JOURNAL J.
MecL Entomol.
VoL 14,
DO.
OF MEDICAL
ENTOMOLOGY 24 December 1977
3: 379-386
PublUhed bimootbly by Department of Entomology, BUhop Mwcum, Hooolulu, Hawaii, U.S.A. Editorial committee: F. J. Radovsky and J. M. Tenorio, Co-editon, J. L. Greositt, Managil1ll Editor, A. R. Barr, G. F. Bennett, J. M. Brenoan, C. M. Clifford, R. H. Dadd, M. Daniel, D. P. Furman, T. D. C. Grace, G. P. Holland, H. Hoogsuul, N. Kumad., G. C. LaBrecque, F. S. Lukoochus, D. E. Sonemhine, A. Spielrnan, R. Traub, M. G. R. Varma, R. Zeled6n. Devoted to .11 brancheo of medical entomology from the world ltandpoint, including oy>tem&lieoof in,,",u and otber arthropod.! of public h~lth and Vf:tninary 3ignificancc.
...~'~~'---.=-~--"--~=~=='============================
MORPHOMETRIC VARIABILITY IN NATURAL AND LABORATORY POPULATIONS OF CULICOlDES VARIIPENNIS (DIPTERA: CERATOPOGONIDAE) By David A. Hensleighl
Culicoides variipennis (Coq.) is a bloodsucking fly which is distributed over much of North America. I t is probably the most economically important species of Culicoides in the United States due to its involvement in the epidemiology of several viral diseases, notably bluetongue disease (Luedke et al. 1967), a serious disease of sheep, cattle and ruminant wildlife, and at least 3 different arboviruses in California (Nelson & Scrivani 1972). In spite of the considerable economic importance of this species, rigorous analyses of biological variation using both laboratory and field populations have been lacking. Extensive variation in morphology, physiology and ecology has long been known to occur among natural populations of C. variipemzis (Wirth & Jones 1957, Rowley 1965, Atchley 1967, Jorgensen 1969). Wirth & Jones (1957) described 5 subspecies of C. variipennis which they felt represented the morphological and ecological variation in this species. Their taxa included C. variiPe,mis variipemzis, a large fly from nonsaline habitats of the eastern United States; C. v. sonorensis, a much smaller fly found in polluted habitats in the 'Department of Biological Sciences, Texas Tech University, Lubbock, Texas 79409, U.S.A. 'Present address: Department of Entomology, University of Wisconsin, Madison, Wisconsin 53706, U.S.A. Request reprints from the second author.
western United States; C. v. australis, a saline or alkaline water form from the western United States; C. v. albertensis from the saline and alkaline pools in the northern Great Plains; and C. v. occidentalis from alkaline pools in the western United States and Canada. More recent work on C. variipennis suggested that the original taxonomic and ecological conclusions of Wirth & Jones were inadequate. Atchley (1967) found forms identifiable as C. v. sonorensis and C. v. australis occurring simultaneously at several localities in eastern New Mexico, while at other habitats he found the total spectrum of morphological variation between these 2 types. Rowley ( 1965) reported similar results for C. v. sonorensis and C. v. occidentalis in the central Columbia River Basin of Washington. Jorgenson (1969), however, argued in favor of recognition of C. v. variiPennis and C. v. occidentalis as distinct taxa since he was able to distinguish the 2 forms in regions of sympatry. In spite of these incongruities in the literature, many ceratopogonid workers have persisted in using the trinomial names although evidence as to their validity has been lacking. Since the proper biological subgroupings in the C. variipennis complex are unclear and apparently quite complex, studies on many facets of the biology of this species have been impaired. High priority should therefore be given to the delineation of true biological subgroups within the C. variiPennis complex, if any exist, and to ascertaining their genetic and ecological status. This paper reports an analysis of the level of morphometric divergence in a number of geographically and ecologically continuous or microspatially separated populations in the southwestern United States. Further, we describe the extent of temporal variation in several populations. Results are also reported on laboratory studies for analyzing the effects of different temperatures during the larval stage on pupal and adult morphology.
Downloaded from http://jme.oxfordjournals.org/ by guest on December 11, 2015
Abstract: Natural popula tions of Culicoides vuriiPellllis (Coq.) vary greatly from one habitat to another even when these habitats are in close proximity. This distinctness of populations was noted when morphological variables were considered singly or when multivariate statistical techniques were employed. Similarly, pronounced temporal variation was revealed in each of 2 populations observed at different times. Subsamples of lan'ae from an inbred laboratory population reared at different temperatures showed diffcrenet's for every variable examined. Regrt'ssion analysis revt'aled a definite relationship between temperature and nearly every morphological variable examined. These results suggest that the present subspecific nomenclature for tht~ C. L'uriipellllis complex is perhaps invalid, and true biological subgroupings can be described only as the result of more refined genetic analyses.
and William R. Atchleyl,2
380
J. Med. Entomol. TABLE 1.
LOCALITY Howard Co., Missouri Lubbock, Texas Roswell, N.M. Bitter Lake, near Roswell, N.M. Loving, N.M. Truth or Consequences, N.M. Berrendo River, near Roswell, N.M.
Population locations, sample sizes and habitat descriptions.
POPULATION ANDLOCALITY CODE Booneslick Park (BSKOI) (1.8 km) Shields farm (SLD02) Texas Tech sewer (TXT06) (May 1972) (0 km-temporal) Texas Tech sewer (TXT28) (November 1972) Berrendo River (ROS09) (May 1972) (0 km-temporal) Berrendo River (ROSI8) (June 1973) Hondo River (ROSI2) (5.5 km) Bitter Lake (BITI3) Salt Lake (JAL21) (5.5 km) Pecos River (PEC22) Roadside pool (TRC25) (I km) Cuchillo Creek (CHL26) Site I-headwater (ROSI6) (1/2 km) Site 2 (ROSI7) (3.1 km)
(35,32) (25,36) (28,33) (36,36) (21,26) (35,34) (31,34) (35,33) (32,32)
slightly saline stream slightly saline stream alkaline pool salt pool clear, nonsaline stream stagnant pool shallow stream standing pool slow stream slightly saline stream slightly saline stream
(35,34)
Wing length (WINGL) Wing width (WINGW) Costa length (COSTL) Length of 3rd maxillary palp (3PALPL) Width of 3rd maxillary palp (3PALPW) Hind femur length (LEG) Length of distal antennomere (DAL) Width of distal antennomere (DA W) Head length (HEADL) Proboscis length (PROBL) Length of 13th antennomere (13AL) Paramere width (PARAW) Aedeagus length (AEDEL) Width of apicolateral process (API C) Telomere width at base (TELO) Spinosity of the aedeagus (SPINE) Length of pupal operculum (OPERL) Width of pupal operculum (OPERW) Length of pupal opercular AM bristle (AM) Length of pupal respiratory horn (HORN) Number of antennomeres with multiple sensory pits (MULPIT) Code for antennal sensoria pattern (SENS) Code for number of antennal sensoria (NUMPIT)
ecological conditions during the larval stage on the pupae and adults. Temporal morphometric variation was also examined at 2 different sites. The Lubbock, Texas population was sampled twice over a period of 7 months and the Roswell, New Mexico population was sampled twice over a 13-month period. The morphological variables employed in the analyses of natural populations are listed in TABLE 2. Typical taxonomic ratios were not used for reasons detailed by Atchley et al. (1976). For the studies with a laboratory population, the colony used is being maintained at the Arthropod-
TABLE 3.
I. 2. 3. 4. 5. 6. 7. 8. 9. 10. I I. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23.
Morphometric variables used In analyses of laboratory populations.
Wing length (WINGL) Wing width (WINGW) Costa length (COSTL) Length of first 8 antennomeres (1st 8) Length of last 5 antennomeres (LAST5) Length of antennomeres 9 + 10 (9 + 10) Length of antennomere 11 (II) Head length (HEADL) Proboscis length (PROBL) Length of 2nd maxillary palpal segment (2PALP) Length of 3rd maxillary palpal segment (3PALPL) Width of 3rd maxillary palpal segment (3PALPW) Length of 4th maxillary palpal segment (4PALP) Length of 5th maxillary palpal segment (5PALP) Number of mandibular teeth (MANTEE) Number of maxillary teeth (MAXTEE) Number of antennal sensory pits (ANTSEN) Number of multiple antennal sensory pits (MULSEN) Length of pupal respiratory horn (HORN) DI bristle length (DI) AM bristle length (AM) Operculum length (OPERL) Operculum width (OPERW)
Downloaded from http://jme.oxfordjournals.org/ by guest on December 11, 2015
22. 23.
sewer runoff slightly saline stream
(36,32)
Morphometric variables used in analyses of natural populations.
HABITAT salt spring hog-lot pool sewer runoff
(34,34) (34,29)
Site 4-terminus (ROSI9)
For the analysis of variation in natural populations, large samples of C. variipennis from several localities in Missouri, Texas and New Mexico were collected as pupae and reared to adults so that each pupal exuvia had an associated adult fly. TABLE 1 provides a list oflocalities with locality codes, sample sizes and a brief habitat description. In cases where microspatial variation is to be examined, the geographic distance between collecting sites is given in parentheses. These latter sites were selected so as to determine the morphometric effects of different
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. II. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.
SAMPLESIZE (d'd',n) (44,38) (17,22) (32,34)
Site 3 (ROSIB) (2.B km)
MATERIALS AND METHODS
TABLE 2.
Vol. 14, no. 4
1977
Hensleigh & Atchley: TABLE
4.
381
Culicoides variipennis morphometric variability
Analysis of variance and posterior identification results of ~~ and 66 for microspatial variation (MS) and temporal differences (T) between natural populations.
~~ LOCALITY Howard Co., Missouri Lubbock, Texas
PARAMETERSANOVA· MS T
10/10 8/14
Significant variables·· (1-10) (1-5,10,18,20)
Posterior identification··· ANOVA 1.7% 2.9%
borne Animal Diseases Research Laboratory, Agricultural Research Service, USDA, Denver, Colorado 80225. This colony (Jones & Foster, 1974: SONORA strain, OOO-line) was established from the "sonorensis" form; the colony has been maintained as a large population, without discrete ~enerations and without adding wild flies, for approximately 19 years without interruption. The subsamples are a by-product of other experiments being carried out by Dr Robert H. Jones. The samples were derived from a single group of eggs which were divided randomly into subgroups that were then reared simultaneously in larval medium at different temperatures. Temperatures of about 20°, 30° and 40°C were used, with an additional group reared under a variable temperature regime of 30° during the day and 20° at night. Except for different larval temperatures, all groups were reared in a similar manner. In the laboratory studies, only results for the females are reported for the sake of brevity. Very similar results were obtained for the males. Twentythree pupal and adult traits were measured (TABLE 3). As can be noted, a slightly different set of characters was used in the laboratory experiments. This discrepancy was due to the fact that the measurements of the laboratory and field-collected specimens were obtained at different times by different persons. In the analyses of the natural populations, the pupal and adult characters were analyzed by analysis of variance to determine if significant interpopulational (microspatial) and intrapopulational (temporal) morphometric divergence had occurred. Factor analysis was carried out on the pooled data sets and analysis of variance carried out on the factor scores to determine the extent of
10115 15115 11115 15/15
(1,3-5,8,11-13) (2-5,11,12,14,15,17, 18,20) (1-3,6,11,13-15,17,20) ( 1-6,11-15,17-20) (1-6,13,15,17,19,20) (1·-6,11-15,17-20)
Posterior identification 3.3% 1.5%
0% 1.5%
0% 13.6%
14115 (1-6,11-15,17,19,20) 35.5% significant at the P. ROS09 ROSI2
ROS09 ROSI2 3.22 BITl3 3.20 5.77 ROSI6 ROS17 4.79 ROSI8 4.07 ROSI9 6.39 5.56 JAL21 3.07 PEC22 TRC25 2.52 3.03 CHC26 ·Locality codes
3.10 3.20 3.93 3.93 3.52 5.27 6.45 2.59 3.56 3.69
BITl3
ROSI6
ROSI7
ROSI8
ROSI9
JAL21
3.71 3.89
5.32 3.30 5.56
5.06 3.10 5.30 1.05
4.20 2.57 4.40 1.60 1.26
6.89 4.52 6.12 2.59 2.50 3.03
4.99 6.35 4.54 6.69 6.63 5.77 8.07
5.60 5.11 4.29 6.28 5.11 3.59 3.19 3.18
3.83 4.16 4.44 7.48 4.85 6.06 5.41
1.39 2.40 6.34 2.71 4.18 3.35
are described in TABLE I.
2.69 5.75 2.13 3.60 2.36
7.79 4.07 5.97 4.71
5.93 4.83 4.73
1/2 relates to
PEC22 TRC25 CHL26 3.25 1.40 3.85 2.98 2.90 2.21 4.07 6.19 2.68 2.52
2.58 2.94 3.60 4.61 4.43 3.46 5.76 4.71 2.91 1.95
3.29 3.23 3.47 3.69 3.43 2.45 4.78 4.16 2.90 1.91
66
Downloaded from http://jme.oxfordjournals.org/ by guest on December 11, 2015
FIG. 2. Projection of sample means onto the first 2 discriminant functions for C. variiPennis 5j>5j>. Samples are linked by the lowest generalized distances (D values).
J. Med.
384 TABLE
]. 2. 3. 4. 5. 6. 9. 10. 17. 18.
Variable (WINGL) (WINGW) (COSTL) (3PALPL) (3PALPW) (LEG) (HEADL) (PROBL) (OPERL) (OPERW)
19.
(AM)
20.
(HORN)
Factor coefficients for ~'? and crcr.*
Factor I
Factor 2
-0.9465 -0.9307 -0.9784 -0.5238 -0.2997 -0.8986 -0.6182 -0.7400 -0.5457 -0.6962 0.1389 -0.4214
0.2231 0.2275 0.1440 0.68]9 0.5025 0.2843 0.4642 0.4962 0.4535 0.5202 0.5155 0.7379
7.47 62.24
Variable 1. 2. 3. 4. 5. 6. 11. 12. 13. 14. 15. ]7. 18. 19. 20.
(WINGL) (WINGW) (COSTL) (3PALPL) (3PALPW) (LEG) (13AL) (PARAW) (AEDEL) (API C) (TELO) (OPERL) (OPERW) (AM) (HORN)
1.00 8.34
Factor I
Factor 2
0.9546 0.9347 0.9639 0.7228 0.5241 0.9517 0.7912 0.7182 0.5974 0.6116 0.6861 0.7055 0.8136 -0.1061 0.5435 8.52 56.78
0.1345 -0.0275 0.0484 0.3676 -0.2571 0.1258 0.2245 0.0772 0.0099 0.2117 -0.0605 0.3086 0.2719 0.5873 0.6369
0.97 6.49
*Character codes are explained in TABLE 2.
Factor scores were computed for each individual, which gave the position of that individual in bivariate space where the 2 dimensions were the previously described factors. Using the factors scores as variables, the previously described analyses were repeated. TABLE 8 gives the results of the analyses of variance and posterior identification procedures for the factor scores. Note that for all comparisons, except for the Berrendo River males, significant divergence among means was noted on both factors. The posterior identification procedures were fairly efficient but there was, In general, more misidentification based on the factor scores than was seen with the raw data.
Laboratory populations.
9 gives the results of the analyses of variance for the 23 adult and pupal characters In the females. All variables were TABLE 8.
TABLE
Analysis of variance and posterior identification results for factor scores.
LOCALITY
Howard Co., Missouri Lubbock, Texas (temporal) Bitter Lake, N.M. Roswell, N.M. (temporal) Loving, N.M. Truth or Consequences, N.M. Berrendo River, N.M.
ANOVA
2/2
Posterior identification
4.4%
erer Posterior identifiANOV A cation
2/2
11%
2/2
7.2%
2/2
7.5%
2/2 2/2
4.9% 0%
2/2
4.3%
2/2
0%
2/2
16.2%
2/2
20%
2/2
61.3%
1/2
49.6%
significant at P
MecL Entomol.
VoL 14,
DO.
OF MEDICAL
ENTOMOLOGY 24 December 1977
3: 379-386
PublUhed bimootbly by Department of Entomology, BUhop Mwcum, Hooolulu, Hawaii, U.S.A. Editorial committee: F. J. Radovsky and J. M. Tenorio, Co-editon, J. L. Greositt, Managil1ll Editor, A. R. Barr, G. F. Bennett, J. M. Brenoan, C. M. Clifford, R. H. Dadd, M. Daniel, D. P. Furman, T. D. C. Grace, G. P. Holland, H. Hoogsuul, N. Kumad., G. C. LaBrecque, F. S. Lukoochus, D. E. Sonemhine, A. Spielrnan, R. Traub, M. G. R. Varma, R. Zeled6n. Devoted to .11 brancheo of medical entomology from the world ltandpoint, including oy>tem&lieoof in,,",u and otber arthropod.! of public h~lth and Vf:tninary 3ignificancc.
...~'~~'---.=-~--"--~=~=='============================
MORPHOMETRIC VARIABILITY IN NATURAL AND LABORATORY POPULATIONS OF CULICOlDES VARIIPENNIS (DIPTERA: CERATOPOGONIDAE) By David A. Hensleighl
Culicoides variipennis (Coq.) is a bloodsucking fly which is distributed over much of North America. I t is probably the most economically important species of Culicoides in the United States due to its involvement in the epidemiology of several viral diseases, notably bluetongue disease (Luedke et al. 1967), a serious disease of sheep, cattle and ruminant wildlife, and at least 3 different arboviruses in California (Nelson & Scrivani 1972). In spite of the considerable economic importance of this species, rigorous analyses of biological variation using both laboratory and field populations have been lacking. Extensive variation in morphology, physiology and ecology has long been known to occur among natural populations of C. variipemzis (Wirth & Jones 1957, Rowley 1965, Atchley 1967, Jorgensen 1969). Wirth & Jones (1957) described 5 subspecies of C. variipennis which they felt represented the morphological and ecological variation in this species. Their taxa included C. variiPe,mis variipemzis, a large fly from nonsaline habitats of the eastern United States; C. v. sonorensis, a much smaller fly found in polluted habitats in the 'Department of Biological Sciences, Texas Tech University, Lubbock, Texas 79409, U.S.A. 'Present address: Department of Entomology, University of Wisconsin, Madison, Wisconsin 53706, U.S.A. Request reprints from the second author.
western United States; C. v. australis, a saline or alkaline water form from the western United States; C. v. albertensis from the saline and alkaline pools in the northern Great Plains; and C. v. occidentalis from alkaline pools in the western United States and Canada. More recent work on C. variipennis suggested that the original taxonomic and ecological conclusions of Wirth & Jones were inadequate. Atchley (1967) found forms identifiable as C. v. sonorensis and C. v. australis occurring simultaneously at several localities in eastern New Mexico, while at other habitats he found the total spectrum of morphological variation between these 2 types. Rowley ( 1965) reported similar results for C. v. sonorensis and C. v. occidentalis in the central Columbia River Basin of Washington. Jorgenson (1969), however, argued in favor of recognition of C. v. variiPennis and C. v. occidentalis as distinct taxa since he was able to distinguish the 2 forms in regions of sympatry. In spite of these incongruities in the literature, many ceratopogonid workers have persisted in using the trinomial names although evidence as to their validity has been lacking. Since the proper biological subgroupings in the C. variipennis complex are unclear and apparently quite complex, studies on many facets of the biology of this species have been impaired. High priority should therefore be given to the delineation of true biological subgroups within the C. variiPennis complex, if any exist, and to ascertaining their genetic and ecological status. This paper reports an analysis of the level of morphometric divergence in a number of geographically and ecologically continuous or microspatially separated populations in the southwestern United States. Further, we describe the extent of temporal variation in several populations. Results are also reported on laboratory studies for analyzing the effects of different temperatures during the larval stage on pupal and adult morphology.
Downloaded from http://jme.oxfordjournals.org/ by guest on December 11, 2015
Abstract: Natural popula tions of Culicoides vuriiPellllis (Coq.) vary greatly from one habitat to another even when these habitats are in close proximity. This distinctness of populations was noted when morphological variables were considered singly or when multivariate statistical techniques were employed. Similarly, pronounced temporal variation was revealed in each of 2 populations observed at different times. Subsamples of lan'ae from an inbred laboratory population reared at different temperatures showed diffcrenet's for every variable examined. Regrt'ssion analysis revt'aled a definite relationship between temperature and nearly every morphological variable examined. These results suggest that the present subspecific nomenclature for tht~ C. L'uriipellllis complex is perhaps invalid, and true biological subgroupings can be described only as the result of more refined genetic analyses.
and William R. Atchleyl,2
380
J. Med. Entomol. TABLE 1.
LOCALITY Howard Co., Missouri Lubbock, Texas Roswell, N.M. Bitter Lake, near Roswell, N.M. Loving, N.M. Truth or Consequences, N.M. Berrendo River, near Roswell, N.M.
Population locations, sample sizes and habitat descriptions.
POPULATION ANDLOCALITY CODE Booneslick Park (BSKOI) (1.8 km) Shields farm (SLD02) Texas Tech sewer (TXT06) (May 1972) (0 km-temporal) Texas Tech sewer (TXT28) (November 1972) Berrendo River (ROS09) (May 1972) (0 km-temporal) Berrendo River (ROSI8) (June 1973) Hondo River (ROSI2) (5.5 km) Bitter Lake (BITI3) Salt Lake (JAL21) (5.5 km) Pecos River (PEC22) Roadside pool (TRC25) (I km) Cuchillo Creek (CHL26) Site I-headwater (ROSI6) (1/2 km) Site 2 (ROSI7) (3.1 km)
(35,32) (25,36) (28,33) (36,36) (21,26) (35,34) (31,34) (35,33) (32,32)
slightly saline stream slightly saline stream alkaline pool salt pool clear, nonsaline stream stagnant pool shallow stream standing pool slow stream slightly saline stream slightly saline stream
(35,34)
Wing length (WINGL) Wing width (WINGW) Costa length (COSTL) Length of 3rd maxillary palp (3PALPL) Width of 3rd maxillary palp (3PALPW) Hind femur length (LEG) Length of distal antennomere (DAL) Width of distal antennomere (DA W) Head length (HEADL) Proboscis length (PROBL) Length of 13th antennomere (13AL) Paramere width (PARAW) Aedeagus length (AEDEL) Width of apicolateral process (API C) Telomere width at base (TELO) Spinosity of the aedeagus (SPINE) Length of pupal operculum (OPERL) Width of pupal operculum (OPERW) Length of pupal opercular AM bristle (AM) Length of pupal respiratory horn (HORN) Number of antennomeres with multiple sensory pits (MULPIT) Code for antennal sensoria pattern (SENS) Code for number of antennal sensoria (NUMPIT)
ecological conditions during the larval stage on the pupae and adults. Temporal morphometric variation was also examined at 2 different sites. The Lubbock, Texas population was sampled twice over a period of 7 months and the Roswell, New Mexico population was sampled twice over a 13-month period. The morphological variables employed in the analyses of natural populations are listed in TABLE 2. Typical taxonomic ratios were not used for reasons detailed by Atchley et al. (1976). For the studies with a laboratory population, the colony used is being maintained at the Arthropod-
TABLE 3.
I. 2. 3. 4. 5. 6. 7. 8. 9. 10. I I. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23.
Morphometric variables used In analyses of laboratory populations.
Wing length (WINGL) Wing width (WINGW) Costa length (COSTL) Length of first 8 antennomeres (1st 8) Length of last 5 antennomeres (LAST5) Length of antennomeres 9 + 10 (9 + 10) Length of antennomere 11 (II) Head length (HEADL) Proboscis length (PROBL) Length of 2nd maxillary palpal segment (2PALP) Length of 3rd maxillary palpal segment (3PALPL) Width of 3rd maxillary palpal segment (3PALPW) Length of 4th maxillary palpal segment (4PALP) Length of 5th maxillary palpal segment (5PALP) Number of mandibular teeth (MANTEE) Number of maxillary teeth (MAXTEE) Number of antennal sensory pits (ANTSEN) Number of multiple antennal sensory pits (MULSEN) Length of pupal respiratory horn (HORN) DI bristle length (DI) AM bristle length (AM) Operculum length (OPERL) Operculum width (OPERW)
Downloaded from http://jme.oxfordjournals.org/ by guest on December 11, 2015
22. 23.
sewer runoff slightly saline stream
(36,32)
Morphometric variables used in analyses of natural populations.
HABITAT salt spring hog-lot pool sewer runoff
(34,34) (34,29)
Site 4-terminus (ROSI9)
For the analysis of variation in natural populations, large samples of C. variipennis from several localities in Missouri, Texas and New Mexico were collected as pupae and reared to adults so that each pupal exuvia had an associated adult fly. TABLE 1 provides a list oflocalities with locality codes, sample sizes and a brief habitat description. In cases where microspatial variation is to be examined, the geographic distance between collecting sites is given in parentheses. These latter sites were selected so as to determine the morphometric effects of different
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. II. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.
SAMPLESIZE (d'd',n) (44,38) (17,22) (32,34)
Site 3 (ROSIB) (2.B km)
MATERIALS AND METHODS
TABLE 2.
Vol. 14, no. 4
1977
Hensleigh & Atchley: TABLE
4.
381
Culicoides variipennis morphometric variability
Analysis of variance and posterior identification results of ~~ and 66 for microspatial variation (MS) and temporal differences (T) between natural populations.
~~ LOCALITY Howard Co., Missouri Lubbock, Texas
PARAMETERSANOVA· MS T
10/10 8/14
Significant variables·· (1-10) (1-5,10,18,20)
Posterior identification··· ANOVA 1.7% 2.9%
borne Animal Diseases Research Laboratory, Agricultural Research Service, USDA, Denver, Colorado 80225. This colony (Jones & Foster, 1974: SONORA strain, OOO-line) was established from the "sonorensis" form; the colony has been maintained as a large population, without discrete ~enerations and without adding wild flies, for approximately 19 years without interruption. The subsamples are a by-product of other experiments being carried out by Dr Robert H. Jones. The samples were derived from a single group of eggs which were divided randomly into subgroups that were then reared simultaneously in larval medium at different temperatures. Temperatures of about 20°, 30° and 40°C were used, with an additional group reared under a variable temperature regime of 30° during the day and 20° at night. Except for different larval temperatures, all groups were reared in a similar manner. In the laboratory studies, only results for the females are reported for the sake of brevity. Very similar results were obtained for the males. Twentythree pupal and adult traits were measured (TABLE 3). As can be noted, a slightly different set of characters was used in the laboratory experiments. This discrepancy was due to the fact that the measurements of the laboratory and field-collected specimens were obtained at different times by different persons. In the analyses of the natural populations, the pupal and adult characters were analyzed by analysis of variance to determine if significant interpopulational (microspatial) and intrapopulational (temporal) morphometric divergence had occurred. Factor analysis was carried out on the pooled data sets and analysis of variance carried out on the factor scores to determine the extent of
10115 15115 11115 15/15
(1,3-5,8,11-13) (2-5,11,12,14,15,17, 18,20) (1-3,6,11,13-15,17,20) ( 1-6,11-15,17-20) (1-6,13,15,17,19,20) (1·-6,11-15,17-20)
Posterior identification 3.3% 1.5%
0% 1.5%
0% 13.6%
14115 (1-6,11-15,17,19,20) 35.5% significant at the P. ROS09 ROSI2
ROS09 ROSI2 3.22 BITl3 3.20 5.77 ROSI6 ROS17 4.79 ROSI8 4.07 ROSI9 6.39 5.56 JAL21 3.07 PEC22 TRC25 2.52 3.03 CHC26 ·Locality codes
3.10 3.20 3.93 3.93 3.52 5.27 6.45 2.59 3.56 3.69
BITl3
ROSI6
ROSI7
ROSI8
ROSI9
JAL21
3.71 3.89
5.32 3.30 5.56
5.06 3.10 5.30 1.05
4.20 2.57 4.40 1.60 1.26
6.89 4.52 6.12 2.59 2.50 3.03
4.99 6.35 4.54 6.69 6.63 5.77 8.07
5.60 5.11 4.29 6.28 5.11 3.59 3.19 3.18
3.83 4.16 4.44 7.48 4.85 6.06 5.41
1.39 2.40 6.34 2.71 4.18 3.35
are described in TABLE I.
2.69 5.75 2.13 3.60 2.36
7.79 4.07 5.97 4.71
5.93 4.83 4.73
1/2 relates to
PEC22 TRC25 CHL26 3.25 1.40 3.85 2.98 2.90 2.21 4.07 6.19 2.68 2.52
2.58 2.94 3.60 4.61 4.43 3.46 5.76 4.71 2.91 1.95
3.29 3.23 3.47 3.69 3.43 2.45 4.78 4.16 2.90 1.91
66
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FIG. 2. Projection of sample means onto the first 2 discriminant functions for C. variiPennis 5j>5j>. Samples are linked by the lowest generalized distances (D values).
J. Med.
384 TABLE
]. 2. 3. 4. 5. 6. 9. 10. 17. 18.
Variable (WINGL) (WINGW) (COSTL) (3PALPL) (3PALPW) (LEG) (HEADL) (PROBL) (OPERL) (OPERW)
19.
(AM)
20.
(HORN)
Factor coefficients for ~'? and crcr.*
Factor I
Factor 2
-0.9465 -0.9307 -0.9784 -0.5238 -0.2997 -0.8986 -0.6182 -0.7400 -0.5457 -0.6962 0.1389 -0.4214
0.2231 0.2275 0.1440 0.68]9 0.5025 0.2843 0.4642 0.4962 0.4535 0.5202 0.5155 0.7379
7.47 62.24
Variable 1. 2. 3. 4. 5. 6. 11. 12. 13. 14. 15. ]7. 18. 19. 20.
(WINGL) (WINGW) (COSTL) (3PALPL) (3PALPW) (LEG) (13AL) (PARAW) (AEDEL) (API C) (TELO) (OPERL) (OPERW) (AM) (HORN)
1.00 8.34
Factor I
Factor 2
0.9546 0.9347 0.9639 0.7228 0.5241 0.9517 0.7912 0.7182 0.5974 0.6116 0.6861 0.7055 0.8136 -0.1061 0.5435 8.52 56.78
0.1345 -0.0275 0.0484 0.3676 -0.2571 0.1258 0.2245 0.0772 0.0099 0.2117 -0.0605 0.3086 0.2719 0.5873 0.6369
0.97 6.49
*Character codes are explained in TABLE 2.
Factor scores were computed for each individual, which gave the position of that individual in bivariate space where the 2 dimensions were the previously described factors. Using the factors scores as variables, the previously described analyses were repeated. TABLE 8 gives the results of the analyses of variance and posterior identification procedures for the factor scores. Note that for all comparisons, except for the Berrendo River males, significant divergence among means was noted on both factors. The posterior identification procedures were fairly efficient but there was, In general, more misidentification based on the factor scores than was seen with the raw data.
Laboratory populations.
9 gives the results of the analyses of variance for the 23 adult and pupal characters In the females. All variables were TABLE 8.
TABLE
Analysis of variance and posterior identification results for factor scores.
LOCALITY
Howard Co., Missouri Lubbock, Texas (temporal) Bitter Lake, N.M. Roswell, N.M. (temporal) Loving, N.M. Truth or Consequences, N.M. Berrendo River, N.M.
ANOVA
2/2
Posterior identification
4.4%
erer Posterior identifiANOV A cation
2/2
11%
2/2
7.2%
2/2
7.5%
2/2 2/2
4.9% 0%
2/2
4.3%
2/2
0%
2/2
16.2%
2/2
20%
2/2
61.3%
1/2
49.6%
significant at P
