J. Med. Ent. Vol. 12, no. 2: 263-264
30 June 1975
A NEW TECHNIQUE FOR REARING INDIVIDUAL CULICOIDES LARVAE (DIPTERA: CERATOPOGONIDAE)
Downloaded from http://jme.oxfordjournals.org/ by guest on June 5, 2016
One major difficulty in assigning larval Culicoides to Industries Pty. Ltd., Brisbane). Subcultures are established every 6-8 weeks and quickly teem with nemspecies, which are defined on the basis of adult features, atodes, which feed on microorganisms growing on the has been the absence of a method of rearing individual porridge. larvae. This has been overcome, in part, by describing In the petri dish, the nematodes burrow through the only larvae collected from habitats known by other means to contain only 1 species of Culicoides, e.g., C. furens, C.agar, disturbing the surface and facilitating the entry of melleus (Wirth, 1952, Fla. Ent. 35: 91-100); C. furens, C. Culicoides larvae. Additionally, the surface of the agar may hoffmani (Linley & Kettle, 1964, Ann. Mag. Nat. Hist. be cut to assist larval entry. Except when being examined, 7: 129-49); C. arboricola (Linley, 1970, J. Med. Ent. 7: the petri dishes are maintained in the dark in a constant temperature room at 27 °C. Pupation takes place on or 717-21). Alternatively, larvae removed from field matein the agar, after which the pupae appear to move very rial have been grouped accordingly to certain criteria, little until immediately before emergence. Consequently, such as head size and color, thoracic pigmentation and the larval exuvia can usually be found below the pupa, pattern, and returned to small amounts of source material for rearing. The latter may already contain Culicoides enabling the association of the larval and pupal exuviae larvae, thus complicating identification. However, this with a particular adult. This method is suitable for individual or grouped larvae. procedure was used successfully to identify 28 species of British Culicoides (Kettle & Lawson, 1952, Bull. Ent. Res. 43: 421-67). Sterilizing the rearing material before adding Culicoides larvae was ineffective, presumably because it killed all organisms on which the larvae might be feeding and encouraged molds. Kettle & Lawson (1952, loc. cit., p. 432) defined 2 basic types of Culicoides larvae: (a) those, including most members of the genus, which have light pharynges suited to sucking and sieving; and (b) members of the nubeculosus group which have massive pharynges adapted for grinding and crushing. Methods are available for the mass colonization of the nubeculosus group (Jones, 1957, J. Econ. Ent. 50: 107-08; 1964, Bull. Wld Hlth Organ. 31: 57172). Some species in the 1st category have also been reared on media high in organic content, similar to those used for the nubeculosus group (Glukhova, 1967, Parazitologiya, Leningr. 1: 171-75; Nevill, 1969, Onderstepoort J. Vet. Res. 36: 265-84), and others have been reared on a sandy substrate to which small nematodes (Anguillula silusiae) have been added (Linley, 1968, Ann. Ent. Soc. Amer. 61: 1486-90; 1969, Ann. Ent. Soc. Amer. 62: 702-11; 1970, Ann. Ent. Soc. Amer. 63: 1016-19). Recently, Sun (1974, J. Med. Ent. 11: 71-73) described a technique for rearing C. arakawae and C. schulzei in an aquatic medium containing yeast and blood agar base cake. We have combined and slightly modified the methods of Sun and Linley to produce a highly successful technique. Ordinary commercial agar (Sanitarium Health Store) is dissolved in distilled water (1 g agar/100 ml water) on a boiling watei bath. Enough hot agar solution to give a layer 5 mm deep is added to each petri dish and the lid immediately replaced. No nutrients or antibiotics are added to the agar solution. When it is cool, small nematodes (species not determined) are added. As their number declines with time, more are added weekly. This nematode has been cultured for about 15 years in the Parasitology Department, University of Queensland on porridge made from "Cerevite" (a mixture of rye, oats, barley, corn and wheat marketed by Queensland Cereal FIG. 1. Larva of C. brevitarsis feeding on a nematode.
264
J. Med. Ent.
Vol. 12, no. 2
Downloaded from http://jme.oxfordjournals.org/ by guest on June 5, 2016
Larvae of C. marksi and C. brevitarsis have been observedreturned to the natural substrate; (2) pupal and larval feeding on living nematodes which are often as long as exuviae are obtained in excellent condition for study, themselves, but narrower (FIG. 1), and on mites which had being completely free from surface contamination; (3) invaded the culture. This extends an observation of individual larvae can be related to particular pupae and Kwan & Morrison (1973, Mosquito News 33: 248) of adults; (4) it has proved suitable for dung-breeding C. C. sanguisuga larvae feeding on dead nematodes and mites. brevitarsis, freshwater C. marksi, brackish water C. marThe nematode/agar technique has proved successful for moratus, sand-dwelling C. molestus and an unnamed treehole species; and (5) molds are no problem, as they appear 8 species of Culicoides: C. austropalpalis, C. brevitarsis, C. only in old, discarded cultures. marksi, C. marmoratus, C. molestus, C. narrabeenensis, C. victoriae and C. undescribed sp. Three other ceratopoNo attempt has yet been made to rear newly emerged gonids, Paradasyhelea minuta, Stilobezzia pictipes and an larvae, but 3rd-instar larvae have been successfully reared unidentified species of Bezzia (Bezzia), were also suc- to adults. The production of adults from 4th-instar cessfully reared employing this method. It is possible larvae ranged from 50% to 100%, losses occurring when that some of these species did not feed on the nematodes, larvae failed to penetrate the agar, when larvae climbed but on microorganisms introduced either with the nem- onto the petri dish and desiccated, or from pupal death. atodes or with the Culicoides larvae. Against this pos- Success with C. brevitarsis was particularly encouraging, as sibility is the fact that microorganisms were not apparent its larvae do not swim in the normal energetic ceratoin the agar when it was examined under 25 x magnifica- pogonid fashion and do not pupate successfully in watei. tion and the plates remained clear and developed molds Since this note was submittee for publication, 2 species, only after being discaided. C. brevitarsis and C. austropalpalis, have been reared from The advantages of the new technique are as follows: egg to adult by the technique described.—D. S. Kettle, (1) the current stage of larval development is known at C. H. WUd and M. M. Elson, Department of Entoall times. Time is not wasted in looking after dead mology, University of Queensland, St. Lucia, Queenslarvae as not infrequently happens when larvae are land 4067, Australia.
30 June 1975
A NEW TECHNIQUE FOR REARING INDIVIDUAL CULICOIDES LARVAE (DIPTERA: CERATOPOGONIDAE)
Downloaded from http://jme.oxfordjournals.org/ by guest on June 5, 2016
One major difficulty in assigning larval Culicoides to Industries Pty. Ltd., Brisbane). Subcultures are established every 6-8 weeks and quickly teem with nemspecies, which are defined on the basis of adult features, atodes, which feed on microorganisms growing on the has been the absence of a method of rearing individual porridge. larvae. This has been overcome, in part, by describing In the petri dish, the nematodes burrow through the only larvae collected from habitats known by other means to contain only 1 species of Culicoides, e.g., C. furens, C.agar, disturbing the surface and facilitating the entry of melleus (Wirth, 1952, Fla. Ent. 35: 91-100); C. furens, C. Culicoides larvae. Additionally, the surface of the agar may hoffmani (Linley & Kettle, 1964, Ann. Mag. Nat. Hist. be cut to assist larval entry. Except when being examined, 7: 129-49); C. arboricola (Linley, 1970, J. Med. Ent. 7: the petri dishes are maintained in the dark in a constant temperature room at 27 °C. Pupation takes place on or 717-21). Alternatively, larvae removed from field matein the agar, after which the pupae appear to move very rial have been grouped accordingly to certain criteria, little until immediately before emergence. Consequently, such as head size and color, thoracic pigmentation and the larval exuvia can usually be found below the pupa, pattern, and returned to small amounts of source material for rearing. The latter may already contain Culicoides enabling the association of the larval and pupal exuviae larvae, thus complicating identification. However, this with a particular adult. This method is suitable for individual or grouped larvae. procedure was used successfully to identify 28 species of British Culicoides (Kettle & Lawson, 1952, Bull. Ent. Res. 43: 421-67). Sterilizing the rearing material before adding Culicoides larvae was ineffective, presumably because it killed all organisms on which the larvae might be feeding and encouraged molds. Kettle & Lawson (1952, loc. cit., p. 432) defined 2 basic types of Culicoides larvae: (a) those, including most members of the genus, which have light pharynges suited to sucking and sieving; and (b) members of the nubeculosus group which have massive pharynges adapted for grinding and crushing. Methods are available for the mass colonization of the nubeculosus group (Jones, 1957, J. Econ. Ent. 50: 107-08; 1964, Bull. Wld Hlth Organ. 31: 57172). Some species in the 1st category have also been reared on media high in organic content, similar to those used for the nubeculosus group (Glukhova, 1967, Parazitologiya, Leningr. 1: 171-75; Nevill, 1969, Onderstepoort J. Vet. Res. 36: 265-84), and others have been reared on a sandy substrate to which small nematodes (Anguillula silusiae) have been added (Linley, 1968, Ann. Ent. Soc. Amer. 61: 1486-90; 1969, Ann. Ent. Soc. Amer. 62: 702-11; 1970, Ann. Ent. Soc. Amer. 63: 1016-19). Recently, Sun (1974, J. Med. Ent. 11: 71-73) described a technique for rearing C. arakawae and C. schulzei in an aquatic medium containing yeast and blood agar base cake. We have combined and slightly modified the methods of Sun and Linley to produce a highly successful technique. Ordinary commercial agar (Sanitarium Health Store) is dissolved in distilled water (1 g agar/100 ml water) on a boiling watei bath. Enough hot agar solution to give a layer 5 mm deep is added to each petri dish and the lid immediately replaced. No nutrients or antibiotics are added to the agar solution. When it is cool, small nematodes (species not determined) are added. As their number declines with time, more are added weekly. This nematode has been cultured for about 15 years in the Parasitology Department, University of Queensland on porridge made from "Cerevite" (a mixture of rye, oats, barley, corn and wheat marketed by Queensland Cereal FIG. 1. Larva of C. brevitarsis feeding on a nematode.
264
J. Med. Ent.
Vol. 12, no. 2
Downloaded from http://jme.oxfordjournals.org/ by guest on June 5, 2016
Larvae of C. marksi and C. brevitarsis have been observedreturned to the natural substrate; (2) pupal and larval feeding on living nematodes which are often as long as exuviae are obtained in excellent condition for study, themselves, but narrower (FIG. 1), and on mites which had being completely free from surface contamination; (3) invaded the culture. This extends an observation of individual larvae can be related to particular pupae and Kwan & Morrison (1973, Mosquito News 33: 248) of adults; (4) it has proved suitable for dung-breeding C. C. sanguisuga larvae feeding on dead nematodes and mites. brevitarsis, freshwater C. marksi, brackish water C. marThe nematode/agar technique has proved successful for moratus, sand-dwelling C. molestus and an unnamed treehole species; and (5) molds are no problem, as they appear 8 species of Culicoides: C. austropalpalis, C. brevitarsis, C. only in old, discarded cultures. marksi, C. marmoratus, C. molestus, C. narrabeenensis, C. victoriae and C. undescribed sp. Three other ceratopoNo attempt has yet been made to rear newly emerged gonids, Paradasyhelea minuta, Stilobezzia pictipes and an larvae, but 3rd-instar larvae have been successfully reared unidentified species of Bezzia (Bezzia), were also suc- to adults. The production of adults from 4th-instar cessfully reared employing this method. It is possible larvae ranged from 50% to 100%, losses occurring when that some of these species did not feed on the nematodes, larvae failed to penetrate the agar, when larvae climbed but on microorganisms introduced either with the nem- onto the petri dish and desiccated, or from pupal death. atodes or with the Culicoides larvae. Against this pos- Success with C. brevitarsis was particularly encouraging, as sibility is the fact that microorganisms were not apparent its larvae do not swim in the normal energetic ceratoin the agar when it was examined under 25 x magnifica- pogonid fashion and do not pupate successfully in watei. tion and the plates remained clear and developed molds Since this note was submittee for publication, 2 species, only after being discaided. C. brevitarsis and C. austropalpalis, have been reared from The advantages of the new technique are as follows: egg to adult by the technique described.—D. S. Kettle, (1) the current stage of larval development is known at C. H. WUd and M. M. Elson, Department of Entoall times. Time is not wasted in looking after dead mology, University of Queensland, St. Lucia, Queenslarvae as not infrequently happens when larvae are land 4067, Australia.
