Viii. Nematode Pathogens of Culicidae (Mosquitos)

VIII. NEMATODE PATHOGENS OF CULICIDAE (MOSQUITOS)

James J. Petersen USDA, Agricultural Research Service GulfCoast Mosquito Research Laboratory Lake Charles, Louisiana 70601, USA

85 86

U-tn o c a- 0% l_ __ -N H l_- H as- o cr0 4.1% _ _ @ 0% r4 U- IN.r- Z "Z -W5-4 0 c C) -% % gdi4 S XH~~d,8 C) 0 r- Nt 0 0 0 ,a 0 i-. PI. r- 54 C% 0% r- co a 0 %-. I -4 co ~~~~~~> m 44I a 0 0 0: 0 0 1-.'a 3-.'CO "$ 00 0 0 3- .4 ',- 0 $) 04 0co co c co C: '0 H~9 0 0 0 go Cs In CO H E-

0 "14

co .0 .0 0 o o 0 N-I N-I C) .0 0 N-4 _C)0 Co r. 00 0 :D C) co P4 II4 'C) HI3- 10 C)0 C. u C) C. C) c) 0' 0~~~ C) 0 0 0 0 0 0 0 O tO 'C 'N-I No- CD I I I -o g I O 0. NO C'S C4 U0'C) :D N4 coI 0n

8 0 N-

CO 0 la"40 I 0 0 0 aC 0 C)coo Cv0. ~~~~~~C) 0 0 40 0 C3 to f eo 0 0 04 I e i1 i 4, 0W 0 Ir "4 -1 "4i It u ci -'4 44 H NI 'C) -4a Xg 0i8~~~~~,-Q~~~" 41 -IOU

10 0 04. 14. 000W 03 : 0: - 4-4 :c o C) -rI

oo .,, al 0 0aa N-I 4 0 0 a0 a co0 0 0 4 -W0 0 C) Hc C) w 0 o C) la 0 0 11i::: co: j 10 10¢ 0 0 87

Un-I U '0 %0N

H 0% 0% H _ %_0

4.4 JJ4

$4 H ,4. Hf o @ i 0) PQ S go 0% 00 X S 4-H 0) > e la^ta 00 H 9 < >s C0t

, 0 0 a

"-40U - - - -

0 o o o "4 0 UA - 0 4.1 0 14. $4 H- -0o 0 LI C- a Ci 0 co0 $4 c A 8 0 ',4 0' Ca co co coC0co 0 H 0 0 0 0 0 X b r-4 1- 0 I 1 I I I I 0 I H4 16 44 0O Cd C1 CY 0 H

0 ~00 co~~~~~~~~~~~~~8 4.1 $4~~~~~~~~~~~~~~~~. co 0 04 N ' 0 0Q i 4H 0 I "4 00 0 4i~~~~~~~~$ "4 of 0 0 0$- 0 * H :0 a :3 0 H4 0. Q 044 LI 0 0 10 0 o 4 :0 8 "i co 0 3 "44 00 co:o "4 0 .1m 04 H- LIC "4

0 co 4.1 '0 Ho

.0 44"4 01 .0 001 "4 ~~~~4~~~~~~~~4~V H4 0 4.1 "4 LI 0 0 to 0 0: 0 0 0o 0 0 0 a 0) co o X co co 4.1 co 0) H000 v4 '0 0 3C 3 0 0: '00) 88

5-d 0%

a, 0% NN l_ a, 5-4 '0

d N r- A-i '.0D c/2 -% 0% 54 a,4 rl- r- 0% %a r- - co HV 0 ca 0% H N- .0 A 54 ad 4a-i%, $4d co .0 5r4 0%

NI NA0% 54 10 0 .04o .4P4r-Lt '4 544

"4- ad .0

-0 a, 4-I0 0 '0 '4 F: 0 0 ' 0-, . 0 Q rzn ddd e 5-I CO _I Q: d H ~ od Cn P 4 o C: Eq

8 CO C 0 a, U U0 a, H I I I I I

5-4 0

cn m _' X x a, a, 54 54 0 0 ae00 P 5- z "4 "4 V N-4 cv0 U 9 :j U .C co Q a 0 U 2 co a, U pE- 4-.0 o 0 a, I V: 4) u 4i .0 OJ "4 Iy :r: 4- 44 c a, 40 . Z) Z4

4100 :j- 54

rA (A 0 4-i ad go oa 0 54 0 4-1 a, 'A a, co Q 0 0 54 0 a, o aa cr 4) "4 " a) 0 p- N-I co0 v 4 a,4) -m1ci4 ~4NI t 0 el co a, 89

ABSTRACTS Andreadis, T. G. & Hall, D. W. (1976). Neoaplectana carpocapsae: encapsulation in Aedes aegypti and changes in host haemocytesand haemolymphproteins. Exper. Parasitol., 39: 252-261. Araki, J. & Kurihara, T. (1975). Observations of Reesimermis nielseni parasite of mosquito larvae. Part 4. Japan. J. Parasitol., 24: 10-11. (In Japanese.) Benham, G. S. Jr (1974). A synopsis of the obligate and facultative insect parasitic nematodes. J. Invertebr. Pathol., 24: 263-270. Review paper. Beresky, M. A. & Hall, D. W. (1977). The influence of phenylthiourea on encapsulated melanization and survival in larvae of the mosquito Aedes aegypti parasitized by the nematode Neoaplectana carpocapsae. J. Invertebr. Pathol., 29: 74-80.

During the first 9 hours after exposure to phenylthiourea, treated larvae had significantly lower mortality, and the amount of melanization was significantly reduced.

Brown, B. J. & Platzer, E. G. (1974). The effect of temperature, light, larval age and exposure time on the infectivity of preparasitic larvae of Reesimermis nielseni. J. Nematol., 6: 157

Time for host location and infection increased as the preparasites aged at all combinations of illumination and temperature. Romanomermis culicivorax infected mosquito larvae more efficiently under constant darkness.

Brown, B. J. & Platzer, E. G. (1975). The effects of salts, conductivity and pH on infectivity of preparasitic larvAe of Reesimermis nielseni. J. Nematol., 7: 320-321.

Preparasites of Romnomermis culicivorax were exposed to 15 inorganic salt solutions over 9 concentrations to determine their effect on infectivity of the parasite. Parasitism occurred in salt solutions with conductivities up to 4700 pmhos/cm and at a pH range of 3.6-8.6

Brown, B. J. & Platzer, E. G. (1977). The effects of temperature on the infectivity of Romanomermis culicivorax. J. Nematol., 9: 166-172.

Preparasites of R. culicivorax were infective at 12-33 C. Lower temperatures decreased the per cent. infectivity but increased the time that the nematodes remained infective. The time required for host infection increased as the preparasites aged at 15, 21 and 27 C.

Brown, B. J. et al. (1977). Field trials with the mermithid nematode, Romanomermis culicivorax, in California. Mosq. News, 37: 603-608.

Chapman, H. C. (1974). Biological control of mosquito larvae. Ann. Rev. Entomol., 19: 33-59. Review article.

Chapman, H. C. (1974). Nematode and protozoan parasites of mosquitoes and their potential use for control. In: Aubin, A. et al., Le Controle des Moustiques/Mosquito Control. University of Quebec Press, Montreal, pp. 195-205.

Chen, P. S. (1976). A study of Reesimermis nielseni for control of Culex pipiens fatigans in Taiwan. Bull. Inst. Zool. Acad. Sin. (Taipei), 15: 21-28.

Nematode production during mass rearing was highest when the host-parasite ratio was at 1:7.5, and with a host density of 4.2/cm2. Nematodes could emerge from the adult stage if the late fourth instar Cx. quinquefasciatus were exposed. Also, pH was an important limiting factor in the habitat of Romanomermis culicivorax. This nematode recycled in natural host populations when Cx. quinguefasciatus were exposed to preparasites. 90

Finney, J. R. (1975). The penetration of 3 simuliid species by the nematode Reesimermis nielseni. Bull. Wld Hlth Org. 52: 235.

Romanomermis culicivorax (a mosquito parasite) was able to parasitize 1-3 instar larvae of Simulium venustum, S. decorum, and S. vittatum after 4 hours of exposure in still water in the laboratory.

Finney, J. R. (1976). The in vitro culture of the mermithid parasites of mosquitoes and blackflies. Proc. 1st Inter. Coll. Invert. Pathol. Queen's Univ., Kingston, Canada, pp. 225-226. J. Nematol., 8: 284.

Attempts were made to culture Romanomermis culicivorax in tissue culture media. Greatest progress was achieved with Grace's insect tissue culture media and foetal calf serum. A lack of trophosome development indicated that the nematodes were not receiving sufficient food. All nematodes so far developed have been females.

Finney, J. R. (1977). The development of Romanomermis culicivorax in vitro. Nematologica, 23: 479-480.

About 30% of Romanomermis culicivorax survived up to a period of six weeks in Grace's insect tissue culture supplemented with 107e foetal calf serum. Nematodes grew to 12-14 mm in length but lack storage materials in the trophosome. Females developed vulval aperture; no differentiation into males was observed.

Finney, J. R. et al. (1977). Laboratory studies on the feasibility of integrated mosquito control using an insect growth regulator and a mermithid nematode. Mosq. News, 37: 6-11 Laboratory studies showed that the insect growth regulator Altosid 5E, applied at doses ranging from 5 to 50 ppb did not interfere with the preparasitic, parasitic or postparasitic development of Romanomermis culicivorax. Host mortality was considerably increased when the mermithid and the insect growth regulator were used concurrently against mosquitos.

*Galloway, T. D. (1975). Application of a mermithid nematode (Reesimermis nielseni Tsai and Grundmann) from Louisiana for mosquito control in Manitoba. Proc. Alberta Mosq. Abatement Symp., pp. 191-205

Preliminary studies were made on the effects of temperature on storage of Romanomermis culicivorax cultures. Also, low temperatures prevented significant parasitism in the spring mosquitoes Aedes dorsalis, Ae. spencerii, and Ae. sticticus under field conditions and a level of 48% parasitism was achieved in Ae. vexans at a rate of 50 000 preparasites/m2.

*Galloway, T. D. & Brust, R. A. (1976). Observations on mermithid parasites of mosquitoes in Manitoba. Proc. Inter. Coll. Invert. Pathol. Queen's Univ., Kingston, Canada, pp. 227-231.

Aedes impiger and Ae. nigripes were found infected with mermithid nematodes (10-70%) from three pools at Churchill, Manitoba. Also Aedes communis and Ae. churchillensis were found parasitized (<1-67%) in 9 of 16 pools at Goose Creek. The nematodes from Goose Creek were successfully reared in the laboratory and studied taxonomically. Crossing experiments suggested the possible co-specificity of the Goose Creek and Louisiana nematode populations. Mermithids were also observed in adult Aedes vexans, Ae. dorsalis and Ae. spencerii in Winnipeg and Portage la Prairie, and in Ae. sticticus at La Salle.

Galloway, T. D. & Brust, R. A. (1977). Effects of temperature and photoperiod on the infection of two mosquito species by the mermithid Romanomermis culicivorax. J. Nematol., 9: 218-221. Successful invasion by the mermithid R. culicivorax declined.linearly in Culex tarsalis and Aedes dorsalis larvae exposed in the laboratory at 18-10 C. Photoperiod had no effect on infection. 91

Gordon, R. et al. (1976). Endocrine relations between certain larval diptera and their mermithid parasites. Proc. 1st Inter. Coll. Invert. Pathol. Queen's Univ. Kingston, Canada, pp. 268-271.

The insect growth regulator Altosid SE did not affect infectivity of preparasites, parasitic or postparasitic development of the mermithid Romanomermis culicivorax. These data suggest that the mermithid develops independently of the hosts' juvenile hormone titre.

Gordon, R. & Webster, J. M. (1974). Biological control of insects by nematodes. Helminthol. Abstr. A., 43: 327-349.

Review paper.

Hall, D. W. et al. (1975). Melanotic encapsulation of the nematode Neoaplectona carpocapsae by Aedes aegypti larvae concurrently parasitized by the nematode Reesimermis nielseni. J. Invert. Pathol., 26: 269-270.

Capsules surrounding N. carpocapsae appeared to be identical regardless of whether Romanomermis culicivorax was present or not. R. culicivorax was never encapsulated even in larvae in which the reaction was initiated against N. carpocapsae.

Hansen, E. L. & Hansen, J. W. (1976). Parasitism of Simulium damnosum by Romanomermis culicivorax. IRCS Med. Science, 4: 508.

First and second instar S. damnosum were either killed or moribund after three to four hours exposure to the mosquito nematode R. culicivorax in still water. Parasitism was also observed in S. damnosum in water flowing at a velocity of 2 cm/sec.

Hughes, D. S. & Platzer, E. G. (1977). Temperature effects on the parasitic phase of Romanomermis culicivorax in Culex pipiens. J. Nematol., 9: 173-175.

Median development times for the parasitic stage of R. culicivorax at 15, 18, 20, 27, and 32'C were 27.6, 17.2, 11.5, 7.1 and 5.8 days respectively; the optimum temperature was 20-32 C.

Ignoffo, C. M. et al. (1974). Lack of susceptibility of mice and rats to the mosquito nematode Reesimermis nielseni Tsai and Grundmann. Mosq. News, 34: 425-428.

No differences were found in weight gain and histology of suckling and adult mice and adult rats subjected to per os, intranasal, intraperitoneal or dermal challenges of the mosquito mermithid Romanomermis culicivorax when compared with untreated animals.

Imbriana, J. L. & Platzer, E. G. (1976). Malate dehydrogenase in Reesimermis nielseni (Mermithoidea). J. Nematol., 8: 289.

The specific activity, pH optimum, substrate, and cofactor affinities of malate dehydrogenase from Romanomermis culicivorax were determined.

*Isaeva, N. M. (1977a). redes caspius Pall. (Culicidae) - a new host of Culicimermis schakhovii (Nematoda, Mermithidael/. Vest. Zool., 6: 88-89. (In Russ., Engl. summ.) Two hundred and eighty-two pupae of Aedes caspius were found to be infected with Culicimermis schakhovii in Crimea, USSR in 1974. 92

Ittycheriah, P. I. et al. (1977). Storage material of the nematode Romanomermis culicivorax, a mermithid parasite of larval mosquitoes. Nematologica, 23: 165-171.

*KGerdpibule, V. et al. (1974). A preliminary study on the control of Mansonia uniformis by nematode parasitism (Reesimermis nielseni). Southeast Asian J. Trop. Med. Pub. Hlth, 5: 150-151.

In the laboratory larvae of Ma. uniformis parasitized with Romanomermis culicivorax died when they were in the first instar.

Kurihara, T. (1974a). Ecology of Reesimermis nielseni parasitizing mosquitoes. Japan. J. Sanit. Zool., 24: 337. (Abstract in Japanese).

Kurihara, T. (1974b). Observations of Reesimermis nielseni, parasite of mosquito larvae. Japan. J. Parasitol., 23: 56. (Abstract in Japanese).

Kurihara, T. (1975). Observation of Reesimermis nielseni parasite of mosquito larvae. Part 3, 4 and 5. Japan. J. Parasitol., 24: 10-11, 86. (Abstracts in Japanese).

Kurihara, T. (1976a). Observations of Reesimermis nielseni, parasite of mosquitoes (Part IV). Japan. J. Parasitol., 25: 74. (Abstract in Japanese).

*Kurihara, T. (1976b). Population behavior of Reesimermis nielseni, a nematode parasite of mosquitoes, with notes on the attraction of infective stage nematodes by mosquito larvae, Culex pipiens molestus. Japan. J. Parasitol., 25: 8-16. (In Japanese, Engl. sumn.) The LT50 for preparasite survival for Romanomermis culicivorax was 1.79 days at 25 C and 5.33 days at 15°C. The phenomenon of aggregation of preparasites to mosquitos was observed and measured.

Levy, R. et al. (1977). Application of a mermithid parasite of mosquitoes with an aerial spray system. Mosq. News, 37: 512-516.

Ground spray applications of preparasites of Romanomermis culicivorax at 25 psi indicated no apparent adverse effects from impact within the spray system and nozzle assemblies.

*Levy, R. & Miller, T.W. jr (1977a). Experimental release of a mermithid nematode to control mosquitoes breeding in sewage settling tanks. Mosq. News, 37: 410-414.

Field release of preparasites of Romanomermis culicivorax directly into two sewage settling tanks resulted in 37 and 54% parasitism of Culex quinguefasciatus larvae at an estimated parasite to host ratio of 3.4 and 4.6:1, respectively.

Levy, R. & Miller, T. W. jr (1977b). Thermal tolerance of Romanomermis culicivorax, a nematode parasite of mosquitoes. J. Nematol., 9: 259-260.

Data suggest that R. culicivorax has little value in habitats with temperature in excess of about 40 C.

Levy, R. & Miller, T. W. jr (1977c). Susceptibility of the mosquito nematode Romanomermis culicivorax (Mermithidae) to pesticides and growth regulators. Environ. Entomol., 6: 447-448 93

Twenty-four-hour exposures of parasites of R. culicivorax to temephos (0.005 mg/i), fenthion (0.003 mg/i), chlorpyrifos (0.001 mg/l) , diflubenzuron (0.005mg/1) and methoprene (0.005 mg/i) had no apparent effects. However concentrations of 0.0035 mg/i fenthion and 0.004 mg/i chlorpyrifos lowered infectivity of the nematodes. Levy, R. & Miller, T. W. Jr (1977d). Experimental release of Romanomermis culicivorax (Mermithidae: Nematoda) to control mosquitoes breeding in southwest Florida. Mosq. News, 37: 483-486.

Ninety-six per cent. of lst-4th instar Psorophora columbiae, Ps. ciliata, Cuiex nigripalpus and Aedes taeniorhynchus from eight potholes and ditches were parasitized when preparasitic R. culicivorax were applied at ca. 3.6 x 103/m2.

Nickle, W. R. (1976). Toward the commercialization of a mosquito mermithid. Proc. 1st Inter. Coll. Invert. Pathol. Queen's Univ.. Kingston, Canada, pp. 241-244. J. Nematol., 8: 298, 1976. (Abstract).

A nematode similar to Romanomermis culicivorax was found parasitizing (75-807.) several species of mosquitos in Maryland including Culex territans. R. culicivorax successfully overwintered in two sites in Maryland after introduction in 1975 and achieved levels of 90 and 30-45% parasitism in 1976.

Nickle, W. R. & Hogger, Ch. H. (1974). Scanning electron microscopy of the mosquito parasite Reesimermis nielseni (Nematoda: Mermithidae). Proc. Helminthol. Soc. Wash., 41: 173-177. Using a scanning electron microscope on the external anatomy of Romanomermis culicivorax, a fine annulation of the cuticle, large amphid openings, three pits in each cephalic papilla, bifurcation of caudal papillae, two spicules in the male and a tooth and a large amphid opening in the preparasitic stage were observed.

Pao-Shu, C. (1976). A study of Reesimermis nielseni for control of Culex pipiens fatigans in Taiwan. Bull. Inst. Zool. Acad. Sin (Taipei), 15: 21-28.

Petersen, J. J. (1975a). Penetration and development of the mermithid nematode Reesimermis nielseni in eighteen species of mosquitoes. J. Nematol., 7: 207-210.

Thirteen species of mosquitos were more susceptible to parasitism by Romanomermis culicivorax than Culex quinquefasciatus. The Anopheles species and Culiseta inornata were the most susceptible and Aedes triseriatus, Culex territans and Psorophora ferox were highly resistant.

Petersen, J. J. (1975b). Development and fecundity of Reesimermis nielseni, a nematode parasite of mosquitoes. J. Nematol., 7: 211-214.

Maturation of Romanomermis culicivorax to the adult stage began by the tenth day after emergence (24-27 C). Most postparasites reached the adult stage after 70 days. The first females exhibited oviposition after 25-30 days and laid an average of 2480 eggs over an 18-day period.

Petersen, J. J. (1975c). Recycling of the nematode Reesimermis nielseni during 1975 in Anopheles crucians in Louisiana. Proc. Utah Mosq. Abat. Assoc., 28: 17-18.

Romanomermis culicivorax has a strong propensity for establishment and recycling for an indefinite period in habitats of Anopheles mosquitos. Eight sites produced significant levels of parasitism for over two years and two sites showed continued activity for more than four years after introduction. 94

Petersen, J. J. (1975d). Status of nematodes as mosquito control agents in North America. Proc. Alberta Mosq. Abat. Symp., pp. 181-190. Review article.

Petersen, J. J. (1976a). Notes on the comparative biology of the Wyoming and Louisiana populations of Reesimermis nielseni, a parasitic nematode of mosquitoes. J. Nematol., 8: 273-275.

Data suggests that the two populations of Romanomermis culicivorax develop at different rates, have different effects on a given species of host, and will not cross-mate in the laboratory.

Petersen, J. J. (1976b). Status and future of mermithid nematodes as control agents of mosquitoes. Proc. 1st Inter. Coll. Invert. Pathol. Queen's Univ. Kingston, Canada, pp. 236-240. Review article.

Petersen, J. J. (1977a). Biology of Octomyomermis muspratti, a parasite of mosquitoes as it relates to mass production. J. Invert. Pathol., 30: 155-159. First and second instar Culex quinquefasciatus were equally susceptible to parasitism by 0. muspratti; third instar hosts were significantly less suceptible. About 4% of hosts exposed as first and second instars and 37% of hosts exposed as third instars pupated prior to emergence of the postparasitic nematodes.

Petersen, J. J. (1977b). Effects of host size and parasite burden on the mosquito parasite Octomyomermis muspratti. J. Nematol., 9: 343-346.

The ratio of nematodes to the host mosquito at the time of exposure had little effect on the ratio of male to female parasites. However, hosts with a single nematode produced fewer than 1% males while hosts with eight parasites produced about 40% males. The size of the host at the time of invasion had no significant influence on nematode sex ratios.

Petersen, J. J. (1978). Observation on the mass production of Romanomermis culicivorax, a nematode parasite of mosquitoes. Mosq. News, 38: 83-86.

Petersen, J. J. & Willis, 0. R. (1975). Establishment and recycling of a mermithid nematode for the control of larval mosquitoes. Mosq. News, 35: 526-532.

Three of five sites treated in 1971 with Romanomermis culicivorax produced mean levels of parasitism of 7-527 in Anopheles crucians through 1974; five of six sites treated both in 1971 and 1973 produced mean levels of parasitism of 2-51% during 1974; and 5 of 12 sites treated only in 1973 produced An. crucians with levels of infection ranging from 11 to 85% in 1974.

Petersen, J. J. & Willis, 0. R. (1976). Experimental release of a mermithid nematode to control floodwater mosquitoes in Louisiana. Mosq. News, 36: 339-342. Significant levels of parasitism were achieved when cultures containing Romanomermis culicivorax were placed in damp habitats of floodwater mosquitos; 527 of Aedes atlanticus, 59% of Ae. tormentor, 35% of Psorophora columbiae, and 51% of Ps. howardii were parasitized in 39 larval collections from 13 habitats.

Platzer, E. G. & Brown, B. J. (1976). Physiological ecology of Reesimermis nielseni. Proc. 1st Inter. Coll. Invert. Pathol. Queen's Univ. Kingston, canada, pp. 263-267. 95

At infection ratios of 1:1-5:1 (Romanomermis culicivorax:mosquito larvae), the corresponding infection competency was 37 to 25%, respectively. The effects of temperature, exposure time, salts, and algacides on nematode survival and development were also studied. Poinar, G. 0. Jr (1975). On the question of human infection by nematodes of the family Mermithidae (Dorylaimida:Adenophora). WHO/VBC/75.564, 8 pp.

Human infection by mermithid nematodes cannot be established at this time and should be accepted as a fact when proven experimentally or when parasites are found developing in situ.

*Poinar, G. 0. Jr (1976). Presence of mermithidae (Nematoda) in invertebrate paratenic host. J. Parasitol., 62: 843-844. Culex pipiens was used as an experimental host of Agomomermis pachysoma.

"'Poinar, G. 0. Jr (1977). Empidomermis cozii n. gen., n. sp. (Mermithidae: Nematoda) a parasite of Anopheles funestus (Culicidae: Diptera) in West Africa. Can. J. Zool., 55: 1475-1479.

Females of Anopheles funestus collected in Upper Volta in 1976 were found parasitized by a mermithid, Empidomermis cozii. Parasitized females were sterilized and died after emergence of the nematodes. The development of the nematodes is described. Poinar, G. 0. Jr & Hess, R. (1974). Structure of the pre-parasitic juvenile of Filipjevi- mermis leipsandra and some other Mermithidae (Nematoda). Nematologica, 20: 163-173.

The preparasitic juveniles of Romanomermis culicivorax were studied and compared with those of five other species. Findings indicate that the mermithids are a phylogeneti- cally diverging group and that certain characteristics of the preparasitic juveniles can be used for specific and generic determinations.

Poinar, G. 0. Jr & Hess, R. (1976). Uptake of Ferritin particles through the body wall of a mermithid nematode. IRCS Med. Sci., 4: 296.

The cuticle of Romanomermis culiciyorax is reduced to a thin membrane containing pores large enough for the entrance of ferritin particles and thus for the passage of all nutrients required for growth.

Poinar, G. 0. Jr & Hess, R. (1977a). Romanomermis culicivorax morphological evidence of trans-cuticular uptake. Exper. Parasitol., 42: 27-33.

Poinar, G. 0. Jr & Hess, R. (1977b). Virus-like particles in the nematode Romanomermis culicivorax (Mermithidae). Nature, 266: 256-257.

Each of 10 preparasitic juveniles of R. culicivorax examined contained virus-like particles in the hypodermal cords, cells associated with the anphidial nerves, and spaces of the pseudocoelom.

Poinar, G. 0. Jr & Otieno, W. A. (1974). Evidence of four molts in the Mermithidae. Nematologica, 20: 370.

Four molts were observed during the developmental stages of Romanomermis culicivorax; the first occurred in the egg; the second occurred four to five days after the nematode entered the host; the third and fourth molts occurred simultaneously in the postparasitic juvenile several days after they had left their host. 96

*Prakash, R. & Husainy, Z. H. (1975). Occurrence of a mermithid nematode Mermis species in the coelom of Anopheles culicifacies. Science and Culture, 41: 441.

A single female Mermis sp. was recovered from the coelom of an adult female An. culicifacies collected from a cattle shed in Madhya Pradesh, India.

*Ross, J. F. & Smith, S. M. (1976). A review of the mermithid parasites (Nematoda:Mermithidae) described from North American mosquitoes (Diptera:Culicidae) with descriptions of three new species. Can. J. Zool., 54: 1084-1102.

The genus Romanomermis was resurrected and the generic description augmented. Three new species of mermithids were described: R. kiktoreac, R. hermaphrodita and R. culicivorax. R. nielseni is a segregate of a complex known previously as Reesimermis nielseni. Rees. nielseni is restricted to a species known only from Wyoming and is transferred to Romanomermis. Reesimermis muspratti is moved to Octomyomermis. Keys are provided for the world species of Romanomermis and for the described mermithids that infect mosquitos in North America.

*Rubtsov, I. A. & Isaeva, N. M. (1975). Culicimermis schakhovii gen. et. sp. n. (Mermithidae) - a new parasite of mosquitoes. Vestnik Zoologii, No. 1: 39-44. (In Russ.)

The mermithid, Culicimermis schakhovii gen. et. sp.n. were found developing in adults of six Aedes mosquito species: Ae. cantans, Ae. riparius, Ae. excrucians, Ae. cataphylla, Ae. behningi, and Ae. communis near Kiev, USSR. Levels of parasitism reached 637.

*Service, M. W. (1974). Further results of catches of Culicoides (Diptera) Ceratopogonidae and mosquitoes from suction traps. J. Med. Entomol., 11: 471-479.

Five adults of Aedes cantans were parasitized by mermithid nematodes.

Service, M. W. (1977a). Mortalities of the immature stages of species B of the Anopheles gambiae complex in Kenya: comparison between rice fields and temporary pools, identifica- tion of predators, and effects of insecticidal spraying. J. med. Entomol., 13: 535-545.

1.8% and 6.9% of the larvae of Anopheles gambiae collected respectively from rice fields, pools and ponds were parasitized by mermithid nematodes.

*Service, M. W. (1977b). Ecological and biological studies on Aedes cantans (Meig.) (Diptera: Culicidae) in southern England. J. Applied Ecology, 14: 159-196.

Undescribed mermithid species found in larval stages of Ae. cantans in southern England.

*Skierska, B. & Szadziewska, M. (1976). [Laboratory tests for usability of the entomophilic nematodes Steinernematidae Chitwood & Chitwood 1937 in biological control of some noxious arthropodsj Bull. Inst. Maritime and Trop. Med. Gdynia, 27: 207-227. (In Polish, Engl. summ . )

The nematode, Neoaplectana DD 136 (N. feltiae) were experimentally infected to larvae of Culex pipiens molestus.

;kierska, B. & Szadziewska, M. (1977). /Kbility to infect larvae of Culex pipiens molestus Forsk. (Diptera, Culicidae) by means of entomophilic nematodes, Neoaplectana feltiae carpocapsae Stan. (1974) (DD 136 strain) Rhabditoidea, SteinernematidaeJ Wiad. Parazytol., 23: 279-281. (In Polish, Engl. summ.n)

Shephard, M. R. N. (1974). Arthropods as final hosts of nematodes and nematomorphs. An annotated bibliography 1900-1972. Technical Communications of the Commonwealth Institute of Helminthology No. 45, 248 pp. 97

*Tsarichkova, D. B. et al. (1975). The influence of mermithids on reproductive capacity of the mosquitoes of the genus Aedes. Int: Parasites and Parasitoses of Animals and People, Kiev, Ukranian SSR, pp. 270-273. The effects of mermithids on the mating behaviour, and oogenesis in six Aedes species: Ae. cantans, Ae. riparius, Ae. excrucians, Ae. cataphylla, Ae. behningi and Ae. cominis. Females infected with one or two nematodes would take a blood-meal and be fertilized but oogenesis proceeded abnormally. When infected with three to nine mermithids females v7ere not reproductively active.

Welch, H. E. (1976). Advances in insect nematology. Proc. 1st Inter. Coll. Invert. Pathol. Queen's Univ. Kingston, Canada, pp. 221-224. Discussion of the resolution of the Romanomermis and Reesimermis confusion. Woodard, D. B. (1978). Establishment of the nematode Diximermis peterseni in the field in southwest Louisiana using laboratory-reared material. Mosq. News, 38: 80-83. Woodard, D. B. & Fukuda, T. (1977). Laboratory resistance of the mosquito Anopheles quadri- maculatus to the mermithid nematode Diximermis peterseni. Mosq. News, 37: 192-195.

Yakubovich, V. Ya. (1975). Discovery of nematode larvae in the eggs and body cavity of female Aedes mosquitoes. Med. Parazitol. Parazit. Bolezni, 44: 102-103. (In Russ.)