bluuebunny/crossref_metadata_2025_split huggingface dataset:
Entomological Studies, relating to Yellow Fever Epidemiology, at Gede and Taveta, Kenya
Authors: Lumsden W. H. R. 
Published: July 2009

The theoretical objections to the explanation of the persistence of yellow fever virus in areas subject to a prolonged dry season by cycles involving only mosquitos and wild primates are discussed in relation to the results of field surveys in areas of this type in Kenya. The localities studied were Gede, on the coast about 65 miles north of Mombasa, and Taveta, near Mount Kilimanjaro.The topography, climate, vegetation and human population of the areas are briefly described.Gede was visited towards the end of the dry season, Taveta during the main wet season. Thus most of the data relating to conditions during the dry season are derived from Gede, the results from Taveta being used mainly for comparative purposes. The work included 24-hour baited catches at two levels, moving catches, and larval collections in all the main typical environments.All the species of biting arthropod encountered at each locality are recorded; in each case most were mosquitos.At Gede the only mosquitos which were abundant as biting adults were species which breed in sea water, Aëdes fryeri (Theo.) and A. pembacnsis (Theo.), and they were practically confined to the close vicinity of their breeding places. The vertical distributions and biting-cycles of these species are defined.At Gede, mosquito larvae could readily be obtained by filling tree holes artificially with water but no naturally water-filled tree holes were discovered by intensive searches in all the natural environments present in the area. Nor were any water-containing leaf axils discovered.
The relative Control Values of different Percentage Mortalities
Authors: Solomon M. E. 
Published: July 2009

Percentage mortality by itself is not a good measure of the practical value of an insecticidal treatment. In a relatively simple case, such as the fumigation of stored products, the control value can be expressed in terms of the time required for the reduced population to return to its former level of density, provided the mode of increase of the population is known.Assuming that increase is at a regular exponential rate, the control values of different mortality percentages can be compared in terms of the calculated recovery times; thus, each of the values in the series 99·6, 93·75, 75, 50 and 29 per cent. mortality is twice as good as the one that follows it. Such relationships can be deduced from the graph provided, which is essentially a curve of constant exponential growth, made linear by the use of the logarithmic scale.The above comparisons do not depend on the value of the constant rate of increase. If the rate of increase varies, control values can still be compared so long as it is possible to calculate the relative times needed for recovery from different levels of density.
Physiological Action of Drugs and Insecticides on Insects
Authors: Naidu Mohan Babu 
Published: July 2009

The action of certain drugs and insecticides on the frequency of the beat of the isolated cockroach heart, immersed in an aerated physiological solution at 29°C., have been studied. The frequency of the heart-beat is counted by eye and the drugs applied in the physiological solution. Acetylcholine at a concentration of 5 × 10-8to 10-5causes a sustained acceleration of the heart-beat which is blocked by atropine (5 × 10-5) and is unaltered by hexamethonium (5 × 10-5), prolonged exposure to nicotine (5 × 1O-5) or ergotamine (3 × 10-6). In this range of concentration ACH has a “muscarine-like” action.Adrenaline (3 × 10-6to 5 × 10-8) also causes an acceleration of the heart-beat, which soon passes off. Nor-adrenaline has the same action. Nicotine, hexamethonium or atropine do not modify the action of adrenaline, but ergotamine antagonises it.Nicotine (5 × 10-5produces an acceleration of the heart-beat which declines with prolonged exposure until ultimately no effect is produced on reapplieation, but recovery occurs with sufficient washing. Hexamethonium antagonises the effects of low concentration of nicotine. It is concluded that nicotine acts on the cardiac ganglia. Since atropine substantially reduces the action of nicotine, it is suggested that the ganglia excited may be chiefly cholinergic.ACH in high concentration (10-3) in the presence of atropine (5 × 10-5) has a stimulant effect which is abolished by nicotine. It is inferred that under these conditions, ACH is stimulating ganglia which may be adrenergic.
Variation in the Hatching-response of Aëdes Eggs (Diptera: Culicidae)
Authors: Gillett J. D. 
Published: July 2009

Eggs of Aëdes do not necessarily hatch on becoming mature, even though conditions are known to be compatible with hatching. Even the eggs laid by a single female in a single batch and kept submerged in a single container may hatch in instalments over a very long period and, although on one occasion a high proportion of the eggs may hatch within a given period, on another, for no apparent reason, very few may hatch.The problem of erratic hatching has been studied here mainly in Aëdes africanus (Theo.) and A. aegypti (L.). It is considered that mature eggs enter a state of diapause, the depth of which varies with the passage of time, and that the manner of this variation with time itself varies from egg to egg. Different batches of eggs laid by females of the same species vary in the proportion of the different kinds of egg present.Variation in response of the eggs has been studied by the application of a suitable hatching-stimulus in equal daily doses. The stimulus used was sufficiently weak to allow variation in response to be manifested, but sufficiently strong to outweigh uncontrolled variables in the environment.
The Susceptibility of various Species of Mosquitos to DDT, Dieldrin and BHC
Authors: Wharton R. H. 
Published: July 2009

The susceptibility of various mosquitos to DDT, dieldrin and BHC has been studied. Adult females were exposed in small tubes lined with filter papers impregnated with insecticide-oil solutions. Larvae were exposed to insecticideacetone suspensions in water.Adult mosquitos tested in London showed no striking differences in susceptibility to DDT, though the median lethal concentration (MLC) of Culex pipiens molestus Forsk. (1·6 per cent.) was greater than the MLC of Aëdes aegypti (L.) (0·9), Anopheles maculipennis var. atroparvusvan Thiel (1·0), or A. quadrimaculatus Say (·7). C. p. molestus and Aë. aegypti showed the same order of susceptibility to dieldrin and BHC, with Anopheles m. atroparvus more susceptible to both insecticides.
Prevention of the spread of tomato yellow leaf curl virus transmitted by Bemisia tabaci (Gennadius) (Homoptera, Aleyrodidae) in Israel
Authors: Venezia Melamed-Madjar S. Cohen , Hameiri J. 
Published: July 2009

AbstractIn the Jordan Valley of Israel, spread of tomato yellow leaf curl virus in tomatoes by Bemisia tabaci (Gennadius) was delayed by three field treatments: (1) a straw mulch at the time of sowing; (2) sprays every four days with azinphos-methyl or methidathion; and (3) a combined treatment of a straw mulch after germination plus azinphos-methyl sprays at four-day intervals starting ten days after germination. The protective effect of straw mulch lasted about three weeks, and then sharply declined. In laboratory tests adult whiteflies were attracted more to straw than to tomato leaves, and more to fresh (yellow) straw than old (grey) straw exposed to field conditions for 25 days.
New field methods for studying the responses of tsetse flies (Diptera, Glossinidae) to hosts
Authors: Vale G. A. 
Published: July 2009

AbstractField studies with Glossina morsitans morsitans Westw. in Rhodesia showed that hand-net catches can reduce slightly the responses of males to mobile baits and can reduce female responses by three-quarters. Description is given of methods of operating baits in the absence of men and of methods of electrocuting flies as they fly near baits, alight on baits and respond to decoy tsetse. These techniques are more efficient and objective than hand-net catching.
Sugars available from flowers visited by the adult cabbage root fly, Erioischia brassicae (Bch.) (Diptera, Anthomyiidae)
Authors: Finch S. 
Published: July 2009

AbstractAnalysis by gas-liquid chromatography showed that flowers open at the time of the first generation of cabbage root flies, Erioischia brassicae (Bch.), contained nectars composed almost entirely of sucrose and fructose whereas those open during the second generation secreted fructose and glucose. There were qualitative as well as quantitative differences in the sugar composition of all the nectars analysed. In both generations, the most highly nutritive sources of nectars, 94% and 86% sugar solutions, were available from the umbellifers Anthriscus sylvestris and Heracleum sphondylium, respectively. Fructose and glucose were also the main sugars on pollen and anthers at the time of the second generation but, in addition, pollen samples contained large quantities of the sugar alcohol inositol. The surfaces of the pollen of the grasses Dactylis glomerata, Holcus lanatus and Arrhenatherum elatius all contained sufficient nutritive carbohydrates for maturation of the first batch of cabbage root fly eggs. One or more of the chemicals found only in water extracts of Arrhenatherum pollen was probably toxic to the flies. To obtain sufficient carbohydrates to mature the first batch of eggs, flies had to probe at least 1–2 mg of grass pollen each day, equivalent to the pollen produced daily by two flowering heads of Dactylis.
Seasonal fluctuations of a natural population of Diclidophlebia eastopi Vondrácek and D. harrisoni Osisanya (Homoptera, Psyllidae)
Authors: Osisanya E. O. 
Published: July 2009

AbstractNymph and adult populations of Diclidophlebia eastopi Vondráček and D. harrisoni Osisanya were counted weekly on 3- or 4-year-old trees, Triplochiton scleroxylon, in Nigeria during 1966–71. D. eastopi showed successively larger peaks in late January or early February, mid-August, and early or mid-September; the smallest populations were in mid or late March. D. harrisoni showed peaks in February, late July or early August, and late October or early November, the second peak being the largest. Multiple regression analysis of Diclidophlebia populations against rainfall, saturation deficit, temperature and time showed that temperature had the greatest, although slight, effect on D. eastopi, while saturation deficit, through the host-plant, had a marked effect on D. harrisoni. D. harrisoni populations were dependent on the availability of young leaves. It is concluded that, to avoid attack by Diclidophlebia, transplanting of Triplochiton seedlings should be in late February or early March.
Dispersal, seasonal flight activity and winter survival of the oak stem Phylloxerid Moritziella corticalis (Kalt.) (Homoptera, Phylloxeridae)
Authors: Barson G. 
Published: July 2009

AbstractThe dispersal and seasonal flight activity of the oak stem Phylloxerid (Moritziella corticalis (Kalt.)) was studied at three localities in southern England by means of field observations and by sticky trap and suction trap catches. Wind displacement of first-instar crawlers occurred mainly during the winter months (76.2%) when this stage of the life-cycle is most active and abundant. No desiccation of these larvae was observed. The flight period of the sexuparae extends from the end of July to the end of October, and in most years three peaks of flight activity were discernible. A succession of days with low temperatures sometimes prevented migration, but large catches usually followed these low temperature spells. Analysis has shown that the temperature threshold for flight was about 17·2°C. Individuals flying at the start of the flight period were significantly smaller than those flying at the end of the season, possibly because factors affecting the host-plant may also effect changes in breeding and development of the insect. In a frost gradient apparatus, the overwintering first-instar larvae of M. corticalis were cold hardy, the LT30 being -23·7°C.
The feeding performance of the IxodidRhipicephalus appendiculatusNeum. on rabbits, cattle and other hosts
Authors: Branagan Denis 
Published: July 2009

AbstractA study was made between 1967 and 1971 at Edinburgh University and at EAVRO, Muguga, of the variability in feeding performance of all three instars ofRhipicephalus appendiculatusNeum., with a view to better prediction of transmissions ofTheileria parva. Variability could be definitely ascribed to factors within the ticks only when vigour was reduced after prolonged storage and when mating opportunity was withheld from attached females. Lower environmental temperatures prolonged engorgement, but it was arguable whether this effect was produced through the tick or through the host. All other sources of variability arose from influences within the host. The most significant of these were recognised in responses by rabbits in which resistance had been induced by successive infestations. Resistance was manifested by prolonged engorgement, by a reduction in numbers engorged and in degree of repletion, and by an increasing severity in host reaction. Three resistance mechanisms were suggested by host reactions—one appearing at the earliest stages of attachment, a second with the deposition of cement, and a third at the start of salivation. Each varied in efficacy, and each was capable of arresting an infestation. Cumulative and synergistic responses were ascribed to interactions between these mechanisms. Storage periods, sizes of infestations and sex ratios ofR. appendiculatuswere standardised within routine procedures, and abundant records of previous and subsequent performances on rabbits and cattle are presented for comparison and reference. Comparison of feeding performances on different animals suggests that cattle, buffalo, eland, waterbuck and oryx are as satisfactory as hosts as the rabbit, whereas Thomson's gazelle, wildebeest, sheep and goat are less so. Immature instars successfully completed engorgement on mongoose, cane rat, genet, domestic fowl and spur-fowl.
The inhibitory effect of seedling grasses on feeding and survival of Acridids (Orthoptera)
Authors: Bernays E. A. , Chapman R. F. , Horsey J. , Leather E. M. 
Published: July 2009

AbstractThe amounts eaten byLocusta migratoria migratorioides(R. & F.) on seedling grasses was less than on mature grasses in four other Acridids,Nomadacris septemfasciata(Serv.),Chortoicetes terminifera(Wlk.),Melanoplus sanguinipes(F.) andSchistocerca gregaria(Forsk.). Palatability of the young grasses increases with age, becoming maximal 6–10 weeks from the time of germination. Similar preferences were shown by other Acridids. Time-lapse film studies onLocustashowed that not only is less time spent feeding on seedling grasses, but that locomotor activity levels are considerably higher. Survival studies on the same species showed higher mortality on the seedlings as compared with the mature leaves at all stages of nymphal development, while on seedlings no individuals survived to the adult stage. Lipid-soluble materials were removed from seedling leaves with chloroform or acetone and this rendered them more acceptable, while the extract applied to mature leaves resulted in reduced palatability.
The Ecology ofGlossina morsitans, Westw., and two possible Methods for its Destruction.—Part II
Authors: Nash T. A. M. 
Published: July 2009

A small belt ofGlossina morsitanshas been studied for four and a half consecutive years.The community has been observed during the period of its prosperity when the population increased and attempted to colonise unsuitable country ; the outward spread of the fly was checked by insuperable natural barriers, and a period intervened when the fly advance had come to a standstill ; the tsetse were observed in their attempt to breed and establish themselves in an area that could only temporarily suffice their needs.This optimum period was brought to a sudden close by the advent of unfavourable climatic conditions. The effort made by the community to establish a habitat in an unsuitable type of bush was frustrated by the almost complete extermination of its population. The country which had been colonised by the tsetse was depopulated, and once more was limited to a small population that had survived in the true and permanent habitats. A long period followed in which the tsetse were seen to make a slow but steady recovery. The investigation closes with recovery assured, but the community still too depleted in numbers to attempt further expansion for a considerable time.Throughout this rise and fall in the fortunes of the fly community, the size of the tsetse population has been seen to fluctuate seasonally with the annual variations in the climate.
The Influence of Temperature and Humidity on the Pupation ofXenopsylla cheopis
Authors: Mellanby Kenneth 
Published: July 2009

1. The conditions of temperature and humidity under whichXenopsylla cheopisis able to complete its metamorphosis are described.2. The larvae and pre-pupae are easily killed by drying, but the pupae are not. The cocoon does not protect the larva from drying.3. Development is much quicker at high than at low temperatures.4. The rate of loss of water from the larva appears to be proportional to the saturation deficiency of the air, at any rate at 18°C., 22°C. and 29°C.—when the time which elapses between spinning the cocoon and the formation of the pupa is taken into account.The writer is indebted to Dr. P. A. Buxton for reading and criticising the manuscript.
Some Ecological Factors involved in the Dispersal of Mosquitos in Queensland
Authors: Hamlyn-Harris R. 
Published: July 2009

(1) Aèdes vigilax migrates for long distances and together with Mucidus alternans disperses over considerable areas under favourable physiological conditions.(2) Migrations are only undertaken when suitable winds make dispersal possible ; north-westerly winds distribute, under suitable atmospheric conditions, untold numbers of A. vigilax all along our foreshores.(3) In summer the appearance in large numbers of both A. vigilax and Mucidus alternans heralds the approach of a storm.(4) The presence of mosquitos found in wide areas in Queensland apparently devoid of water may be explained : (a) By the existence of breeding facilities in tree-cavities and similar breeding-places not visible to a casual observer ; (b) by the prevalence of suitable carrying winds by which mosquitos are blown for short or long distances from their native breeding-places ; (c) by extreme localisation of mosquitos breeding in small quantities of water mostly inaccessible to the casual observer.
Observations on some Diptera and Myiasis in Kenya Colony
Authors: Lewis E. Aneurin 
Published: July 2009

The study of Dipterous insects in Kenya Colony has been restricted, to a large extent, to the Culicidae and their relation to malaria, and to the Tabanidae and the genus Glossina in connection with trypanosomiasis, the non-bloodsucking Diptera having received but little consideration.“ Blowflies ” or “ maggot-flies ” are by no means uncommon in the Colony, and evidences of myiasis in its various forms are numerous. Symes & Roberts (1932) cite instances of the larvae of Sarcophaga haemorrhoidalis and of Lucilia sericata in the exposed brain substance of a woman ; and of Chrysomyia bezziana in an ulcer on the foot. Cordylobia anthropophaga, parasitic in the skin of man and other animals, is common, and Auchmeromyia luteola (in reality a blood-sucker in its larval stage) is distributed from the coast to the southern boundary of Abyssinia. The “ sheep nasal fly ” is extremely abundant, and many other larvae of Oestrus species have been recorded from game in the Colony.Wounds, ulcers and sores in natives and in animals are often infested with maggots. I have seen, on several occasions, maggots in the ears, and in sores under the eyes, of native children, and in leg-wounds of native labourers. Still more frequently have I observed maggots in wounds of animals ; they occur at the bases of distorted, and in the scars of broken, horns, in the lesions caused by tick-bites, in injured eyes, and in the soiled fleece of sheep. Animals on the point of death are often attended by myriads of sarcophagous flies, the vast numbers of Chrysomyia marginalis in particular presenting an extraordinary sight.
The Immunity of Apple Stocks from Attacks of Woolly Aphis (Eriosoma lanigerum, Hausmann). Part II. The Causes of the Relative Resistance of the Stocks
Authors: Staniland L. N. 
Published: July 2009

1. A short account of gall formation is given.2. The stylets of Eriosoma lanigerum penetrate to within three or four cells of the cambium. Penetration is mainly intracellular, but the stylets cannot pass through the masses of sclerenchyma.3. When a mass of sclerenchyma is encountered the stylets bend round it; if they cannot bend round it, they are usually withdrawn.4. So far as can be seen at present, immunity cannot be explained by mechanical considerations.5. There is strong evidence for supposing that resistance above ground is directly proportional to the percentage of sclerenchyma round the circumference of the stem.6. The above statement must be qualified, if necessary, by a consideration of the extent to which the masses of sclerenchyma are broken up, i.e. the number of spaces that are available for the penetration of the stylets.7. The middle lamella can be dissolved by the saliva of the Aphid; so that the check formed by a mass of sclerenchyma can eventually be overcome.8. Variations in the character of the sclerenchyma and its position are shown to be of possible importance. There would also seem to be some connexion between the size of the Aphid and the size of the openings between the masses of sclerenchyma.9. The relations of the stylets and stylet track to the cells of the stock are briefly summarised.
Report on an Investigation into the Epidemiology of Sleeping sickness in Central Kavirondo, Kenya Colony
Authors: Carpenter G. D. Hale 
Published: July 2009

The epidemic of sleeping sickness in Central Kavirondo was introduced about 1903 from Usoga across a chain of islands, and finally from Mageta Island to the coast of Kadimu close by. Mageta was evacuated, and subsequent return of the population brought back the disease, leading to a second evacuation, second return, and renewal of the disease about 1920–21, leading to final evacuation two years ago.Glossina palpalis occurs plentifully along the 100 miles of coast examined, between the Sio River and the mouth of the Kavirondo Gulf, except just south of Sio, and in the neighbourhoood of the mouths of the Yala and Nzoia Rivers. Ample evidence was obtained that non-mammalian blood is much preferred to that of the hippopotamus, which was the only source of mammalian blood, except man and cattle at some localities.