The Behaviour and Mortality of Anopheles maculatus and Culex fatigans in experimental Huts treated with DDT and BHC

Experimental huts fitted with window traps, of the same basic design as those described by Thomson (1948), modified for Malayan conditions, were used in studying the behaviour and mortality of A. maculatus in relation to DDT and BHC. Other species of Anophelines formed a large proportion of the human bait trap catch but rarely entered the huts.In untreated huts, A. maculatus fed at all hours of the night with a peak between 9 p.m. and midnight. The large majority left before 8 a.m. in search of outdoor resting places, at least 50 per cent. before dawn. It appeared that attraction to light was the strongest, but not the only factor influencing exit from the huts.Large numbers of Culicines (mostly Culex fatigans) were recovered. In untreated huts about 80 per cent. were blood fed ; 28 per cent. were in the window traps.DDT (33 per cent.) and BHC (“ Gammexane P530 and P520 ”) water dispersible powders were tested.An application of 100 mg. DDT and 20 mg. γ BHC (P530) per sq. ft. was unsuccessful, due in part to the small numbers of mosquitos recovered. No conclusions are drawn from the results.DDT at 200 mg. and BHC (P520) at 40 mg. γ isomer per sq. ft. were both effective for at least 12 to 16 weeks against A. maculatus. With DDT, 63 per cent. initial, and 83 per cent. 24-hour corrected mortalities were recorded over 16 weeks. With BHC, though the initial mortality dropped from 100 per cent. in weeks 1–4 to 19 per cent. in weeks 12–16, the 24-hour mortality, almost 100 per cent. for weeks 1–10, was still 88 per cent. for weeks 12–16.DDT apparently had little effect on the feeding of A. maculatus ; with BHC there was a reduction in the percentage fed.DDT was relatively non-lethal to C. fatigans, but had a marked irritant effect driving them into the light trap and the biting rate was reduce to 45 per cent. BHC killed all C. fatigans which entered for 2 weeks but most of its toxic effects were lost by the eighth week. The biting rate was reduced to 27 per cent. for weeks 1 to 8 and the majority of mosquitos were recovered in the light trap.Ants, cockroaches, spiders, etc., were found to affect the number of mosquitos recovered and special precautions had to be taken against losses.The results suggested that BHC when freshly applied acts as a repellent to mosquitos.Mansonia uniformis was shown to be susceptible to both DDT and BHC residual deposits.

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The Effects of House Spraying with Pyrethrum and with DDT on Anopheles gambiae and A. melas in West Africa

Bulletin of Entomological Research ◽

10.1017/s0007485300022276 ◽

1947 ◽

Vol 38 (3) ◽

pp. 449-464 ◽

Cited By ~ 39

Author(s):

R. C. Muirhead Thomson

Keyword(s):

West Africa ◽

Lethal Dose ◽

Substantial Reduction ◽

Lethal Effect ◽

Mosquito Population ◽

Effective Control ◽

Repellent Effect ◽

Experimental Huts ◽

Large Numbers ◽

Window Traps

1. The behaviour of A. gambiae and A. melas in houses is described in relation to possible use of pyrethrum and DDT.Pyrethrum.2. Mass spraying of isolated villages with pyrethrum in kerosene four times a week reduces the day-time catch of Anopheles to one-third. The sporozoite rate of mosquitos in sprayed villages remains much the same as before treatment.3. Observations in experimental huts with window traps attached show that pyrethrum exerts a repellent effect on many hungry Anopheles for a day or two after spraying, provided blood meals can be obtained easily in adjacent untreated houses.4. Where all available huts occupied by man are sprayed, there is no great repellence to hungry mosquitos, which continue to feed in large numbers even in huts sprayed every day.5. In untreated huts about 20 per cent. of the blood-fed females leave the house at dawn after feeding. In huts sprayed daily the proportion increases to about 80 per cent.6. The fall in the house catch in villages sprayed 4–6 times a week is not due to any great reduction in the mosquito population, but to a shift from indoor to outside resting places.7. As intense house spraying with pyrethrum fails to bring about any substantial reduction either in the mosquito population or in their infectivity, it is not likely to be of great anti-malaria value in West Africa.DDT.8. Mass spraying of village houses with 5 per cent. DDT in kerosene produces a dramatic fall in the day catch of resting Anopheles in houses. The catch remains very low for 4 weeks after treatment and it is still fairly low after 2 months.9. Observations in experimental huts (fitted with window traps) treated with DDT in kerosene show that mosquitos may enter and feed within a few days of treatment. By the second week after treatment large numbers of Anopheles may feed every night in treated huts.10. There is no evidence of mosquitos succumbing to the effects of DDT in kerosene inside the hut. Nearly all the Anopheles feeding in such huts leave after feeding and show no appreciable mortality in the following 48 hours.11. The DDT in kerosene has a marked residual irritant effect on Anopheles, driving them out of the house after they have fed, and preventing mosquitos resting long enough on treated surfaces to absorb a lethal dose of DDT.12. The few days complete protection from biting mosquitos which follows spraying inside the house with DDT in kerosene, is shown to be due mainly, if not entirely, to the repellent effect of the heavy dose of kerosene which accompanies the DDT.13. Treatment of all rooms in an isolated village reduced the day catch to nil during 5 weeks after treatment. In outside resting places beside the village, bloodfed and gravid Anopheles, of which 2 per cent. had sporozoites in the salivary glands, Were taken regularly during this period.14. The apparent elimination of mosquitos from houses following treatment of rooms with DDT in kerosene is due to a complete shift from inside to outside resting places, on account of the residual irritant, but not lethal, effect of DDT-in-kerosene treated surfaces.15. The sharp fall in the house catch of Anopheles following treatment Of West African village houses with DDT in kerosene can not, therefore, be accepted as evidence of mosquito reduction or effective control.

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Role of modified CDC miniature light-traps as an alternative method for sampling adult anophelines (Diptera: Culicidae) in the National Mosquito Surveillance Programme in India

Bulletin of Entomological Research ◽

10.1079/ber2003281 ◽

2004 ◽

Vol 94 (1) ◽

pp. 55-63 ◽

Cited By ~ 11

Author(s):

C. Sadanandane ◽

P. Jambulingam ◽

S. Subramanian

Keyword(s):

Light Trap ◽

Light Traps ◽

Surveillance Programme ◽

Seasonal Trends ◽

Large Numbers ◽

Distribution Vector ◽

Outdoor Resting ◽

Laboratory Bioassays ◽

Indoor And Outdoor

AbstractThe efficiency of modified CDC miniature light-traps for sampling adult mosquitoes was evaluated in comparison with indoor resting, outdoor resting, indoor man-landing and outdoor man-landing collections in the hilly district of Koraput, Orissa, India. Overall, light-traps captured 78% of adult mosquitoes collected by all methods. Of the 16 anopheline species recorded in the study area, light-traps effectively sampled 13, contributing about 72% of the total anophelines collected by all methods. Light-traps also caught a large number of female Culex vishnui Theobald (96%). As fully-fed mosquitoes were predominant (82%) and caught alive, light-traps can be used to catch large numbers of vector mosquitoes for studies on vector prevalence, distribution, vector incrimination and also for laboratory bioassays. Light-trap and indoor resting collections revealed similar seasonal trends in numbers of Anopheles culicifacies Giles, A. fluviatilis James, A. jeyporiensis James, A. vagus Doenitz, and A. splendidus Koidzumi. Age-structure of the samples did not vary significantly between the two methods. Light-traps could be used as an alternative to daytime indoor resting collections to monitor the seasonal fluctuations in the abundance and parity rates of these species. The light-trap collections correlated with indoor and outdoor man-landing collections of A. jeyporiensis and the outdoor man-landing collections of A. maculatusTheobald in measuring seasonal trends. Light-trap collections can thus be used as a substitute for man-landing collections of A. jeyporiensis and A. maculatus.

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Light-Trap Catch of Turnip Moth (Agrotis segetum Denis et Schiffermüller, 1775) in Connection with the Night Sky Polarization Phenomena

Global Journal of Research and Review ◽

10.21767/2393-8854.100022 ◽

2017 ◽

Vol 04 (02) ◽

Cited By ~ 1

Author(s):

Laszlo Nowinszky ◽

Miklos Kiss ◽

Janos Puskas ◽

Andras Barta

Keyword(s):

Light Trap ◽

Agrotis Segetum ◽

Trap Catch ◽

Turnip Moth ◽

Polarization Phenomena ◽

Night Sky

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Experiments on the Effect of Residual Insecticides in Houses against Anopheles gambiae and A. funestus

Bulletin of Entomological Research ◽

10.1017/s0007485300023051 ◽

1953 ◽

Vol 44 (2) ◽

pp. 231-254 ◽

Cited By ~ 45

Author(s):

G. Davidson

Keyword(s):

Lethal Dose ◽

Significant Proportion ◽

Internal Surface ◽

The Other ◽

Wall Surface ◽

The Third ◽

Experimental Huts ◽

Wettable Powder ◽

Window Traps ◽

Very High

Experimental huts similar in construction to the dwellings commonly used in East Africa, but with exit window traps, were sprayed with various formulations of the three residual insecticides, DDT, BHC, and dieldrin, and the effect on the A. gambiae and A. funestus entering them was observed.The almost complete absence of kill recorded by Muirhead Thomson (1950) in experiments in similar huts in Tanganyika treated with DDT Ditreen was not confirmed by these experiments.A significant proportion of the A. gambiae and A. funestus entering huts treated with DDT did, however, escape unharmed, even immediately after treatment, whereas with the other insecticides, BHC and dieldrin, none of these mosquitos escaped the effect at least in the first month after treatment.In preliminary experiments in which observations were carried on for nine months after treatments, BHC P.530 still showed some effect after seven months. This was almost certainly due to the fumigant effect of the small amount of insecticide still remaining below the wall surface. The irritant properties of the two DDT formulations, Ditreen and the oil-bound suspension “Supona” D, still existed after nine months.In a second group of experiments, dosages of less than 80 mg. DDT and less than 60 mg. BHC (8 mg. of the gamma isomer) per sq. ft. gave over 50 per cent. kills of A. gambiae and A. funestus for only one month.In a third group of experiments, using two formulations of BHC, five of DDT, one of a mixture of DDT and BHC and one of dieldrin:—(a) Dieldrin was by far the most efficient insecticide and gave very high kills for over seven months.(b) The DDT formulations, Murphy paste, Murphy wettable powder, suspensions of DDT crystals <30 μ and 30–70 μ in diameter, when applied to the whole internal surface of the huts, produced fairly high kills over the period of the observations (six to seven months), but significant proportions of the mosquitos escaped their action even immediately after treatment.(c) The BHC formulations, P.520 and the oil-bound suspension “Supona” B, gave high kills for three to four months only.(d) The mixture of BHC and DDT in oil-bound suspension “Supona” DB gave the high initial kill of BHC and the long-lasting moderately high kill of DDT.(e) Against C. fatigans all the DDT formulations used in the third group of experiments gave very low kills, the BHC formulations high initial kills and dieldrin high long-lasting kills.BHC has marked fumigant and particulate properties lasting for three to four months. Dieldrin has a remarkable particulate action, which produces for the whole six-month period of the experiment, very high kills among mosquitos suspended without actual contact with the insecticidal surfaces; DDT only shows this particulate effect to a slight extent.It is probable that the differences in the toxicities to mosquitos of the insecticides used in these experiments is due partly to differences in the irritant properties of the insecticides. In the case of DDT many of the mosquitos having contact with this insecticide are irritated and escape from the treated surface before acquiring a lethal dose.

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A verandah-trap hut for studying the house-frequenting habits of mosquitos and for assessing insecticides. II.—The effect of dichlorvos (DDVP) on egress and mortality of Anopheles gambiae Giles and Mansonia uniformis (Theo.) entering naturally

Bulletin of Entomological Research ◽

10.1017/s0007485300056364 ◽

1965 ◽

Vol 56 (2) ◽

pp. 275-282 ◽

Cited By ~ 24

Author(s):

Alec Smith

Keyword(s):

Anopheles Gambiae ◽

Chemical Analyses ◽

Window Traps ◽

Anopheles Gambiae Giles ◽

Mansonia Uniformis

Assessment of the effects of dichlorvos (DDVP), released from a Ciba XI dispenser, on females of Anopheles gambiae Giles and Mansonia uniformis (Theo.) entering a verandah-trap hut in the Umbugwe area of Tanzania was made over a period of two months in 1964. Of the numbers of A. gambiae that entered one treated and one untreated hut, 27 per cent, of those entering the hut treated with dichlorvos and 48 per cent, of those entering the untreated hut left again. Of the numbers leaving each hut, 38 per cent, left through the eaves of the treated hut as compared with 9 per cent, in the untreated one. In the case of M. uniformis, 88 per cent, of those entering the treated hut and 94 per cent, of those entering the untreated hut left again. Of the numbers leaving each hut, 59 per cent, left through the eaves of the treated hut as compared with 61 per cent, in the untreated one.Over-all mortalities were 56 per cent, for A. gambiae and 34 per cent, for M. uniformis when the eave-egress fraction from the treated hut was taken into account, compared with 62 per cent, for A. gambiae and 43 per cent, for M. uniformis when the eave-egress fraction was ignored.The results of bioassays and of chemical analyses showed that the problem of mortality from fumigation in situ was considerably less in verandah traps than indoors or in window traps fitted with funnels of cotton netting.

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Light-trap catches of African armyworm moths, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae), in relation to rain and wind

Bulletin of Entomological Research ◽

10.1017/s0007485300008907 ◽

1983 ◽

Vol 73 (2) ◽

pp. 315-319 ◽

Cited By ~ 18

Author(s):

M. R. Tucker

Keyword(s):

East Africa ◽

Light Trap ◽

Spodoptera Exempta ◽

Trap Catch ◽

Early Season ◽

African Armyworm ◽

Light Wind ◽

Trap Catches ◽

Lepidoptera Noctuidae ◽

Very High

AbstractThe association between weather and light-trap catches of Spodoptera exempta (Wlk.) was examined for four traps in East Africa, using whole–night catches and several years' data. Large increases in trap catch were found to be (1) significantly associated with rain at all four traps for the period December–March, but not for later in the season; (2) significantly associated with light wind periods at Muguga for December–May, but not later in the year, and not at Nakuru, due to the very high overall frequency of light winds there; and (3) not significantly associated with windshifts at either Muguga or Nakuru. These results suggest that high densities of flying moths, which may give rise to caterpillar outbreaks early in the year, often occur where the rather infrequent early–season rains fall.

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The analysis and standardisation of light-trap catches of Heliothis armiger (Hübner) and H. punctiger Wallengren (Lepidoptera: Noctuidae)

Bulletin of Entomological Research ◽

10.1017/s0007485300008245 ◽

1981 ◽

Vol 71 (2) ◽

pp. 207-225 ◽

Cited By ~ 32

Author(s):

R. Morton ◽

L. D. Tuart ◽

K. G. Wardhaugh

Keyword(s):

Wind Speed ◽

Light Trap ◽

Adult Emergence ◽

Wind Speeds ◽

South Wales ◽

Large Numbers ◽

Successive Generations ◽

Hourly Distribution ◽

A Site ◽

Trap Catches

AbstractHourly and nightly catches of Heliothis armiger (Hb.) and H. punctiger Wllgr. at a site adjacent to 2000 ha of commercial cotton in the Namoi Valley of New South Wales, were analysed in relation to various environmental factors and showed that wind speed, temperature, night-length and (H. armiger only) moonlight exerted a significant influence on trap-catch. For H. punctiger and H. armiger respectively, these factors accounted for 80 and 60% of the deviance in hourly catches but only 70 and 40% of the variation in nightly catches. Wind speeds of more than 1·7 m/s suppressed the catch of both species but had a greater effect on H. punctiger than H. armiger. Whereas with both species, the optimum temperature for trapping was about 27°C, temperature had a greater influence on the catch of H. punctiger than of H. armiger. Bright moonlight was estimated to reduce the catch of H. armiger by 49%, but no significant effect was detected for H. punctiger. The analysis revealed a number of occasions for both species in which the hourly distribution of catch and/or the change in catch between successive nights was aberrant. With H. armiger, these inconsistencies appeared to be associated with changes in population due to adult emergence, whereas for H. punctiger the most likely cause seemed to be changes due to movement. The combined effects of wind speed, temperature, night-length and moonlight were used to adjust the nightly catches of each species according to the environmental conditions prevailing on a ‘ standard’ night. This was defined as a typical summer's night with temperatures decreasing from 28·8°C at dusk to 20·6°C at dawn and ideal catching conditions, i.e. no moon and wind speed never exceeding 1·7 m/s. As such, the adjusted catches could be taken as indices of moth abundance. These showed that H. armiger had three discrete periods of abundance, characterised by the presence of large numbers of young moths and spaced at intervals suggesting successive generations. A similar pattern was lacking in H. punctiger, which was abundant only during the first half of the season. Except during periods of emergence (H.armiger), or once when spraying occured during daylight, the aerial application of insecticides to the cotton adjecent to the light-trap resulted in marked reductions in the populations of both species.

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