" F‘”'°f"'~“ “ .‘ ' -"= R.’ “fr“? ‘ ’-.’-’..E'-"."=.= "' .Q‘ fl“ ‘ THE Eriida: C}? A’KN :KRAMALQQ \‘i’é‘ifigkz "HE: vl‘é - ERIN N SEA 3 N INSECTS # V O f .l,, f 7’ ——— _———— —— f ’A g f ’ _'___———— _ _ ('fi l l' ‘. H H1” ‘ Thesis for #319 Degree of M. S MICHIGAN STATE UME’ERSHY Ronaifl ‘1?! imam. Redges 1957 -~ *--.—.‘ THESIS THE EFFECTS OF AN IRILADIATED WHEAT DIET ON CERTAIN GRAIN INSECTS by Ronald William Hodges AN ABSTRACT Submitted to the College of Science and Arts Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology Year 1957 Approved EM? 744, five-u" < RONALD w. Homes A35 M Experiments were conducted to determine whether a diet of irradiated wheat had any affects on certain grain insects, EZEESLEEE.ESQ£E§HE Duval, Sitophilug granarius (Linnaeus), and.Sitotroga cerealeyla (Olivier). The wheat was irradiated at three levels: 10,000 rep, 100,000 rep, and 1,000,000 rep. Each filial generation was reared on wheat given the same treatments as for that of the parents and under controlled laboratory conditions of temperature and humidity. The results of the experiments indicate that there were significant differences among treatments for the three insects; however, an analysis of the variance of the data reveals that there were interactions occur- ring between generations and the various treatments for the three insects. Thus, while there appeared to be an increase in the rate of reproduction of Tribolium confusum at 10,000 rep, the interactions preclude a definite conclusion as to the effects of the irradiation. The experimental results do indicate that these insects can survive on wheat irradiated at three levels. THE EFFECTS OF AN IRRADIATED WHEAT DIET ON CERTAIN GRAIN INSECTS by Ronald William Hodges A THESIS Submitted to the College of Science and.Arts Michigan State University of.Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology Year 1957 AWN T3 The author wishes to express his appreciation to Professor Ray Hutson for procuring the assistantship which enabled him to complete the work for this thesis and for making the arrangements with the Agricul- tural Engineering Department of Michigan State University to carry out the thesis project. The author expresses his sincerest thanks to Dr. Gordon Guyer for his careful guidance and aid throughout the entire program. He wishes to thank Dr. Don Kayne for his design of part and for his review of all of the statistical analysis. He gratefully acknowledges the pertinent discussions and suggestions of his colleague, Richard Nicholas. ‘lhe author also wishes to thank the other nembers of his graduate comittee, Drs. Roland Fischer, Herman King, Gerald Prescott, and Pro- fessor Dennis Hiant, for their criticisms and review of the thesis. TABLE OF CONTENTS PAGE I. INMDUCHOPI C . O ' O O O O O O C O O O O 1 II. LITERATURE REVIEW . . . . . . . . . . . . 2 III a PROCEWRE o o o o o o o o o o o o o o o 5 IV. PRESENTATION OF KATA . . . . . . . . . . . 10 V. DISCUSSION OF RESULTS . . . . . . . . . . . 21 VI 0 SLTE'IARY MEI; COR! CLUSIO his 0 e o o o o o o o o 2 3 LITERATURE CITED . . . . . . . . . . . . . . 2n INTRODUCTION The application of cathode rays to biological materials in recent years has led to a wide variety of interesting and valuable studies. The major line of study has been in the field of food sterilization. It is possible to sterilize many foods and other'naterials with cathode rays without producing a rise in the temperature of the materials. At the same time workers have studied the effects on essential constituents of foods, amino acids, enzymes, and vitamins, to determine whether these constituents were adversely affected by the irradiations. At the pre- sent time it appears possible to sterilize food without destroying the essential ingredients. Another aspect of cathode ray research is that of direct irradia- tion of grain insects. It has been found that insects can be killed with these irradiations; however, experiments are now in progress which will determine whether the level of irradiation necessary to kill the insects produces any effects which result in unpalatable food. The purpose of this experiment was to determine whether there were any effects on certain grain insects produced by'a diet of irradiated wheat as empared with insects reared on non-irradiated wheat. The au- thor has conducted experiments with the confused flour beetle, Tribolium confusum.Duva1; the granary weevil, Sitgphilus granarius (Linnaeus); and the Angoumois grain moth, Sitotroga cerealella (Olivier). LITERATURE REVIEW There is little available literature concerning the rearing of ani- mals on food.materials subjected to high energy cathode rays. Luckey 22 El. (1955) carried out a series of experiments in.which they reared a group of mice on a high vitamin, semi-synthetic diet. This diet was var- ied.by having treatments of non-sterilized, steam sterilized, and cathode ray sterilized food. The rate of irradiation, averaging 2.8 x 106 rep (rep-roentgenpequivalentqphysicalsone roentgen), was high enough to sterilize the food. Their experiments were designed to subject three generations of mice to feeding on the irradiated food. They concluded that the mice fed a diet treated with high energy electrons grew at near- ly the same rate as the mice fed.a non-treated diet. They were able to make observations on the reproductive rate, number of young weaned.per litter, size of young at weaning, and the age at which the adults cast their litters. In each of these observations they found that the mice fed the cathode ray treated food differed in no significant manner from the mice fed the non-treated food. In both groups the appearance and activity of the various animals were described as ”good”. The diet of the mice was of a dry nature. One major point to be noted in relation to the experiments of Luckey'gt_§l. is that the diet was composed in such a manner that a reduction of any of the constituents would not be sufficient to lower its nutritional value sufficiently to have a dele- terious effect on the mice. Poling gt a}. (1955) conducted a series of experiments on labora- tory rats using a diet composed.mainly of beef subjected to cathode rays at average levels of 2.7 x 106 rep and 3.7 x 106 rep. These two rates of irradiation were assumed to be the same in the eXperiments. The rats 2 were fed on this diet for a period of two years. The authors concluded that the rats fed an irradiated diet were in no respect different from the control animals. Proctor and Goldblith (191s) and Goldblith and Proctor (19149) have shown that cathode rays have a destructive effect on niacin, carotene, and riboflavin. They found that the amount of destruction of niacin was less when it was in the presence of methionine than when it was a pure substance. Pnoctor and Bhatia (1950) conducted tests with haddock and found that at an irradiation of 900,000 rep there was no significant loss or gain of the following amino acids: phenylalanine, tryptophan, methionine, cystine, valine, leucine, histidine, arginine, lysine, and threonine. They concluded that more energy is required for complete destruction of enzymes in food.materials by irradiation than is neces- sary for complete destruction of bacteria. The author has found no literature dealing with the action of ca- thode rays on vitamins and.amino acids in wheat; however, the analogy can be made that results of such investigations might yield.results simr ilar to those of the workers mentioned above. Due to the interest in food sterilization several experiments have been conducted with bacteria,.molds, and insects using high energy ca- thode rays. The application of cathode rays to foods for purposes of sterilization has been studied from several aspects. Huber (l9h8) has conducted tests on meats, fish, eggs, vegetables, and fruits to eval- uate the effects of various radiations on these products. Individual enzyme activity has been studied by Dunn §£.§;f (l9h8). These authors found that the enzymes were slightly affected at a level of irradiation sufficient to sterilize foods. These authors have killed bacteria, yeasts, and molds in pure cultures and in mixed cultures. Other workers who have found either deleterious effects or no ef- fects on foods, enzymes, and. amino acids due to cathode ray irradiation are Goldblith gt a}: (1952), Hannan (19514), Nickerson it". al. (1950), Proctor and Goldblith (1951), and hump and Van de Graaff (l9h8). Baker (1953) and Taboada (1953) have applied high Speed electrons to grain insects. They found that 10,000 rep killed the eggs of Tribe- lLum oonfusum and Sitcphilus granarius. This dose was sufficient to prevent adults from producing viable eggs, and it was sufficient to kill 100 percent of the bean weevil, Acanthoscelides obtectus (Say) within one week. At 75,000 rep 100 percent of Tribolium confusum larvae irra- diated in an empty dish died within one week, and 100 percent of .533." M granarius irradiated in an empty dish died within one week. At 200,000 rep 100 percent of Tribolium confusum irradiated in an empty dish died immediately. At 250, 000 rep 100 percent of Sitgphflus granar- E irradiated in wheat died immediately. One-hundred percent of Triba- lium confusum died immediately when they were irradiated at 500,000 rep in flour. There appears to be distinct differences between insects as to their reactions to cathode rays. PROCEDURE EXPERIMENT A The insect used for this experiment was Tribolium.confusum. Approx- imately eighty pounds of Yorkwin white wheat in a cleaned seed condition were milled to a coarse degree in a hammermill. Six portions of ten pounds each were weighed out, and of these portions, three were subjec- ted to irradiation. The levels of irradiation were 10,000 rep, 100,000 rep, and 1,000,000 rep. These dosages were used because each represents a level at which certain organisms are killed by the irradiations. Ac- cording to Nicholas (1956) 10,000 rep is a dose sufficient to kill §l§2f philug granarius; the rice weevil, §, ggygg_(Linnaeus); Tribolium.ggn¢ fusum; and most saw-toothed grain beetles, Oryzaephilus surinamensis (Linnaeus). One-hundred thousand rep is a dose which is probably enough to kill Sitotroga cerealella; Indian meal moth, Elgdig interpunctella (Hfibner); Mediterranean flour moth, Anagasta kuehniella (Zeller); cadelle, Tenebroides mauritanicus (Linnaeus); and mites. One-million rep is a dose which will kill some bacteria and.molds. After the wheat was irradiated, it was milled to a finer texture in a burr mill. The wheat was stored in a fiber drum at room.tempera- ture. The test with Tribolium.confusum was designed to determine whether there would be any effect on the length of life cycle (period from egg to adult) and on the rate of reproduction (number of filial generation per adult of parental generation) brought about by different levels of irradiation. The test was carried out for three generations. Four treatments were used: control, 10,000 rep, 100,000 rep, and 1,000,000 rep. There were five replications of each treatment. The milled wheat was sifted with a forty-mesh sieve. Thirty grams of flour were placed in each of five one-half pint jars. This procedure was followed for each of the four treatments. Twenty adult Tribolium confusum from a stock colony were then placed in each of the jars which was then covered with a fine mesh cloth, held in place by the ring sec- tion of the lid. The jars were then placed in the constant temperature (80 degrees Fahrenheit) and constant humidity (70 percent) room. The adult beetles were allowed to remain in the flour for seven days, and then, they were sifted from the flour with a twenty-mesh sieve and des- troyed. This sieve size allows the eggs to pass through the mesh. The flour was returned to the jars, and the jars were returned to the con- stant temperature and constant humidity room. When the adults began to emerge, the flour was sifted to determine the mmber of larvae, pupae, and adults present. This procedure was repeated seven days later when it was found that most of the adults pre- sent were dead and that many of them had not transformed normally from the pupal stage. Possibly the sifting of the previous week affected their transformation in some manner. The second generation test was set up in the same manner as the first generation test except that the adults used were those reared from flour from the different treatments. The adults of the first gen— eration were used to start the second generation of the same treatment as the one in which they were reared. After the adults had been coun- ted and the second generation test was started, the adults were destroyed. The observations on the second generation adults were the same as for the first generation with the exception that the flour was sifted only once. The numbers of adults, pupae, and larvae were recorded at this time, and the adults for the third generation were saved. The third generation test was carried out in the same manner as the second generation test. EXPERIMENT B The insect used for this test was Sitophilu§_granarius. The design of this experiment was the same as that used for Tribolium confusum. Three tenepound portions of whole Yorkwin white wheat were irradiated at the levels of 10,000 rep, 100,000 rep, and 1,000,000 rep. The wheat was stored in a fiber drum at room temperature. Fifty grams of wheat'were placed in each of five one-half pint jars for each of the four treatments. Twenty adult Sitophilus granarius were placed in each of the jars. Two layers of a fine mesh cloth were placed over the jars; the ring portion of the jar lids was returned; and the jars were placed in the constant temperature and constant humidity room. The adults remained in the wheat for seven days and then.were removed. When the adults began to emerge, the wheat was sifted to determine their number. The adults were counted at intervals of one week. Twen- ty adults, if that many emerged, from each replication were used to start the second generation test. The second and third generation tests were carried out in the same manner as the first generation test. EXPERIMENT C The insect used for experiment C was Sitotrgga cerealella. This series of tests was designed and carried out in the same manner as ex- periments A and B; however, there were some differences in handling procedures. In order to count the adult specimens to start each series, it was necessary to have the moths in a quiescent state. The adult moths were placed in the cold room (0 degrees Fahrenheit) for approxi- mately three minutes. They were then counted at room temperature. The adults used to start the second and third generations were aspirated and placed in the jars for the succeeding generation. The remaining specimens were killed with methyl ethyl ether. The adults were counted when.they began to emerge, seven days later, and fourteen days later. There were certain factors which appeared to affect all of the ex- periments in the same manner. They were: 1. Humidi z. The humidistat either lost its sensitivity or failed to function.properly for some other reason. As a result, the humidifier failed to shut off during the second generation of experiments A and B and the third generation of experiment C. This failure occurred at night, and by the time of discovery, the following morning, one inch of water had accumulated on the floor. There were droplets of water on the jars. The humidifier was turned off, and all of the jars were taken into another room which had no controls for temperature and humidity. The wheat and flour were dried as quickly as possible by playing a stream of air from a fan over the jars and opening the windows of the room to permit adequate ventilation. The jars were returned to the constant temperature room after three days had elapsed. There was no sign of mold in any of the cultures after this occurrence, and none of the wheat germinated. The humidistat was replaced; however, the new one also failed to function properly. The humidity in the room was much higher than that fer which the control was set. Following this dis- covery the door of the constant temperature room was allowed to remain slightly ajar, and the humidifier was turned off; so the humidity would be lowered. The humidity was finally held at fifty percent for the re- maining tests. 2. EEEEE? Mites were found in the constant temperature room during the second generation of experiments A.and B and the third generation of ex- periment C. The jars which contained these generations were removed.to another room, whereas all other material in the constant temperature room.was placed in the freezer. The interior of the constant tempera- ture room and the hall leading to the room.were sprayed with Aramite. After the mites were discovered, the jars which contained the experimen- tal specimens were placed in low trays which contained Aramite in water. Mites were found later in some of the Sitotroga cerealella cultures. These jars were removed to the freezer. The adult Specimens in the jars ‘were counted after the mites were thought to be dead. Some mites were also found in the third generation of Sitophilus granarius. The jars which contained the mites were removed to the freezer, and the adults were counted later. PRESENTATION OF DATA The data for the three experiments were handled in the same manner. For each generation of each insect the total number of adults of a filial generation per adult of the parental generation was calculated (Tables 1, 2, and 3). An analysis of the variance(Snedecor, 1956) was made to determine whether any significant differences were present among the treatments. A multiple range test as described by Snedecor (it?) was then used to determine where the differences between treatments (if any were present) lay. The results of this test are given in Tables h, 5, and 6. The outstanding result of this test is that the number of adults from treatment two (10,000 rep) was significantly higher that all others in the second and third generations of Tribolium.confusum. For each of the experiments the differences of means between gen- erations appear large. An analysis of variance of the number of off- spring for the three generations combined is presented in Tables 7, 8, and 9. This analysis was carried out to determine whether there might be interactions present in the experiments, 3,3,, whether there was evidence that the effects of treatment varied from generation to gener- ation. This analysis indicates that the interaction was significant for the Tribolium.confusum experiments. Furthermore, most of this in- teraction occurred.among the irradiated treatments. The same analysis for Sitophilus granarius indicates that the interaction "treatment x generation" was significant; however, in this experiment the interaction probably occurred in the “control versus irradiated" treatments. An interaction was significant at the five percent level in the experiment for.Sitotroga_cerealella. According to the analysis this probable inter- 10 11 action is not attributable with any high probability to either the ”con- 01‘ trol versus irradiated" treatments at "among the irradiated" treatments. TABLE 1 NUMBER OF FILIAL GENERATION PER ADULT 0F PARENTAL GENERATION 0F TRIBOLIUMICONFUSUM REARED ON IRRADIATED FLOUR GENERATION 1 Replications Treatments 1 2 3 h S 0 rep 3.00 b.15 2.90 3.55 b.95 lo“ rep 2.75 p.15 n.50 7.65 h.10 10S rep 3.25 3.95 3.55 3.60 5.15 106 rep 5.60 5.30 6.80 6.70 b.60 GENERATION 2 Replications Treatments 1 2 3 h S 0 rep 3.10 3.25 3.85 b.75 1.20 10h rep n.ao 5.70 3.65 6.85 b.90 10S rep 3.h0 2.61 3.85 2.00 3.20 106 rep 1.31 3.57 2.85 3.52 2.00 GENERATION 3 Replications Treatments 1 2 3 h 5 0 rep 0.27 0.26 0.90 0.95 0.23 10h rep 1.63 2.95 2.00 0.30 2.21 105 rep 0.h5 1.05 0.19 0.80 0.95 106 rep 0.95 1.15 0.85 1.35 0.h0 NUMBER OF FILIAL GENERATION PER ADULT OF PARENTAL GENERATION TABLE 2 OF SITOPHILUS GRANARIUS REARED ON IRRADIATED WHEAT GENERATION l Treatments 0 rep 10’4 rep 10S rep lO6 rep GENERATION 2 Treatments 0 rep 10h rep r 10) rep 6 10 rep GENERATION 3 Treatments 0 rep h 10 rep 10S rep 106 rep 1 0.90 1.20 1.05 0.80 1 5.70 5.00 10.90 3.90 l 7.50 b.30 l.h0 3.30 Replications 2 0.25 1.35 0.65 0.25 Replications 2 3.h0 7.30 5.50 3.h0 Replications 2 8.00 2.80 b.20 1.10 1.85 1.15 2030 3 3.h0 10.20 10.60 9.50 8.25 5.00 3.60 u.30 1.20 1.80 1.00 0.55 12.00 10.70 3.90 5.10 3.30 0.50 0.60 1.10 2.70 2.55 0.85 6.70 6.10 7.20 5.60 h.20 1.60 b.80 2.60 NUMBER OF FILIAL GENERATION PER ADULT OF PARENTAL GENERATION TABLE 3 OF smomogg CEREALELIA REARED 0N IRLADIATED wan GENERATION 1 Treatments 0 rep wrap 105 rep 106 rep GENERATION 2 Treatments 0 rep 10h rep 10S rep 106 rep GENERATION 3 Treatments 0 rep 10h rep 10S rep 6 10 rep 1 15.35 8.35 16.h0 11.55 29.15 20.90 19.50 15.20 1 2.80 12.25 15.15 17.70 Replications 2 16.30 9.h0 13510 10.85 Replications 2 19.70 31.65 20.20 23.65 Replications 2 11.25 11.20 13.75 13.80 8.15 10.20 13.10 8.05 18.90 22.75 ‘ 27.85 18.35 10.75 8.35 15.50 18.80 10.10 12.20 12.05 12.30 20.70 23.20 33.90 33.80 8.85 12.50 20.h0 16.55 7.50 10.05 17.60 6.30 13.35 32.85 25.20 28.95 10.05 13.65 10.80 15.10 15 TABLE ’4 COMPARISON OF MEANS OF NUMBER OF FILIAL GENERATION" PER ADULT 0F PARENTAL GENERATION 0F TRImLIUM CONFUSUM REARED 0N IRRADIATED FLOUR GENERATION l Treatments 3 106 rep 10’4 rep 105 rep 0 rep M68118: 5.80 11.63 3.90 3.71 GENERATION 2 Treatments: 10h rep 0 rep 105 rep 106 rep Means: 5.18 3.23 3.01 2.65 GENERATION 3 Treatments : 10h rep .106 re 105 rep 0 rep Means: 1.82 0.9 0.69 0.56 Note: Am tum means not underscored by the same line are significantly different. Amt two means underscored by the same line are not significantly different. 1131.735 16 COMPARISON OF MEANS OF NUMBER OF FEIAL GENERATION PER ADULT 0F PARENTAL GENERATION OF SITOPHILUS GRANARIUS REARED ON IRRADIATED WHEAT GENERATION 1 Treatments : Means: GENERATION 2 Treatments : Means x GENERATION 3 Treatments: Means : Note : 10" reg 10S rep 106 rep 0 rep 1.? 1.28 0.95 0.91 10h rep 105 re . 0 rep 106 rep 7086 7062 6.214 5028 0 rep 10h rep 6.61 17.00 105 rep 106 rep 2.91 2 .70 m two means not underscored by the same line are significantly different. Aw two means underscored by the same line are not significantly different. 17 TABLE 6 COMPARISON OF MEANS OF NUMBER OF FILIAL GENERATION PER ADULT OF PARENTAL GENERATION OF SITOTROGA CEREAIELIA REARED 0N IRRADIATED WHEAT GENERATION 1 Treatments : 105 rep 0 rep 10h rep 106 rep Means: 1!: .115 11 .118 10 .011 9 .81 GWERATION 2 Treatments: 10b rep 105 rep 106 rep 0 rep Means: 26.27 25.37 23.95 20.36 GENERATION 3 Treatments: 106 rep 105 10h rep 0 rep Means: 16.31 153 11.52 8.71: Note: Arw two means not underscored by the same line are significantly different. Aw two means underscored by the saxne line are not significantly different. TABLE 7 ANALYSIS OF VARIANCE OF THE NUMBER OF OFFSPRING OF TRIBOLIUM CONFUSUM REARED 0N IERADIATED FLOUR Source of Variation Total Treatment control vs. irradiated among irradiated Generation Treatment x Generation (control vs. irradiated) x generation (wrong irra- diated) x generation Error Degrees of Freedom 59 3 0\ L8 % significant at 5% level ** significant at 1% level 13.58 131.61 18.7h 0089 17.85 h5.62 mean Square 6.32 5.39 6.79 65.80 3.12 0.hb 8.86 0.95 6.65** 5.67% 7.1h** 69.26** 3.28** 0.h6 b.69** 18 19 ANALYSIS OF VARIANCE OF THE NUMBER OF OFFSPRING 0F SITOPRILUS GRANARIUS REARED ON IRRADIATED WHEAT Source of Variation Total Treatment control vs. irradiated among irradiated Generation Treatment x Generation (control vs. irradiated) 1: generation (among irra- diated) x generation Error * significant at 5% level ** significant at 1% level 1 Degrees of Freedom 581 3 Sum of Squares 560.118 25.h2 6.63 18.79 308.76 h7o56 39.39 8.17 109.76 Mean Square 8.h7 6.63 9.h0 152.38 7.93 19.70 2.01; 2.33 3.63* 2.8h 11.035 65.39“ 3.h0** 8.h5** 0.87 One of the replications failed to yield any adults in the second gene eration; therefore, there was no replication in the third generation. For this reason the degrees of freedom were reduced by one. 20 TABLE 9 ANALYSIS OF VARIANCE OF THE NUMBER OF OFFSPRING 0F SITOTROGA CEREALELLA REARED 0N IRRADIATED WHEAT Source of Degrees of Sum.of Mean F Variation Freedom Squares Square Total 59 3,108.69 Treatment 3 176.76 58.92 5.3h** control vs. irradiated l 13h.59 138.59 l2.20** among irradiated 2 112.17 21 .08 1.91 Generation 2 1,883.01 981.50 85.35** Treatment x Generation 6 169.17 28.19 2.55 (control vs. irradiated) x generation 2 70.11 35.06 3.17 (among irra- diated) x generation A 99.06 2h.76 2.2h Error A8 529.82 11.03 * significant at 5% level ** significant at 1% level DISCUSSION OF RESULTS The results of the multiple range test indicate that the treat- ment of 10,000 rep may have been more favorable to the production of Tribolium confusum than the other treatments including the control. This difference is difficult to interpret in view of the described inter— actions. Since the rank of treatment means varies from generation to generation, it is questionable whether the significance of a particular mean in a particular generation is significant to the experiment as a whole. The variability of means in relation to one another from generation to generation indicates that there is an interaction present in the pro- cess related to time, and therefore, and perhaps only incidentally, re- lated to generation. One of the factors which may have been the cause of the variability of means is that in selecting adults to start a test there was no effort made to determine the sexes of the insects; there- fore, the possibility is present that in some tests there was an une- qual number of males and females. According to Brindley (1930), however, the sexes of Tribolium confusum were present in the ratio of L6:5h (males:fema1es) in a study of 500 specimens; thus this possibility might not be expected with this inseot. Another factor which might cause some of the variability among generations is that the rate of oviposition decreases sharply each day of adult life for Sitotrogggcerealella; there- fore, if the specimens used to start a test were not the same age (from eolosion), there would be significant differences present in the number of eggs laid per female. The analysis of variance also indicates that there were significant 21 22 differences among treatments for the three eXperiments. This variation probably occurs in the "control versus irradiated" treatments for Tribo- lium confusum and Sitotrgga cerealella and.among the irradiated treat- ments for Sitophilus granarius. Because the measurements are repeated for each generation on the progeny of a group of insects, any strain differences are associated with treatment effects. It was noted in the literature review that irradiation of foods with cathode rays probably affects foods in a deleterious manner (in re- spect to their nutritional value) if it affects them at all. There is a distinct possibility that if any effect of treatment were present, it would be expected to lower the production of adults from the irradia- ted treatments. SIMMARY AND (IENCLUSICNS A series of experiments was designed to determine whether there was any effect on grain insects fed on a diet of irradiated grain as compared with grain insects fed on a diet of non-irradiated grain for three generations. For this investigation three insects were used: 2537 bolium.confusum, Sitophilus granarius, and Sitctroga cerealella. Tribo- liumzconfusum‘was reared on flour and the others were reared on.whole wheat. The wheat and flour were irradiated at 10,000 rep, 100,000 rep, and 1,000,000 rep. There was one control series in each experiment. Specimens of the filial generations were placed in material irradiated at the same level as the one in which they had been reared. The same procedure was followed for three generations. Evidence is present throughout the experiments that there are dif- ferences associated with the level of irradiation; however, these dif- ferences are not consistent over all the experiments. Further, the ef- fect appeared to be that of increasing the rate of reproduction rather than decreasing it as would be expected if irradiation had a deleterious effect upon the insects. 23 LITERATURE CITED Baker, V. H. 1953. Some effects of electromagnetic energy and subatomic particles on certain insects which infest wheat, flour, and.beans. Dissertation for degree of Ph. D., Dept. of Agr. Engin., Mich. State Coll., (Unpublished). Brindley, T. A. 1930. The growth and development of hestia kuehniella Zeller (Lepidoptera) and Tribolium confusum Duval (COIeoptera) under controlled conditions of temperature and relative hmfityo Ann. Ento SOC. mere 23: 7111-7570 Dunn, C. G.,‘W. L. Campbell, H. Fram, and A. Hutchins. l9h8. Biological and photo-chemical effects of high energy, elec- trostatically produced, Roentgen rays and cathode rays. Jour. of App. Physics. 19: 605-616. Goldblith, S. A., B. E. Proctor, and O. A. Hammerle. 1952. Evaluation of food irradiation procedures. Indus. and Engine Chem. 141?: 310-3111. Goldblith, s. A., and B. E. Proctor. 19h9. Effect of high-voltage x-rays and cathode rays on vitamins (liboflavin and carotene). Nucleonics. S (2): 50-58. Hannah, R. S. 195h. Preservation of food.with ionizing radiations. Nature (London). 173: 752-794. HUber, W. l9h8. Electronic preservation of food. Electronics. 21 (3): 7h- 79. Luckey, T. D., M.‘Wagner, J. H. Reyniers, and F. L. Foster, Jr. 1955. Nutritional adequacy of a semi-synthetic diet sterilized by steam or by cathode rays. Food Res. 20: 180-185. Nicholas, R. 1956. Unpublished data. at 25 Nickerson, J. T. R., S. A. Goldblith, and B. E. Proctor. 1950. A comparison of chemical changes in mackeral tissues treated by ionizing radiations. Food Tech. h: 8h-88. Poling, C. E., W. D. warner, F. R. Humburg, E. F. Reber,'w. M. Urbain, and E. E. Rice. 1955. Growth, reproduction, survival and histcpatholcgy of rats fed beef irradiated with electrons. Food Res. 20: 193- 21h. Pn>ctor, B. E., and D. S. Bhatia. Effect of high voltage cathode rays on amino acids in fish 1950. Food Tech. L: 357-361. muscle. Proctor, B. E., and S. A. Goldblith. Effects of high-voltage x-rays and cathode rays on vitamins 19h8. (niacin). Nucleonics. 3 (2): 32-h3. 1951 Food processing with ionizing radiations. Food Tech. 5: 376-380. Snedecor, O. 3 1956. Statistical methods. 5th Ed. Iowa State College Press: Ames, Iowa. XIIJ5+S3IJ pp. Taboada, O. 1953. Some effects of radiant energy on the beetles, Tribolium ranarius (L.), and.Icanthoscel- confusum Duv., Sito hilus Thesis For M. . Degree, Dept. of Ent., Mich. Iaas'rsay). State Coll., (Unpublished). Trump, J. 0., and R. Van de Graaff. 19h8. Irradiations of biological materials by high energy Roentgen rays and cathode rays. Jour. of App. Physics. 19: 599- 60h. ,03 '5'? I" .L‘ r a. .3- Date Due Demco-293 STATE UN RSITY LIBRARIES IIIULJI IIII I IIIIIIIIIIIIIIII III 1293