30 June 1975
J. Med. Ent. Vol. 12, no. 2: 256-258
THE IMMATURE STAGES OF CULICOIDES BELKINI WIRTH & ARNAUD (DIPTERA: CERATOPOGONIDAE), WITH NOTES ON PUPAL TERMINOLOGY By D. S. Kettle and M. M. Els on1 Abstract: The 4th-stage larva and pupa of Culicoides belkini larva was held by the thorax while the subgenal Wirth & Arnaud are described from material collected by Dr band and mandibles were cut off. Then a 2nd cut E. J. Reye in Fiji. Comparison with other species will be made was made posterior to the pharynges, isolating a in a later paper.
METHODS
The chaetotaxy of 4th-instar larvae was studied in specimens bisected at the 1st abdominal segment and cleared in warm lactic acid for a few minutes, but not long enough to remove the eye pigment. Temporary mounts were made in lactic acid, enabling the larva to be rolled to the desired position for study. As the only material available had been preserved in alcohol, the larval thoracic pigment pattern was observed under dark field illumination and reflected light under a stereoscopic microscope. For examination, the pharynges were dissected out of the head in phenol-balsam (Wirth & Marston 1968) and mounted in the same medium. The 'Department of Entomology, University of Queensland, St. Lucia, Queensland .4067, Australia.
tube-like section of the head from which the pharynges were easily removed. Pupal exuviae were placed in saturated alcoholic phenol for about 24 hr and then transferred to the same phenol-balsam mounting medium as used for pharynges. The exuvia was dissected into 4 parts—head, operculum, thorax and abdomen— which were mounted separately. TERMINOLOGY
Terminology for larval chaetotaxy is based on Lawson (1951). In describing the epipharynx, the terminology of Kettle & Lawson (1952) has been used. Carter et al. (1921) were the first to describe the chaetotaxy of Culicoides pupae. They named the tubercles on the ventral surface simply "ventral tubercles" on the grounds that only posteromarginal tubercles were present. Mayer (1934), Lawson (1951), Linley & Kettle (1964) and Linley (1970) concurred. Jones (1961) and Jamnback (1965) used the more precise term "ventral posteromarginals." However, the shorter term causes no ambiguity and is to be preferred. Mayer (1934) numbered the abdominal tubercles beginning at the mid-ventral line. This was adopted by Jones (1961) and Jamnback (1965). Lawson (1951) used the reverse notation, numbering from the mid-dorsal line, a practice which has been followed in this paper. Both numbering systems are equally useful and neither causes confusion providing it is explicitly stated which system is being followed. Terminology used in this paper for pupal chaetotaxy is based on Carter et al. (1921) and Lawson (1951) with 1 exception. Carter et al. (1921) refer to the armature on the operculum as "squamose spines," Lawson (1951) as "spinules" and Linley (1970) as "teeth." We have designated them "thorns." DESCRIPTION LARVA:
Head (FIG. 1,2): Yellow, collar and subgenal band
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Culicoides belkini Wirth & Arnaud was described recently (Wirth & Arnaud 1969) from material collected in the Society Islands where the species is a pest of man. There is some doubt as to whether C. belkini occurred in French Polynesia before modern development of the islands or was introduced by modern transportation. It appears to be extending its range as a pest because Dr Reye informs us that C. belkini is a major nuisance on Guadacanal in the Solomon Islands. It is clearly a species on which much more research will be needed in the near future, and the accompanying descriptions of the immature stages are intended to facilitate such investigations. Our descriptions are based on material kindly made available by Dr E. J. Reye, who collected the new species on Fairway 6, Pacific Harbor Development, Deuba, Viti Levu, Fiji from an algal mud substrate in a dead sago swamp. We are currently preparing descriptions of immature stages of Australian Culicoides and will leave consideration of comparisons between C. belkini and other species until they are available.
1975
Kettle & Elson:
Culicoides belkini immature stages
257
darker. Length 199.4 ± 5.1 y., width 133.4 ± 4.5 y., breadth comb 2 the smallest, bearing about 8 long, thin, sharply pointed of subgenal band 95.4 ± 3.2 [z; head ratio 1.50 ± 0.27 (n =30). teeth; comb 3 with about 11 pointed teeth, variable in width Eyes of 2 separate elements, hind one larger. Setae and sensilla and length; comb 4, conical body bearing 16 sharp teeth of normal for Culicoides. Epipharynges (FIG. 3): Dorsal comb 32.4 ± variable width. Thoracic markings (FIG. 4): Neck—narrow band 1.7 y. wide (n = 5), 22 teeth, variable in width, 11 in each 1/2; of reddish brown pigment which may be joined posteriorly to
9*
lasm
dasm
( o
ad
y vm
FIG. 5-8. C. belkini, pupa: (5) lateral view of 4th abdominal segment; (6) dorsal thoracic tubercles; (7) head tubercles; (8) dorsal view of caudal segment; (all X200).
Downloaded from http://jme.oxfordjournals.org/ by guest on June 7, 2016
FIG. 1-4. C. belkini, 4thinstar larva: (1) dorsal view of head, x264; (2) right lateral view of head, x264; (3) ventral view of epipharynx, X648; (4) distribution of pigment in thoracic segments, X64.
258
J. Med. Ent.
Vol. 12, no. 2
to scales on distal part of horn up to dark tip. Two to 3 papillae laterally in basal 1/3, occasionally 1 in middle 1/3 and 7-10 terminal papillae. Abdomen: Segment IV (FIG. 5): Dorsal posteromarginals—i ridge bearing minute seta, ii and Hi curved ridge with no setae, iv ridge with short stiff seta and v tubercle with short blunt spur on outer side and long thin seta. Lateral posteromarginals—i, Hi tubercles with single, blunt spur, thin seta, ii similar tubercle but seta longer, stouter. Ventrals (ventral in nearest midventral line)—i tubercle with short blunt spur and short seta; ii rounded tubercle with long, thin seta; tit ridge with minute seta. Dorsal anterosubmarginals—i tubercle with short seta; ti tubercle with longer, thinner seta. Lateral anterosubmarginal tubercle with blunt spur and thin seta. Spicules— anteromedian band of spicules present dorsally and ventrally but absent laterally. Caudal segment (FIG. 8): Anterior band of spicules complete except for anteromedian gap dorsally. Spines pigmented at least on terminal 1/3, spicules present on inner, dorsal and ventral surfaces, slightly divergent from long axis of body, but variable.
LITERATURE CITED
Carter, H. F., I. Ingram & J. W. S. Macfie. 1921. Observations on the ceratopogonine midges of the Gold Coast, with descriptions of new species. Part II. Ann. Trop. Med. Parasitol. 14: 187-210. Jamnback, H . 1965. The Culicoides of New York State (Diptera: Ceratopogonidae). New York State Museum and
FIG. 9-10. C. belkini, pupa: (9) prothoracic horn; (10) operculum; (both x280). pigment in prothorax. Prothorax—even layer of pigment over segment, more strongly developed at hind border, usually connected posteromedially to pigment in mesothorax. Mesothorax— even pigment layer, deficient posterolaterally. Metathorax— pigment pattern as in metathorax but more strongly developed posteromedially and extending into 1st abdominal segment.
Science Service. Bull. No. 399. 154 p. Jones, R. H. 1961. Descriptions of pupae of thirteen North American species of Culicoides (Diptera: Ceratopogonidae). Ann. Ent. Soc. Amer. 54: 729-46.
Kettle, D. S. & J. W. H. Lawson. 1952. The early stages of British biting midges Culicoides Latreille (Diptera: Ceratopogonidae) and related genera. Bull. Ent. Res. 43: 421-67. Lawson, J. W. H. 1951. The anatomy and morphology of the early stages of Culicoides nubeculosus Meigen (Diptera: Ceratopogonidae = Heleidae). Tram. Roy. Ent. Soc. Land. 102: 511-74. Linley, J. R. 1970. The immature stages of Culicoides arboricola Root and Hoffman (Diptera: Ceratopogonidae). J. Med. Ent. 7: 717-21. Linley, J. R. & D. S. Kettle. 1964. A description of the
PUPA: Head (FIG. 7): Ventromedian setae distinct, paired, posterior one shorter; ventrolateral setae similar; anterodorsal tubercle rounded, with stout dagger-like seta and shorter, thinner one; anteromarginal tubercle with short bluntly pointed lateral larvae and pupae of Culicoides furens Poey and Culicoides spurs and a stout pointed seta (FIG. 10). Sensillum at the base hoffmani Fox (Diptera: Ceratopogonidae). Ann. Mag. Nat. of tubercle. Operculum (FIG. 10): Covered with stout, sharp Hist. 7: 129-49. thorns, particularly well developed on lateral margins, posterior Mayer, K. 1934. Die Metamorphose der Ceratopogonidae to lateral angles. Anterior to lateral angles and between anterior (Dipt.). Arch. Naturgesch. 3: 205-88. marginal tubercles, thorns smaller. Thorns absent from small Wirth, W. W. & P. H. Arnaud, Jr. 1969. Polynesian biting posterior zone. Thorax: Dorsals (FIG. 6): i and ii each with stout midges of the genus Culicoides (Diptera: Ceratopogonidae). tubercle and stiff, sharply pointed seta; Hi rounded tubercle and Pad/. Ins. 11: 507-20. very short seta; iv large tubercle bearing long thin seta; v a Wirth, W. W. & N. Marston. 1968. A method for mounting sensillum. Dorsomedian seta single; dorsolateral (FIG. 9) small insects on microscope slides in Canada balsam. prominent base with 2 unequal, thin setae, longer one terminal, Ann. Ent. Soc. Amer. 6 1 : 783-84. shorter one lateral. Prothoracic horn (FIG. 9): Pigmented throughout, but darker at base and tip. Basal 1/3 with folds, changing
Downloaded from http://jme.oxfordjournals.org/ by guest on June 7, 2016
Acknowledgments: This work has been supported financially by the Nuffield Foundation and the Australian Research Grants Committee. We wish to express our gratitude to both bodies. We are indebted to Dr E. J. Reye for kindly making available the material described in this paper.
J. Med. Ent. Vol. 12, no. 2: 256-258
THE IMMATURE STAGES OF CULICOIDES BELKINI WIRTH & ARNAUD (DIPTERA: CERATOPOGONIDAE), WITH NOTES ON PUPAL TERMINOLOGY By D. S. Kettle and M. M. Els on1 Abstract: The 4th-stage larva and pupa of Culicoides belkini larva was held by the thorax while the subgenal Wirth & Arnaud are described from material collected by Dr band and mandibles were cut off. Then a 2nd cut E. J. Reye in Fiji. Comparison with other species will be made was made posterior to the pharynges, isolating a in a later paper.
METHODS
The chaetotaxy of 4th-instar larvae was studied in specimens bisected at the 1st abdominal segment and cleared in warm lactic acid for a few minutes, but not long enough to remove the eye pigment. Temporary mounts were made in lactic acid, enabling the larva to be rolled to the desired position for study. As the only material available had been preserved in alcohol, the larval thoracic pigment pattern was observed under dark field illumination and reflected light under a stereoscopic microscope. For examination, the pharynges were dissected out of the head in phenol-balsam (Wirth & Marston 1968) and mounted in the same medium. The 'Department of Entomology, University of Queensland, St. Lucia, Queensland .4067, Australia.
tube-like section of the head from which the pharynges were easily removed. Pupal exuviae were placed in saturated alcoholic phenol for about 24 hr and then transferred to the same phenol-balsam mounting medium as used for pharynges. The exuvia was dissected into 4 parts—head, operculum, thorax and abdomen— which were mounted separately. TERMINOLOGY
Terminology for larval chaetotaxy is based on Lawson (1951). In describing the epipharynx, the terminology of Kettle & Lawson (1952) has been used. Carter et al. (1921) were the first to describe the chaetotaxy of Culicoides pupae. They named the tubercles on the ventral surface simply "ventral tubercles" on the grounds that only posteromarginal tubercles were present. Mayer (1934), Lawson (1951), Linley & Kettle (1964) and Linley (1970) concurred. Jones (1961) and Jamnback (1965) used the more precise term "ventral posteromarginals." However, the shorter term causes no ambiguity and is to be preferred. Mayer (1934) numbered the abdominal tubercles beginning at the mid-ventral line. This was adopted by Jones (1961) and Jamnback (1965). Lawson (1951) used the reverse notation, numbering from the mid-dorsal line, a practice which has been followed in this paper. Both numbering systems are equally useful and neither causes confusion providing it is explicitly stated which system is being followed. Terminology used in this paper for pupal chaetotaxy is based on Carter et al. (1921) and Lawson (1951) with 1 exception. Carter et al. (1921) refer to the armature on the operculum as "squamose spines," Lawson (1951) as "spinules" and Linley (1970) as "teeth." We have designated them "thorns." DESCRIPTION LARVA:
Head (FIG. 1,2): Yellow, collar and subgenal band
Downloaded from http://jme.oxfordjournals.org/ by guest on June 7, 2016
Culicoides belkini Wirth & Arnaud was described recently (Wirth & Arnaud 1969) from material collected in the Society Islands where the species is a pest of man. There is some doubt as to whether C. belkini occurred in French Polynesia before modern development of the islands or was introduced by modern transportation. It appears to be extending its range as a pest because Dr Reye informs us that C. belkini is a major nuisance on Guadacanal in the Solomon Islands. It is clearly a species on which much more research will be needed in the near future, and the accompanying descriptions of the immature stages are intended to facilitate such investigations. Our descriptions are based on material kindly made available by Dr E. J. Reye, who collected the new species on Fairway 6, Pacific Harbor Development, Deuba, Viti Levu, Fiji from an algal mud substrate in a dead sago swamp. We are currently preparing descriptions of immature stages of Australian Culicoides and will leave consideration of comparisons between C. belkini and other species until they are available.
1975
Kettle & Elson:
Culicoides belkini immature stages
257
darker. Length 199.4 ± 5.1 y., width 133.4 ± 4.5 y., breadth comb 2 the smallest, bearing about 8 long, thin, sharply pointed of subgenal band 95.4 ± 3.2 [z; head ratio 1.50 ± 0.27 (n =30). teeth; comb 3 with about 11 pointed teeth, variable in width Eyes of 2 separate elements, hind one larger. Setae and sensilla and length; comb 4, conical body bearing 16 sharp teeth of normal for Culicoides. Epipharynges (FIG. 3): Dorsal comb 32.4 ± variable width. Thoracic markings (FIG. 4): Neck—narrow band 1.7 y. wide (n = 5), 22 teeth, variable in width, 11 in each 1/2; of reddish brown pigment which may be joined posteriorly to
9*
lasm
dasm
( o
ad
y vm
FIG. 5-8. C. belkini, pupa: (5) lateral view of 4th abdominal segment; (6) dorsal thoracic tubercles; (7) head tubercles; (8) dorsal view of caudal segment; (all X200).
Downloaded from http://jme.oxfordjournals.org/ by guest on June 7, 2016
FIG. 1-4. C. belkini, 4thinstar larva: (1) dorsal view of head, x264; (2) right lateral view of head, x264; (3) ventral view of epipharynx, X648; (4) distribution of pigment in thoracic segments, X64.
258
J. Med. Ent.
Vol. 12, no. 2
to scales on distal part of horn up to dark tip. Two to 3 papillae laterally in basal 1/3, occasionally 1 in middle 1/3 and 7-10 terminal papillae. Abdomen: Segment IV (FIG. 5): Dorsal posteromarginals—i ridge bearing minute seta, ii and Hi curved ridge with no setae, iv ridge with short stiff seta and v tubercle with short blunt spur on outer side and long thin seta. Lateral posteromarginals—i, Hi tubercles with single, blunt spur, thin seta, ii similar tubercle but seta longer, stouter. Ventrals (ventral in nearest midventral line)—i tubercle with short blunt spur and short seta; ii rounded tubercle with long, thin seta; tit ridge with minute seta. Dorsal anterosubmarginals—i tubercle with short seta; ti tubercle with longer, thinner seta. Lateral anterosubmarginal tubercle with blunt spur and thin seta. Spicules— anteromedian band of spicules present dorsally and ventrally but absent laterally. Caudal segment (FIG. 8): Anterior band of spicules complete except for anteromedian gap dorsally. Spines pigmented at least on terminal 1/3, spicules present on inner, dorsal and ventral surfaces, slightly divergent from long axis of body, but variable.
LITERATURE CITED
Carter, H. F., I. Ingram & J. W. S. Macfie. 1921. Observations on the ceratopogonine midges of the Gold Coast, with descriptions of new species. Part II. Ann. Trop. Med. Parasitol. 14: 187-210. Jamnback, H . 1965. The Culicoides of New York State (Diptera: Ceratopogonidae). New York State Museum and
FIG. 9-10. C. belkini, pupa: (9) prothoracic horn; (10) operculum; (both x280). pigment in prothorax. Prothorax—even layer of pigment over segment, more strongly developed at hind border, usually connected posteromedially to pigment in mesothorax. Mesothorax— even pigment layer, deficient posterolaterally. Metathorax— pigment pattern as in metathorax but more strongly developed posteromedially and extending into 1st abdominal segment.
Science Service. Bull. No. 399. 154 p. Jones, R. H. 1961. Descriptions of pupae of thirteen North American species of Culicoides (Diptera: Ceratopogonidae). Ann. Ent. Soc. Amer. 54: 729-46.
Kettle, D. S. & J. W. H. Lawson. 1952. The early stages of British biting midges Culicoides Latreille (Diptera: Ceratopogonidae) and related genera. Bull. Ent. Res. 43: 421-67. Lawson, J. W. H. 1951. The anatomy and morphology of the early stages of Culicoides nubeculosus Meigen (Diptera: Ceratopogonidae = Heleidae). Tram. Roy. Ent. Soc. Land. 102: 511-74. Linley, J. R. 1970. The immature stages of Culicoides arboricola Root and Hoffman (Diptera: Ceratopogonidae). J. Med. Ent. 7: 717-21. Linley, J. R. & D. S. Kettle. 1964. A description of the
PUPA: Head (FIG. 7): Ventromedian setae distinct, paired, posterior one shorter; ventrolateral setae similar; anterodorsal tubercle rounded, with stout dagger-like seta and shorter, thinner one; anteromarginal tubercle with short bluntly pointed lateral larvae and pupae of Culicoides furens Poey and Culicoides spurs and a stout pointed seta (FIG. 10). Sensillum at the base hoffmani Fox (Diptera: Ceratopogonidae). Ann. Mag. Nat. of tubercle. Operculum (FIG. 10): Covered with stout, sharp Hist. 7: 129-49. thorns, particularly well developed on lateral margins, posterior Mayer, K. 1934. Die Metamorphose der Ceratopogonidae to lateral angles. Anterior to lateral angles and between anterior (Dipt.). Arch. Naturgesch. 3: 205-88. marginal tubercles, thorns smaller. Thorns absent from small Wirth, W. W. & P. H. Arnaud, Jr. 1969. Polynesian biting posterior zone. Thorax: Dorsals (FIG. 6): i and ii each with stout midges of the genus Culicoides (Diptera: Ceratopogonidae). tubercle and stiff, sharply pointed seta; Hi rounded tubercle and Pad/. Ins. 11: 507-20. very short seta; iv large tubercle bearing long thin seta; v a Wirth, W. W. & N. Marston. 1968. A method for mounting sensillum. Dorsomedian seta single; dorsolateral (FIG. 9) small insects on microscope slides in Canada balsam. prominent base with 2 unequal, thin setae, longer one terminal, Ann. Ent. Soc. Amer. 6 1 : 783-84. shorter one lateral. Prothoracic horn (FIG. 9): Pigmented throughout, but darker at base and tip. Basal 1/3 with folds, changing
Downloaded from http://jme.oxfordjournals.org/ by guest on June 7, 2016
Acknowledgments: This work has been supported financially by the Nuffield Foundation and the Australian Research Grants Committee. We wish to express our gratitude to both bodies. We are indebted to Dr E. J. Reye for kindly making available the material described in this paper.
