Harshbarger, eds.). Natl. Cancer Inst. Monograph. 31, 399-418. SUTHERLAND, D. J., AND CHILLSEYZN, J. M. 1968. Function and operation of the cockroach salivary reservoir. 3. Insect Physiol. 14, 2131. TAYLOR, R. L. 1969. Formation of tumorlike lesions in the cockroach Leucopka maderae after nerve severance. J. Inuertebrate Pathol. 13, 167-187. WILLEY, R. B. 1961. The morphology of the stomadeal nervous system in Periplaneta americana (L.) and other Blattaria. J. Morphol. 108, 219-261.
OF
INVERTEBRATE
Influence
PATHOLOGY
15, 281-283
(1970)
of Food on Lesions Induced by Nerve in the American Cockroach1 DONALD
J. SUTHERLAND
Department of Entomology and Economic Rutgers-The State University, New Brun.swick, Receiued
Severance
August
Zoology, New Jersey
08905
25, 1969
Adult Peripluneta americana (the American cockroach) were subjected to nerve severance and maintained on various diets for 2 months to determine the effect of food type on incidence of crop lesions. Incidence was highest among individuals on lab food and lowest on bread crumbs, which formed a more malleable food bolus. Intermediate incidence was observed among those on banana, a diet which was malleable but apparently consumed in much greater quantity.
INTRODUCTION
Since it was first reported that severance of the recurrent nerve (oesophageal nerve, Willey, 1961) in the cockroach Leucophaea maderae induced “tumors” in organs supplied by this nerve (Scharrer, 1945), other researchers have investigated the phenomenon in this (Matz, 1961; Taylor, 1969) and other speciesof Blattaria (Hema, 1966; Sutherland, 1969). Schlumberger ( 1952)) studying the response to injury in the American cockroach, Periplaneta americanu, and reviewing the effect of nerve severance in L. muderae, opinioned that in the latter case, “hemocytes appeared to figure prominently, suggesting that the epithelial proliferation is hyperplasia accompanying a reaction to injury. The injury may be sought in stasis following nerve section and the resultant accumulation of food and secretions.” This view is supported by studies of similarly induced “tumors,” more appropriately termed lesions, in P. americana, 1 Paper of the Journal Series, New Jersey Agricultural Experiment Station, Rutgers-The State University. This investigation was supported by National Science Foundation Grant No. GB-7446. 281
wherein special attention was given to late stages of development ( Sutherland, 1969). In this species nerve severance at least reduces the flow of food passing the paralyzed proventriculus but does not interrupt the normal feeding rhythm. Consequently, the increase in crop contents stressessome of the insertions of the muscularis which, with subsequent Iocal destruction of epithelium, hemocyte encapsulation, and epithelial regeneration, are destroyed, leaving the muscularis detached in varying degrees. In some instances these processes are modified by epithelial rupture and probable leakage of crop contents into the hemolymph. Recently, it has been suggested that in L. maderae some similar events are involved after nerve severance, although in such studies the intervals may not have been sufficiently extended to allow lesion development to proceed to observable muscle detachment and epithelial repair (Taylor, 1969) . If crop distension by food is one of the most important stimuli for crop lesions, then it follows that the incidence and sites of lesions could be influenced by both the amount and physical type of diet ingested. To determine if this might explain the dif-
282
SUTHERLAND
ferences in the major sites of lesions in P. americana (midgut, Hema, 1966; crop, Sutherland, 1969), a series of experiments has been conducted in which adult P. americana were subjected to nerve lesion and maintained thereafter on various diets ad lib. for 2 months prior to examination for lesions. MATERIALS
AND METHODS
Young adult female and male cockroaches within 2 weeks after the adult molt were used. Nerve severance was performed as previously described ( Sutherland, 1969)) and cockroaches were maintained under a 1ight:dark regimen of 12 hr: 12 hr. Prior to the examination of the crop, the organ was excised, fixed in Carnoy’s solution, and its contents were removed to allow its luminal surfaces to be exposed. Certain diets initially employed, such as fresh apple, potato, or banana, were unsuitable because of rapid drying, decay, and loss of apparent attractiveness. Therefore, diet types were restricted to: (1) pelletized laboratory animal food, which was used in previous experiments and with which crops became distended at the major site of lesions; (2) commercially prepared bread crumbs, which formed a much softer food bolus than 1; and (3) commercially prepared strained banana. It was felt that diets 2 and 3, particularly the latter, were sufficiently malleable to pass more readily through a paralyzed proventriculus.
INCIDENCE
OF
RESULTS AND DISCUSSION
Although food consumption was not measured, it was apparent that diet 3 was very attractive and consumed in such large quantities as to necessitate frequent replenishment. In contrast to treated individuals fed diets 1 or 2, the hindguts of those on diet 3 were full with food. Since the oesophageal nerve does not innervate such posterior portions of the alimentary canal, it is reasoned that large amounts of diet 3 in the hindgut and crop indicate not only the ingestion of large quantities but also at least partial passage through the paralysed proventriculus. Although the crops of over 90% of the treated individuals were full irrespective of diet, those of individuals on diet 1 (laboratory food) generally appeared more distended and their contents so solidly packed as to reduce markedly their possible passage posteriorly. The incidence of crop lesions in young adult females after nerve severance and maintenance for 2 months on various diets is given in Table 1. Incidence was highest in treated groups receiving diet 1 and lowest for diet 2. Lacking knowledge of the possible chemical effect of various foods on lesion formation, it appears lesion incidence is at least dependent on the quantity and/or physical consistency of food. Lesions in all cases were restricted to the crop, and no abnormal changes were observed in the midgut as noted by Hema (1966). In another series with young adult males ( 74 individuals ) , in which incidence
TABLE 1 CROP LESIONS IN FEMALE COCKROACHES MAINTAINED DIETS FOR 2 MONTHS AFTER NERVE SEVERANCE No. l-Lab food NSa Control
Numbers examined Percent with lesions in crop a NS, nerve severance.
39
50
21 0
ON VARIOUS
Diets No. e--Bread Control NS
No. 3-Banana NS Control
20 5
28 19
8 0
27 0
FOOD
AND
LESIONS
INDUCED
of crop lesions of individuals on diets 1 and 3 was 33% and 18%, respectively, approximately 10% of the treated individuals possessed midgut abnormalities. The latter consisted of excessive exfoliation accompanied by hemocyte encapsulation, Therefore, in addition to the influence of consistency and/or quantity of food, sites of lesions may vary with sex in this species. Such sex differences have been reported for L. muderae ( Scharrer, 1949). However, other differences in the incidence and sites of lesions in this latter species (Scharrer, 1945; Matz, 1961) may be due to strain differences or technique differences between researchers. Some differences between species may be due to slight morphological differences. For example, in L. muderae the salivary glands and reservoirs are tightly bound by muscle and connective tissue to the crop (Sutherland and Chillseyzn, 1968), so that crop distension after nerve severance might also be expected to stress physically and induce lesions in the glands and reservoir. Possibly the absence of lesions in BZatteZZu germunica after nerve severance (Johansson and Schreiner, 1966) may be attributed to a combination of all or several factors discussed in this report. ACKNOWLEDGMENT I gratefully Chillseyzn in
acknowledge these studies.
the
aid
of Mrs.
Jean
BY
NERVE
SEVERANCE
283
REFERENCES HEMA,
P.
1966.
Induced
gut tumors in cock(India) 35, 624-626. A. S., AND SCHREINER, B. 1966. Intumors in the German cockroach germanica L. Nature 212, 845.
roaches. Current Sci. JOHANSSON, testinal Blattella MATZ,
G. 1961. Tumeurs experimentales chez Leucophaea muderae F. et Locusta migratoriu L. J. Insect Physiol., 6, 309-313. SCHARRER, B. 1945. Experimental tumors after nerve section in an insect. Proc. Sot. Exptl. Biol. Med. 60, 184-189. SCHARRER, B. 1949. Tumor mortality and sex in Leucophaea maderae. Anat. Record 105, 624-625. SCHLUMBERGER, H. G. 1952. A comparative study of the reaction to injury. I. The cellular response to methylcholanthrene and to talc in the body cavity of the cockroach (Periplaneta americanu). A.M.A. Arch. Pathol. 54, 98-113. SUTHERLAND, D. J. 1969. Nerve severance and tumor induction in Peripluneta americana (L.). In “Neoplasmisms and Related Disorders of Invertebrate and lower Vertebrate Animals” (C. J. Dawe and J. C. Harshbarger, eds.). Natl. Cancer Inst. Monograph. 31, 399-418. SUTHERLAND, D. J., AND CHILLSEYZN, J. M. 1968. Function and operation of the cockroach salivary reservoir. 3. Insect Physiol. 14, 2131. TAYLOR, R. L. 1969. Formation of tumorlike lesions in the cockroach Leucopka maderae after nerve severance. J. Inuertebrate Pathol. 13, 167-187. WILLEY, R. B. 1961. The morphology of the stomadeal nervous system in Periplaneta americana (L.) and other Blattaria. J. Morphol. 108, 219-261.