Laird (1960) has tried a new approach with Coelomomyces that has promise of yielding interesting results. T h e idea for this came to Laird (1956a) while making an intensive two-year study of mosquitoes and fresh
water ecology in the South Pacific. It involved using the remote T o k e l a u Islands in the South Pacific as an outdoor laboratory. T h e only important mosquito on the islands is Aedes polynesiensis which transmits Wuchereria bancrofti, the filarial worm of tropical elephantiasis. These mosquitoes breed in the rain water which accumulates in tree holes and in other natural and artificial containers. By examining many Aedes larvae it was established that Coelomomyces was absent from the Tokelaus. T h e group consists of three islands and the project involved treating each island as follows: (1) on N u k u n o n o the resting sporangia of Coelomomyces stego
myiae were introduced into 761 of the larval habitats; (2) on Atafa diel-drin-cement briquettes were placed in 6500 breeding places for compari
son with any Coelomomyces control; and (3) Fakaofo was left untreated as an experimental control. A b o u t two years later (April, 1960) Laird returned to the Tokelaus and found that Coelomomyces stegomyiae was well established in the local Aedes polynesiensis p o p u l a t i o n following its introduction from Singapore in 1958. I n a letter he reports as follows:
' O n e h u n d r e d and eighteen larval habitats were carefully searched this April (1960) and parasitized larvae were present in 11 of these, while viable sporangia were found in the bottom debris of others. T h e over-all incidence was approximately five to seven times that found in n a t u r e at Singapore, and the over-all percentage of parasitized larvae per habitat was twice as high as there. T h e r e was evidence, too, of b o t h natural
186 J. Ν. COUCH AND C. J. UMPHLETT
spread (to dried coconut shells near infected tree holes) and adult mos
quito population reduction. These results seem encouraging in view of the crude introduction procedures that had to be used."
V I I I . CONCLUSIONS
A review such as this is useful to the reviewers in focusing attention on the unsolved problems. I n Coelomomyces there are many. T h e life history of Coelomomyces is still incompletely known. A n u m b e r of questions on the life history and other matters need to be answered: (1) H o w widespread and how a b u n d a n t are the species of Coelomomyces in mosquitoes and related insects and what are the factors that determine their peculiar distribution, i.e., their apparent abundance in some areas and total absence in others? (2) H o w nearly host specific are the species of Coelomomyces; i.e., are the species which have been reported on more than one host composed of morphologic races? (3) W h e t h e r the zoospores from the resting sporangia are the agents of infection. (4) H o w does in
fection take place? (5) H o w widespread is the occurrence of the thin-wall sporangia in the different species of Coelomomyces and what is the function of these structures? (6) W h e t h e r there is an alternation of hosts.
(7) W h e t h e r there is an alternation of a sporophytic and a gametophytic generation as occurs in certain other Blastocladiales. (8) W h e t h e r any of these fungi can be cultured u n d e r controlled conditions on laboratory-reared mosquitoes. (9) W h e t h e r they can be cultured on artificial media.
(10) W h e t h e r any of these pathogens can be used by m a n for the micro
bial control of susceptible insects.
T h e species of Coelomomyces are very highly specialized parasites, as indicated in part by the remarkable mycelium, which lacks a wall, thus permitting free movement of the larvae. T h o u g h well established in the natural population of mosquitoes and exceedingly ancient historically, the species are so rare in natural occurrence that u n d e r normal conditions Coelomomyces is a mere pin prick in controlling or reducing the popula
tion of mosquitoes. It is only when the ecological balance as applied to mosquitoes occurs as in the small-scale concrete tank experiments of Walker (1938) and Muspratt (1946b) or in large-scale irrigation projects, as in Alberta, Canada (Shemanchuk, 1959), that Coelomomyces may be
come a menace to the mosquito population. If Coelomomyces stegomyiae could be grown in large quantity with the production of a b u n d a n t rest
ing sporangia, it would be interesting to introduce this oriental species into the population of the salt marsh mosquitoes in the southeastern United States.
REFERENCES
Barr, A. R. 1958. T h e mosquitoes of Minnesota (Diptera: Culicidae: Culicinae).
Univ. Minn. Agr. Expt. Sta. Tech. Bull., 2 2 8 , 1-154.
Bogoyavlensky, N . 1922. Zografia notonectae, n. g., n. sp. Arkh. Russ. Protist.
Obshch., 1 , 113-119.
Couch, J. N . 1945a. Revision of the genus Coelomomyces parasitic in insect larvae.
/. Elisha Mitchell Sei. Soc, 6 1 , 124-136.
Couch, J. N . 1945b. Observations o n the genus Catenaria. Mycologia, 3 7 , 163-193.
Couch, J. N., and Dodge, H. R. 1947. Further observations on Coelomomyces, parasitic in mosquito larvae. / . Elisha Mitchell Sei. Soc, 6 3 , 69-79.
De Meillon, B., and Muspratt, J. 1943. Germination of the sporangia of Coelomo
myces Keilin. Nature, 1 5 2 , 507.
Ekstein, F. 1922. Beiträge zur Kentniss der Stechmückenparasiten. Zentr. Bakteriol.
Parasitenk., 8 8 , 128.
Feng, L.-C. 1933. Some parasites of mosquitoes and flies found in China. Lingnan Sei. J., 2 3 (Suppl.).
Garnham, P. C. C , and Lewis, J. D . 1959. Parasites of British Honduras with special reference to Leishmaniasis. Trans. Roy. Soc. Trop. Med. Hyg., 5 3 , 12-35.
Gibbins, E. G. 1932. Natural malaria infection of house-frequenting Anopheles mosquitoes in Uganda. Ann. Trop. Med. Parasitol., 2 6 , 239.
Haddow, A. J. 1942. T h e mosquito fauna and climate of native huts at Kisumu, Kenya. Bull. Entomol. Research, 3 3 , 91-142.
Hatch, W . R. 1935. Gametogenesis in Allomyces arbusculus. Ann. Botany (London), 4 9 , 623-649.
Hatch, W . R. 1944. Zoosporogenesis in the resistant sporangia of Allomyces ar
busculus. Mycologia, 3 6 , 650-663.
Iyengar, Μ. Ο. T . 1935. T w o new fungi of the genus Coelomomyces parasitic in larvae of Anopheles. Parasitology, 2 7 , 440-449.
Keilin, D . 1921. On a new type of fungus: Coelomomyces stegomyiae, n. g., n. sp., parasitic in the body-cavity of the larva of Stegomyia scutellaris Walker (Diptera, Nematocera, Culicidae). Parasitology, 1 3 , 225-234.
Keilin, D . 1927. O n Coelomomyces stegomyiae and Zografia notonectae, fungi para
sitic in insects. Parasitology, 1 9 , 365-367.
King, W . V., Bradley, G. H., and McNeel, Τ . E. 1944. T h e Mosquitoes of the Southeastern States. U.S. Dept. Agr. Misc. Publ. No. 3 3 6 , 1-96.
Laird, M. 1956a. Studies of mosquitoes and fresh water ecology in the South Pacific. Roy. Soc. New Zealand Bull., 6 , 1-213.
Laird, M. 1956b. A new species of Coelomomyces (fungi) from T a s m a n i a n mos
q u i t o larvae. / . Parasitol., 4 2 , 53-55.
Laird, M. 1959a. Parasites of Singapore mosquitoes, with particular reference to the significance of larval epibionts as an index of habit pollution. Ecology, 4 0 , 206-221.
Laird, M. 1959b. Fungal parasites of mosquito larvae from the oriental and Aus
tralian regions, with ä key to the genus Coelomomyces (Blastocladiales: Coelomo-mycetaceae). Can. J. Zool, 3 7 , 781-791.
Laird, M. 1960. Coelomomyces, and the biological control of mosquitoes. In "Con
ference on Biological Control of Insects of Medical Importance." Am. Inst. Biol.
Sei., Tech. Rept. (unnumbered).
Laird, M. 1961. N e w American locality records for four species of Coelomomyces (Blastocladiales, Coelomomycetaceae). / . Insect Pathol, 3, 249-253.
188 J . Ν. COUCH AND C. J. UMPHLETT
Manalang, C. 1930. Coccidiosis in Anopheles mosquitoes. Philippine J. Sei., 42, 279.
Mead, F. W. 1949. Ecology of Central Ohio Mosquitoes. M.S. Thesis, Ohio State Univ., Columbus, Ohio.
Muspratt, J. 1946a. On Coelomomyces fungi causing high mortality of Anopheles gambiae larvae in Rhodesia. Ann. Trop. Med. Parasitol., 40, 10-17.
Muspratt, J. 1946b. Experimental infection of the larvae of Anopheles gambiae (Dipt., Culicidae) with a Coelomomyces fungus. Nature, 158, 202.
R i o u x , J. Α., and Pech, J. 1960. Coelomomyces grassei n. sp. parasite d'Anopheles gambiae (note preliminaire). Acta Trop., 17, 179-182.
Shemanchuk, J. A. 1959. N o t e o n Coelomomyces psorophorae Couch, a fungus parasitic o n mosquito larvae. Can. Entomologist, 91, 743-744.
Steinhaus, Ε. Α. 1949. "Principles of Insect Pathology," 757 p p . McGraw-Hill, N e w York.
U m p h l e t t , C. J. 1961. Comparative Studies in the Genus Coelomomyces Keilin.
Ph.D. Dissertation, Univ. N o r t h Carolina, Chapel Hill, N o r t h Carolina,
van T h i e l , P. H. 1954. Trematode, Gregarine and fungus parasites of Anopheles Mosquitoes. / . Parasitol., 40, 271-279.
Walker, A. J. 1938. Fungal infections of mosquitoes, especially of Anopheles costalis.
Ann. Trop. Med. Parasitol, 32, 231-244.