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1972 The cologE ical Impact of Common and Coastal Bermudagrasses, Cynodon Dactylon (L.) Pers., on Populations of the Grasshoppers Dichromorpha Viridis (Scudder) and Melanoplus Femurrubrum (Deg.). Walter Carl Roddy Louisiana State University and Agricultural & Mechanical College
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Recommended Citation Roddy, Walter Carl, "The cE ological Impact of Common and Coastal Bermudagrasses, Cynodon Dactylon (L.) Pers., on Populations of the Grasshoppers Dichromorpha Viridis (Scudder) and Melanoplus Femurrubrum (Deg.)." (1972). LSU Historical Dissertations and Theses. 2372. https://digitalcommons.lsu.edu/gradschool_disstheses/2372
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73-21,120 RODDY, Walter Carl, 1944- THE ECOLOGICAL IMPACT OF CCMMON AND COASTAL BERMUDAGRASSES, CYNODON DACTYLON CL.) PERS., ON POPULATIONS OF THE GRASSHOPPERS DICHROMORPHA VIRIDIS (SCUDDER) AND MELANOPLUS FEMURRUBRUM----- (DeG.).
The Louisiana State University and Agricultural and Mechanical College, Ph.D., 1972 Entomology
University Microfilms, A XEROX Company , Ann Arbor, Michigan
THIS DISSERTATION HAS BEEN MICROFLIMED EXACTLY AS RECEIVED THE ECOLOGICAL IMPACT OF COMMON AND COASTAL BERMUDAGRASSES, CYNODON DACTYLON (L.) PERS., ON POPULATIONS OF THE GRASSHOPPERS DICHROMORPHA VIRIDIS (SCUDDER) AND MELANOPLUS FEMURRUBRUM (PEG.).
A Dissertation
Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillm ent of the requirements for the degree of Doctor of Philosophy
in
The Department of Entomology
by Walter Carl Roddy B.S., Lamar University, 1966 M .S ., Louisiana State University, 1968 December, 1972 ACKNOWLEDGEMENTS
The author wishes to thank his ma|or professor, Dr. L. D. Newsom and
Drs. S. D. Hensley, C. D. Steelman, H. B. Boudreaux, and Clair Brown for their guidance, advice, and encouragement in the researching and preparation of this dissertation.
Thanks are also expressed to Dr. D. W . Newsom, Head of the Depart ment of Horticulture for the use of his department's facilities; to Mr. Dawson
Johns, director, for the use of the facilities on the North Louisiana H ill Farm; and to Mr. E. A. Epps, director of the Wilson Feed and Fertilizer Laboratories, for analysis o f grass samples.
The author also wishes to thank his wife, Jane, whose never ending encouragement and careful proof-reading aided in the preparation of this dissertation. TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS...... ii
LIST OF TABLES...... iv
ABSTRACT...... vi
INTRODUCTION ...... 1
REVIEW OF LITERATURE...... 2
SECTION I - GROWTH AND DEVELOPMENT...... 4
Method and Materials ...... 4
Results ...... 7
SECTION II - PREFERENCE STUDIES...... 18
Method and Materials ...... 18
Results ...... 23
DISCUSSION ...... 38
CONCLUSIONS...... 50
SUMMARY...... 51
BIBLIOGRAPHY...... 53
APPENDIX ...... 56
V IT A ...... 117
• • • mi LIST OF TABLES
Table Page
I. Mortality of M. femurrubrum and D. viridis nymphs reared on four diets in the laboratory ...... 10
II. Mean duration in days of M . femurrubrum and D. viridis second, third, fourth, and fifth instars and adult stage reared in the la b o ra to ry ...... 12
III. Mean weight in milligrams of M. femurrubrum and D. viridis nymphs and adults reared on four diets in the laboratory ...... 14
IV. The efficiency of conversion of four diets by M . femurrubrum and D. viridis in the laboratory ...... 15
V. Percent Total Digestible Nutrients (TDN) of the four diets fed to D. viridis and M . femurrubrum during laboratory tests ...... 17
V I. Preferences for cellucotton squares soaked in aqueous and acetone extracts of coastal and common Bermudagrasses by D. viridis and M . femurrubrum ...... 28
V II. Mean number of grasshoppers feeding on flats of coastal and common Bermudagrasses growing in the greenhouse ...... 29
V III. Mean number of grasshoppers feeding on coastal Bermudagrass or coastal Bermudagrass and weeds ...... 30
IX. Mean number of grasshoppers feeding on common or common Bermudagrass and weeds ...... 31
X. Mean number of grasshoppers feeding on coastal Bermudagrass and weeds versus common Bermudagrass ...... 32
X I. Mean number of grasshoppers feeding on common Bermudagrass and weeds versus coastal Bermudagrass ...... 33
iv Table Page
XI,I. Mean number of grasshoppers feeding on coastal Bermudagrass and weeds or on common Bermudagrass and weeds ...... 34
X III. Analysis of coastal and common Bermudagrass for protein fiber, and shear strength ...... 35
XIV. The mean estimated weekly population of D. viridis and M. femurrubrum on coastal and common Bermudagrass. Homer, Louisiana, 1968 ...... 36
XV. Theoretical change in M. femurrubrum populations with time as influenced by the presence of weedsin Bermudagrass fields ...... 49
v ABSTRACT
Melanoplus femurrubrum (DeG.) nymphs reared on coastal Bermudagrass or on common Bermudagrass, Cynodon dactylon (L.) Pers., suffered 97% and 94% m ortality, respectively. Comparable figures for Dichromorpha viridis (Scudder) were 95% and 98%, respectively. Replacing 20-25% of the Bermudagrass in the diet with weeds reduced mortality to 49% and 45% for M . femurrubrum and 51% and 49% for D. viridis, respectively.
There were non-significant differences in longevity of all nymphal instars when each species was reared on any of the four diets except for the fifth instar of D. viridis. The addition of weeds to either of the Bermudagrasses significantly increased duration of adult life in both species of grasshoppers.
None of the diets affected weight at any state of development. The amount of each diet consumed by both species during the nymphal period was similar.
In laboratory tests, both species of grasshoppers were more attracted to flats containing weeds in addition to the Bermudagrasses than to weed-free flats.
In weed-free flats common Bermudagrass was preferred to coastal Bermudagrass after the first week of growth. This preference was probably related to fiber content and "toughness", since the grasshoppers showed no preference to water or acetone extracts of the two Bermudagrasses harvested during the third and fourth weeks of growth. • • VII
It appeared that the presence of weeds allowed the development of much
larger grasshopper populations in both coastal and common Bermudagrass field plots than in plots that were free of weeds. INTRODUCTION
Common Bermudagrass, Cynodon dactylon (L.) Pers. and its related hybrid c u ltiv a r coastal Bermudagrass are tw o o f the most common grasses used in improved pastures and in hay production in the southeastern United States
(Burton, 1972). Studies initiated in 1966 indicated that Melanoplus femurrubrum
(DeG.) and Dichromorpha viridis (Scudder) are the major pest insects of these two forage grasses in Louisiana (Roddy, 1968). Losses ascribed to these two species of grasshoppers were greater in highly fertilized fields than in unfertilized fields. It was also noted in these studies that there was a highly significant difference in the preference of each species for common Bermudagrass.
In 1968, investigations were begun to determine the ecological impact of coastal and of common Bermudagrass on populations of D. viridis and of M. femurrubrum. The objectives in this study were to determine:
1 . the effect of coastal and of common Bermudagrass diets on the growth and development of both species of grasshopper.
2. some of the factors effecting the preference of M. femurrubrum and D. viridis for common Bermuda grass .
1 LITERATURE REVIEW
Roddy (1968) showed that in coastal and common Bermudagrass fields in
the Crowley, Louisiana, area, a highly significant loss of hay resulted from the
damage to both Bermudagrasses by the endemic grasshopper population. The two
most prevalent species of grasshoppers were M . femurrubrum (DeG.) and D.
viridis (Scudder). In the course of that work, it was noted that each species showed a highly significant preference for common Bermudagrass over coastal
Bermudagrass in field plots.
There are many papers referring to the diets and dietary habits of
Melanoplus species. Isley (1938) reported M . femurrubrum to be a forb feeder
in Texas; Mulkern (1964) et al. showed this species to be a mixed feeder pre ferring forbs to grasses; and Criddle (1933) described it as a mixed feeder.
Mulkern (1964) et a l. in a detailed study of 34 species of rangeland grasshoppers of North Dakota, showed that, although M . femurrubrum was a mixed feeder preferring forbs, Poa pratensis (L.) was the most frequently ingested plant and th a t the amount eaten was in proportion to the abundance of the plant in the area. Sanderson (1939) and Barnes (1955) both reported M . femurrubrum to feed voraciously on Bermudagrass. Barnes (1955) reported that M . mexicanus mexicanus (Sauss.) was unable to survive beyond the second instar when its diet was restricted to Bermudagrass. Published papers referring to the food preference and dietary habits of
D. viridis are few in number. Wilbur (1936) reported that this species damaged the inflorescenses of pasture grasses, particularly Andropogon furcatus M uhL, and A . scoparius M ic h , in the M anhattan, Kansas area.
Davey (1954) found that a nymphal desert locust, Schistocerca gregaria
(Forsk.) consumed an amount of vegetation daily approximately equal to its own w e ig h t.
Williams (1954) used a "sand resevoir" method to determine "toughness" of plants selected as food by grasshoppers in Great Britain. The toughness of the plant was determined by the weight of sand necessary to drive a no. 10 entomology pin through the blade of the grass. He found that the "toughness" of a plant was of great importance in whether or not it was selected or rejected by grasshoppers.
He also found that the intensity of color and the odor of the plant, while impor tant to other insects, were not so important as "toughness" to the grasshoppers in their food selections.
Smith (1959) showed that a change in phosphorus content of the plant would affect its selection by M . bilituratus (Say). Thorsteinson and Nayer (1963) showed that phospholipids were a feeding stimulant to grasshoppers. Harley and
Thorsteinson (1967) indicated that feeding was significantly reduced in M. bilituratus by chemicals such as gramin, veratrine, hordenine sulfate, and other related compounds. GROWTH AND DEVELOPMENT STUDIES
METHODS AND MATERIALS
All grasshoppers used in the laboratory experiments were collected on
either the Louisiana State University Ben-Hur Farm or Perkins Road Farm in
Baton Rouge, Louisiana. They were held for 24 hours before using them in the
studies in order to eliminate any that may have been injured.
A feeding cage for individual grasshoppers was made by modifying a
clean, sterile, 128-gram baby food jar by removing a portion of the center of
the lid and covering this opening with 10-mesh plastic screen. A small plastic
lid was filled with cellucotton and saturated with deionized water and placed
within the baby food jar to provide moisture for the grasshopper. One second
instar nymph was placed within each jar and supplied daily with 1.0 gram of
freshly cut coastal or common Bermudagrass. Water was added to the cellucotton
as needed. Fecal pellets and any unconsumed grass were removed from the jar
daily, oven dried at 100° C for 24 hours and weighed. All weights of the grass
hoppers presented are the weights obtained immediately prior to the molt for that
instar. The weight o f food consumed during each instar is expressed as dry weight.
W eight gain for each grasshopper is expressed as the difference in weight from
instar to instar. Four diets were tested— common Bermudagrass, coastal Bermuda grass and each of these plus a mixture o f weeds consisting of P. annua L .,
Pospalum dilatatum Poir., Solanum caroliense L., and Rumex crispis L. Ten replications were conducted with twenty grasshoppers assigned to each diet in individual replicates. The extremely high mortality of grasshoppers being fed only coastal or common Bermudagrass suggested the addition of weeds to the diets.
The amount of diet offered remained the same, 1.0 gram, but 0.25 gram of weeds were substituted for an equal amount of Bermudagrass.
The number of days each grasshopper spent in each nymphal instar, amount of food consumed, m ortclity, and weight gained were recorded.
The percent efficiency of conversion for each species of grasshopper fed on each of the four diets was then calculated, using a formula from Smith
(1959):
Dry weight gain ------X 100 Food utilized
The percent total digestible nutrients (TDN) was calculated for the four diets using the following formula from Smith (1959):
Dry weight consumed - feces ------X 100 Dr/ weight consumed
The theoretical amount of daily damage per population density was calculated by the formula:
(Population density) (amt. consumed per third instar)
days in instar
The daily damage per acre was then calculated to get an estimate of the total daily consumption by populations at various levels of density. 6
The data were analyzed by appropriate statistical procedures. RESULTS
Mortality during nymphal development proved to be an important
criterion of the adequacy of the various diets for both species of grasshoppers.
Rates of mortality for the two species of grasshoppers reared on the four diets are
presented in Table I. Neither coastal nor common Bermudagrass provided an
adequate diet for each species of grasshopper. Nymphs of M . femurrubrum fed
either on coastal or on common Bermudagrass suffered high mortality during the
early instars. Total mortality of nymphs was 97% for those reared on coastal
Bermudagrass and 94% for those reared on common Bermudagrass. M ortality was
reduced markedly among grasshoppers fed on Bermudagrass diets containing 20%
weeds.
The D. viridis nymphs reared on coastal or on common Bermudagrass
suffered 95% and 98% mortality, respectively. Mortalities of nymphs reared on
coastal Bermudagrass and weeds or on common Bermudagrass and weeds were 51%
and 49%, respectively.
Statistical analysis indicated highly significant differences in mortalities
among diets when grasshoppers were reared on coastal or on common Bermudagrass
compared to that found when grasshoppers were reared on each Bermudagrass plus
weeds. The differences in mortality between nymphs reared on coastal and on
common Bermudagrass were non-significant as were those between nymphs reared on coastal Bermudagrass and weeds and those reared on common Bermudagrass and weeds.
The mean duration of the second, third, fourth, and fifth nymphal
instars and adult stages of M . femurrubrum and D. viridis reared on the four diets are presented in Table II. The mean longevity of M . femurrubrum reared on the
four diets was 41 .9 days and the differences in duration of the second, third, fourth, and fifth instars among the four diets are non-significant. Differences
in the duration of the instars due to diet were also non-significant in second, third, and fourth instar D. viridis nymphs. However nymphs reared either on coastal or common Bermudagrass required more time to complete the fifth instar than those reared on Bermudagrass and weeds. Thus, differences in duration of. fifth instars was significant when Bermudagrass diets were compared to Bermuda grass and weed diets. The mean longevity of D. viridis on all diets was 42.0 days.
Statistical analysis indicates a highly significant difference in the duration of adult stages of both M . femurrubrum and C). viridis reared on coastal or on common Bermudagrass when compared with those reared on coastal Bermudagrass plus weeds or on common Bermudagrass plus weeds.
The mean weights of nymphs and adult M . femurrubrum and D. viridis reared on the four diets are presented in Table III. Statistical analysis indicates non-significant differences in weights and rates of gains among individual stages of each species of grasshoppers reared on each of the four diets.
Furthermore, the amount of diet consumed by individuals of each of the instars reared on each of the four diets did not differ significantly for either species 9 of grasshopper.
The efficiency of conversion of fhe four diefs by M . femurrubrum and
D. viridis are presenfed in Table IV. The mean dry weighf gain of M. femurru- brum from fhe second instar to adult was 126.2 m g., the dry weighf of food consumed was 1108.0 mg. for a mean efficiency of 8.8 to 1 or 11 .8%.
The mean dry weight consumption of diet by D. viridis was 986 mg. and the dry weighf gain for the nymphal period was 110.0 mg.. This is a 8.9 to 1 ratio for efficiency of conversion or 11 .2% . The differences between nymphs of both species of grasshoppers in efficiency of conversion was non-significant.
The percent total digestible nutrients (TDN) of the four diets are pre sented in Table V. Differences among diets were non-significant for each grass hopper species. 10
TABLE I
M ortality of M. femurrubrum and D. viridis nymphs reared on four diets in the laboratory.
M . femurrubrum
DIET
1 2 3 4
Second Instar Number 200 200 200 200 Mortality 92 11 101 8 % 46 6 51 4
Third Instar Number 108 189 99 192 Mortality 73 11 61 14 % 68 6 61 7
Fourth Instar Number 35 178 38 178 Mortality 24 24 15 21 % 68 13 39 12
Fifth Instar Number 1 1 154 25 157 Mortality 5 52 13 47 % 45 34 52 30
Total Mortality 194 98 188 90 % 97 49 94 45 11
TABLE I (cont.)
D . v irid is
DIET
1 2 3 4
Second Instar Number 200 200 200 200 Mortality 15 18 13 15 % 8 9 6 8
Third Instar Number 185 182 187 185 Mortality 23 27 34 25 % 12 15 18 14
Fourth Instar Num ber 162 155 153 160 Mortality 42 30 55 25 % 26 19 36 16
Fifth Instar Number 120 125 98 135 M o rta lity 110 27 94 33 % 92 22 96 24
Total M o rta lity 190 102 196 98 % 95 51 98 49
Diet 1 Coastal Bermudagrass
2 Coastal Bermudagrass and weeds
3 Common Bermudagrass
4 Common Bermudagrass and weeds 12
TABLE II.
Mean duration in days of M . femurrubrum and D. viridis second, third, fourth, and fifth instars and adult stage reared on four diets in the laboratory.
M. femurrubrum
Second Third Fourth
N XNX NX
Coastal 197 7 .2 ± 1 .6 a 108 6 .5 1 3 .0a 30 8 .0 ± 1 .3 a Common 196 7 .1 ± 1 .5 a 99 7 .8 H .3 a 38 8.1=11,6a Coastal/weeds 196 7 .1 ± 1 .2 a 185 7 .6 1 1 ,3a 178 7.8il.7a Common/weeds 196 6.51=1.5a 178 7 .1 ± 1 .5 a 168 7.3±1.4a
F ifth A d u lt Total
N X N X N X
11 10.5 fl.la 6 3.2H .4a 6 37.2+-5.0 25 11.7*2.3a 12 3 .4 1 2 .2a 12 39.515.1 122 8.141.9a 98 16.314.2b 98 46.9t5.2 138 9.411.7a 110 15.7i4.7b 110 45.0*5.1 13
TABLE II (cont.)
D . v irid is
INSTAR
Second Third Fourth
N X N X N X
Coastal 189 6 .3 * 1 .3a 166 6 .7 * 1 .6a 152 7 .2 * 1 .6a Common 197 7 .5 * 1 ,6a 174 7 .8 * 1 .2a 133 8 .2 * 1 .9a Coasta l/weeds 193 6 .3 * 1 . la 175 8 .3 * 1 .6a 143 7 .8 * 1 .3a Common/weeds 197 7 . 9 * 1 . la 165 6 . 9 * 0 . 9a 153 7 .2 * 1 .9a
Fifth A d u lt Total
N X N X NX
74 1 5 .8 * 4 .3a 10 3 .3 * 1 .9a 10 3 7 .9 * 5 .7a 71 15.8*4.7a 4 2.5*1.2a 4 3 8 .0 * 7 .4a 11 7.9*1.5b 111 16.4±5.4b 98 46.7*8.3a 11 7.4*1.7b 102 16.2*5.lb 102 45.6*7.6a
Means not followed by fhe same leffer in each insfar differ significantly at fhe 5% level of confidence when compared by Duncan's new multiple range test. 14
TABLE III.
The mean weight in milligrams of M. femurrubrum and D. viridis nymphs and adults reared on four diets in the fakorafory.
D. viridis1
INSTAR
Second Third Fourth Fifth Adult
NN N NN Coastal 185 208a 162 339a 118 431a 10 493a 10 492a Common 187 213a 153 341a 98 419a 4 490a 4 503a Coastal/weeds 182 210a 155 349a 125 426a 98 483a 98 499a Common/weeds 185 207a 160 346a 135 427a 102 499a 102 501a
M. femurrubrum1
______INSTAR______
Second Third Fourth Fifth Adult
Coastal 108 268a 35 399a 23 501a 11 579a 6 636a Common 99 273a 38 403a 25 493a 12 582a 12 626a Coastal/weeds 189 275a 178 401a 154 498a 102 586a 102 637a Common/ weeds 192 271a 178 400a 157 505a 110 566a 110 626a
1 Mean weights within each stage were non-significant when analyzed according to Duncans M ultiple Range Test. 15
TABLE IV .
The efficiency of conversion of four diets by M. femurrubrum and D. viridis in the laboratory.
M . femurrubrum
M ean1 Mean Amt.1 Efficiency Instar G ain Consumed of Conversion
dry w t . dry w t , mg. mg.
Second D iet 1 47 153 3.2 : 1 2 49 123 2.6 : 1 3 48 164 3 .3 : 1 4 50 135 2 .7 : 1
Third 1 34 251 7 .4 : 1 2 32 260 7.0 : 1 3 33 247 7 .7 : 1 4 33 242 7.3 : 1
Fourth 1 26 320 12.3 : 1 2 24 322 13.4 : 1 3 22 301 13.7 : 1 4 23 309 13.4 : 1
Fifth 1 21 394 18.7 : 1 2 22 399 18.1 : 1 3 22 397 18.0 : 1 4 19 352 18.5 : 1 16
TABLE IV. (cont.)
D . v irid is
Mean Mean Amount Efficiency Instar G ain m g, Consumed mg. of Conversion
Second D iet 1 4 0 .0 121 3 .0 1 2 4 1 .3 118 2 .9 : 1 3 4 0 .5 125 3.1 : 1 4 3 9 .8 117 2 .9 : 1
Third 1 3 2 .8 203 6.1 1 2 3 4 .7 212 6.1 : 1 3 3 2 .0 209 6 .5 : 1 4 3 4 .8 219 6 .3 : 1
Fourth 1 2 3 .0 293 1 2 .7 : 1 2 19.2 276 14.3 : 1 3 19.5 261 13.4 : 1 4 21.0 290 13.8 : 1
F ifth 1 15.5 309 19.3 : 1 2 14.2 266 1 8.7 : 1 3 17.8 354 1 9.9 : 1 4 18.0 329 18.3 : 1
Diet 1 Coastal Bermudagrass
2 Coastal Bermudagrass and weeds
3 Common Bermudagrass
4 Common Bermudagrass and weeds
1Mean differences within each instar were non-significant according to Duncans M ultiple Range Test. 17
TABLE V .
Percent total digestible nutrients (TDN) of the four diets fed to D. viridis and
M . femurrubrum during laboratory tests.
M . femurrubrum1
coastal common coastal and weeds common and weeds
24% 25.6 26.8 25.6
D. viridis1
coastal common coastal and weeds common and weeds
26% 26.7 27.8 27.1
1 Differences among diets were non-significant accourding to Duncans M ultiple Range Test. PREFERENCE STUDIES
METHOD AND MATERIALS
The preference studies Included a comparison of the extracts of each grass to determine whether a chemical attractant or a chemical repellent was present In either of the Bermudagrasses. Actively growing plants were compared at various stages of growth to determine whether there was a preference at any stage of growth.
The coastal and common Bermudagrass was grown from sprigs obtained from the North Louisiana Hill Experiment Station, Homer, Louisiana. These sprigs were planted in galvanized metal flats (50 x 34 x 10 cm .), and fertilized initially at the rate of 90 kg. nitrogen as prilled ammonium nitrate, 90 kg. potassium oxide, and 90 kg. phosphorus as rock phosphate per hectare. The
Bermudagrass was watered daily. It was clipped according to accepted agronomic indicators, i.e . slight lodging of the leaves, yellowing of the lowest leaves on the stem, or the development of inflorescences. The grass was clipped on an average of every five weeks. After each clipping, the grass was fertilized with
90 kg. of nitrogen per hectare applied as prilled ammonium nitrate. After every fifth clipping, the grass was fertilized with the balanced 90-90-90 kg. per hectare mixture described above.
18 19
To test whether the grasshoppers' preference for common Bermudagrass was due to the presence of attractive or repellent substances, aqueous and or ganic solvent extracts of coastal and common Bermudagrass were prepared. A
100 gram sample of freshly clipped Bermudagrass plus 500 ml. deionized water was mixed in a Waring Blender for two minutes. This slurry was filtered through
Whatman's No. 1 filter paper. The filtrate was poured into a petri dish contain ing 10 pieces of cellucotton cut into squares, and then oven dried at 100° F until slightly moist to the touch (approximately 24 hours). Five of these squares were placed in a cage (25 x 25 x 50 cm.) containing 10 adult grasshoppers and the grasshoppers were observed to determine whether attractive or repellent sub stances were present. The criterion for repellency was the total absence of feed ing on the cellucotton squares. An extract was considered attractive if the grass hopper fed on the squares. The organic solvent extracts were prepared by the same method except for the use o f acetone as a so lve n t. The acetone solvent was dried completely from the squares and the squares slightly moistened with deionized water before being placed in cages. The first tests paired the aqueous and acetone solvent extracts of the same grass. The aqueous extracts of the two grasses were then compared and finally the acetone solvent extracts of the two
Bermudagrasses. A total of 10 adult grasshoppers were used per test with twenty replications for each of the four comparisons.
Studies conducted in the laboratory compared the preference of M. femurrubrum and D. viridis for coastal or common Bermudagrass. Two galvanized 20 metal flats containing either coastal Bermudagrass, or coastal and weeds, or common Bermudagrass, or common and weeds were placed in a plastic screen cage (92 x 62 x 67 cm.)- Twenty unsexed grasshoppers of various ages (either
M. femurrubrum or D. viridis) were placed in the cage and after one hour the number o f grasshoppers feeding on each fla t o f grass was counted. Those resting on the sides or top of the cage were counted as being on the nearest flat of grass.
The weeds in flats containing one of the Bermudagrasses and weeds were Da 11 is grass (P. dilatatum Poir.), horsenettle (S. caroliense L.) and annual bluegrass
(P. annua L.). The weed infestation level was maintained at 20 to 25% of the stand. The line transect method (O osting, 1956) was used to determ ine percent species composition by running four lines the length of the pan (7 cm. apart) and five lines the width of the pan (8 cm. apart). The plants growing at the transect of the lines were recorded as either Bermudagrass or weeds. The comparisons were coastal Bermudagrass— common Bermudagrass, coastal Bermudagrass— coastal Bermudagrass plus weeds, coastal Bermudagrass plus weeds— common
Bermudagrass, coastal Bermudagrass plus weeds— common Bermudagrass plus weeds, coastal Bermudagrass— common Bermudagrass and weeds, and common Bermuda grass— common Bermudagrass and weeds. After each preference study, the grass was clipped, oven dried for 3 days at 100w F and analyzed at the Feed and
Fertilizer Laboratory, Louisiana State University, Baton Rouge, Louisiana, for nitrogen, phosphorus, potassium, and fiber content using methods approved by the Association of O fficial Analytical Chemists (AOAC). 21
Ten adult grasshoppers of each species were confined in each of two one
gallon glass containers containing 45.0 grams Bermudagrass plus 50 grams of each
of the following weeds—dock, dal I Is grass, and horsenettle. Two identical con
tainers containing similar plant materials but no grasshoppers were employed as
checks. After 72 hours the plant material in all containers was removed, sepa
rated to species, and oven dried at 100° C for one hour. The difference in dry
plant weight between jars containing grasshoppers and those employed as checks
was used to measure grasshopper food consumption. In addition, the weight of
each species of plant consumed was determined in order to measure grasshopper
prefernce for the different plants as food.
Samples of fresh Bermudagrass were tested for shear strength of the
fibers using an Allo-Kramer Shear Press, Model SPIZ with an accompanying
Varian Associates Recorder model G -11A. The tops of 10 Bermudagrass plants
containing three leaves per top were placed side by side and at right angles to
the blade of the shear press. The tops were placed so that the blade would shear
them 16 cm. from the tip of the leaf blades. The amount of pressure required to shear the Bermudagrass was recorded on a graph by the recorder and this informa- -2 tion converted to grams per square centimeter (pern ).
Field populations of grasshoppers were sampled on the North Louisiana
Hill Farm, Homer, Louisiana, during 1968. Field 56, a pure stand of coastal
Bermudagrass and the adjacent field, field 57, a field predominately of common
Bermudagrass with dalEIs grass, horsenettle, curly dock, and other weeds were 22 sampled weekly from May until September. A total of 20 weekly samples of each of four replications per field were samples. The fields were sampled with a 45 cm. diameter sweep net. One hundred sweeps were made per plot, sweeping in such a manner that the lowest rim of the net passed through the plants at a height of approximately 10 cm. from the soil surface. RESULTS
The results of the preference tests for chemicals, attractive or repellent
to D. viridis and M . femurrubrum, in coastal or in common Bermudagrass, are
presented in Table VI. In these tests there were sizable numbers of grasshoppers
that did not make a choice, i.e . did not feed on cellucotton squares soaked in either extract. Those grasshoppers which did not make a choice are expressed as a percentage of the total number of grasshoppers in the test and appear in Table
VII as "No Preference". Those grasshoppers which showed a preference, i.e .
fed on the squares of cellucotton soaked in one of the extracts are expressed as a percentage of the grasshoppers that fed.
A significantly greater number of M . femurrubrum fed on the cellucotton squares than did not feed; and, of those that did show a preference, a highly significant number preferred the aqueous extract of coastal Bermudagrass to the acetone extract. D. viridis showed the same trends; significantly more feeding than not feeding. Thus there was a significant preference for the squares soaked
in aqueous extract of coastal Bermudagrass over acetone extract of coastal Ber mudagrass .
The same preferences occurred when either species of grasshopper was exposed to aqueous and acetone extracts of common Bermudagrass: significantly more feeding than not and highly significant preference for squares of cellucotton soaked in aqueous extract over squares soaked in acetone extract.
23 24
The comparison of aqueous extracts of coastal and common Bermuda grass showed that a highly significant number of both species of grasshoppers fed, and those that did feed showed a non-significant preference for squares soaked in aqueous extracts of either coastal or common Bermudagrass.
The comparison of acetone extracts of coastal and of common Bermuda grass showed that highly significant numbers of both grasshoppers did not feed.
O f those that did feed, there was a non-significant preference for cellucotton squares soaked in acetone extracts of either coastal or common Bermudagrass.
The results of the laboratory preference studies comparing coastal Ber mudagrass, coastal Bermudagrass and weeds are presented in Table V II. During the first two weeks of plant growth, there were non-significant differences in the numbers of M_. femurrubrum or D. viridis feeding on the Bermudagrasses. During the third, fourth, and fifth weeks of plant growth there were significantly greater numbers of M . femurrubrum feeding on common than on coastal Bermudagrass.
During the third and fourth weeks of plant growth, a significantly greater number of D. viridis preferred common to coastal Bermudagrass; and by the fifth week, this preference was highly significant.
The comparison of coastal Bermudagrass with coastal Bermudagrass and weeds is presented in Table VIII. M . femurrubrum showed a non-significant preference the first week of plant growth, a significant preference the second and third weeks of plant growth, and a highly significant preference the fourth and fifth weeks of growth for coastal Bermudagrass and weeds. 25
During the first two weeks of plant growth, D. viridis showed no prefer
ence, the third and fourth weeks a significant preference, and the fifth week a
highly significant preference for coastal Bermudagrass and weeds over coastal
Bermudagrass.
The comparisons of common Bermudagrass with common Bermudagrass
and weeds are presented in Table IX. The first week of plant growth, there
were non-significant differences in the numbers of both species of grasshoppers
feeding on the two flats of grasses. During the four remaining weeks of plant
growth, both species of grasshoppers showed a significant preference for common
Bermudagrass and weeds.
The results of the studies comparing coastal Bermudagrass and weeds with
common Bermudagrass are presented in Table X . Both species of grasshoppers
showed non-significant preferences during the first two weeks of plant growth,
however, significant preferences were exhibited for the remaining three weeks for
coastal Bermudagrass and weeds over common Bermudagrass.
The comparison of common Bermudagrass and weeds with coastal Bermu
dagrass is presented in Table XI. During the first week of plant growth, neither species of grasshopper showed a significant preference for either grass. The second week of plant growth, both species showed a significant preference for common Bermudagrass and weeds over coastal Bermudagrass. The third, fourth, and fifth weeks of plant growth, M . femurrubrum showed a highly significant preference for common Bermudagrass and weeds, while D. viridis showed a 26
significant preference the third week, and highly significant preferences the
fourth and fifth weeks for common Bermudagrass and weeds.
The results of the studies comparing coastal Bermudagrass and weeds
with common Bermudagrass and weeds are presented in Table X II. Neither species of grasshopper displayed a significant preference during the five weeks o f g ro w th .
The preferences studies conducted to measure feeding differential aver aged 14.3 grams (24%) of dry weight plant material. The M. femurrubrum adults consumed 9.7 grams (68%) of the Bermudagrass, 0.91 grams (73%) of the dock,
0.78 grams (62%) of the da 11 is grass and 0.88 grams (70%) of the horsenettle, and D. viridis consumed 7.0 grams (62%) of the Bermudagrass, 0.79 grams (59%) of the da 11 is grass, 0.74 grams (55%) of the dock, and 0.63 grams (50%) of the horsenettle.
The analyses of coastal and common Bermudagrass for protein and fiber content and shear strength of the leaves are presented in Table X III. The pro tein content of the Bermudagrasses is negatively correlated with age, but the differences in protein content of coastal and of common Bermudagrass at the same ages are n o n -s ig n ific a n t.
The fiber content increased as the age of the grass increased. The fiber content in coastal Bermudagrass increased more rapidly than the fiber content of common Bermudagrass. By the third week of growth, the differences in fiber content were significant and by the fifth week, highly significant. 27
The shear strength of the Bermudagrass tops also increased with the age of the plants. The fourth week of growth, there was a highly significant differ ence in the shear strength of coastal and of common Bermudagrass.
A summary of the work done in the fields on the North Louisiana Hill
Farm is presented in Table XIV. The sampled area of 100 sweeps per plot represented an area that was approximately 220 square feet. The mean weekly population of D. viridis was 6.5±3.3 per sample in the coastal Bermudagrass field, and 80.4±40.4 per sample in the common Bermudagrass field. The efficiency of collection was estimated to be approximately 33%. This would represent an estimated density of 0.09 grasshoppers per square foot or 3921 per acre from the coastal Bermudagrass, and 1.1 per square foot or 47,916 per acre from the common
Bermudagrass fie ld .
The mean weekly population of M . femurrubrum in the coastal Bermuda grass field was 8.5±2.8 or 0.12 per square foot or 5049 per acre. In the common
Bermudagrass field, the population density was 90.9^36.8 or 1.26 per square foot or 53,994 per acre.
The field of common Bermudagrass contained as much as 75% weeds in some places, but the average weed content of the field was 20%. The coastal
Bermudagrass field was virtually a 100% pure stand of grass. 28
TABLE V I.
Preferences for cellucotton squares soaked in aqueous and acetone extracts of coastal and common Bermudagrasses by D. viridis and M . femurrubrum.
D. vi idis M. femurrubrum
Coastal Bermudagrass No. % N o . % No preference 8.1 JVJT “7 7 5 ------38 70” Preference 11.9 59.0 12.5 62.0 Aqueous extract 8.6 72.0 8.2 66.0 Acetone extract 3.3 28.0 4.3 34.0
Common Bermudagrass No Preference 5.9 39.0 7.2 36.0 Preference 14.1 61.0 12.8 64.0 Aqueous extract 10.6 75.0 8.8 69.0 Acetone extract 3.5 25.0 4.0 31.0
Aqueous Extract No Preference 5.4 27.0 8.0 40.0 Preference 14.6 73.0 12.0 60.0 Coastal 7.3 50.0 6.1 51.0 Common 7.3 50.0 5.9 49.0
Acetone Extract No Preference 15.5 77.0 14.6 73.0 Preference 4.5 23.0 5.4 27.0 Coastal 2.4 53.0 3.0 55.0 Common 2.1 47.0 2.4 44.0 ZY
TABLE V II.
Mean number of grasshoppers feeding on flats of coastal and common Bermudagrasses growing in the greenhouse.
average number observed per flat
M. femurrubrum
Age of Grass Common Coastal Ratio
1 week 10.0 10.0ns 1 2 10.2 9.8ns 1.04 3 11.8 8 .2 * 1.40 4 12.5 7.5* 1.66 5 14.0 6.0* 2.33
D. v irid is
1 week 10.2 9.8ns 1 .04 2 10.9 9.9ns 1.02 3 12.1 7.9* 1.53 4 13.4 6.6* 2.03 5 15.3 4.7** 3.25
ns - non-significant
* - significant (5% probability level)
** - highly significant (1% probability level)
N - 20 30
TABLE V III.
Mean number of grasshoppers feeding on coastal Bermudagrass or coastal Bermudagrass and weeds.
mean number/flat
M . femurrubrum
Age of Grass Coastal Coastal & Weeds Ratio
1 week 9 .8 10.2ns 1 1 .04 2 6 .8 13.2* 1 1 .94 3 5 .9 1 4 .1 * 1 2 .3 9 4 5 .7 14.3** 1 2.51 5 5 .8 1 4 .2 * * 1 2 .4 5
D. v irid is
1 week 10.1 9.9ns 1 1.02 2 9.1 10.9ns 1 1.20 3 8 .3 1 1 .7 * 1 1.41 4 6 .6 1 3 .4 * 1 2 .0 3 5 5.6 14.4** 12.57
ns - non-significant
* - significant (5% probability level)
** - highly significant (1% probability level) 31
TABLE IX.
Mean number ofof grasshoppersgrasshoppers feeding feeding on on common common or or common common Bermudagrass Bermudagrass and weeds.
mean number/flat
M . femurrubrum
Age of Grass Common Common & Weeds Ratio
1 week 9.8 10.2ns 1 : 1.04 2 7.7 12.3* 1 : 1.60 3 7 .6 1 2 .4 * 1 : 1.63 4 7.8 12.2* 1 : 1.56 5 7.2 12.8* 1 : 1.78
D. v irid is
1 week 8.9 11.1ns 1 : 1.25 2 7.7 12.3* 1 : 1.60 3 6.9 13.1* 1 : 2.15 4 6.1 1 3 .9 * 1 : 2 .2 8 5 6.3 13.7* 1 : 2.17
ns Non-significant
Significant at 5% probability level. 32
TABLE X .
Mean number of grasshoppers feeding on coastal Bermudagrass and weeds versus common Bermudagrass.
mean number/flat
M. femurrubrum
Age of grass Coastal & Weeds Common Ratio
1 week 10.1 9.9ns 1.02 2 11.3 8.7ns 1.30 3 12.5 7.5* 1.66 4 12.7 7.3* 1.74 5 13.4 6.6* 2.03
D. v irid is
1 week 9.6 10.4ns 1.08 2 11.1 8.9ns 1.25 3 12.7 7 .3 * 1.74 4 12.9 7.1* 1.81 5 13.6 6 .4 * 2 .1 3
ns - Non-significant at 5% level
* - Significant at the 5% level 33
TABLE X I.
Mean number of grasshoppers feeding on common Bermudagrass and weeds versus coastal Bermudagrass.
mean number/flat
M . femurrubrum
Age of Grass Common & Weeds Coastal Ratio
1 week 11.1 8.9ns 1.25 2 13.3 6 .7 * 1.99 3 14.7 5.3** 2.77 4 15.5 4.5** 3.44 5 16.6 3.4** 4.88
D. viridis.
1 week 10.7 9.3ns 1.15 2 12.9 7.1* 1.82 3 14.1 5.9* 2.39 4 14.7 5.3** 2.77 5 15.3 4.7** 3.25
ns - Non-significant
* - Significant at 5% probability level.
** - Significant at 1% probability level. 34
TABLE X II.
Mean number of grasshoppers feeding on coastal Bermudagrass and weeds or common Bermudagrass and weeds.
mean number/flat
M. femurrubrum1
Age of Grass Coastal & Weeds Common & Weeds Ratio
1 week 9.1 1 0 .9 1 1.20 2 8 .7 11.3 1 1.30 3 8 .3 1 1 .7 1 1.41 4 8.1 1 1 .9 1 1.53 5 8.2 11.8 1 1.40
D. viridis1
1 week 10.1 9 .9 1 .02 2 9 .9 10.1 1.02 3 9 .7 10.3 1.06 4 9 .3 10.7 1.15 5 8.8 10.2 1.27
1 Differences among means were not significant at the 5% level according to the "F“ test. TABLE X III.
Analysis of coasfal and common Bermudagrass for protein, fiber, and shear strength.
Age of grass in weeks
Protein
1 2 3______4______5
Coastal 24.8% 21.9% 17.9% 14.2% 12.0% Common 23.2 19.6 17.1 15.2 11.8 diff 1.6ns 2.3ns 0.8ns 1.0ns 0.2ns
Fiber
Coastal 19.8% 21.4% 2 2 .7 % 23.5% 25.0% Common 17.8 18.4 19.6 20.1 20.4 diff 2.0ns 3.0ns 3.1* 3.4* 4.6**
Shear strength
Coastal 44.3% 48.5% 60.5% 64.0% Common 40.8 45.0 46.4 49.2 d iff 3.5ns 3 . 5ns 1 4 .1 * * 14.8 * *
ns - Non-significant
* - Significant
** - Highly significant 36
TABLE X IV .
The mean estimated weekly population of D. viridis and M. femurrubrum on coastal and common Bermudagrass from May through September. Homer, Louisiana, 1968.
Number per 100 sweeps
Week Coastal Common Beginning M ay 1, 1968 D . v . 1 Mo f . 2 D . v . 1 M . f . 2
1 4 .8 4.5 58.8 64.2 2 3 .2 4 .5 3 8 .8 5 0 .2 3 2 .8 3.2 33.8 43.8 4 6 .2 8.2 7.65 88.0 5 3 .5 7 .2 4 2 .5 5 6 .8 6 7 .8 8 .8 102 .5 121.2 7 4 .2 8 .5 5 5 .2 6 5 .0 8 2 .0 5 .5 2 3 .5 6 0 .2 9 4 .2 7 .5 5 3 .2 5 7 .0 10 6 .2 8 .5 7 6 .2 9 1 .0 11 8 .0 7 .8 10 2 .0 9 4 .8 12 9 .0 9 .8 111.2 109.0 13 11.2 11.2 138.5 142.0 14 1 3 .0 15.5 1 48 .0 133.2 15 10.0 1 0 .5 131 .0 115.8 16 11.2 1 1 .0 132.5 148.8 17 9.5 9.8 116.0 134.8 18 8 .0 1 0 .0 100 .0 145.5 19 3 .8 9 .8 5 1 .2 8 3 .2 20 2 .8 7 .8 1 8 .8 2 6 .2
6.5t3.3 8.5±2.8 80.4±40.8 90,,9±36.8
i D . v . - D . v irid is
a M . f . - M . femurrubrum 37
TABLE XIV. (cont.)
The estimated mean weekly field population density of D. viridis and M . femurrubrum on coastal Bermudagrass and common Bermudagrass and weeds from May through August. Homer, Louisiana, 1968.
Number per acre
Coastal Bermudagrass Common Bermudagrass & Weeds
D . v 1 M . f 2 D . v 1 M . f 3
93 0 .6 9 0 1 .8 6 1 3 .8 8 7 1 .2 11632.4 12711.6 5 3 4 .6 6 3 3 .6 7682.4 9959.4 1207.8 1623.6 6672.6 8672.4 673.2 1425.6 15166.8 17443.8 1623.6 1742.4 8 41 5.0 11226.6 871.2 1702.8 2 0 3 1 4 .8 2 40 17.4 376.2 1108.8 10949.4 12889.8 8 5 1 .4 1504.8 4 6 7 2 .8 11039.4 1227.6 1702.8 10533.6 11305.8 1603.8 1544.4 15107.4 18018.0 1762.2 1940.4 20215.8 18790.2 2217.6 2217.6 2 2 0 3 7 .4 216 01.8 255 4.2 30 4 9 .2 2 7 4 2 3 .0 281 16.0 1999.8 2 0 9 8 .8 2 9 3 0 4 .0 263 73.6 2217.6 2178.0 2 5 9 5 7 .8 229 08.6 1861.2 1940.4 22986.0 29462.4 1564.2 1980.0 19800.0 28789.2 772 .2 1940.4 10137.6 16493.4 534.6 1544.4 3 7 2 2 .4 5 2 0 7 .4
1306.8 1683.0 15919.2 17998.2
Estimated efficiency of collection — 33.3%
1 D. v - D. viridis
3 M. f - M. femurrubrum DISCUSSION
The growth, development, reproduction, and longevity of an organ ism reared on a specific diet can be used as criteria for judging the adequacy of that diet. The high mortality observed while rearing M. femurrubrum and
D. viridis nymphs on either coastal or common Bermudagrass exclusively indi cates an inadequate diet. This high level of mortality of nymphs reared on either of the two Bermudagrasses apparently can be attributed to the presence of a toxic substance or to a nutritional deficiency. Painter (1951) describes both the presence of toxic substances and nutritional deficiencies as antibiosis.
The presence of toxic substances can apparently be ruled out since the replace ment of 25% of the Bermudagrass in the diet with weeds resulted in a marked increase in nymphal survival. With the addition of weeds to the diets, survival among nymphs of M . femurrubrum and D. viridis increased about 48% and 46%, respectively. Mulkern and Toczek (1970) found that the addition of aqueous extracts of certain plants to a meridic diet could have a tremendous effect on the survival of M. femurrubrum. Aqueous extracts of Cleome serrulata Pursh, or Asclepias syriaca L. when added to the basic diet increased survival 100% and the addition of R. crispus L. increased survival 36%. However, extracts from some plants such as Elymus canadensis L. or Rosa arkansana Porter had no effect on survival. Mulkern and Toczek's results on M . femurrubrum plus this
38 work indicates that Bermudagrasses apparently lack some essential nutrient and
that the addition of weeds to a Bermudagrass diet supplies this essential sub stance. Longevity data on nymphs reared on the four diets also provided infor
mation to determine which of the species was best adapted to a Bermudagrass
diet. The greatest nymphal mortality of M. femurrubrum (68%) occurred in the
third and fourth instars when nymphs were reared on coastal Bermudagrass and
in the second (51%) and third (68%) when comparable nymphs were reared on
common Bermudagrass. Nymphal mortality of D. viridis was highest in the fifth
instar (92%) for nymphs reared on coastal Bermudagrass and 96% for those reared on common Bermudagrass. Comparison of the two species using longevity as a criterion indicated that D. viridis was better adapted for existence on a Ber mudagrass diet than was M . femurrubrum.
The absence of an essential nutrient in the Bermudagrass diets is reflected in differences in rate of development of D. viridis. Fifth instar D. viridis nymphs reared on the Bermudagrass diet required 7 days more develop mental time in the stadium than did comparable nymphs reared on Bermudagrass plus weeds. Evidence for the lack of an essential nutrient is also reflected in the duration of the adult stage. Adults of M . femurrubrum and D. viridis reared on Bermudagrass plus weeds survived significantly longer than did comparable stages reared exclusively on either of the Bermudagrasses. A l though there were significant differences in the duration of the fifth instar nymphal stage and also in the adult stage reared on either of the diets exclu sively of Bermudagrass or Bermudagrass plus weeds, the mean longevity of these 40 grasshoppers did not differ significantly. Individuals of both species reared on the Bermudagrass diet required longer periods of time to develop within the fifth instar and survived for significantly shorter periods of time in the adult stage than did comparable individuals reared on Bermudagrass plus weeds.
Mulkern and Toczek (1970) found that although there were non-significant differences in mean life duration, the addition of aqueous plant extracts to a basic diet could drastically improve survival of M . femurrubrum nymphs.
Addition of aqueous plant extracts to the basic diet not only improved survival of nymphs but also shortened their development period.
The non-significant differences in weight gain, TDN, and efficiency of conversion also fends to indicate that some necessary ingredient for growth and development is not present in the coastal or common Bermudagrass diets.
Lack of some essential growth substance in grasshopper diets developed from several plants were also found by Mulkern and Toczek (1970). Smith (1959) considers the efficiency of conversion to be one of the best overall measures of dietary quality used in biology. The mean efficiency of conversion for nymphs reared on the four diets averaged 8.8:1 for M . femurrubrum and 8.9:1 for D. viridis. These data are similar to the efficiency of conversion ratios of 8.9:1,
9.1:1, and 10.4:1 obtained by Smith (1959) when M . bilituratus nymphs were reared on wheat, oats, and western wheatgrass, respectively. Davey (1954) calculated an efficiency ratio of 4.5:1 for S. gregaria feeding on mixed grasses, and Smith (1959) calculated a lower value of 2.34:1 for Carausius morosus feeding on ivy from work published by Lafon. Smith also calculated an e ffi
ciency of conversion ratio of 14.40:1 for Chorthippus albomarginatus reared on
Bromus inermis Leys from w ork by Rubtzov (1932).
The percent TDN for coastal Bermudagrass, common Bermudagrass,
coastal Bermudagrass plus weeds, and common Bermudagrass plus weeds was 24.0,
25.6, 26.8, and 25.6, respectively when they were fed to M . femurrubrum and
26.0, 26.7, 27.8, and 27.1, respectively, when they were fed to D. viridis.
Mulkern and Toczek (1970) calculated a mean TDN of 43% for M . femurrubrum
reared on the basic meridic diet with no change in the value when plant extracts
were added. The main ingredients of their basic diet were cellulose powder,
sucrose, casein, brewers yeast, and corn. Davey (1954) calculated a TDN
value of 48% for wheat bran fed to S. gregaria and Smith calculated a value
of 32% for young wheat leaves when fed to M . bilituratus. The values obtained
by Mulkern and Toczek and by Davey are much higher than those obtained by
Smith and those in this study. These differences may be due in part to the
nature of the diets. Those used by Mulkern and Toczek and by Davey are both refined meridicdiets and are low in indigestible material while those used by
Smith and in this study were composed exclusively of the leaves of green plants.
The bioassay for preference using aqueous and acetone extracts of coastal and common Bermudagrass showed non-significant differences between the two Bermudagrasses. The methods of extraction and preparation could have eliminated or altered the attractiveness of any heat-labile, volatile, or pH 42
sensitive compounds in either of the two Bermudagrasses. The preference of
both species of grasshopper became more pronounced as the age of the grass
increased. During the first week of growth the differences in numbers of grass
hoppers feeding on each of the four diets were non-significant. As the plants
matured the differences in preference became more pronounced. When the
plants were fully mature (fifth week of growth) the preference of both species
of grasshopper was for common Bermudagrass over coastal Bermudagrass. How ever, when weeds were present in either of the Bermudagrasses, there was
always a significant preference for the Bermudagrass and weeds. There was no
difference in preference between coastal Bermudagrass plus weeds and common
Bermudagrass plus weeds. These data indicate that the presence of weeds in a field provide a more desirable diet for the grasshoppers. The preference of both species of grasshopper for common Bermudagrass over coastal Bermudagrass in the field also occurs under laboratory conditions.
The protein content of the two Bermudagrasses decreased as the age of the plant increased, but the differences in protein content between the two grasses was non-significant. There appeared to be no correlation between the diffe ences in protein content of the Bermudagrasses and the preferences of both species of grasshopper observed in the laboratory. As the age of the Bermuda grass increased, differences in its fiber content and shear strength were closely correlated with the increase in preference for common Bermudagrass over coastal
Bermudagrass. Since the grasshoppers showed no preference between extracts 43 of coastal or common Bermudagrass, it appears that the greater "toughness" of
coastal Bermudagrass more than two weeks old was due to its increased fiber strength and shear strength. This may be the reason why common Bermudagrass was preferred by both species of grasshopper.
Data from field plots indicated that the estimated population density of M . femurrubrum was 10.7 times as great in the field of common Bermuda grass plus weeds as in the field of coastal Bermudagrass. The estimated popula tion density of D_. viridis was 12.2 times as great in the common Bermudagrass plus weeds as that in the coastal Bermudagrass. Although these field data show a greater preference by the grasshoppers for common Bermudagrass plus weeds than was shown in the laboratory, other factors undoubtedly affected the ratio.
The ratio of populations between these two fields was probably also affected by the high mortality of nymphs feeding exclusively on coastal Bermudagrass as observed earlier in this study. The type of utilization of the two fields might also have affected the populations. The coastal Bermudagrass field was being used continuously for hay production prior to the study while the common
Bermudagrass plus weeds field was being used to pasture a horse and it was also clipped occasionally.
The estimated daily yield losses were calculated using the population density estimate of grasshoppers of both species in field plots located in Homer,
Louisiana. The mean daily consumption of food for the third instar of each species of grasshopper was m ultiplied by the estimated population of that species 44
per acre to determine the estimated daily yield loss per acre.
The mean daily food consumption of the third instar nymph was used
in these calculations. This particular nymphal period was selected because it
was believed that this stadium represents a mid-point between the increasing
food consumption of each instar and a decreasing number of individuals in
each older stage of growth. The estimated population density of M . femurrubrum
was 1683 per acre in the coastal Bermudagrass field and 17,998 per acre in the
common Bermudagrass plus weeds field. This is an average loss per day of 0.6
pounds per acre in the coastal Bermudagrass field and 6.3 pounds per acre in
the common Bermudagrass plus weeds field or a loss differential of 5.7 pounds
per acre per day. The estimated population density of D. viridis in the coastal
Bermudagrass field was 1307 per acre and 15,919 per acre in the common Ber
mudagrass plus weeds field. The daily loss to D. viridis was calculated to be
0.4 pounds per acre in the coastal Bermudagrass field and 4.9 pounds per acre
in the common Bermudagrass plus weeds field. This is a difference of 4.5 pounds
per acre per day in the estimated yield loss. Thus, the estimated population of
both species of grasshoppers in Homer, Louisiana would consume 11 .2 pounds
per acre dry weight of food daily in the common Bermudagrass plus weeds field
and 1 .0 pounds per acre dry weight of food daily in the coastal Bermudagrass
field or a differential yield loss of 10.2 pounds per acre per day dry weight.
This estimated daily loss is directly attributable to the greater population density of both species of grasshoppers in the common field due to the presence 45
of weeds. During 1971, good qualify Bermudagrass hay was selling for $40.00
a ton ($0.02 a pound) and the cost of herbiciding with 2,4-dichlorophenoxy
acetic acid was estimated to be $1 .50 per acre including labor. Thus, the
amount of grass saved every eight days by maintaining a weed-free field of
Bermudagrass would offset the expense of one herbicidal application per acre.
There are other factors of economic importance to be considered.
Hay buyers w ill not pay as much for weedy Bermudagrass hay as for a bale of
weed-free Bermudagrass hay and the weeds in the field compete with the
Bermudagrass for nutrients, moisture, and sunlight thereby reducing yields.
The high level of mortality and greatly reduced longevity of adults of both species of grasshoppers reared on diets composed solely of either Bermudagrass
tremendously reduced the population density.
The theoretical change in M . femurrubrum populations with time as
influenced by the presence of weeds in the Bermudagrass fields is presented in
Table XV. This theoretical population change is based on the following
assumptions:
1 . the sex ra tio is 1:1
2. the females lay 1 egg pod
3. there is an average of 24 eggs per pod (Shotwell, 1941)
4. the average mortality for each of the four diets obtained in the laboratory for M . femurrubrum
5. there is an initial population of one adult per square foot 46
6. there are no other factors causing m ortality.
In coastal Bermudagrass fields the population density would decrease 64% per generation and by the end of the tenth generation the population density would be 0.0001 per square foot. The population would decrease 18% in the common
Bermudagrass fields and the population density would be 0.05 adults per square foot at the end of the tenth generation. Thus, it is theoretically possible to eliminate losses of grass to M . femurrubrum and D. viridis by maintenance of weed-free coastal and common Bermudagrass fields.
The population of grasshoppers in the coastal Bermudagrass plus weeds would increase by 612% each generation and the theoretical population density at the end of the tenth generation would be 12,042,118.79 per square foot and in a field of common Bermudagrass and weeds would increase by 660% to a density of 23,762,116.29 per square foot at the end of the tenth generation.
As can be determined from the preceding calculations, the absence of weeds from coastal or common Bermudagrass fields has a subsequent deleterious effect on populations of M. femurrubrum and D. viridis. In this study the re moval of weeds from fields of coastal or common Bermudagrass apparently removed some essential component from the diet of M. femurrubrum and D. viridis. The removal of this essential nutrient from the diet resulted in a higher mortality and shorter adult stage in both species of grasshopper and should therefore reduce the possibility of successful population maintenance. 47
The concept of ecological diversity in entomology is generally con
cerned with the effect of this diversity on predator-parasite populations and
their interaction with agricultural pests. Van Emden (1964) believes the pest
problems in the U.S. "which so much exceed those of Great Britain" can be
partly attributed to our large scale monocultures. He points out that in England small acrage plots are never far from the beneficial effects of uncultivated land.
He supports this statement with data showing the effect of syrphids and coccinellids from uncultivated areas on aphid populations in fields of brussels sprouts (van Emden, 1965). However, Way (1965) disagrees with the concept of agricultural diversity reducing pests and believes that uncultivated land holds pests which can then invade cultivated land.
The results of this study indicate that diversity of an agroecosystem involves more than just the predators and parasites. This study tends to show that food may also be a lim iting factor that needs consideration in the overall view of diversity. The high mortality of both species of grasshopper reared on either Bermudagrass and the resultant increase in survival when weeds replaced
20-25% of the Bermudagrass in the diet, would tend to indicate that a diverse
(weedy) agroecosystem provides for a greater grasshopper population than does weed-free Bermudagrass. In this study the predators and parasites were not studied, but dietary limitations which caused the high mortality apparently were the lim iting factors. It is essential that entomologists should remember that the environment is divided into four categories: (1) weather, (2) food, (3) other 48 plants and animals, and (4) a place to live (Rolston and McCoy, 1966). From the laboratory data obtained in this study which apparently is sufficient to explain population differences between weedy Bermudagrass fields and weed- free Bermudagrass fields, food was the lim iting factor for D. viridis and M . femurrubrum in this particular agroecosystem thus reducing the importance of the other three. It must be emphasized, however, that "diversity" refers to all four factors and to generalize for all agroecosystems everywhere is extremely dangerous and can give rise to erroneous theories. 49
TABLE X V .
Theoretical change in M . femurrubrum populations with time as influenced by the presence of weeds in Bermudagrass fields.
No. adults / square foot
Coastal Common Coastal Bermuda Common Berrru G eneration Bermudagrass Bermudagrass grass & weeds grass & weei
1 1 1 1 1
2 .36 .72 6.12 6 60
3 .13 .52 3 7 .4 5 43.56
4 .05 .37 229.19 28 7 .4 9
5 .02 .27 1,402.64 1,8 9 7 .4 3
6 .006 .19 8 ,5 8 5 .1 5 12,523 .0 3
7 .002 .14 52,534.99 82,651.99
8 .0008 .100 321,574.13 545,503.13
9 .0003 .07 1,967,666.47 3,600,320.65
10 .0001 .05 12,042,188.79 23,762,116.29 CONCLUSIONS
1 . There were high levels of m ortality in both species of grasshoppers reared on diets restricted to coastal or to common Bermudagrass.
2. The preference of M. femurrubrum and D. viridis for common over coastal Bermudagrass is probably due to the increase in "toughness" of the grass due to increased fiber content.
3. The maintenance of weed-free fields of either coastal or of common Bermudagrass would reduce damage caused by M. femurrubrum and D. viridis since neither species appears to be capable of developing damaging populations in weed-free fields of either Bermudagrass.
50 SUMMARY
M . femurrubrum and D. viridis suffered very high mortality when reared on either coastal or on common Bermudagrass exclusively. This mortal
ity was reduced by approximately 50% with the substitution of 20-25% of the
Bermudagrass diet with weeds. This substitution also significantly lengthened the adult longevity.
No chemical was found whose presence or absence could explain the preference of both species of grasshoppers for common Bermudagrass over coastal Bermudagrass. The probable cause of this preference is the increase in
"toughness" of the plants due to the increase in fiber content.
Maintenance of weed-free fields of Bermudagrass should decrease
losses of Bermudagrass because o f increased m ortality of the grasshoppers.
The estimated daily losses per acre with a population density esti mated to be 0.12 Mi. femurrubrum and 0.09 D. viridis per square foot is 1.0 pound dry weight daily in a virtually pure stand of coastal Bermudagrass. In a weedy common Bermudagrass fie ld , the population was estimated to be 1.26
M . femurrubrum and 1.14 D. viridis per square foot and they would cause a daily loss of 11.2 pounds dry weight per acre.
The high m ortality in both species of grasshoppers reared on diets of either coastal or common Bermudagrass would theoretically cause eradication.
The populations of M . femurrubrum decreased by 64% each generation when
51 52 reared on coasfal Bermudagrass, 18% per generation when reared on common
Bermudagrass; and increased by 612% on coastal Bermudagrass and weeds and
660% on common Bermudagrass and weeds with each generation. These data indicate that neither M . femurrubrum nor D. viridis could maintain a popula tion in stands of pure Bermudagrass. LITERATURE CITED
Barnes, O . L. 1955. Effects of Food Plants on the lesser migratory Grasshopper. J. Econ. Entomol. 48: 119-24.
Burton, W. 1972. The Worlds Greatest Grassland? Progressive Farmer. 87: 3 , 2 2 -4 .
C rid d le , N . 1933. Studies in the biology of North American Acrididae, development, and Habits. Proc. World's Grain Exhib. Conf., Canada 2, 474-94
D avey, P.M. 1954. Quantities of food eaten by the desert locust, Schistocerca gregaria (Forsk.) in relation to growth. Bull. Entomol. Res., 45, 539-51.
H a rle y , K. L. S., and A. J. Tborsteinson. 1967. The influence of plant chemicals on the feeding, behavior, development, and survival of the two-striped grasshopper, Melanoplus bivittatus (Say) Acrididae: Orthroptera. Can. J. of Zoo1. 45, 305-19.
Isle y, F . B. 1938. The relationship of Texas Acrididae to plants and soil. Ecol. Monographs, 8, 551-604.
M u I kern , G . B. and D. R, Toczek. 1970. Bioassays of Plant Extracts for Growth-Promoting Substances for Melanoplus femurrubrum (Qrtho- ptera: Acrididae). Ann. Entomol. Soc. Amer., 63 : 272-284.
M ulkern , G . B., D. R. Toczek, and M. A. Brusven. 1964. Biology and Ecology of North Dakota Grasshoppers. II. Food Habits and Preferences of grasshoppers associated with the Sand Hills prairie. N . D ak. A g r. E xpt. S ta t. Res. Rept. I I , 59pp.
O osting, , H. J. 1956. The Study of Plant Communities 2nd Ed. W . H. Freeman and C o., San Francisco. 440pp'.
P ainter, R. H . 1951. Insect Resistance in Crop Plants U niversity o f Kansas Press. Lawrence. 520pp.
53 54
Roddy, W. C. 1968. The Effect of Insect infestation on yield and quality of coastal and common Bermudagrass hay. Masters Thesis. Louisiana State University, Baton Rouge, Louisiana.
Rolston, L. H. and C. E. McCoy. 1966. Introduction to Applied Entomology. The Ronald Press. New York. 208pp.
Rubtzov, I. A . 1932. On the amount of food consumed by Locusts, (in Russian; English Summary) Trudy Zashchite Rastenii, Ser. 1, Entomol, No. 2: 31-40.
Sanderson, M . W , 1939. Crop replacement in relation to grasshoppers abun dance. J. Econ. Entomol. 32 , 484-88.
Shotwell, R. L. 1941. Life histories and habits of some grasshoppers of economic importance on the great plains. USDA Tech Bull., 774, 48pp.
Smith, D. S. 1959. Utilization of Food Plants by the migratory grasshopper Melanoplus bilituratus (Walker) (Orthoptera: Acrididae), with some observations on the nutritional value of the plants. Ann. Entomol. Soc. Amer. 52 : 674-680.
Thorsteinson, A . J. and J. K„ Nayar. 1963. Plant phospholipids as feeding stimulants for grasshoppers. Can. J. Zool. 41, 931-35.
Van Emden, H. F. 1964. The role of Uncultivated land in the Biology of Crop Pests. Sci. Hort. 17pp. 121-135.
1965. The effect of uncultivated land on the distribution of cabbage Aphid (Brevicoryne brassicae) on an adjacent crop. J. Appl. Ecol. 2: 1 pp. 171—196.
Way, M . F. 1965. "The natural Environment and Integrated methods of pest control." in Pesticides in the Environment and their effects on w ild life. The Proceedings of an Advanced Study Institute Sponsored by the North Atlantic Treaty Organization. Monks Wood Experiment Station, England. July.
W ilbur, D. A . 1936. Grasshopper injury to the inflorescence of pasture grasses. J. Kans. Entomol. Soc. 9: 1. 55
W illiams, L. H. 1954. The feeding habits and food preferences of Acrididae and factors that determine them Trans Roy Entomol Soc London. 105: 423-54.
Uvarov, B„ P. 1928. Locusts and Grasshoppers. In [Smith, D. S. 1959. Utilization of Food Plants by the migratory grasshopper Melanoplus bilituratus (Walker) (Orthoptera: Acrididae), with some observations on the nutritional value of the plants. Ann. Entomol. Soc. Amer. 52: 6 7 4 -6 8 0 .] 56
Appendix I. Duration of nymphal instars and adult stage in days of D. viridis reared on coastal Bermudagrass.
SECOND INSTAR replication 1 2 3 4 5 6 7 8 9 1( individual 1 5 5 4 7 4 7 6 7 8 7 2 7 6 5 6 6 6 6 5 6 10 3 6 7 7 7 5 7 5 7 5 6 4 8 8 6 8 7 7 6 4 7 7 5 7 7 6 7 5 5 4 7 7 10 6 6 5 7 6 8 7 8 6 6 7 7 5 6 4 5 7 6 6 6 5 7 8 4 5 4 7 7 7 6 8 8 6 9 5 7 8 4 5 6 6 5 8 5 10 6 6 7 8 6 7 7 5 6 6 11 4 6 6 4 7 8 8 8 7 4 12 7 7 6 6 7 4 4 5 6 7 13 7 8 8 5 7 7 8 5 7 6 14 8 7 7 8 8 6 7 9 8 9 15 7 6 8 6 7 6 9 8 7 6 16 6 5 6 6 8 7 9 7 7 7 17 5 7 6 4 7 •i 5 7 6 7 6 18 7 6 5 6 4 6 7 4 5 19 7 7 8 7 6 7 6 20 5
N = 189 57
Apendix I. continued
THIRD INSTAR
1 2 3 4 5 6 7 8 9 10 1 4 9 7 7 6 7 5 7 7 7 2 8 6 8 7 6 4 9 8 6 4 3 5 7 8 7 7' 8 5 •* 5 6 4 8 7 6 6 8 6 8 6 7 5 6 5 7 6 6 9 6 7 7 6 7 8 7 9 5 6 8 6 8 7 8 7 7 9 7 7 8 5 8 8 8 5 7 6 5 6 8 10 7 9 6 6 6 7 7 8 7 7 9 10 7 8 8 4 7 7 7 9 6 11 7 8 7 6 5 6 6 6 8 12 7 6 5 6 7 9 8 7 5 13 6 7 7 7 6 6 8 8 7 14 8 8 6 6 8 7 6 8 9 15 7 8 6 7 8 6 4 7 6 16 7 6 8 7 5 7 7 7 7 17 7 6 6 6 8 6 5 5. 18 8 7 7 7 8 8 6 19 8 8 8
N = 165 •
FOURTH INSTAR
1 2 3 4 5 6 7 8 9 10 1 8 9 8 6 10 6 8 6 5 8 2 6 8 7 6 7 8 9 6 10 7 3 8 5 7 5 8 9 7 6 10 4 7 6 8 11 7 8 8 9 8 5 10 8 9 6 7 11 6 7 9 6 8 8 9 5 9 7 6 9 6 7 6 6 10 6 6 9 9 8 5 8 6 7 9 8 8 8 6 7 7 9 7 6 8 8 7 6 7 6 8 10 9 8 10 7 7 9 7 6 8 11 8 8 7 8 6 6 6 7 6 12 7 10 8 8 9 9 8 8 9 13 9 9 8 8 8 9 9 9 9 14 6 8 8 8 7 8 6 8 7 15 7 7 9 7 7 6 8 11 8 16 6 7 7 7 7 17 8 6 7 6
N = 152 58
Appendix I. continued
FIFTH INSTAR
1 2 3 4 5 6 7 8 9 10 1 14 21 9 10 22 11 8 17 16 2 17 16 17D 14 21 20. . 12 20 17 3 16 17 18 16 20 17 16 21 16 4 12 12 13 20 11 19 17 27 18 5 20 19 15 17 22 12 19 16 22 6 17 17 14 16 17 23 14 12 7 25 12 15 18 21 18 8 26 11 14 15 15 9 11 18 17 19 10 19 17 14
N = 74
ADULT
10 1 3 4 2 4 2 2 14 3 1
1-2 48 N = 10 2-2 38 3-2 37 1-3 32 1-4 32 2-4 34 1-7 31 2-7 40 1-9 44 1-10 43 379 37.9±5.7 59
Appendix II. Duration of nymphal instars and adult stage in days
of viridis reared on coastal Bermudagrass and weeds.
SECOND INSTAR replication 1 •2 3 4 5 6 7 8 9 10 individual 1 5 7 8 7 7 10 6 7 6 8 2 8 6 9 7 4 6 5 6 7 7 3 7 6 8 7 5 6 8 7 7 9 4 7 6 8 6 7 9 8 7 9 10 5 6 5 5 8 6 6 8 7 5 8 6 6 7 9 8 5 6 9 5 6 6 7 8 10 7 5 6 7 6 4 8 5 8 4 8 6 7 7 7 5. 8 6 7 9 7 9 6 9 7 7 7 6 6 7 10 7 7 5 6 9 4 8 4 8 10 11 6 7 6 4 6 9 5 8 7 7 12 8 5 9 5 10 6 7 7 ' 7 7 13 5 8 7 8 7 7 8 5 6 9 14 11 6 5 7 6 5 8 8 4 6 15 4 13: 4 7 8 6 7 9 6 8 16 8 5 12 9 8 7 8 8 9 5 17 6 6 4 10 7 8 6 6 . 6 7 18 9 7 8 8 8 7 7 5 5 6 19 4 7 8 9 7 6 5 6 7 5 20 7 5 10
N = 193 60
Appendix II. continued
THIRD INSTAR
1 2 3 4 5 6 7 8 9 10 1 6 7 4 8 8 8 9 7 11 8 2 7 8 8 9 5 7 7 9 6 8 3 8 7 10 8 9 ■ 5 8 8 7 8 4 9 9 9 7 8 6 9 6 8 7 5 7 7 7 8 9 9 6 7 6 7 6 7 7 5 8 8 5 6 7 7 6 7 9 9 6 8 6 9 8 9 7 8 8 5 8 9 7 7 - 7 7 7 6 9 8 9 7 10 7 8 5 8 6 6 10 11 11 5 12 8 6 9 4 8 5 11 9 8 8 8 8 7 7 5 7 9 12 5 7 8 11 6 6 7 7 6 6 13 9 6 9 6 7 8 6 6 7 9 14 5 9 7 0> 7 8 8 8 . 6 5 15 6 7 9 6 8 4 9 7 4 6 16 9 8 8 8 5 7 6 7 7 6 17 6 8 7 6 8 8 5 6 18 9 6 8 7 7 8 19 6
175
FOURTH INSTAR
1 2 3 4 5 6 7 8 9 10 1 7 7 8 8 10 6 6 7 11 6 2 8 7 6 11 8 7 7 10 6 11 3 10 6 9 7 7 9 7 6 9 7 4 9 10 7 9 6 9 5 9 7 6 5 8 9 9 8 8 9 8 6 8 9 6 7 10 5 8 6 10 4 7 7 8 7 7 9 7 9 7 8 8 7 6 6 8 7 9 5 8 8 8 7 5 5 7 9 8 6 9 7 9 8 7 9 7 8 10 6 8 8 7 4 9 6 9 8 6 11 8 12 5 10 8 9 8 8 7 12 6 6 9 6 7 7 8 11 6 13 7 11 7 11 7 9 8 7 7 14 7 8 7 9 8 7 8 15 9 8 12 8 9 6 9 16 6 9 11
N » 143 61
Appendix II. continued
FIFTH INSTAR
1 2 3 4 5 6 7 8 9 10 1 8 8 5 7 7 7 8 7 7 9 2 9 9 6 5 6 5 9 10 9 9 3 8 7 8 9 8 7 8 6 8 8 4 9 7 6 7 7 6 9 10 8 6 5 7 6 10 8 6 6 9 4 7 10 6 7 5 7 7 7 7 7 9 9 7 7 8 7 6 7 6 8 8- 8 5 9 8 9 6 7 6 5 6 7 6 7 6 9 8 4 7 5 7 7 6 7 7 7 10 8 5 10 6 10 6 8 8 11 8 7 8 6 6 7 12 6 8 7 . 8 13 9 8 14 11
N <= 111
ADULT
1 2 3 4 5 6 7 8 9 10 1 16 21 21 13 13 19 13 17 15 12 2 13 18 17 22 18 11 18 16 14 10 3 20 21 20 11 17 13 17 18 17 16 4 19 19 11 22 12 15 10 17 13 15 5 16 17 18 17 24 16 13 15 14 16 6 17 12 13 15 17 26 16 11 16 17 7 19 19 18 16 16 19 15 13 12 14 8 12 13 17 15 17 17 17 11 14 9 15 16 8 27 12 19 19 10 20 20 25 25 17 21 11 15 16 23 12 18 15
N = 109 62
Appendix III. Duration of nymphal instars and adult stage in days of D. viridis reared on common Bermudagrass.
SECOND INSTAR
1 2 3 4 5 6 7 8 9 1C 1 8 6 7 5 8 7 <1 8 4 8 2 5 4 8 6 6 5 7 5 6 8 3 8 6 8 7 7 6 6 5 7 7 4 7 5 6 7 5 8 5 4 5 5 5 6 8 7 6 6 9 7 7 6 6 6 7 7 7 8 6 6 6 6 8 8 7 8 6 12 9 8 4 8 6 7 7 8 7 8 8 7 7 7 7 7 9 5 9 6 9 8 6 7 9 9 7 6 7 10 11 7 8 6 7 8 6 9 8 8 11 5 8 6 4 9 7 7 7 5 7 12 6 7 12 9 8 6 8 9 • 6 8 13 7 9 7 7 9 9 5 7 7 8 14 6 8 8 7 8 4 7 7 6 11 15 8 7 6 7 10 7 8 10 12 7 16 8 6 5 9 6 4 9 10 9 6 17 9 7 7 4 8 9 6 7 8 8 18 6 9 6 11 7 9 7 7 8 6 19 7 10 7 5 8 5 7 6 4 20 6
N = 197 63
Appendix III. continued
THIRD INSTAR
1 2 3 4 5 6 7 8 9 10
1 9 8 9 7 8 7 7 10 7 9 2 6 7 10 6 9 8 8 8 10 8 3 9 8 7 7 8 9 9 8 9 7 4 6 6 10 7 8 10 6 8 7 8 5 8 10 8 8 8 9 9 11 9 9 6 10 9 6 5 7 8 8 6 8 7 7 7 8 6 8 9 7 7 8 9 8 8 9 9 6 11 9 8 6 8 10 7 9 6 7 9 7 11 9 9 6 7 8 10 8 7 8 7 9 8 8 7 8 11 11 7 9 9 7 8 6 6 8 . 8 8 12 6 8 7 8 7 8 8 9 7 7 13 7 6 9 6 10 7 10 7 9 6 14 8 7 6 7 6 8 8 5 9 7 15 7 7 7 6 8 10 6 9 7 8 16 11 6 9 7 8 7 6 9 7 17 7 6 7 6 7 9 7 8 18 9 8 6 9 8 5 19 10
N = 174
FOURTH INSTAR
1 2 3 4 5 6 7'-, 8 9 10 1 9 4 5 7 9 6 7 7 9 7 2 6 8 7 7 6 8 8 9 8 8 3 7 7 9 10 6 7 9 8 7 6 4 8 8 9 7 7 11 6 9 11 9 5 10 7 8 10 8 6 8 8 8 7 6 6 8 8 9 9 7 7 9 8 7 7 8 7 8 8 6 7 7 7 7 8 8 7 9 11 8 7 8 6 10 7 10 9 8 8 10 9 9 8 8 8 7 7 10 5 8 7 7 11 6 8 8 8 9 11 7 6 8 8 9 9 10 9 6 7 12 8 10 7 6 8 10 6 7 8 8 13 6 7 8 9 7 7 14 6 6 15 7 8 16 9 17 7 64
Appendix III. continued
FIFTH INSTAR
.... 1 • '2 3 4 5 6 7 8 9 10
1 8 9 15 16 19 16 18 26 12 21 2 16 12 14 27 17 17 22 15 17 22 3 16 17 19 16 16 17 11 16 19 24 4 11 18 14 17 20 15 10 25 18 21 5 19 15 13 15 18 14 13 17 19 19 6 13 12 18 13 25 13 19 18 12 7 12 12 23 12 11 12 16 11 8 16 11 9
N = 71 •
ADULT
1 2 3 4 5 6 7 8 9 10
N = 4 1-2 29 1-9 35 2-9 45 3-9 43 152 = 38.0±7.4 65
Appendix XV. Duration of nymphal instars and adult stage in days of D. viridis reared on common Bermudagrass and weeds.
.'SECOND IN STAR
1 2 3 4 5 6 7 8 9 10
1 7 7 7 8 8 8 9 9 7 6 2 6 10 5 6 5 7 8 8 7 7 3 7 7 8 6 9 7 6 . 6 8 9 4 9 8 6 12 6 6 7 9 8 7 5 8 7 7 5 8 8 9 7 8 5 6 6 7 7 9 7 6 6 5 6 7 7 9 9 9 6 7 8 9 6 8 7 8 8 8 6 6 8 7 7 8 6 7 9 9 7 8 6 9 8 8 7 • 9 8 10 7 7 7 6 9 7 7 8 9 5 11 10 8 8 8 8 3 9 7 7 11 12 8 8 6 11 7 6 8 9 6 7 13 9 7 6 8 6 5 7 7 5 4 14 7 5 6 9 8 8 4 7 6 8 15 9 10 9 7 7 6 8 7 8 6 16 8 7 7 7 8 8 7 7 6 8 17 6 6 7 5 • 7 6 10 6 7 8 18 8 6 7 4 8 10 6 10 8 7 19 9 7 9 8 6 7 7 7 9 9 20 6 5 11 7 8 6 8
N = 197 66
Appendix XV. continued
' THIRD INSTAR
1 2 3 4 5 6 7 8 9
1 7 6 9 6 8 7 7 9 8 2 5 8 6 9 7 10 5 9 7 3 5 7 6 6 7 8 8 8 9 A 7 8 7 9 11 7 5 6 7 5 8 4 5 8 5 8 5 7 6 6 6 9 8 6 7 6 7 7 6 7 6 7 7 7 7 5 7 6 7 8 8 7 6 9 7 6 8 7 7 9 7 8 7 10 8 6 5 7 6 10 7 7 5 7 7 6 8 . 8 11 10 7 7 7 5 6 7 8 12 5 7 9 6 7 6 6 10 13 7 8 9 6 7 7 6 8 14 7 8 6 9 5 6 6 15 5 5 6 7 6 5 7 16 9 7 6 7 9 6 17 8 7 7 9 9 8
18 6 7 10 5 7 OONjvOLnslONO'O'^OiOOOVOvlLnO'O'O'O) 19 7
N = 165 67
Appendix IV. continued
FOURTH INSTAR
1 2 3 4 5 6 7 8 9 10 1 8 7 7 8 10 7 4 8 7 11 2 7 7 6 7 9 10 5 9 9 6 3 9 7 8 9 8 4 7 5 8 5 4 8 6 7 6 6 7 8 7 9 6 5 10 6 7 7 0 5 5 7 6 8 6 7 8 7 8 7 7 9 6 7 7 7 7 9 5 5 8 6 8 9 8 6 8 6 8 6 8 7 7 9 7 6 5 9 6 8 7 6 7 8 6 6 6 7 10 6 9 6 9 9 7 7 8 10 11 7 8 7 7 10 8 9 7 6 12 6 6 4 6 7 8 7 ' 7 8 13 8 7 6 6 8 8 9 ‘ 8 8 - 14 7 5 8 9 9 7 8 9 15 7 7 6 10 7 7 8 9 16 7 6 6 6 7 8 6 17 7 6 7
N = 153
FIFTH INSTAR
1 2 3 4 5 6 7 8 9 10 1 8 6 9 7 7 6 8 6 6 7 2 7 9 6 8 8 7 7 11 10 10 3 8 9 8 8 7 7 6 9 6 8 4 9 9 8 6 7 7 9 8 8 7 5 8 8 8 8 5 9 7 7 9 7 6 7 6 6 8 8 7 4 7 8 9 7 6 10 5 7 10 9 7 5 8 8 8 9 7 8 7 9 9 8 6 6 6 9 5 8 9 12 10 7 6 11 9 10 8 6 9 8 7 9 7 7 14 11 8 8 5 11 8 9 12 9 7 6 8 6 5 13 7 6 7 14 6 15 8
N = 118 CO vO o OO^Mn O'. OOrlaiO>\OniNrllflN rH H iHtHi-HiHtHt—irH 00 m^firiNooHrsvonvONH rlHHHHHriHHHHW COvDOONHOHfO^® HHHHHHHNrlrlH VO CMOrl\OOONNOOIN COHHHHHMriH ui vO 00 CSS Ov rH O'. CTv rH H rH H CH rH H rJ ooovoocooovor^ovvoinm !=> HHHHHHHHHHH n ovvoi^voovcHoOrHcnr^ HHHHHHHMHH ch H'CtcintsHinncoN NrlrlNrtNHHrlH no d) 3 MOvOr'OvO'O'tvON C HHHrHHNHHHH •H ■U C o a > H X •H 'O rH(NOO<-LnvOr'~COOvO!-HCN e rH rH rH 102 a; Cu II < 53 69 Appendix V. Duration of nymphal instars and adult stage in days of M. femurrubrum fed on c o a sta l Bermudagrass. ' SECOND INSTAR R ep licate 1 •2 3 4 5 6 7 8 9 10 1 8 8 5 7 4 12 5 11 8 9 2 9 7 7 8 8 7 7 11 4 8 3 7 5 6 6 8 6 10 8 7 5 4 5 8 6 9 5 5 5 9 7 11 5 6 7 9 8 7 6 8 7 9 6 6 7 6 9 7 6 7 9 6 5 5 7 6 7 5 6 6 8 6 6 6 10 8 5 6 11 5 14 9 6 5 6 9 9 6 6 7 6 11 6 7 7 7 8 10 7 6 5 7 9 8 5 4 9 7 11 8 9 8 7 7 8 12 12 9 N = 108 THIRD INSTAR 1 2 3 4 5 6 7 8 9 10 1 8 7 6 7 8 7 9 10 7 11 2 6 6 9 5 7 8 6 9 7 4 3 9 5 7 8 10 11 9 4 6 7 9 7 5 12 9 6 8 7 7 N = 35 FOURTH INSTAR 1 2 3 4 5 6 7 8 9 10 1 8 9 7 10 7 9 8 5 9 10 2 8 10 6 10 7 8 10 9 3 9 7 8 9 8 N » 24 70 Appendix V. continued FIFTH INSTAR 1 2 3 4 5 6 7 8 9 10 1 13 12 8 11 10 11 10 10 9 12 2 10 N = 11 ADULT 1 2 3 4 5 6 7 8 9 10 1 4 3 4 5 1 2 2 N = 6 71 Appendix VI. Duration of nymphal instars and adult stage of M. femurrubrum fed on coastal Bermudagrass and weeds. SECOND INSTAR No./Rep. 1 2 3 4 5 6 7 8 9 10 1 4 5 10 9 7 7 4 7 7 8 2 7 5 6 6 8 6 10 8 7 5 3 7 6 9 8 7 7 9 6 7 5 4 9 6 5 6 9 13 10 5 6 5 5 7 8 7 6 6 7 6 7 6 11 6 6 6 11 7 10 7 7 7 9 10 7 5 8 6 11 7 9 6 5 6 6 8 5 6 6 6 5 6 6 8 9 13 9 6 7 5 7 6 8 7 6 6 7 10 12 6 9 6 7 5 7 8 6 6 11 7 6 5 7 9 8 5 4 • 9 7 12 8 7 7 6 7 6 6 7 7 6 13 7 9 5 8 9 8 7 5 6 7 14 9 7 9 10 8 4 7 6 7 8 15 7 8 7 5 7 6 4 6 8 7 16 5 8 6 8 6 7 5 7 6 9 17 7 6 6 6 5 12 6 8 5 6 18 5 11 5 6 12 9 7 7 10 8 19 7 8 8 7 6 7 8 6 9 7 20 7 9 8 9 7 6 72 Appendix VI. continued THIRD INSTAR 1 2 3 4 5 6 7 8 9 10 1 8 10 7 7 7 9 6 7 11 6 2 7 8 9 6 5 9 7 7 5 7 3 6 9 7 7 7 8. 6 6 6 6 4 7 8 6 9 4 7 8 5 8 7 5 9 7 6 8 6 6 9 7 7 8 6 8 9 6 5 8 6 7 8 5 7 7 7 7 8 9 9 7 8 7 6 11 8 5 8 7 8 8 6 8 7 10 6 9 7 6 9 11 9 6 9 9 9 8 10 10 11 5 8 7 8 6 7 7 8 11 8 9 11 7 6 8 12 7 ■ 8 7 12 8 12 9 8 9 9 9 9 8 9 13 6 5 7 7 7 9 8 7 6 8 14 9 5 7 8 9 10 9 12 10 8 15 6 6 9 5 7 8 6 9 7 4 16 8 7 6 8 7 9 10 7 11 8 17 6 8 7 6 6 7 9 7 9 18 9 6 7 8 8 7 19 • 8 7 10 N = 189 73 Appendix VI. continued FOURTH INSTAR 1 2 3 4 5 6 / 8 9 1 7 8 9 5 7 8 6 10 6 2 6 11 6 7 9 10 6 8 9 3 7 8 7 9 8 8 7 7 7 4 8 7 5 8 9 7 8 9 9 5 7 8 8 7 7 8 6 6 8 6 6 7 9 6 6 6 10 7 9 7 8 9 7 8 8 8 7 6 6 8 8 8 9 8 10 9 8 8 6 9 11 7 5 6 8 8 9 7 6 10 7 8 9 11 6 7 11 7 8 11 8 9 7 8 8 8 9 7 ■ 10 12 9 7 8 8 9 9 9 11 7 13 9 10 8 8 6 10 7 8 10 14 8 9 7 10 7 8 5 9 15 6 7 10 7 8 8 8 8 7 16 7 9 9 8 9 7 8 7 6 17 8 9 6 8 9 7 18 OOvlOO^O'OOO^OvlNlVDOOONvlNlvOOivl N = 178 74 Appendix VI. continued FIFTH INSTAR 1 • 2 3 4 5 6 7 8 9 10 1 8 r.> 6 8 7 10 9 13 7 6 2 6 9 7 6 9 7 7 8 9 9 3 7 8 8 7 8 9 9 9 7 7 4 5 7 6 9 8 7 11 8 10 6 5 8 9 7 9 8 7 9 10 8 8 6 8 8 8 8 7 9 8 7 10 9 7 9 7 8 9 7 9 7 7 11 9 8 7 9 7 7 7 6 6 6 7 12 9 7 10 9 8 9 9 9 7 7 8 10 10 7 8 6 9 8 8 8 6 6 11 8 7 7 8 7 8 9 9 8 7 12 9 8 9 5 6 7 8 8 6 13 9 10 8 . 6 14 9 N = 122 ADULT STAGE 1 2 3 4 5 6 7 8 9 10 1 18 10 9 19 17 13 14 18 19 17 2 . 16 19 18 18 21 16 15 17 17 16 3 12 22 20 7 19 14 17 12 13 17 4 9 21 17 17 23 17 12 8 20 12 5 20 30 20 18 16 16 11 25 18 18 6 17 17 14 16 27 15 17 9 26 9 7 21 21 16 13 11 9 14 26 12 20 8 18 24 13 8 9 17 7 13 25 21 9 18 17 27 12 4 8 16 22 10 12 19 30 12 . 24 11 17 75 Appendix VII. Duration of nymphal instars and adult stage in days of M. femurrubrum fed on common Bermudagrass. SECOND INSTAR 1 2 3 4 5 6 7 8 9 10 1 4 9 7 5 9 6 7 8 7 9 2 7 8 6 8 9 5 5 6 9 8 3 6 6 5 11 6 9 10 8 4 7 4 7 7 8 5 6 8 6 4 7 12 5 6 6 9 10 7 7 6 7 5 7 1 6 6 7 7 6 9 6 9 10 7 8 7 6 5 5 9 7 5 12 9 5 7 8 7 9 6 7 8 6 7 9 5 11 9 5 9 5 11 6 9 6 13 9 10 7 8 9 6 5 11 7 6 6 12 9 13 8 • THIRD INSTAR 1 2 3 4 5 6 7 8 9 10 1 7 9 8 11 10 9 9 9 7 9 2 9 6 8 8 7 7 7 7 6 7 3 5 6 7 ■8 11 8 8 7 4 11 7 7 7 7 8 8 5 6 9 6 7 FOURTH INSTAR 1 2 3 4 5 6 7 8 9 10 1 7 8 9 7 8 9 8 10 7 9 2 8 7 9 6 9 5 6 11 6 8 3 8 9 7 11 10 8 8 4 6 7 6 7 9 10 5 9 6 6 6 FIFTH INSTAR 1 2 3 4 5 6 7 8 9 10 1 13 18 12 10 10 18 12 11 8 12 2 19 18 19 7 7 14 12 10 12 17 3 20 20 12 4 9 18 76 Appendix VII. continued ADULT 1 2 3 4 5 6 7 8 9 10 1 1 2 1 712624 2 6 4 ' 3 5 77 Appendix VIII. Duration of nymphal instars and adult stage in days of M. femurrubrum reared on common Bermudagrass and weeds. SECOND'INSTAR 1 2 3 4 ' 5 6 7 8 9 10 1 7 6 8 8 9 7 7 8 6 9 2 9 5 10 7 9 6 6 6 7 8 3 5 7 5 6 7 6 6 9 8 8 4 8 6 9 7 7 5 8 6 9 6 5 5 9 8 10 8 9 4 9 7 7 6 8 6 8 5 9 6 6 5 11 7 7 5 7 6 7 6 8 8 8 7 10 8 7 6 7 8 9 8 9 8 7 6 9 6 8 5 7 7 7 6 6 . 7 6 10 5 7 5 9 6 7 8 5 8 7 11 7 7 6 6 7 7 6 9 10 8 12 6 8 8 7 9 8 11 5 9 6 13 7 9 7 7 5 7 7 7 7 8 14 7 7 6 6 7 7 8 4 6 8 15 6 6 5 8 5 9 7 7 10 7 16 7 7 7 6 6 4 6 6 8 7 17 6 5 7 9 7 8 7 8 6 9 18 8 7 6 6 6 7 9 9 8 6 19 7 7 10 7 5 8 7 6 6 6 20 6 6 6 8 9 8 N = 196 continued THIRD INSTAR 1 2 3 4 5 6 7 8 9 10 7 8 7 9 6 7 5 10 7 9 8 9 7 9 8 6 4 7 8 7 9 6 8 6 8 9 9 8 6 7 6 10 7 7 5 6 8 7 10 6 9 7 8 7 7 8 6 9 7 8 6 8 6 9 6 8 6 7 9 6 9 7 10 8 7 6 6 8 7 8 7 6 6 6 7 7 7 7 8 8 9 6 7 7 7 6 7 7 6 6 4 8 6 8 8 8 • 7 10 6 6 7 7 8 6 5 7 6 6 7 9 6 9 7 7 6 7 8 7 7 7 9 5 5 6 9 6 5 8 6 7 5 8 6 8 6 6 6 7 5 6 9 6 6 7 7 8 6 9 7 5 6 8 8 6 8 7 8 6 10 8 6 7 7 7 8 6 4 8 8 5 6 10 6 7 6 8 7 7 6 7 8 7 7 8 79 Appendix VIII. continued FOURTH INSTAR 1 2 3 4 5 6 7 8 9 10 1 8 6 7 7 6 10 7 6 7 6 2 4 7 7 8 9 8 6 8 5 7 3 9 6 8 6 10 8 9 7 8 6 4 6 7 9 8 8 8 7 9 7 7 5 8 8 7 7 9 7 7 8 6 8 6 9 6 6 10 7 6 9 8 9 9 7 7 8 9 7 10 7 8 9 8 9 8 7 7 8 6 8 10 9 7 8 5 9 7 5 8 8 8 8 8 9 8 7 10 9 7 6 9 7 5 7 8 6 11 11 6 8 9 6 7 9 8 7 8 6 12 8 9 7 8 7 6 5 7 5 8 13 5 6 8 7 6 8 6 8 • 6 8 14 7 4 9 9 7 7 4 8 7 5 15 9 8 7 10 7 5 6 7 8 8 16 5 6 8 7 6 7 8 8 5 6 17 6 7 7 7 8 5 18 8 5 N = 168 FIFTH INSTAR 1 2 3 4 5 6 7 8 9 10 1 9 7 10 7 9 7 8 '”11' J b 2 7 8 8 9 8 7 9 6 8 8 3 8 8 9 8 6 8 7 10 7 8 4 7 6 9 8 7 8 11 6 5 9 5 9 7 8 8 9 9 7 7 6 14 6 6 9 7 8 8 7 10 10 6 11 7 5 8 7 9 6 6 9 9 7 6 8 4 7 8 8 7 5 7 8 8 7 9 9 6 9 6 7 7 8 7 9 7 10 7 10. 8 12 8 6 9 8 9 5 11 8 8 10 9 8 6 8 9 8 6 12 6 7 6 11 10 5 6 7 6 8 13 6 7 10 9 7 8 7 7 9 14 8 9 7 8 7 8 15 9 9 80 Appendix VIII. continued ' ADULT 1 ----- 2 3 4 5 6 7 8 9 10 1 20 21 17 9 18 19 13 15 19 18 2 18 22 18 17 18 20 17 19 17 16 3 16 25 13 12 20 18 21 17 9 17 4 17 19 15 14 19 20 14 19 8 9 5 8 12 20 18 15 12 19 18 19 11 6 25 18 18 19 16 17 20 16 18 17 7 11 14 13 27 27 10 19 21 16 15 8 13 12 18 16 18 8 17 22 15 14 9 14 17 15 16 16 19 8 9 20 11 10 12 15 14 13 12 16 18 12 • 12 18 11 11 19 12 20 12 16 12 10 14 13 14 14 81 Appendix IX. The weight' in milligrams of IK_ viridis nymphs and adults reared on coastal Bermudagrass in the laboratory. ' SECOND INSTAR Replication 1 2 . 3 4 5 6 7 8 9 10 Ind ivid u al 1 200 204 211 217 229 212 196 191 197 211 2 205 203 202 172 236 230 217 173 172 196 3 230 255 194 192 197 235 203 243 210 202 4 229 207 199 208 229 175232 209.. 177 244 5 171 188 242 181 248 209 192 221 239 167 6 203 209 182 179 207 236 208 254 204 256 7 175 190 250 206 228 233 199 197 219 227 8 210 210 205 161 238 207 206 236 178 200 9. 160 194 208 196 230 239 192 221 168 212 10 183 203 231 245 208 201 198 196 229 183 11 227 182 163 177 251 249 238 203 246 204 12 240 187 210 206 241 208 207 255 213 249 13 214 212 187 204 214 222 213 202 196 201 14 212 208 232 255 170 239 168 230 209 197 15 241 178 205 180 204 194 220 231 213 171 16 187 203 215 251 206 246 163 171 207 203 17 242 179 220 191 181 251 172 216 165 186 18 204 201 197 238 242 232 168 177 217 19 201 222 161 205 181 191 N = 185 82 Appendix IX. continued THIRD INSTAR Replication 1 2 3 4 5 6 7 8 9 10 Individual 1 344 324 334 358 338 349 326 344 337351 2 201 350 323 312 349 336 343 369 355343 3 318 335 344 356 355 375 338 359 346 4 311 344 342 367 345 327329 342 338 5 295 354 306 325 337 355 335 342 343 6 343 329 315 332 359 346 373 360 320 7 309 356 311 342 351 356 346 306 303 8 338 353 355 350 354 363 336 355 331 9 353 347 307 302 307 347 366 353 348 10 348 359 315 353 315 340 349 308 353 11 331 339 326 355 327 353 351 351 339 12 303 349 347 304 347 359 363 342 321 13 320 358 355 362 350 355 350 333 343 14 343 309 319 322 353 349 352 327 315 15 338 347 314 358 363 361 367 367 331 16 333 327 325 356 341 337 340 356 319 17 346 335 305 346 356 348 332 311 18 326 323 350 357 358 344 19 355 339 ■ / N » 162 83 Appendix IX. continued FOURTH INSTAR 9 Replication ...... 1 2 3 4 5 6 7 8 10 Individual 1 446 397 437 409 441 433 419 435 428 436 2 433 427 442 428 496 432 426 458440 433 3 426 458 439 437 417 438. 441 432 409 4 418 433 417 441 440 434432 431 426 5 399 437 446442 427 440 430 417 421 6 442 427 441 432 417 428 433 435447 7 440 415 431 443 435 439428 419 429 8 399 407 428 417 406 431 416 445 422 9 426 429 436 429 399 426 422 419 441 10 445 440 405 431 441 448 443 425437 11 451 426 434 462 437 439 435432 12 443 437 441 447 441440 ' 417 426 13 434 461 451 443 429 14 441 439 436 431 417 N = 118 FIFTH INSTAR Replication______1____2____3____4____5____6____7____8____9____10 Individual 1 502 500 529 508 517 464 2 485 480 479 3 468 N = 10 84 Appendix IX. Continued ADULT Replication ____1 2 3 4 5 6 7 8 9 10 Individual 1 511 486 520 491 489 486 2 496 451 493 3 499 N = 10 85 Appendix X. The weight of D. viridls second, third, fourth, and fifth instar nymphs and adults reared in the laboratory on coastal Bermudagrass and weeds. • SECOND INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 In d ivid u al 1 217 204 229 187 206 182 250 209 190 232 2 242 186 204 203 202 242 205 188 192 210 3 187 171 208 215 230 199 218 208 194 203 4 241 203 203 171 213 194 199 207 182 187 5 212 175 207 251 197 206 231 255212 208 6 214 210 255 206 192 211 163 203 218 278 7 240 160 210 298 171 202 229 204 206 279 8 227 183 238 246 163 211 210 206 187 232 9 180 207 251 191 222 197 220 215 185 205 10 213 203 217 196 212 230 235 175 209 212 11 168 236 208 242 208 232 238 228 207 200 12 220 233 222 205 251 180 161 206 248 227 13 163 207 239 161 241 255 196179 229 256 14 172 239 194 238 214 204 245 181 197 167 15 232 201 246 181 170 206 177 208 236 244 16 181 249 251 206 204 217 172 192 229 202 17 178 219 204 239 177 210 172 197 211 196 18 168 229 247 213 196 209 213 207 165 177 191 168 86 Appendix X. continued THIRD ' INSTAR R ep licate 1 2 •• • 3 4 5 6 7 8 9 10 Ind ivid u al 351 339 348 331 363 349 321 317 349 350 1 340 358 345 351 325 343 331 309 358 301 2 336 333 310 320 326 336 351 343 310 335 3 341 350 334 347 341 339 317 355 329 341 4 349 353 329 354 335 336 305 348 330 322 5 320 331 346 356 356 319 355 369 333 329 6 350 320 349 319 355 320 325 320 361 343 7 330 366 355 348 337 351 327 353 349 351 8 322 329 349 346 347 359 347346 343 345 9 333 357 327 333 346 341 351 323 338 349 10 350 351 308 359 357 346 339 357 341 340 11 320 349 339 347 343 329 344 346 339 320 12 349 345 343 329 351 345 349 341' 345333 13 361 320 341 335 337. 320 339 351 349 357. 14 319 341 345 351 348 327 330 359 329 342 15 339 353 355 322 332 347 16 FOURTH INSTAR R ep licate 1 2 3 4 5 6 7 8 9 10 Ind ivid u al 1 435 417 423 416 423 433,451 425 427 417 2 437 430 432 417 424 441 407 424415 433 3 426 425 415 418 433 416 426 425416 422 4 430 418 422 421 422 432 319 452 408 407 5 441 421 419 411 431 416418 422 430 399 6 416 441 433 425 423 438 396 431 422416 7 439 433 430 406 409 418 433 422406 424 8 405 426 425 424 431431 415 415 416 422 9 421 429 421 419 428 443 409 409 427 438 10 418 409 433 422 420 431 431 430 441 11 432 427 416 421 423 423 416 423 12 419 425 395 436 419 434430 401 13 439 416 427 437 427 421 14 448 437 407 407 15 421 87 Appendix X. continued FIFTH INSTAR R ep licate 8 10 Individual 1 479 488 471 476487 467491 497 475 499 2 499 483 496 483 497 488493 487 479 478 3 493 496 476 469489 480 457 497468 493 4 487 488480 497 475 489459 489 480 498 5 489 478 489 485 476 484498 475 489 493 6 484 497496 479482 469 473 476479 476 7 465 489 488 495 479 476472 440 488 472 8 449 491 473 498 496 467497 498 493 480 9 476 501 493 479 457 487496 473 10 467 476 496 480 480 501 11 449 479 490 12 459' ADULT STAGE R ep lciate 1 2 3 4 5 6 7 8 9 10 Individual 1 494 510 505 473 506 481 496528 491'506 2 491 495 510 491 511 504 495 472 490 483 3 487 474 503 500 508 518 497 515 519 498 4 493 512 482 494 521 486 471 529 502 506 5 474 517 480 492 501 490 495 511 500 511 6 488 531 501 498 470 512 521 520 497 507 7 511 488 516 505 483 487 527 510 526 499 8 524 489 508 480 523 493 479 496 485496 9 499 476 520 525 514 500 526 478 10 509 515 484 477 513 491 11 510 12 492 88 Appendix XI. The weight in milligrams of second, third, fourth, and fifth instar nymphs and adult stage of D. viridis reared in the laboratory on common Bermudagrass. SECOND INSTAR Replication______1 2 3 4 5 6 7 8 9 10 Individual 1 232 197 199 211 216 204 187 202 189 212 2 207 183 210 207 203 188 212 196 228 197 3 221 212 206 204 212 179 215 211 195 200 4 201 215 210 204 211 217 196 201 202 207 5 199 213 207 195 206 179 221 196 206. 199 6 211 217 199 211 201 202 191 207 231 203 7 208 182 202 213 191 211 227 212 176 212 8 204 210 216 204 187 198 204 211 205 199 9 216 211 192 199 217 201 215 189 207 221 10 206 199 211 177 203 185213 212 165 211 11 196 209 179 210 187 166 411 216 197 212 12 207 221 197 228 169 212 188 203 207 210 13 210 215 201 200 195 211 215 232 207 167 14 213 179 208 211 206 215 197 179 210. 216 15 392 402 195 211 204 206 182 191 211 201 16 187 166 199 213 207 411 417 195 201 199 17 213 197 203 207 221 212 206 204 212 173 18 199 198 204 202 211 196 211 215 217 213 19 211 201 185 203 187 210 201 20 89 Appendix XI. continued THIRD INSTAR .ic a te 1 2 V 3 4 5 6 r 8 9 10 .vidual 1 331 349 346 319 323 351 340 333 347 315 2 351 346 331 349 351 309 346 335 341 346 3 345 343 321 343 357340 361 340 339 357 4 329 336 349 331 337 331 347 336 341 341 5 341 348 346 317 349309 346 357 343 325 6 320 355 350 349 336 360 349 345 320 351 7 349 331 346 343 351 326 343 338 351 356 8 361 358 320 329 343 317 331 321 311 349 9 319 349 351 339 325 347 336 305 '361 348 10 341 339 353 329 351 319 344 343 336 349 11 340 335 356 329 337 353 341 33Q 331 355 12 336 341 333 347352 344 298 320 358 336 13 320 322 351 316 336 363 326 336 331 324 14 330 355 351 332 325 331 347 310 15 326 329 349 349 335 16 351 319 337 351 339 17 345 310 321 331 349 90 Appendix XI. continued FOURTH INSTAR R ep licate • 2 3 4 ’ 5 6 7 8 9 10 Individual 1 452 407 419 431 436 424 397 423389 432 2 435 437 433 421 430 407 431 405 448408 3 431 416 431 422 424 418 419 433 417 423 4 415 421 419 389 432 424 426 432 441 427 5 420 422 426 427 396 431 451 395 427 430 6 421 427 416 451 432 425 427 431 416 387 7 435 419 441 423 447 419 409 432 429 427 8 430 433 399 428 431 436 435 417399 9 424 426 402 411 431 421 436 430 10 431 415 422 412 407 11 433 419 386 12 437 431 FIFTH INSTAR R ep licate 1 2 3 4 5 6 7 8 9 10 Individual 1 506 459 2 523 3 471 ADULT STAGE R ep licate 1 2 3 4 5 6 7 8 9 10 Individual 1 507 499 2 521 3 475 91 Appendix XII. The weight in milligrams of second, third, fourth, and fifth nymphal instars and adult stage of D. viridis reared on common Bermudagrass and weeds in the laboratory. SECOND INSTAR R ep licate ______1 2 3 4 ' 5 ' 6 7 8 9 10 Individual 1 207 210 210 176 191 216 207 197 215 202 2 220 211 . 166 207 211 185 205 201 201 204 3 201 231 199 216 227 202 228 218 199 207 4 215 206 .206 196 212 213 204 202 210 211 5 201 189. 212 207 195 207 228 206 211 204 6 215 204 209 215 203 211 206 221 187 191 7 213 187 210 187 227 205 199 217 177 207 8 207 228 191 211 191 199 214 207 227 175 9 210 199 169 203 205 169 201 199 213 205 10 211 204 211 189 212 193 219 187' 209 201 11 221 213 207 211 212 197 200 191 212 191 12 210 187 199 216 197 198 211 207 211 211 13 199 192 208 217 204 197 212 217 213 205 14 167 210 203 231 199 214 205 195 202 216 15 199 204 213 177 217 200 201 185 203 203 16 202 207 211 204 187 213 206 200 231 199 17 206 219 216 221 209 193 203 215 207 18 199 215 188 175 203 220 169 210 19 213 197 191 211 192 201 20 210 167 92 Appendix XII. continued THIRD INSTAR Replicate ______1 2 v 3 4 5 6 7 8 9 10 Individual 1 357 338 353 329 351 346 332 343 335 354 2 359 352 339 341 355 337368 339 367 335 3 360 327 347 355 367 359 315 343 359 337 4 361 331 319 343 330 356 341 345 36 356 5 359 318 359 353 330 337 348 367 365 363 6 349 353 369 342 345 350 345 347 369 337 7 353 330 346 347 351 338352 358 357 371 8 356 355 359 349 357 356 366 361 347 341 9 335 346 360 369 326 349 341 335 357342 10 329 337 357 331 339 330 326 363 353 11 335 366 334 354 341 329 366 339 346 12 357 359 346 363 351 333 332 349 353 13 322 336 347 349 367 351 329 330 337 14 341 329 353 345 356 349 351 341 15 352 365 337 328 311 351 340 322 16 346 359 356350 360 361 332 17 365 333 330 349 325 359 349 18 351 332 348 19 327 ro Appendix XII. continued FOURTH INSTAR 3 Replicate 1 2 4 5 ' 6 ■ 7 8 9 10 Individual 1 427 419 407 411 427 437 415 405 420 418 2 440 487 412 389 435 451 423 422 433 431 3 421 419 430 431 407 397 447 433 429432 4 435 422 424 427 431 424 411427 395 425 5 421 430 427 419 423 436 425 431 411421 6 435 431 426428 409 408 432 425 430 432 7 433 451 419 423 431 417 432 419 427 413 8 427 426 433 433 436 411 417 389 425 423 9 430 409 430 431 431 424 413448 431 10 431 424 386 439 447 419 417 424 417 11 441 407 419 435 432 437 418 448421 12 430 448 426 396 407 417 426 438 13 419 432 427 441 434 419 422 14 424 429 436 436 434 426 15 433 430 416 401 441 16 439 437 FIFTH INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 503 471 497 512475 495 486 493 476 499 2 510 505 475 485495 512 513 495 473514 3 499 498 518484 479479 481 510 495 475 4 506 495 512 507 491 506 500 506 484 495 5 489 512 497 500 509 490 503 481 491 501 6 516 505 506 479 490 473 505 487508 511 7 512 497 515 489 470 498 483 513 489 503 8 491 488 487485 516 506 496 511 499 482 9 504 487 493 505 503 471 502 505 479 10 482 488 491 521 484 513 500 513 11 515 478 519 480 489 94 Appendix XII. continued ADULT STAGE Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 503 489 502 511 501 518 493 489 487499 2 497 52.0 487 493 511 501 512 505 509 487 3 495 489 505 483 495 516 496 498501 511 4 488 503 510 489 489 497 507 489495 492 5 480 510 486 483 492 501 496 503 498 512 6 489 507 504 506 505 495 491 498 507 489 7 498 497 511 489 503 514 511 489488 513 8 501 506 503 502 498 504 497 506 497 503 9 505 497 511 503 512 489 494492 476 10 501 508 505 487 478 506 488 514 11 496 510 503 493 501 95 Appendix XII_. The weight in milligrams of M. femurrubrum second, third, fourth, and fifth nymphal instars and adult stage reared on coastal Bermudagrass in the laboratory. SECOND INSTAR Replicate 1 ' 2 ' 3 4 5 6 7 8 9 10 Individual 1 276 266 219 251 276 260 297 276 281 267 2 251 271 266 281 251 281 276 260 279 296 3 259 287 271 279 259 271 252 281 245 270 4 260 279 269 269 270 280 270 272 266 272 5 266 243 257 287 204 279 280 279 289 276 6 270 276 256 265 298 281 263 275 281 263 7 282 281 250 292 285 257 246270 269 260 8 266 272 271 267 288 249 281 278 269 276 9 277 210 279 233 276 251 291 272 265 239 10 269 256 261 266 262 258 237 259 281 261 11 278 299 280 301 245 214 12 295 285 N = 108 THIRD INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 416 367 407 379 411 403 389 405 398 406 2 428 401 415 389 402 411 392 399 391 403 3 405 402 389 395 406 407 417 379 4 410 405 396 396 5 387 392 6 399 N = 35 FOURTH :INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 503 489 495 502 501 493 514 510 487 512 2 497 488 511 518 505 496 504 497 511 3 480 504 514 4 497 N = 23 96 Appendix XII.continued FIFTH INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 583 589 579 521 563586 591 579 606 574 2 589 N = 11 ADULT STAGE Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 621 630 624 641 639 2 661 97 Appendix XIV. The weights in milligrams of second, third, fourth, and fifth nymphal instars and adult stage of femurrubrum reared in the laboratory on coastal Bermudagrass and weeds. SECOND INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 288 286 287 279 286 284 251 283 259 271 2 279 278 298 286 289 285 283 284274 271 3 225 250 289 280 296 259 286 278 283 287 4 279 239 280 269 289 271 275 276281 279 5 289 279 263 268 271 279 301 269 279 276 6 278 271 270 273 269 240 273 239309 301 7 269 274 280 280 291 273 283 283 288 28b 8 267 277 249 281 286 266 276 289 281 283 9 267, 281 283 300 287 269 253 277 287 271 10 275 289 299 250 283 286 280 259 286 276 11 263 \ 287 240 280 228 266 279 281 273 290 12 271 293 295 271 273 291 279 271 273 276 13 251 279 288 289 281 250 280 271 279 285 14 301 291 278 276234 281 266 261 247 293 15 273 271 276 291 261 267239 281 281 288 16 240 277 255 269 275 270 283 284 286 291 17 279 273 265 279 266 288 280 286 257 279 18 277 269 285 257 279 276 278 247 266 19 271 251 263 261 263 257 264 286 20 253 249 N = 189 98 Appendix XIV. continued THIRD INSTAR Replicate ______1____2____3____4____5____6____7____8____9____10 Individual 1 415 401 398 379 388 428 398 403 418 406 2 413 397 418 387 417 387 419 413 400 407 3 401 389 403 395 389 402 402 396 402 404 4 396 379 402 396 379 402 387 392 432 386 5 410 419 386 400 403 413 389 397 405 407 6 428 402 407 396 411 411 395 404 407 406 7 410 417 398 401 423 410 431 401 396 409 8 385 413 391 396 376 396 421 405 380 389 9 395 406 419 387 411 379 413 403 307 390 10 392 411 402 402 410 398 370 401 396 397 11 408 383 411 414 395 401 391 360 413 403 12 393 376 399 405 382 385 415 395 401 409 13 418 416 406 383 411 408 404 396 399 392 14 375 417 415 407 393 387 397 406 417 401 15 410 405 403 407 421 398 392 389 411 406 16 379 412 399 404 407 399 407 396 410 405 17 376 397 412 405 415 421 411 404 379 18 393 385 413 396 401 392 19 419 373 401 20 N = 178 99 Appendix XIV. continued. FOURTH INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 494 488 511509 476 489 508 515 520 526 2 483 510 500 494 492 498 505 480 497 496 3 487 490 505 491 478 506 481 500 528 472 4 506 474 472473 518 504 502 491 495 527 5 511 502 503 495 506 519 490 497 521 479 6 507 500 529 500 491 481 471 495 514 490 7 499 497 511 471 508 504 496 484512 481 8 496 526 520 495 486 518 511 528 525 487 9 500 485 510 521 490 521 497 495 491 493 10 526 514 496 527 512 501 494 515 510 506 11 483. 478 525479 487 470 492 482 519 491 12 498 506 491 520 493 483 498 480 512 498 13 478 508 483 513 476 523 505 401 517 493 14 491 496 511 510 477 499480 488 531 475 15 485 513 499 509 484 524 508 516 488 16 526 507 515 489 511 N = 154 FIFTH INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individaul 1 584 597 601 567 589 597 589 593 579 616 2 589 610 591 589 587 598598 588 599 587 3 593 601 589 581 569 571 597 589 598 593 4 589 596 531 600 588 582 601 597 589 589 5 569 579 587589 596 556 543607 585 576 6 575 591 580 566 603 549 593 555 547 597 7 579 565 583 531 566 589 576 589 589 576 8 585 581 589579 576598 589 601 586 583 9 579 599 586 597 602 587588 600 588 579 10 593 584 589 596586 587 593 11 618 601 587 N = 100 100 Appendix XIV. continued ADULT STAGE Replicate _____ 1 2 3 4 5 6 7 8 9 10 Individual 1 607 629 651 647 612666 615 631 646 631 2 637 606 617 627 644617 630 643 640 617 3 648 651 609 639 630 633 640 636 621 639 4 650 630 631 619 623 633 641 617 634 629 5 679 622 667 637611 641 636 637 629 656 6 637 689 651 621 617 657 643 639 619 612 7 655 649 647 646 647630 613 653 642 647 8 663 638 611 617 616 660 651 647 616 645 9 687 651 631 629 657 637 639 615 10 639 673 646 649 629 11 681 N = 94 101 Appendix XV. The weight of second, third, fourth, and fifth nymphal instars and the adult stage of M^_ femurrubrum reared on common Bermudagrass. SECOND INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 263 273 270 288 283 298 250 289 293 296 2 260 217 282 251 267 280277 217 279290 3 293 239 232 279 279 288 297 297254 288 4 271 289 276 256 276 312 278 270 265 290 5 291 248 249 286 278 261 297 287244 289 6 283 261 289 254 296 289210 289 261 305 7 300 289 277 271 283 301 223 223 236 216 8 224 288 244270 279 217 288 215 259 289 9 301 270 271 214 289 269 283 290 289 10 289 289 261 289 279 279 253 11 273 297 293 12 286 13 291 N = 99 THIRD INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 411 396 428 412 411 421 431 399 404 412 2 386 407 369 375 412 415 406 411 407 369 3 387 431 413 397389 377 398 427 4 410 397 385 416 407 404 411 5 379 413 6 409 N = 38 FOURTH INSTAR P.eplicate 1 2 3 4 5 6 7 8 9 10 Individual 1 494 505 481 508 506 495 481 482 473506 2 500 473 496 491 483 504 510 473 479487 3 506 490 511 512 508 505 N = 25 102 Appendix XV. continued FIFTH INSTAR Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 589 571 591 587 585 598 578 601 2 581 567 563 589 576 N = 12 ADULT STAGE Replicate 1 2 3 4 5 6 7 8 9 10 Individual 1 636 621 617 607 605 610 645 647 2 601 630 637 676 632 N = 12 103 Appendix XVI. The weight of nymphs and adults of femurrubrum reared on common Bermudagrass and weeds. SECOND INSTAR Replication 1 2 3 4 5 i 6 7 8 9 10 Individual 1 246 263 289 290 253 286 274 279 281290 2 279 240 279 272 286 289 247289 259 271 3 276 288 271 259 275 298 287 290 293 281 4 271 280 284 279 264 289 283 293 279287 5 239 279 278 235 263 288 216 290 286 245 6 251 288 289 244 232 289 285 293 289 270 7 274 293 267 283 232 281 287 276 263 260 8 279 237 288 282 269 270 290 296 276 291 9 286 289 273 275 289274 285 279 274 247 10 265 211 287 282 287 256 250 276269 280 11 223 310 250 228 259 289 280 273 275 283 12 274 273 223 249 281 270 301 246 295 290 13 279 293 243 270 233246 286 239 249266 14 288 236 287 283 225 277 296 293276 233 15 259 288 279 263 265296 289 252 291 261 16 259 271 271 276 222 290 227 278 289 297 17 287 290 266 276 273 283 229 297 230 250 18 245 278 255 259 282 282 297 287 257 294 19 272 232 257 300 278 290 223 290 278 20 246 241 270 104 Appendix XVI. continued THIRD INSTAR >lication 1 2 3 4 5 6 7 8 9 10 .vidaul 1 407 413 399 397 405 379 404410 412 395 2 417 420 409 406 393 402 399 417 411 377 3 403 403 401 398 407 407 381 393 404 403 4 421 410 375 415 369 404 415 369 411 399 5 387 400 396 397 401 410 410 420 407 414 6 406 404 391 399 399 415 421 392 410 401 7 397 401 403 414 406 401 413 411 387 391 8 402 395 410 389 405 412 407 407 389 399 9 403 412 496 419 409 405 409 403 410 405 10 418 388 407 412 411 391406 367 495411 11 397 405 415 401 389 417 399405 421 412 12 401 381 405 408 407 402 413 410 411 401 13 407 401 403 404 410 403 403 369 396 497 14 397 417 418 411 413 394413 416 404 406 15 411 402 413 399 399 390 407 397 402 397 16 410 396 404 418 402 376 416412 391 403 17 379 393 387 406 415 385 406 390 391 401 18 403 394 418 419 402 366 405 19 20 N = 177 105 Appendix XVI. continued FOURTH INSTAR Replication______1 2 3 4 5 6 7 8 9 10 Individual 1 519 481 504 499 495 613 508 499 510 521 2 509 501 503 490 496 497 516 500 497 501 3 495 519 495 506 504 499 510 505 498 513 4 513 497 507 489499 481 506 501 497 499 5 507 507 491 513 497 519 509 503 502 500 6 508 487 519 481 499513 496 510 507 516 7 490 480 508 499 498 489 500 507 510 499 8 493 485 497 513493 499 501 493 412 494 9 500 510 499 486 499 486 579 487 505 510 10 493 521 507 496 505 498 508 511 497 511 11 491 499 505 495 501 511 419 520 509 507 12 500 506 501 485 490 487 483515 517 501 13 509 513 499 495 507498 520 505 485 508 14 515 497 503 515 506508 500 499 511 500 15 501 503 499 481 489 495 489 493 512 497 16 509 491 497 500 493 17 511 519 18 19 20 N = 157 106 Appendix XVI. continued FIFTH INSTAR 1 2 3 4 5 6 7 8 9 10 1 579 588 531 576 587567 591 597 575 597 2 599 583 596583 597 587 588 588586 578 3 593 596 566576 569 589565 596 589601 4 587 587 587 580 597 575 589598 579 576 5 589 588 545 589 585576 593 580 580 559 6 584 597 567 596579 540 589 570 579 583 7 565 589 596 588 595 601580 593 598 567 8 549 591 573 598 579 557 587587 606 577 9 576 581 587593 596 595 580 588 616 539 10 563 567 599 576590 559 543 601 590 579 11 571 545 597 579 590 699 587 12 582 570 13 589 N = 110 ADULT 1 2 3 4 5 6 7 8 9 10 1 639 681 631 644 616 619649 617 623 606 2 622 687 673 617 641 615 637 621 619 638 3 609 649 663651 637 621 629 639661 611 4 639 631 689 655 639 625 634 631 650 652 5 640 619 667638 637 649 650 629 643 645 6 616 630 637 650651 679 689 612 619 636 7 633 651 620 621 647 653 650 622 642 624 8 637 642 642 610 646 611 661648 651630 9 636 615 655 661620 617 631 651637 607 10 651 640 620 630 615 640 629 647 617 11 627 637 650 631 646 627 12 639 612 13 613 N = 110 107 Appendix XVII. The numbers of D. v ir id is adults responding to aqueous and acetone extracts of coastal and common Bermudagrass in the laboratory. COASTAL BERMUDAGRASS D. v ir id is TEST AQUEOUS ACETONE NO PREFERENCE 1 4 1 5 2 6 1 3 3 5 1 4 4 5 1 4 5 2 2 7 6 6 2 2 7 5 2 3 8 3 4 3 9 2 1 7 10 3 3 4 11 2 1 7 12 2 3 5 13 5 1 4 14 4 1 5 15 2 2 6 16 7 1 2 17 5 3 2 18 6 1 3 19 4 2 4 20 7 1 2 N = 20 108 Appendix XVII. continued COASTAL BERMUDAGRASS M. femurrubrum TEST AQUEOUS ACETONE NO PREFERENCE 1 4 3 2 5 " 2 3 3 3 4 2 1 5 2 4 6 4 2 7 5 4 8 3 2 9 5 1 10 6 2 11 5 2 12 5 1 13 6 2 14 4 2 15 4 4 16 3 2 17 3 2 18 5 1 19 3 1 20 5 1 N = 20 IU7 Appendix XVII. continued COMMON BERMUDAGRASS D. v ir id is TEST AQUEOUS ACETONE NO PREFERENCE 1 5 1 2 6 2 3 5 2 4 7 1 5 5 1 6 7 1 7 5 1 8 7 2 9 5 3 10 5 2 11 4 1 12 2 3 13 5 1 14 2 2 15 3 2 16 3 1 17 4 1 18 2 1 19 6 2 20 3 1 0'N)'JUiO\UiO'JM^iLnWNH-l>ts)-P'NUN5.P> N = 20 110 Appendix XVII. continued COMMON BERMUDAGRASS M. femurrubrum TEST AQUEOUS ACETONE NO PREFERENCE 1 5 2 2 4 2 3 6 3 4 4 2 5 5 1 6 6 0 7 5 2 8 4 4 9 7 1 10 4 2 11 1 4 12 3 3 13 5 2 14 3 1 15 4 2 16 4 1 17 4 2 18 4 0 19 6 4 20 4 2 N = 20 I l l Appendix XVII. continued AQUEOUS EXTRACT D. v irid is TEST COASTAL COMMON NO PREFERENCE 1 4 4 2 4 2 3 5 3 4 7 3 5 3 4 6 4 2 7 4 3 8 6 2 9 3 3 10 6 2 11 3 4 12 7 1 13 3 5 14 2 4 15 1 4 16 2 5 17 4 6 18 2 5 19 3 4 20 1 7 NUWOUUl.MONUro^lOUt-UONMO N = 20 112 Appendix XVII. continued AQUEOUS EXTRACT M. femurrubrum test coastal common no preference 1 . 3 4 3 2 2 5 3 3 2 3 5 4 0 4 6 5 4 0 6 6 5 3 2 7 2 3 5 8 2 4 4 9 1 4 5 10 3 3 4 11 4 3 3 12 4 1 5 13 5 2 3 14 4 4 2 15 5 2 3 16 2 3 5 17 3 4 3 18 3 2 5 19 6 2 4 20 2 4 4 N = 20 113 Appendix XVII. continued ACETONE EXTRACT D. v irid is TEST COASTAL COMMON NO PREFERENCE 1 2 1 7 2 1 1 8 3 1 0 9 4 2 2 6 5 1 0 9 6 1 1 8 7 3 1 6 8 1 2 7 9 1 2 7 10 2 0 6 11 1 4 5 12 1 1 8 13 0 1 9 14 2 1 7 15 0 0 10 16 1 1 8 17 2 1 7 18 0 1 9 19 1 1 8 20 1 0 9 N = 20 114 Appendix XVII. continued ACETONE EXTRACT M. femurrubrum TEST COMMON COASTAL NO PREFERENCE 1 2 1 2 1 1 3 2 0 4 2 2 5 1 1 6 1 0 7 2 2 8 0 0 9 2 1 10 2 1 11 1 2 12 2 1 13 0 1 14 2 3 15 2 1 16 1 1 17 2 2 18 1 1 19 3 1 ffiOOO'CO'JLnvOvjslvjNjHOMflOSO'tBCONi 20 1 2 7 N = 20 115 Appendix XVIII. Weekly population samples of Dj_ v ir id is and M. femurrubrnm from a common Bermudagrass fie ld in Homer, Louisiana, 1968. D. v irid is M. femurrubrum Replication 1 2 3 4 1 2 3 4 wk. /May 1 73 47 53 62 67 57 71 62 2 38 39 47 31 41 71 42 47 3 26 34 35 40 28 49 55 43 4 87 70 91 58 93 79 98 82 June 5 34 41 66 29 77 49 61 40 6 97 120 113 80 104 125 140 116 7 30 43 111 37 71 70 56 63 8 3 22 41 28 58 41 82 60 July 9 49 42 64 58 69 51 63 45 10 62 66 95 82 86 85 97 96 11 117 103 100 88 97 90 99 93 12 97 98 145 105 111 102 120 103 13 127 128 154 145 133 117 168 150 August 14 133 156 192 111 143 117 141 132 15 141 142 124 117 108 83 175 97 16 144 119 137 130 141 159 167 128 17 91 109 146 118 104 139 155 141 18 87 98 115 100 97 166 182 137 Sept. 19 41 40 57 67 87 76 91 79 20 3 31 20 21 30 19 35 21 100 sweeps per sample, approximately 220 square feet per sample. 116 Appendix XIX. Weekly population samples of v ir id is and M. femurrubrum from coastal Bermudagrass fie ld s in Homer, Louisiana, 1968. D. v ir id is M. femurrubrum Replication 1 2 3 4 1 2 3 4 wk. /May 1 4 3 7 5 5 4 6 3 2 3 3 4 3 4 5 5 4 3 2 3 4 ' 2 4 3 6 2 4 7 4 10 4 6 9 10 8 June 5 4 4 6 0 7 7 10 9 6 12 6 11 2 9 7 13 6 7 3 4 7 3 7 8 12 7 8 2 2 3 1 5 4 7 6 July 9 4 2 8 3 4 6 12 8 10 7 5 8 5 5 7 12 10 11 9 5 11 7 10 8 8 5 12 10 8 10 4 11 8 13 7 13 11 10 21 8 10 11 17 12 August 14 9 9 14 8 18 10 21 13 15 8 12 11 9 11 5 19 7 16 9 14 12 10 11 7 17 9 17 6 6 18 8 9 14 13 11 18 6 6 10 10 7 11 12 10 Sept. 19 4 3 6 2 12 12 15 10 20 3 1 4 3 12 6 11 2 100 sweeps per sample, approximately 220 square feet swept per sample. VITA Walter Carl Roddy was born on February 16, 1944, in Port Arthur, Texas. He attended school in the Port Arthur Independent School District and graduated from Thomas Jefferson High School in May, 1962. In September, 1962, he enrolled in Lamar State College of Tech nology (now Lamar University) and graduated in May, 1966, with a Bachelor of Science degree in Biology. He was employed as an entomologist trainee by the Jefferson County Mosquito Control Board from May until September, 1966. August 20, 1966, he married the former Jane Lukenbill and now has two sons, Andy and Sean. He entered Louisiana State University in September, 1966, as a graduate Fellow on a NDEA Title IV Fellowship and graduated with a Master of Science degree in Entomology in 1968. In 1968, M r. Roddy began work on the Doctor of Philosophy degree at Louisiana State University and he is presently a candidate for the Doctor of Philosophy degree in Entomology. Currently, he is employed as Instructor of Biology at Galveston College, Galveston, Texas. 117 EjAAininiAxiui> niMiis ivrjruin Candidate: Walter Carl Roddy Major Field: Entomology Title of Thesis: The ecological impact of common and coastal Bermudagrasses, Cynodon dactylon (L.) Pers., on populations of the grasshoppers Dichromorpha viridis (Scudder) and Melanoplus femurrubrum (DeG.) Approved: Major Professor and Chairman Dean of the Graduate School EXAMINING COMMITTEE: Date of Examination: July 27, 1972