The Egyptian Journal of Hospital Medicine Vol., 2 : 70 – 83 March, 2001

I.S.S.N: 12084

Effect of Some Environmental Factors on the Predation Efficiency of the ; splendens (Diptera: Culicidae)

Hanaa I. Mahmoud Zoology Department, Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt.

Abstract The present work investigates the optimum conditions for the application of the predaceous mosquito, as a biological control agent for other vector mosquito species in Egypt such as, Culex pipiens, Anopheles pharoensis and Aedes caspius under field conditions. The predation efficiency of T. splendens larvae was found to increase as the C the predaceous larvae consumed greater numbers of؛temperature increased. At 30-35 both C. pipiens and Ae. Caspius than that of A. pharoensis. The predation of T. splen – dens occurred almost similarly in all degree of salinity. On the other hand, light was found to have little effect on Toxorhynchites larvae where predation efficiency was decreased in the dark. The crowding had no effect on the predation. Also no mortality or natural diseases were observed among the tested larvae during the experim ental period, whereas the insect preferred to live in highly concentrated population. Toxorhynchites splendens larvae could live in turbid and distilled water. The maximum number of prey larvae consumed by all instars of T. splendens was at PH (8) followed by (7) and (9). However, pH, below (6) and above 11 had a bad effect on the predaceous activity. The predation efficiency of T. splendens larvae increased gradually as the depth of water decreased .However captures of prey occurred either on the surface or at the bottom of the container.

Introduction Although insecticides continue aquatic stages of mosquitoes. Among to play a significant role in the control the organisms most extensively studied of mosquitoes involved in disease trans in this regard are the larvae of the -mission, biological control of mosquito mosquito, Toxorhynchites splendens with predatory organisms in most instan ( Mkoji et al., 1999). This species is -ces is more acceptable from an enviro - considered to be one of the most useful nmental stand point and has been appl - agents for the biological control of other ied in many situations with reason -able vector and nuisance mosquitoes (Cheo - success (WHO, 1995). ng and Ganapathipillai, 1964, Chan Biological control with indige - 1968; Yasuno and Tonn, 1970) and also nous predators/parasites may be more for aedine vector of various diseases available, comparatively less expensive, such as filariasis, dengue and yellow and more compatible with the economic fever (Horio et al., 1990). realities of many countries of sub-Saha Recently, T. splendens mosq - -ran Africa. Predatory organisms are uito has been also recognized for use in particularly suitable for control of the isolation of arboviruses and filariae.

Prfree : Prof. Wedad Attwa 70 Hanaa I.Mahmoud

Advantages of Toxorhynchites adults lie provided. For crossing experiments, in their safety (nonbiting) and large size larv -ae were reared individually in (Eshita et al., 1982). 100ml. plastic vials each containing Unlike many other insect preda - 50ml. of distilled water. For routine tors T.splendens can not search for a maintenance, however, larvae were suitable prey patch, but is committed for reared in masses in plastic tray (20 x 30 pre adult life to the oviposition site of x 6.5 cm) containing 2 liters of distilled the female (Lounibos 1979). The depth water. They were fed on larvae of Aedes preference for the oviposition site of aegy -pti (Linn) with a prey/predator Toxorhynchites species need to be inves ratio of 15:1. Pupae were sexed and -tigated in both laboratory and field. placed individually into small capsules. Successful biological control prog - rams requires finding the proper match b- Culex pipiens, Anopheles pharoensis betw -een the preferred oviposition sites and Aedes caspuis of the most suitable species of Colonies of Anopheles pharoensis, Toxorhynchites and the intended Culex pipiens and Aedes caspius were mosquito prey. raised in the laboratory. The The capacity of Toxorhynchities were obtained as larvae or pupae from larvae as a predators on some mosquito Ain Shams University and Faiyum species larvae had been observed by a governorate. The cultures of these insect number of authors ( e.g. Paiva ,1910; species were reared in the laboratory as Jenkins, 1964; Focks, 1985; Annis et al. described by Geberg (1970). 1989 and Rawlins et al.1991). The present study was carried Number of prey larvae consumed by out to determine the effect of some envi Toxorhynchites splendens larvae. -ronmental factors on the predation effi A colony of T. splendens was -ciency of T. splendens larvae on C .pip maintained as described before. Eggs -ens, Ae. caspius and A. pharoensis for experimentation were removed from larvae . the container in the colony cages as soon as possible after oviposition and Materials and Methods placed in separate vials (2x3 cm) Maintenance of mosquitoes containing distilled water. All materials a-Toxorhynchites splendens : was kept at 30°C ±1 and monitored for Immature and adult mosquitoes eclosion. Prey consumption were coun were maintained under insectary cond - –ted in all instars. Each freshly hatched itions of 26+1°C temperature, 75+5% T. splendens larvae were offered 100 1st RH and light : dark regime of 14: 10h at instar C. pipiens, Ae. Caspinus and A. the department of Zoology, Faculty of pharoensis larvae as prey separately Science (for girls), Al-Azhar before the head capsule hardened. When University. About 50 adults were kept the 1st moult occurred, the Toxorhyn - in each cage (20× 20× 30cm) with a chites larvae were transferred to clean stainless wire frame enclosed with vials and the remaining prey were white nylon mesh with a sleeve at a counted. The procedure was repeated lateral end. Adults were fed on an 8% supplying the newly moulted 2nd instar sucrose solution in a 150-ml Toxorhynchites with 100 2nd instar C. Ehrlemeyer flask with a cellu –lose pipiens, A. pharoensis and Ae caspius wick. For oviposition a black plas –tic (each in a separate vial). When the cup containing distilled water was Toxorhynchites larvae moulted to the 3rd

71 Effect of Some Environmental Factors instar, they were transferred to larger salinity. The larvae were put in plastic jars (5 x 7 cm ) and offered 100 third boxes filled with water of different instar C. pipiens, A. pharoensis and Ae. salinities. The numbers of prey larvae caspius daily until pupation occurred. consumed from the three mosquitoes All jars were cleaned every 24 hrs to species at the different salinities were minimize microbial contamination. calculated. Five replicates of hundred indivi -duals were used. The vials were exam - III- Dark and light ined daily and the number of prey consu In order to evaluate the response -med by T. splendens larvae were and the predation efficiency of T. splen calculated. -dens larvae under daylight and comp - lete darkness, fifty 1st insatr larvae of T. Effect of certain factors affecting the splendens were divided into two groups predation efficiency: with Culex larvae as host. In the 1st I- Temperature : group, the larvae were transferred into The predation efficiency of transparent plastic boxes. These boxes T.splendens was tested under different were exposed to diffused sunlight in the temperature degrees. Seven temperature laboratory. Larvae in the second group degrees were tested ranging between were kept in the same plastic boxes but 15°C up to 45°C. Temperature degrees incubated inside a tight wooden cage below and above this range level was which didn’t permit any day light. Num found to have an undesirable effect on -bers of Culex larvae consumed were the activity of the insects. The tested recorded in each group. The expe - larvae were reared in the laboratory at riments were carried out using the 1st, 30°C ±1 in distilled water. 2nd, 3rd and 4th, instar larvae. The Groups of thirty to fifty larvae number of prey larvae consumed by T. were used in these experiments and splendens was calculated. Also, 50 T. were divided into 5 replicates, at each splendens larvae (in two groups) from temperature degree. The predation effic each of 1st, 2nd, 3rd and 4th instars were -iency of T.splendens from 1st instars to tested against Ae.caspius and A.phar - 4th instars was determined. The tested oensis larvae. larvae were incubated at 45, °C, 40°C , 35°C, 30°C, 25°C, 20°C and 15°C ±1. IV- Crowding : Examination for larval preda -tion were To detect the effect of crowding continued daily for 3 days. on the predation of Toxorhynchites larv -ae, the fourth instar larvae were transf - II – Salinity erred to plastic boxes. The larvae were In order to trace the effect of divided into groups of different numb - different salinity degrees on the preda - ers ranging from one to twenty in each. tion of T. splendens larval instars they Five replicates for each group was were tested against, Ae. caspius, C. tested. Larvae were given different num pipiens, and A. pharoensis at salinity -bers of their prey mosquito larvae degrees of 0.39 ٪, 0.12 ٪ , 0.16 ٪ and from C.pipiens, A.pharoensis, and Ae.ca spius. The number of consumed larvae- . ٪ 0.675 This salinity was prepared acco - were counted in each group. rding to a procedure suggested by Ward V- Water – type preference (1962). Fifty larvae from each instar in These experiments were carried two replicates were tested at each out to investigate the preferred type of

72 Hanaa I.Mahmoud water for the predation of T. splendens The first instar larvae were put larvae on the other mosquito larvae in 3 plastic boxes filled with water of tested. different depths 40, 20 and 15cm. Fifty Eggs were removed from the larvae were used in five replicates for container in the colony cage as soon as each depth. The same experiments were possible after oviposition and placed in carried out on the 2nd , 3rd and 4th instar separated vials ( 2 x 3 cm ) containing larvae. The number of prey larvae consu distilled water. Another vials containing -med by all instars and at different polluted water (Sewage) and turbid depth were calculated. water with some of the eggs were test - ed. All materials were kept at 30°C ±1 Results and Discussion and monitored for eclosion. The Fre - Number of prey larvae consumed by shly hatched T.splendens larvae were Toxorhynchites splendens larvae: offered hundred 1st instar C.pipines as a prey in 3 vials. The 3 vials with the These experiments were carried different types of water were examined out to test the number of prey larvae daily and the number of prey consumed consumed by Toxorhynchites splendens by T. splendens were calculated. The from the three mosquito species Culex same experiment were carried out using pipiens, Anopheles pharoensis and Aed the 2nd, 3rd, and 4th instar larvae against -es caspius. To confirm the results obtai A.caspius, and A.pharoensis larvae. -ned from the experiments, they were Five replicate were tested for each repeated 3 times. Results obtained on instar. the response of Toxorhynchites splen - dens to the 3 species of mosquitoes are VI- Water PH : presented in the (Table, 1). In order to trace the effect of The data in table (1), show that different water PH on the predation of the average number of preys consumed out to investigate the preferred type of the 1st larval instar of Toxorhynchites Toxorhynchites larval instars against splendens from their prey Culex tested Ae.caspius, C.pipiens and A.phar pipiens, Anopheles pharoensis and -oensis larvae. 4,5,6,7,8,9,10,11PH we - Aedes caspi -us are 6.5 ±0.557 , 2.75± re used . These PH were prepared by 0.5 and 4.5± 0.33 larvae per potentiometric instrument. The range of respectively. In case of the 2nd instar tested PH almost brackts the PH in the larvae, the number of prey consumed field and that of the tap water. Fifty are 9.5± ,0.577, 3.5±0.57 and 9± 1.154 larvae from each instar of T. splendens larvae per larva respectively. Also, it is were tested in five replicates at each clear that the number of prey larvae PH. The larvae were put in plastic consumed by the 3rd and 4th instars were boxes filled with water of different PH, 8.25± 0.957, 3.75± 0.5 and 9± 1.154 in and provided with their host. The case of the former; 6.5 ± 0.577, 2.5± number of prey larvae consumed from 0.57 and 5.5± 1.29 respectively in case the three mosquito species at different of the latter instar larvae. PH were recorded. From these data it is clear that Toxorh - ynchites splendens larvae respo -nded VII- Water depth: similarly to Culex pipiens and Aedes The effect of water depth on the caspius larvae. The feeding capacity of predation of T. splendens larval instars the 2nd and 3rd instar is greater than that were tested. in the 1st and 4th larval instar. From the

73

Effect of Some Environmental Factors statistical analysis of the data, it is clear 35°C than at 20-25°C. It may be that: (i) There are significant differences pointed out that the temperature surrou - between the number of both Culex pipi - nding the larvae affect their feeding capacity. ens and Aedes caspius larvae and those The data shown in Table (3) of Anopheles pharoensis consumed by represent the effect of salinity on the Toxorhynchites splendens lar -vae in predation efficiency of T.splendens all instars. (ii) There is no significant larvae. The response of the insect larvae difference between the number of Culex in all salinities studied are nearly equal pipiens larvae and those of Aedes casp - in their predation to C.pipiens and Ae. ius consumed by Toxorhynchites splen - caspius. Also it was clear that the dens larvae. number of Anopheles larvae consumed The effect of different tempe - by all instars of Toxorhynchites larvae rature degrees on the predation efficie - was less than in case of the former two ncy of T. splendens larvae is shown in mosquito species. Moreover the data Table (2), the results indicated that the (Table 3) indicated that (i) In all instars predation efficiency of T.splendens there was significant difference between larvae was increased as the temperature the number of prey larvae (C.pipiens, A. increased , where more prey of C.pipi - pharoensis and Ae.caspius) consumed ens and Ae.caspius were consumed at by Toxorhynchites larvae reared in degree from 30-35°C than that of water at salinity of 0.16٪ and those A.pharoensis. reared in water at the salinity of 0.39٪ The analysis of the data (Table except that in case of the 3rd instar. 2) showed that, in case of the 1st insatr, There was no significant difference there were significant differences between the number of Anopheles lar - between the number of prey larvae of vae consumed by Toxorhynchites larv - C.pipiens, A.pharoensis and A.caspius ae at the salinity of 0.16٪ and those at consumed by Toxorhynchites larvae . 0.675٪ incubated at 30°C ± 1 and those (ii) There was no significant difference incubated at 15, 20, 40 and 45°C. In case of the 2nd, 3rd and 4th between the number of prey larvae (C. pipiens, A. pharoensis and Ae. caspius) instars, there were significant differe - st nd rd th nces between the number of prey larvae consumed by 1 , 2 , 3 and 4 instars consumed by Toxorhynchites larvae inc of T. splendens reared in water at a -ubated at 30°C ±1 and those incubated salinity of 0.16 and those at the salinity at15,20,25,40 and 45°C . At 30 C. there 0.12. were significant differences between the (iii) In all instars, there was a unmber of both C. pipiens and Ae. Caspius larvae consumed by Toxorhy - significant difference between the nchites larvae and those of A.. number of host larvae (C. pipiens, A. pharoensis larvae. Also the results pharoenies and Ae. caspius) consumed showed that at the degrees from 30- by Toxorhynchites larvae reared in 35°C the predator larvae consumed water at the salinity 0.16٪ and those greater numbers of both C. pipiens, Ae. reared at 0.675٪ except in case of the caspius than that of A. pharoensis.These 2nd and 3rd instars where there was no results agree with the findings of Trips (1972) who tested the effect of significant difference between the temperature on the predation of Toxorhy number of Ae.caspius larvae consumed -nchites brevipalpis. this data indicated by Toxorhynchites larvae. that predation in T. brevipalpis larvae (iv) There was a significant difference was greater at high temperature degrees between the number of larvae consumed with more prey was consumed at 30- from C. pipiens, Ae. caspius, and those

74 Hanaa I.Mahmoud consumed from A. pharoensis in all predation of T. brevipalpis condradi, salinities. but it greatly increased predation in T. These results agree well with that raimosi larvae. obtained by Richards (1938) who found The results of the crowding that Ae. stimulans (Walker) and Ae. experiment (table 5) revealed that in all wexans (Meigen), (the two flood water groups used the crowding had no effect mosquitoes usually found in water low on the predation. Also no mortality or in salts) respond differently when reared natural diseases were observed among in a graded series of saline solution. But the tested insects larvae during the Kardatzk & Lien (1972) reported that experimental periods. This phenomenon the two coexisting mosquitoes Ae. may be return to that these insect larvae vexans and Ae. stimulans have different prefer always to live in highly abilities to tolerate varied salinities, concentrated population, which doesn’t where Ae. vexans larvae were able to permit any pathological effects and tolerate higher saline conditions than doesn’t affect their predation. those of Ae. stimulans. These results are on contrarily Results in Table (4) revealed with some others as those of Terzian that light seemed to have little effect on and Stahler (1949) who found that in Toxorhynchites larvae but it increased the case of mosquito larvae living in predation than that in the dark due to the over crowding condition generally resu greater activity of the prey in the light. -lted in retarted growth , high mortality Also the results cleared that the among the small larvae ,adults of non- response of all larval instar of T. uniform size and a decreased fecundity. splendens to their host C. pipiens and Meanwhile Andrewartha and Birch Ae. caspius in both light and dark was (1954) reported that over crowding of nearly equal. It was 6.5± 0.5, 8.75± 0.5, organisms produced adverse effects on 8.75± 0.5, & 5.5± 0.57 and 4.5± 0.57, their survival, rate of development, and 8.75± 0.5, 8.78±0.5 & 5.5± 0.5 prey for population growth. These findings contr 1st, 2nd, 3rd and 4th instars, respectively. -adict with the present results, since the The number of Anopheles larvae cons crowding has no effect on the predation -umed by the Toxorhynchites larvae in efficiency of T. splendens larvae. Also both dark and light was decrease it was no mortality or natural diseases was 1.5±0.57, 1.5±0.5, 2.75±0.5 & 3.25± 0.5 observed amon the tested insects larvae and 2.5± 0.57, 3.75± 0.5 , 3.75± 0.577 during the experimental periods. & 4.5± 0.54 prey in case of 1st, 2nd, 3rd The results of water type preference and 4th instars , respectively. So, light is of T. splendens larvae are presented in one of the important ecological factors Table (6). From these data it is clear that that affect predation. Toxorhynchites larvae and their prey The statistical analyses of the could not be live in the polluted Table (4) cleared that in general there water.The data indicated that the are significant differences between the average number of prey ( C. pipiens, A. number of host larvae C. pipiens, A. pharoensis and Ae. caspius) consumed pharoensis and those of Ae. caspius, by the 1st instar was 6.5+0.57, 3.25±0.5, consumed by all instars of T. splendens and 5.5±0.57 prey in distilled water and larvae which kept in light and those kept 4.5±0.57, 1.5±0.5 and 6.5 ± 0.57 prey in dark. These finding support those in turbid water for the 2nd instar . obtained by Goma (1964) who reported Meanwhile , this average was 8.75±0.5, that light seemed to has a little effect on 4.7±0.5, 8.75±0.5 prey and 9±1.154

75 Effect of Some Environmental Factors prey and 3.25± 0.5 and 7.78± 0.5 prey 2nd , 3rd and 4th instars were fewer in for the 3rd instar in distilled and turbid number than at any of the other PH. It is water , respectively . Also the data clearly indicated that the maximum revealed that the 4th instar consumed number of prey larvae consumed by all 6.5±0.57, 3.5±0.57 and 5.5± 0.57 larvae instars of Toxorhynchites larvae was at from C. pipiens, A. pharoensis, Ae. PH8 then followed by the PH7 and 9 caspius in distilled water and 5.5± 0.57, where the number of consumed larvae 3.25± 0.5 and 6.5± 0.57 in turbid water were nearly the same .At the PH6 as respectively. well as PH10, the Toxorhynchites larvae From the statistical analysis of showed a bad appetite where they cons the data ( table 6) it is clear that: (i) -umed few number of their prey. So the There are no significant differences insect larvae responded differently to between the number of prey larvae the same host at different PH. (from C. pipiens, A. pharoensis and Ae. The statistical analysis of the data caspius) lived in distilled water and ( table 7 ) indicated there was highly those lived in turbid water which significant difference between the consumed by the 2nd and 3rd number of prey larvae, from C. pipiens, Toxorhynchites larvae. A. pharoensis and Ae. caspius, (ii) There are no significant differences consumed by 2nd , 3rd and 4 instars of between the number of prey larvae Toxorhynchites larvae which lived at Toxorhynchites larvae. PH8 and those placed at PH (4,5 and (ii) There are no significant differences 11) .Also there was highly significant between the number of prey larvae (C. difference between the number C. pipiens, Ae. caspius) lived in distilled pipiens ,A. pharoensis and Ae. caspius water and consumed by 1st and 4th larvae consumed by 1st 2nd 3rd and 4th Toxorhynchites larvae and those lived in instars of Toxorhynchites larvae which turbid water . But in case of Anopheles lived at PH8 and those lived at PH ( 6, host. There are significant differences 7,9 and 10 ). It was seemed that the between these lived in distilled water insect larvae responded differently to and those lived in turbid water which the same host at different PH. These consumed by 1st or 4th Toxorhynchites results are in agreement with that found larvae. These findings support those by Laird (1947). reached by Jenkins (1946) who found The effect of water depth on the ability that the larvae of T. rutilus septentr - of Toxorhynchites to prey is shown in ionalis died when placed in sewage table (8) The data indicated that contaminated water or tap water predation increased as the depth containing approximately 0.3 PPM of decreased. Also the predator larvae chlorine. These results confirm that the consumed more larvae in case of the C. insect larvae respond differently to the pipiens, Ae. caspius in all instars than in same host at different type of water. case of A. pharoensis larvae. The The effect of PH on the predation statistical analysis of data ( table 8 ) efficiency of Toxorhynchites larvae is indicated no significant differences shown in table (7). The results indicated between the number of consumed larvae that PH below 6 and above 11 had bad from C. pipiens, A. pharoensis and Ae. effect on the activity of the 1st instar caspius, by 2nd, 3rd and 4th instars of larvae hence these tests were excluded. Toxorhynchites larvae at the of depth Also the results cleared that the number 15cm and 20cm, but there was a of consumed larvae at the same PH by significant difference between the

76 Hanaa I.Mahmoud

number of consumed hosts of these two eptentrionalis. Mosq. News. 37: depth and the depth of 40 cm in case of 207-211. the same three instars. In case of 1st 7. Eshita , Y.; Kurihara, T. ; Toxorhynchites larval instar there was Ogawa, T. and Oya, A. (1982): significant difference between the Studies on the susceptibility of number of consumed larval host at the mosquito dengue virus.II) improved three depth used. The results are in methods for the laboratory rearing agreement with that obtained by on Toxorhynchites amboinesis Breland (1949), Furumizo et al(1978) (Doles -chall), as laboratory hosts of and Crans and Staff (1977), using the virus, JPn. J.Sanit - Zool . 33: T.rutilus Septentrionalis, where the 65-70 subsurface predation appeared to be 8. Focks, D.A. (1985): Toxorhy more common. -nchites .pp. 42.45 in: H.C Chapman The present results may be (ed.), biological control of mosq - recommended as a useful control meas - uitoes. J. Am. Mosq. Cont rol ure for mosquitoes. Assoc. Bull.6 9. Furumizo, R.T. and Reference Rundnick, A. (1978): laboratory 1. Andrewartha , H.G. and studies Toxorhynchites splendens Birch, L.C. (1954):The distribution Biological observation . Ann. and abundance of . Univ. Entomol .Soc. Am . 71:670-673. Chicago press, Chicago 782p 10. Geberg, E.J. (1970): Manual 2. Annis, B.S.; krisnowardajo, for mosquito rearing and S.; Atmosoedjono and Supardi P. experimental techniques. Bull. Am. (1989):Suppression of larval Aedes Mosq. Control Assoc. 5. 1-109 aegypti populations. In household 11. Goma, L.K.H. (1964): water storage containers in Jakarta, laboratory observation on the habits Indonesia, through releases of first of Toxorhynchites lavae. Ann. Trop. instars Toxorhynchites splendens Med. Parasital . 58:350-54. larvae. J. AM. Mosq. Control Assoc. 12. Horio, M. and Tsukamoto, 5: 235-238 M. (1985): Successful laboratory, 3. Breland , O. P. ( 1949): The colonization of Japanese species of biol -ogy and the immature stages of Toxorhynchites mosquitoes. Jpn the mosquito, Megarhinus septentri .J.Sanit .Zool. 36: 87-93. -onalis Dyar and Knab. Ann. 13. Horio, M. ;Tsukamoto, M. Entomol. Soc. Am. 42:38–47. and lchiro, M. (1990): Anew 4. Chan, K.L. (1968): mutant, white larvae of the mosquito Observation on Toxorhynchites Toxorhynchites splendens: genetics splendens (weide -man) in and cannibalism. J . Am. Mosq. Singapore.Mosq. News. 28:91 -95. Control Asso. Vol. 6 no.3: 441-445 5. Cheong , W.H., and 14. Jenkins, D.W. and Carpenter, Ganapathipillai , A. (1964): S. J. (1946): Ecology of the tree- Preliminary observation on the hole breeding mosquitoes of aquatic stages of Toxorh -ynchites in nearetic North America. Eol Malaya. Med. J. Malaya 19:58. Monoger. 16: 31-47. 6. Crans, W.J. and staff. M.E. 15. Jenkins, D.W. (1964): (1977): Growth and behavior of Pathogen, parasites and predators of colonized medically important

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(Annotated list and bibiorgraphy). Bull . WHO. 30:1-150 (suppl). 22. Richard, A. G. ( 1938): 16. Kardatzke, J. I. and Khian, k. Mosquitoes and mosquito control on L. (1972): Growth of Aedes long Island, New York, with stimulans and A. vexans (Diptera: particular reference to the marsh Culicidae) in saline solution. Ann. problem. Bull. N. Y.st. Mus. 316: Entomol .Soc. Am , Vol.65, no.6. 85– 180. 17. Laird, M. ( 1947 ): Some 23. Rosen, L. (1981): The use of natural enemies of mosquitoes in the Toxorhynchites mosquitoes to detect vicinity of pal mol mal, New Britain and propagate dengue and other . Trans. K. Soc. N. Z. 76: 453– 76. arboviruses. Amer. J. Trop. Med. 18. Lounibos, L.P. (1979): Hyogo, 30:177. Temporal and spatial distribution 24. Terzian, L.A. and Stahler, N growth and predatory behavior of (1949): The effects of larval popul - Toxorhy -nchites brevipalpis on the ation density on some laboratory Kenya coast. J. Anim .Ecol. 48:213- characteristics of Anopheles quadri - 36. maculatus.J. Parasital. 35: 487-98. 19. Mkoji, G.M; Boyce, T.G.; 25. Trpis M. (1972): Boyce, T.G.; Mungi, B.N Development and predatory ;Copeland, R.S; Hofkin, B.V. and behavior of Toxorh -ynchites Loker, E.S. (1999): predation of brevipalpis (Diptera: Culicidae) in aquatic stages of Anopheles gom - relation to temperature Environ . biae by the Louisiana red swamp Entomol 1:537-46. crawfish. J.Am. Mosq Control 26. Ward, J. (1962): Effect of kcl Assoc., 15(1): 69-71 and dolometric limestone on growth 20. Paiva, G.A. (1910): The and ion uptake of sweet Soil. Sci, Toxorhynchites splendens Larvae 89:347-352. were predators of number of 27. World Health organization mosquito larvae. Res. Indian, Mus, (1995): Vector control for malaria 5:187-190. and other mosquito — borne 21. Rawlins, S.C.; Clark, G.G; diseases: report of a who study and Martinez, R. (1991): Effects of group. Technical report series 857. single introduction of Toxorh - Geneva Switzerland ynchites moctezuma upon Aedes 28. Yasuno, M. and Tonn, R.J aegypti on Acaribbean island J. (1970): Bionomics of Toxorhy - Am. Mosq. Control Assoc. vol. 7, nchites splendens in the larval no.1: 7-10 habitats of . In Bangkok, Thailand. Bull . WHO 43: 762-66

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79 Effect of Some Environmental Factors

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81 Effect of Some Environmental Factors

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تأثير العوامل البيئية على فعالية اإلفتراس للبعوضة

توكسورينكيتس سبلندنز)رتبة ثنائية األجنحة – كيولسيدى(

د/ هناء ابراهيم محمود محمد

كلية العلوم جامعة االزهر قسم علم الحيوان فرع بنات

يبحثث ىثث ا امل ثثظ ام ثثثلى استخثثم الثثوض ا امبلثث توكسووونكنتي س لوونلند ك لثثةخل مخ فجة ثثل اةة يثثل من ىثثج ثث

نجقالت األ ثا األن اع األخثى مخبل .

03 03 لج أن ةلجمةل ااةرتاس م قجت امبل توكسوونكنتي س لونلند تزيث ززيثج د اجثجت اةثثااد ث ْ -

تسوهخك ام قجت استرتلل د أك ر ث التيوولتس بيننو و األكود كسونيس دث يثقثجت أ ووفليس فرعوون ل تثو د خةثل

ااةرتاس م قجت توكسونكنتي س تقثيبجً زنتس اسسو ي يف كظ اججت اسخ حل.

ل جهل أخثى لج أن امض ء مو تأث ضئةظ دخث يثقثجت زلث توكسوونكنتي س ث حةث اتذوث اء حةث أن ةلجمةثل

ااةرتاس تقظ يف ام ال .

أيضجً لجث أن اموثزاح مثةس مثو تثأث دخثم د خةثل ااةثرتاس لقث مث ح دث لجث لةةثجت أل يهث ا أ ثثا بةلةثل زث

يثقجت اةشثات اسضو رد أثنجء ةرتات ااخوبجا . لى ه ام جىثد ت ضح أن ىث ه اةشثثات تتضثظ املثةجم م او لثجت دجمةثل

اموزاح . ل تسوطةع يثقجت توكسونكنتي س أن تلةجم حةجد بةلةل م كظ اسةجه املفثد لاسةجه اسقطثد لمفنهثج وث ت ا ا

لضثثثل م ةثثثجه خ ثثثثل) ةثثثجه اثثثجاى(. لأن أكثثث ر دثثث ثثث يثقثثثجت امتثثثثا س تخثثثوه ز الثثثطل يثقثثثجت توكسوووونكنتي س- كثثثظ

األد جا- يف ن دن PH )8( , يخةهج م اموثأث PH )7( مث PH )9( أ ثج PHدنث األقثظ ث )6( ل أكث ر ث

)11( ةق لج أن هلج تأث لئ دخم امنشجط ااةرتالم منتس ام قجت.

لتثز ا ةلجمةثل ااةثرتاس م اسثجء تث امةجً ث د ثث 03لث ا 13لث , لقث مث ح أن يثقثجت ال وكسووونكنتي س

تقونص امتثيسل ا ج دخم لطح اانجء أل م امقجع .

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