bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oviposition in DDT-resistant and susceptible strains ofAëdes aegypti(L.) in relation to light preference.
Authors: Wood R. J. 
Published: July 2009

Seven strains ofAëdes aegypti(L.), three DDT-resistant (from Trinidad (2) and Haiti) and four susceptible (from West Africa (2), Arabia and U.S.A.) have been investigated with respect to their attraction to oviposition sites illuminated at different levels. The resistant strains have tended to choose the darker sites (at 0·02 lumen per sq. ft. and below) and susceptible strains those illuminated at between 3·5 and 6·5 lumens per sq. ft.Genetical crosses between a ‘dark-laying’ (resistant) strain and a ‘light-laying’ (susceptible) strain indicated that ‘light laying’ was fully dominant over ‘dark laying’ and it is suggested that the mechanism involved is probably simple. No linkage with the gene for physiological resistance to DDT could be demonstrated.The expressivity of this character varied in certain circumstances with a tendency among most strains to lay at darker sites after the second and subsequent blood-meals. In spite of these variations, behaviour at any one time remained reasonably predictable.The reflectance of the oviposition site did not appear to be important in determining the difference in behaviour between ‘dark-laying’ and ‘light-laying’ strains. On the contrary, it seemed probable that ‘dark-laying’ strains were attracted more to the dark situation in which the dimly-lit site was found rather than to the site itself. There was some evidence of exploratory activity in the initial stages of oviposition by a ‘dark-laying’ strain.Resting habits proved very similar in two strains differing markedly in oviposition habit. For both strains, 0·1 lumen per sq. ft. was apparently too low to be attractive and 12 lumens per sq. ft. too high. Besting behaviour did not appear to be under such critical control by light as was oviposition.Possible explanations for the differences in ‘oviposition light preference’ are discussed.
An experiment in the use of discriminative clearing for the control of Glossina morsitans Westw. in Ankole, Uganda
Authors: Harley J. M. B. , Pilson R. D. 
Published: July 2009

The situation following different degrees of discriminative clearing against G. morsitans Westw. was examined in eastern Ankole District, Uganda. In one area, where the treatment had been more intensive, the fly density was low, and it seemed that the population might be maintained by immigration from an adjacent area to the west, where treatment had been less intensive and in parts of which fly density was relatively high. The application of more intensive discriminative clearing of the fly's concentration sites to the western area, together with completion of the treatment of the eastern, failed to result in any marked effect on the tsetse population except as regards its distribution. Before this intensive clearing, concentrations of G. morsitans occurred in a double-storey vegetation type, the chief component of the upper storey of which consisted of Acacia gerrardii. After the upper-storey trees in this were felled, concentrations were found in groups of tall Acacia hockii, 12–18 ft. high, which had appeared to be of little importance to the fly before clearing. A year after the treatment of the western area there was no apparent reduction in fly density. The feeding habits and rate of utilisation of reserves of the flies showed no significant change as a result of clearing.It seems that the failure of the discriminative clearing régime applied in this area, compared with the effect produced by less intensive clearing elsewhere in Ankole, is due to the presence in this area alone of the groups of tall A. hockii.
Seasonal variation in size and colour, and daily changes in the distribution of Glossina pallidipes Aust. in the South Busoga forest, Uganda
Authors: Glasgow J. P. 
Published: July 2009

SummaryThe daily distribution of G. pallidipes Aust. was studied on a spiral fly-round covering 180 acres in the South Busoga forest of Uganda in 1954–55. G. brevipalpis Newst. also occurred in the forest, and, rarely, G. palpalis fuscipes Newst. Seasonal changes occur in the size of G. pallidipes, but are less marked than those reported from other places. The size of G. brevipalpis also varies with season. Seasonal colour changes in G. pallidipes indicate that in the driest season about half the puparia experience relative humidity as low as 70 per cent.Catching was done at 349 (later increased to 373) points on the spiral. Mathematically, the catches on a single day, or the sum of many days, conformed to a negative binomial distribution. Although this indicates an uneven distribution, it is pointed out that one negative binomial is compatible with many different distributions on the ground. For this reason the negative binomial is not a satisfactory summary of data which at present can only be shown satisfactorily on a map.Comparison of maps of catches on successive days shows a confusing pattern of vague and ill-defined patches of flies moving about in an unpredictable fashion. A definitive pattern appears only when many days' catches are summed. Such apparently random movement explains the high variance between days' catches previously reported. Sometimes very large numbers of G. pallidipes were found in a small area. As an index of such concentrations, the smallest area which could contain half the day's total catch was determined. Arbitrarily, when half the day's total catch was found in 5 per cent, or less of the total area, a concentration was said to exist. During 16 months' work, concentrations of tsetse, as defined by this criterion, were observed 16 times. Sometimes, but not always, the concentrations followed immediately after the passage of a herd of elephants or buffaloes, and it is concluded that these animals probably caused these concentrations, although the manner in which they may do so remains obscure.
The susceptibility of tsetse flies to topical applications of insecticides. II.—Young adults of Glossina morsitans Westw. and organophosphorus compounds, pyrethrins and Sevin
Authors: Burnett G. F. 
Published: July 2009

SummarySolutions of six organophosphorus compounds, Sevin, and pyrethrins (alone or synergised with piperonyl butoxide) were applied by microburette in drops of constant volume (0·0216 μl.) to the dorsum of the thorax of young adults of Glossina morsitans Westw., 2–5 days old that had taken their first blood-meal the previous day. The solvents used were decalin (decahydronaphthalene), toluene and lighting kerosene, respectively.Malathion, methyl-parathion, DDVP (dichlorvos) and Sevin were eliminated in preliminary tests as insufficiently toxic. Muscatox (coumaphos) was reasonably toxic but not readily soluble and was therefore not considered further. Diazinon and Baytex (fenthion) were fully evaluated; the former was about as lethal as DDT, the latter as γ BHC (LD50 about 0·004 μg.). The LD50 of diazinon for males (0·0115 μg.) was significantly smaller than that for females (0·016 μg.) but the LD95 was much the same for both sexes.Pyrethrins were about equitoxic with dieldrin (LD50, 0·002 μLg.); when synergised with 15 parts of piperonyl butoxide to one of pyrethrins the LD50 for males was reduced to less than half this value, and there was a significant difference in susceptibility of the sexes, the LD50 for females being 1·4 times that for males. However, the slopes of the regression lines were such that at LD95 the difference between synergised and plain pyrethrins was too small to be of any practical use.These results show that, judged by innate toxicity to young flies, none of these insecticides can compete with dieldrin or Telodrin for practical control, although Baytex is a useful reserve should Glossina acquire resistance to chlorinated hydrocarbons.
Culture of an organophosphorus-resistant strain ofBoophilus microplus(Can.) and an assessment of its resistance spectrum
Authors: Shaw R. D. 
Published: July 2009

Field observations indicated that a strain ofBoophilus microplus(Can.) in the Rockhampton area in Queensland was resistant to an organophosphorus insecticide, dioxathion (applied as Delnav), which had previously controlled it successfully. Ticks of this strain were despatched to the Cooper Technical Bureau in England, where a culture was established and maintained under selective pressure from dioxathion.The non-parasitic stages of the culture were maintained in an incubator under controlled conditions, and the parasitic stages on cattle in a tick rearing house designed for the purpose. Careful security precautions were taken to ensure that there was no dissemination of tick life outside the confines of the culture. The tick rearing house was provided with double doors, the inner ones of which were screened with copper gauze to prevent the possible transmission of anaplasmosis by biting flies.The activities of 23 insecticides against larvae of this strain and larvae of a strain ofB. microplussusceptible to organophosphorus poisoning were compared. The test method was an immersion technique, usually employing the insecticide in the form of an emulsion. Mortality was assessed 17 hours after treatment. These comparisons indicated that the strain was resistant to the organophosphorus insecticides carbophenothion (62 ×), dioxathion (25 ×), diazinon (15 ×), parathion (10×) and a carbamate, carbaryl (38×). It is suggested that these resistances may be due to a specific mechanism effective against these compounds.Nine other organophosphorus insecticides, one carbamate and rotenone were subject to low-order resistance by this strain significant at P ≤0·05. This was considered to be non-specific resistance.Dioxathion had been in use for tick control on the property concerned for four years before resistance was demonstrated. The property is situated in an area where the tick season lasts for ten months. In other parts of the world, dioxathion has been in use againstBoophilusticks for seven years without the development of resistance to it. The length of time resistance has taken to develop suggests that the resistance mechanism is not the expression of a single dominant gene, as has been demonstrated for dieldrin-resistance.The results suggest that resistance to one or more organophosphorus insecticides will not necessarily prevent the use of other members of this wide and diverse group for tick control. Several of the insecticides shown here to be subject to low-order non-specific resistance are known to be effective tick dips, and one of them, ethion, has been used with success against the resistant strain.An interesting corollary of the results was that the organophosphorus thions showed greater activity than their corresponding oxons against the susceptible strain.
Effects of DDT on oxygen consumption of Rhodnius prolixus Stål
Authors: Spiller D. 
Published: July 2009

When fasting fifth-instar larvae of Rhodnius prolixus Stål were poisoned with a lethal dose of DDT, the rate of oxygen consumption increased from the onset of hyperactivity, reached a marked peak shortly after knockdown, and then declined. For some days after the peak the oxygen consumption was markedly in excess of that prior to poisoning with DDT. Eventually, the oxygen consumption fell below the pre-teatment value and continued at this low level for some days, although the insect was then undoubtedly dead and in one case had been bisected. There was no marked discontinuity in the declining phase of oxygen consumption and therefore there is no indication of when death occurred. It is concluded that the time of death in DDT-poisoned larvae of Rhodnius cannot be determined by measurements of oxygen consumption.The total oxygen consumed from poisoning until death was always less than that consumed in the normal use of all metabolic reserves by the fasting insect, and these experiments do not support the hypothesis that death in DDT poisoning is due to total exhaustion of metabolic reserves. However, it is pointed out that, in Rhodnius, some of the metabolic reserves are contained in the undigested residue of the blood-meal and in the massive endocuticle and that there is no reason to think that either digestion of the remaining blood-meal or resorption of the endocuticle could be speeded up during DDT poisoning. Hence there is a strong possibility that, in DDT-killed Rhodnius, death is brought about by exhaustion of the available reserves.The peak rate of oxygen consumption during poisoning was greatest in very recently fed larvae and decreased as the interval between moulting and DDT-treatment was increased. This suggests that knockdown occurs when the fuel demands of the DDT-induced activity exceed the rate at which the fuel can be mobilised from the metabolic reserves.
Relative persistence on vegetation in northern Nigeria of DDT deposits from two formulations
Authors: Riordan K. 
Published: July 2009

The persistence of DDT deposits on vegetation in the Northern Guinea Savannah zone of Nigeria was studied by chemical analysis of leaf samples and by bioassay tests with teneral females of Glossina palpalis (R.-D.). Two formulations of DDT were used, one (A) made by mixing a 75 per cent, wettable powder with water to give a 5 per cent, suspension, the other (B) made by adding a household detergent to A at the rate of 3·8 g. per gal. suspension. They were applied to foliage by knapsack sprayer in August 1964, about the middle of the rainy season.It was noted that the particles deposited from B were finer and more evenly distributed over the leaf surface than were those from A. Chemical analysis of leaf samples showed that the deposit from B was initially the higher. Both deposits declined greatly during the first six weeks after application, coinciding with the period of heaviest rainfall. Those from A and B reached 49·8 and 46·2 per cent., respectively, of their initial levels at the end of the second week, and 9·2 and 5·2 per cent, at the end of the sixth. From then to the end of the sixteenth week, when the observations ended, no further decline was observed. In the tests with G. palpalis, deposits from A and B caused mortalities of 60.3 and 66.8 per cent., respectively, in the fourth week and 79·4 and 82·8 in the fifth, no mortalities below the latter being subsequently observed up to the tenth week.It is considered that rainfall was the main factor responsible for removing the deposits from foliage. After the end of the rainy period, losses of the deposits became negligible. Deposits from B at first declined faster than those from A. It is considered that this was due to the faster removal by rain of the smaller particles.Heavily weathered deposits were highly toxic to G. palpalis under the test conditions, and it seems likely that under natural conditions of contact they would have exerted still greater toxicity.
The effects of rearing conditions on the immature stages and adults ofSpodoptera littoralis(Boisd.)
Authors: Rivnay E. , Meisner J. 
Published: July 2009

Some effects on the adult of environmental conditions during the larval and pupal stages ofSpodoptera littoralis(Boisd.) were investigated in the laboratory in Israel. The conditions studied were temperature during larval life, temperature and humidity during pupal life and the density at which larvae were kept, and their effects were found by varying one of them at a time. Except for such variations, larvae were reared in batches of 30–50 at 22–24°C. and 60–70 per cent, relative humidity, pupae were kept at 23–24°C. and 70–80 per cent, relative humidity, and adults were kept in pairs at 20–21 °C. and 75–85 per cent, relative humidity. Larvae were fed on clover leaves and adults on sugar solution.High temperature during the larval stage reduced fecundity; whereas at 22°C. the resultant females laid about 1,200 eggs each and 12·5 per cent, produced non-viable ones only, at 30°C. they averaged about 700 eggs each and 50 per cent, produced non-viable ones only. Temperature during the pupal stage affected fecundity similarly and life-span to a lesser extent; at 20 and 34°C., 40 and 5 per cent, of the resultant adults lived 15 days or more, the percentages of females laying only non-viable eggs were nil and 70 and the mean numbers of eggs laid were about 1650 and 700, of which about 60 and 2 per cent, were viable, respectively. High temperatures were directly inimical to pupae, less than half of which survived at 26°C. or over.The effects of humidity during the pupal stage were in general less than those of temperature. The mean life-span was longest in adults from pupae kept at an intermediate humidity of 76 per cent., as also were the proportion of barren females and the mean number of eggs laid; the percentage of viable eggs was reduced only amongst those from females kept as pupae at over 95 per cent, relative humidity. Pupal mortality was affected only by low relative humidities, which raised it.Larvae reared singly tended to be brighter in colour than those reared in batches of 30–50; fewer died and the subsequent pupae were heavier and longer. The mean life-span of the resultant adults was longer, and they laid more eggs.The results are compared with those of other workers onS. littoralisand other insects.
The distribution of Empoasca lybica (de Berg.) (Hemiptera, Cicadellidae) on cotton in the Sudan
Authors: Evans D. E. 
Published: July 2009

The distribution on cotton plants of the eggs, nymphs and to a lesser extent the adults of Empoasca lybica (de Berg.) was studied on the varieties Bar XL1 and BAJ 7/57 in the Sudan during 1961–64. Counts of jassid nymphs in the process of hatching from eggs buried in the leaf veins showed that hatchlings were most numerous on the third to fifth expanded leaves from the main-stem apex and that most eggs had been laid either close to the point of insertion of the petiole into the leaf lamina or about half-way along the length of the veins on the underside of the leaves. The greatest number of hatchlings was found in the central leaf vein. It was concluded that eggs are most frequently laid in this position on newly expanded leaves at the apices of the main stems or side branches.The distribution of the early instars on the main-stem leaves was peaked, with maximum numbers occuring on or about the fifth expanded leaf from the apex; a similar distribution with a less prominent peak nearer to the apex leaf was found on side branches. The later instars, being more mobile, had a more even distribution. In the over-all distribution of nymphs on a typical cotton plant, a combination of the patterns found on main-stem and side-branch leaves, the greatest numbers of jassids occurred in the upper half or upper third of the plant. Co-variance analyses showed that the relation between numbers of jassids per zone and number of leaves per zone was not close and that the manner in which the plants were divided into zones for analysis of the relation greatly affected the correlation coefficients obtained.Regular counts of nymphs and adults on the upper surface of leaves throughout a period of two complete days showed that both nymphs and adults moved to the upper surface of leaves each day between 1400 and 1800 hr. local time and returned to the under surface at about 0300–0400 hr. Neither the environmental factor that stimulated this movement nor the way in which it benefited the insect was clear.
New evidence on the migration of moths of the African armyworm, Spodoptera exempta (Wlk.) (Lepidoptera, Noctuidae)
Authors: Brown E. S. , Swaine G. 
Published: July 2009

Fresh evidence is described which supports the theory that moths of the Noctuid Spodoptera exempta (Wlk.) (the adult stage of the African armyworm) are migratory. The evidence comes from four main sources: a study of fluctuations in numbers of moths caught in a network of light-traps operated in East Africa; the fertilisation rates in samples of females as shown by dissection; the sex ratios in samples of moths caught in light-traps; and a study of the behaviour of moths in the field during the period immediately following emergence. In certain of these features S. exempta is compared and contrasted with the related S. triturata (Wlk.), in which the evidence points against extensive migration.It is concluded that migration occurs in S. exempta, probably on an extensive scale, and that it therefore has an important bearing on the occurrence and distribution of outbreaks of the larvae.
Biting cycles and parity of the mosquitoMansonia (Mansonioides) uniformis(Theo.) in Ceylon
Authors: Samarawickrema W. A. 
Published: July 2009

Two series of all-night hourly catches ofMansonia (Mansonioides) uniformis(Theo.) on the verandah of a house and at an outdoor open site with man as bait and a third series at the same outdoor site with calf as bait were carried out during 1960–62 on an open mixed rubber and coconut estate overlooking a swamp, in Aggona, a village three miles south-east of Colombo. The physiological age of the mosquitos captured was determined by a count of the follicular relies in the ovarioles.The mosquitos were active only at night; the biting cycle on human bait showed two peaks in both situations—a well-defined early peak and an irregular late peak on the verandah and a minor early peak and a larger lat peak at the outdoor site. In the verandah series the two oldest age-groups, 2-parous and 3-parous females, showed more activity during the second peak, while in the outdoor series the oldest age-groups were most active during the early peak, a result suggesting a difference in behaviour on the part of the older females compared with the overall population in both situations.M. uniformiswas strongly attracted to cattle bait; much activity was recorded at this bait site during the first four hours of the night.Age-composition of the populations in all three series was found to be similar irrespective of the site and bait used. The results were more or less constant from month to month in spite of weather changes. Daily mortality ofM. uniformistaken at the two baits was similar and showed consistency from month to month.A large proportion (73.4%) of females returned to feed directly from oviposition.
Anopheline mosquitos found breeding in Israel in 1963–1965 during the last stage of the malaria eradication project
Authors: Barkai A. , Saliternik Z. 
Published: July 2009

Intensive surveys for breeding places of anopheline mosquitos have been carried out in Israel since 1948, and have proved to be very effective for following the dynamic changes in anopheline populations. An account is given is given of the situation with regard to the breeding of anopheline mosquitos in Israel between 1963 and 1965, in the final stage of the malaria eradication project. During this period only nine of the 14 species ofAnophelesrecorded in Israel were found, and of theseA. sergentii(Theo.) andA. superpictusGrassi were the most abundant.About 85 per cent. of the breeding places were found in the northern part of the country. Fifty-four per cent. of the breeding places in the whole country were man-made. Seventeen per cent. of the 1330 samples of larvae determined contained larvae of more than one species. The distribution of different species in various biotopes and the seasonal variation in the number of breeding places of malaria-transmitting anophelines are also described.A. sacharoviFavr., the most important malaria vector in the past, has not been found in Israel since 1960. The observations onA. sergentiisuggest that an exophilic strain of this species has been selected in Israel.A. coustaniLav., hitherto a rare species, has been found breeding more frequently in recent years.The information collected during 1963–1965 is discussed for each species.