bluuebunny/crossref_metadata_2025 huggingface dataset:
A large-scale scheme for the eradication of Glossina morsitans morsitans Westw. in the Western Province of Zambia by aerial ultra-low-volume application of endosulfan
Authors: Park P. O. , Gledhill J. A. , Alsop N. , Lee C. W.
Published: July 2009

An effective method of tsetse eradication has been demonstrated on a practical scale in country infested with Glossina morsitans morsitans Westw. in the Western Province of Zambia. An area of slightly over 600 miles2 (1 600 km2) was sprayed from aircraft five times, at approximately three-week intervals, with endosulfan in oil solution at an average of 8·2 gal/mile2 (14·4 litre/km2), so that the area dosage of active ingredient was 17 lb/mile2 (3 kg/km2) per application or approximately 2 oz/acre (0·15 kg/ha) for the whole operation. The insecticide was dispensed as an aerosol (most droplets of 20 μm diameter) made by injecting the spray liquid into the extended exhausts of the aeromotors. Post-spray fly-rounds showed that tsetse eradication was apparently achieved except near an unsatisfactory isolation barrier. The total cost was about K300/mile2 (£175 sterling).
Preliminary louvre-trap hut studies on the egress of Anopheles gambiae Giles, Mansonia uniformis (Theo.) and Culex pipiens fatigans Wied. from untreated huts
Authors: Smith A. , Hudson J. E. , Obudho W. O.
Published: July 2009

The louvre-trap hut was designed to be cheaper and simpler to use than the verandah-trap hut. The eaves are closed, and mosquitoes enter by way of a row of five louvre frames and leave by a window fitted with a window trap. In three trials at Magugu, Tanzania, window traps fitted over one or all louvre frames showed that the efficiency of the louvres in preventing egress was 66–79% for Anopheles gambiae Giles, 51–73% for Mansonia uniformis (Theo.) and 74–78% for Culex pipiens fatigans Wied. Egress through the louvres of A. gambiae is only slightly more, and of M. uniformis much less, than through the eaves of a verandah-trap hut.
A new species of Tenuipalpus (Acarina, Tenuipalpidae) from West Pakistan, with notes on its biology
Authors: Kazimi S. K.
Published: July 2009

Descriptions are given of the immature and adult stages of Tenuipalpus ghanii sp. n., and the characters distinguishing this species from T. punicae Pritchard & Baker and T. granati Sayed are listed. In West Pakistan the preferred host-plant is Pyrus communis. T. ghanii overwinters in the adult stage; it reproduces parthenogenetically and populations of all stages reach their peak in June or July. Of the four predators recorded, Exothorhis sp. (Eupalopsellidae) was the most abundant but was restricted to Pyrus communis.
Two new species of Hymenoptera Dryinidae, with notes on some other species
Authors: Richards O. W.
Published: July 2009

Neogonatopus brunneicollis reared from Cicadellids in Israel, and Pseudogonatopus saccharivorae from Saccharosydne saccharivora (Westw.) (Delphacidae) in Jamaica, are described as new. N. dimidiatus (Sahlberg) and Gonatopus ruficollis Hellén are redescribed from the holotypes. Descriptive notes are given on two new species of Neogonatopus, parasites of Cicadellids, and one of Pseudogonatopus, parasite of a Delphacid, in Israel.
The biting habits of Culicoides furens (Poey) and C. barbosai Wirth & Blanton. III. Seasonal cycle, with a note on the relative importance of ten factors that might influence the biting rate
Authors: Kettle D. S.
Published: July 2009

The biting rates of Culicoides furens (Poey) and C. barbosai Wirth & Blanton on Florida Beach, Jamaica, were observed in 50 trials conducted 40–115 min after dawn from 5 February 1960 to 10 February 1961. The data were logarithmically transformed and non-zero biting rates standardised. Biting rates of both species varied markedly from week to week but monthly mean rates were significantly higher and lower for C. furens in September (111·4) and March (13·7), respectively. Monthly mean rates for C. barbosai fell into three groups, (i) March-June (15·3); (ii) November–December (9·1); (iii) January–February and July–October (3·1). These changes were negatively correlated with mean sea level. Biting rates of C. barbosai were highest at new moon (10·3) and lower but similar (4·3–5·2) for the other three phases of the moon. Those of C. furens were maximal at new moon (62·8), minimal at full moon (20·4) and intermediate (35·9, 39·5) at the quarters. The lunar effect is assumed to act through the tides. There were no significant differences between the standardised biting rates at different times after dawn. In a comparison of the quantitative effects of ten factors on the biting rates of C. furens, C. barbosai and Leptoconops becquaerti (Kieff.), most important were month of year and wind speed; of less importance were lunar cycle, temperature, collector and limb exposed; while site position, intensity of illumination, time after dawn, saturation deficit were of minor or no importance. It is concluded that the biting rate of L. becquaerti should be the least affected by changes in these factors, C. barbosai more affected and C. furens most affected.
A review of estimates of numbers in some types of desert locust (Schistocerca gregaria (Forsk.)) populations
Authors: Bennett L. V. , Symmons P. M.
Published: July 2009

A review is given of estimates, both published and unpublished, of numbers in some
types of desert locust (Schistocerca gregaria (Forsk.)) populations, and suggestions are made for further work in this field. For swarming adult populations, estimates of volume and area density and of the relative sizes of settled and flying swarms have been reviewed. For gregarious nymphal (hopper) populations, the area density of late-instar bands and the infestation rate following gregarious breeding have been examined. There is insufficient evidence to give estimates of the average numbers in any of these types of population with confidence, or to be able to estimate the environmental and physiological factors with which variation in density is correlated. It is not possible to make generally valid estimates of the densities of non-gregariously behaving populations. Practically no research has been done on population estimation methods suitable for such populations, although, in practice, estimates are made during field surveys. The principles underlying valid sampling techniques, and valid selection of the sample in various situations, are described.
On the origin of the wet-season form of Zonocerus variegatus (L.) (Orth., Acrididae) in southern Nigeria, with some biological notes
Authors: Taylor T. Ajibola
Published: July 2009

Previous reports and field observations at Ibadan and in northern Nigeria have established the occurrence of a dry-season form and a wet-season form of Zonocerus variegatus (L.). The wet-season form in the savanna areas of northern Nigeria is shown to be virtually identical with that from southern Nigeria on the basis of breeding seasons, habitat and morphometrics. Morphometrics show the wet- and dry-season forms to be distinct. It is suggested that the dry-season form in the wet rain forest zone spread into the dry savanna areas giving rise to a wet-season form adapted to the different climatic conditions. The increasing occurrence of the wetseason form in the south probably represents a re-invasion by the northern wetseason form.
Extracellular ducts within the wall of the spermatheca of tsetse flies (Glossina spp.) (Dipt., Glossrnidae)
Authors: Jordan A. M.
Published: July 2009

Each spherical spermatheca of Glossina austeni Newst. is composed of a cuticular lining of the lumen which is surrounded by a layer of secretory cells. When the spermatheca is immersed in Amann's lactophenol the cells of the cellular layer lift away from the cuticular intima revealing numerous clubbed processes projecting outwards from the surface of the intima. Sections of spermathecae examined by transmission electron microscopy show that one clubbed process is associated with each cell of the cellular layer. The “porous” head of the process is within a fluidfilled cavity in the cell, lined with microvilli. The stalk of each process is an extracellular duct down which secretions from the cellular layer pass into the lumen of the spermatheca. It is considered that these secretions are the medium, probably containing nutrients, in which spermatozoa are held while in the spermatheca.
Comparative studies on sibling species of the Anopheles gambiae Giles complex (Dipt., Culicidae): bionomics and vectorial activity of species A and species B at Segera, Tanzania
Authors: White G. B. , Magayuka S. A. , Boreham P. F. L.
Published: July 2009

Collections of Anopheles gambiae Giles complex, A. funestus Giles group and other mosquitoes were made by spray-catch from twelve catching stations indoors and by hand-catch from pit shelters at two catching stations at Segera, Tanzania, between January 1970 and June 1971. Females of A. gambiae were identified cytotaxonomically as sibling species A or B of the complex. In houses during 1970, A. gambiae species B was more numerous at first than A, but A became predominant during the long rains of March-May. In the cool dry weather of June-November both A and B densities declined and the A:B ratio surpassed 50:1. The short rains in December produced a population explosion of species B and less multiplication of species A, the B:A ratio reaching >11:1. In 1971, hot dry weather during January-March caused declines of species A and B with a maximum B: A ratio of 13:1. Long rains, coming in late March, provoked a resurgence of A and a concurrent decline of B, so that the A:B ratio again reached 20:1 in June. Similar cycles of species A and B were observed outdoors, although the relative numbers outdoors/indoors averaged 2·3 times more for species B than for species A. In A. funestus, A. gambiae species A and A. gambiae species B Human Blood Indices were 97·5%, 91·2% and 60·9% indoors and 24%, 2% and 7% outdoors, respectively. Respective malaria sporozoite rates were 1·62%, 4·23% and 0·32% and minimum rates of stage-Ill filarial infection were 0·33%, 0·44% and 0·57%. Sporozoite-positive and sporozoite-negative mosquitoes exhibited similar HBF's in species A and discrepant HBI's in species B. The HBI's were higher in filariapositive A and B females than in filaria-negative females. Gregarines occurred in 1·36% of species A and 0·38% of species B. Trematode cysts were seen in two specimens of species A.

Of A and B females 28% and 4%, respectively, had four-banded palps. It is shown mathematically that the discrepant malaria sporozoite rates in species A and B may be explained by extrapolating from the man-biting rate and probable daily survival rate for each species. This implies that no unrecognised factors play a major role in causing the contrasting efficiency of these two sibling species as malaria vectors.
The inseminating potential of male Glossina austeni Newst. and G. morsitans morsitans Westw. (Dipt., Glossinidae)
Authors: Jordan A. M.
Published: July 2009

In laboratory experiments individual male Glossina austeni Newst. were each mated, at two- or three-day intervals, to nine different females. In one series of matings the males were restricted to one pairing and in a second series the sexes were left together for 24 h, when more than one copulation could have occurred. The technique followed in the second series was repeated with G. morsitans morsitans Westw. when the males were presented successively with 12 different females. The fecundity of female G. austeni, after mating with males previously mated on 0 to 5 occasions, was consistently higher when left with their mates for 24 h (mean puparia produced per mature female day=0·102) than when restricted to a single copulation (0.085). When the sexes were left together for 24 h, female fecundity of both species was maximal when mated with males used for up to six times (ca 0·10 puparia produced per mature female day) but became progressively poorer as the males were used more frequently (0·022 for G. m. morsitans females mated with males used for the twelfth time). The testes of muchmated males are markedly smaller than those of virgin males of the same age. Maximum disposable output of males from colonies of Glossina engaged in production for the sterile insect release method could be obtained by using males retained in the colony for mating on six occasions. It is speculated that in nature the absence of both teneral and old males from the following swarm ensures the presence of only fully sexually potent males in the swarm.
The collection of spray droplets by flying locusts
Authors: MacCuaig R. D.
Published: July 2009

An account is given of work carried out since that of Wootten & Sawyer (1954) on the pick-up of spray droplets by flying locusts. The same species,Schistocerca gregaria(Forsk.), was used. The values given in their work for the amounts of spray collected were confirmed, but when observations were extended to cover smaller droplets (less than 50-μ. diameter), locusts were found to collect these much less efficiently.

Other factors affecting pick-up were sex (females collected more spray than males) and flying speed (faster-flying locusts tended to collect less spray per unit of distance flown). When the angle of approach of the droplets to the flying locusts was varied between 1 and 11° from the horizontal no difference in the pick-up of spray could be detected.

For droplets between 60- and 300-μ diameter, the dose of insecticide collected by the locusts is given by the formula 9xPC μg. for males, and 11·5xPC for females, when the locusts fly through a concentration of spray ofCml. per cu. m. for a distancePm. and the spray solution containsxper cent, (w/v) of insecticide.
Dispersal of alates and establishment of new colonies in Cryptotermes havilandi (Sjöstedt) (Isoptera, Kalotermitidae)
Authors: Wilkinson W.
Published: July 2009

Cryptotermes havilandi (Sjöst.) is an important pest of domestic timber in West Africa, and in 1957 a study of certain aspects of its biology was made at Port Harcourt, Nigeria.

The alate is positively phototactic on emergence, and the main flights occur at dusk, between 1800 and 1900 hr. Heavy flights continue until 2200 hr., but few alates can be seen after 0100 or before 1600 hr. There is a peak of activity in the drier months of January and February, but flights take place in every month. Emergence for flight is associated with drier atmospheric conditions.

After a change to negative phototaxis, followed by shedding of the wings, the dealates search for a nest site. Tandem behaviour does not occur. The dealates cannot bore into sound wood, and a hole or crack is essential for colony foundation. The entrance to the hole is sealed with material carried in the gut of the insect, according to a fixed behaviour pattern. Dealates seeking to enter wood prefer holes between one and a half and three millimetres in diameter, and cannot use those of less than one or more than five millimetres in diameter. Preference by dealates for particular species of wood was not shown conclusively. There was no discrimination against wood containing lethal doses of borax or Celcure (a proprietary mixture consisting essentially of potassium dichromate, copper sulphate and acetic acid or chromium acetate).

The rate of egg-production, the incubation period, and the duration of the first three instars are recorded. At the rate estimated, egg-production by a physogastric queen could maintain populations in excess of 3,000. Neoteinics are readily produced in isolation from all but the first three larval instars. They may lay eggs from 35 days onwards, and in their first year have much greater fecundity than primary queens.

The economic applications of the observations and experiments are discussed, together with some factors affecting testing of timbers against termite attack.
A diurnal and seasonal study of the resting behaviour ofGlossina pallidipesAust.
Authors: Pilson R. D. , Leggate B. M.
Published: July 2009

In conjunction with an investigation of the diurnal and seasonal feeding behaviour ofGlossina pallidipesAust. in dense riverine vegetation in the Zambezi Valley, Southern Rhodesia, gorged flies caught on a stationary ox were marked and released and their subsequent resting places recorded. Fallen logs, a rot hole, boles and branches were found to be utilised in the late hot dry season (November), but in the rainy season (February), the cool season (May) and the early dry season (August), flies were found almost entirely on branches. Of the total resting flies observed, 89 per cent, were at heights of 0 to 9 ft., but whereas in November 49 per cent, of resting flies were at heights between 0 and 3 ft., only 10 to 19 per cent, rested at this level in the other seasons. The choice of more deeply shaded resting sites in November is thought to be due to a reversal, at temperatures over 35°C., of a normally positive reaction to light. The resting behaviour did not appear to differ greatly between sexes, although females do not move so readily as do males on to sites other than branches.

In November, a diurnal pattern of resting behaviour was noted. A branch type of site was preferred in the early morning, but a shift to the rot hole and boles was evident during the middle of the day, followed by a return to branches in the evening; there was evidence that flies rested in yet another type of site at night. In May, searches from 1930 to 2100 hr. for flies marked with reflecting paint revealed some on leaves and small twigs.
A note on Eulophonotus myrmeleon Fldr. (Lepidoptera, Cossidae), a stem borer of cocoa in West Africa
Authors: Entwistle P. F.
Published: July 2009

The biology of Eulophonotus myrmeleon Fldr., the larva of which bores in the woody stems and branches of cocoa throughout West Africa, was studied in Ghana and Nigeria. In the laboratory the adult lives for a maximum of four days during which about 500 eggs are laid. The larval period is not less than three months and the pupal stage lasts three weeks. Larvae desert galleries in drying wood, and the excavation of new galleries in fresh wood is begun beneath the protection of a tent of wood particles bound together with silk. Populations are seldom large enough for their activities to be serious in Ghana, but the severe dry season in Western Nigeria causes considerable die-back in cocoa, creating conditions favouring larval migration and thus increasing the injurious effects of E. myrmeleon.
A simple apparatus for use in removing corpora allata from locusts
Authors: Strong L.
Published: July 2009

Details are given of the design, construction and use of a new apparatus for use in the operation for removal of the corpora allata of locusts and in certain operations within the head capsule.
Control of ground beetles (Col., Carabidae) attacking strawberry fruits
Authors: Briggs J. B. , Tew R. P.
Published: July 2009

Experiments in south-east England are described in which insecticides were tested against the Carabid beetles Harpahis rufipcs (Deg.) and Feronia melanaria(111.), which cause damage to strawberry fruits.

In preliminary screening tests, the mortality of H. rufipex was low when adults were caged with fruits or straw treated with rotenone at 0·004 per cent, or with carbaryl, DDT, dimethoate, malathion, mevinphos, nicotine, TEPP, toxaphene and trichlorphon at one or more concentrations in the range 0–06–0–2 per cent. In small-scale field trials, γ BHC at 0·026 per cent, gave poor results but chlordane and dieldrin exhibited persistent toxicity.

In further tests with fruits, field-weathered deposits from sprays containing 0·1 or 0·2 per cent, dieldrin caused over 90 per cent, mortality for 7 and 21 days, respectively, but left residues at harvest of 0·5 p.p.m., which were considered too high for consumer safety.

Dieldrin applied to soil at 5 lb. per acre resulted in 100 per cent, mortality for 28 days in 1957, but gave very variable results in 1958. Conversely, aldrin at 5 lb. gave effective mortality for only 14 days in 1957 but for the maximum test period of 89 days in 1958; no satisfactory explanation was found for the seasonal differences. Aldrin at 10 lb. per acre gave 100 per cent, mortality for 77 and 89 days, respectively, in the two years. Tests of soils into which measured quantities of insecticide had been incorporated, resulted in 100 per cent, mortality, after 4 days' exposure, with aldrin and dieldrin at levels of 2–4 and 16–32 p.p.m., respectively; endrin at 64 p.p.m. was only slightly toxic.

In field trials in 1959–60, application of aldrin at 10 lb. per acre to the surface of the soil around the plants in sprays in late April immediately before flowering, or at 5 lb. per acre in late May before laying straw below the fruit, reduced fruit damage due to H. rufipes or F. melanaria by 66–94 per cent. Residues at harvest were of the order of 0·03 p.p.m., and no effect on flavour was detected in processed fruit from plots treated at either time of application.
External sex differences in stored-products Coleoptera
Authors: Halstead D. G. H.
Published: July 2009

The known external characters, and some new ones, for separating the sexes of pupae and adults of stored-products Coleoptera are described and in many cases figured.
A key to the larvae of some species of Phycitinae (Lepidoptera, Pyralidae) associated with stored products, and of some related species
Authors: Aitken Audrey D.
Published: July 2009

A key to the fully grown larvae of 11 species of Phycitinae is given. Of these, the following eight are known in Britain either as stored-products pests or associated with imported food:—Ephestia elutella(Hb.),Anagasta kuehniella(Zell.),Cadra cautella(Wlk.),C. calidella(Gn.),C. figulilella(Gregson),Plodia interpunctella(Hb.),Mussidia nigrivenellaRag. andEctomyelois ceratoniae(Zell.). The key is preceded by a brief account of the economic importance of these species in Britain.

The other three species areEctomyelois decolor(Zell.),E. muriscis(Dyar) andParamyelois transitella(Wlk.). Although these are native to the Americas and are unknown in Britain, they comprise, together withE. ceratoniae, the economically important species formerly of the genusMyeloisHuebner.

The larvae ofMussidia nigrivenella, P. transitellaand of the three species ofEctomyeloisare described.
The influence of environmental conditions on the contact toxicity of some insecticide deposits to adult mosquitos, Anopheles stephensi List
Authors: Hadaway A. B. , Barlow F.
Published: July 2009

Investigations have been made on the influence of environmental conditions on the contact toxicity to adult mosquitos (Anopheles stephensi List.) of two kinds of insecticidal deposits of importance in sprayed houses, superficial deposits from wettable powders and insecticides sorbed on dried soils.

Increasing the relative humidity from 43 to 80 per cent, during the contact period had no effect on the toxicity of wettable-powder deposits on plywood of dieldrin, Sevin and O-methyl O-(2,4,5-trichlorophenyl) ethylphosphoramidothioate. On the other hand, the availability of DDT, dieldrin and 3-isopropylphenyl N-methylearbamate sorbed on dried soils increased considerably as atmospheric humidity increased. The logarithm of the median lethal exposure time was linearly related to atmospheric humidity, and decreased by a factor of 2·8, 2·2 and 2·1 for the carbamate, dieldrin and DDT, respectively, for each 10 per cent, increase in relative humidity. There was also a linear relationship between the logarithm of the water uptake of a given soil and humidity.

Temperature affected the action of insecticides during both the contact period and the post-treatment period. Median lethal doses of dieldrin, Sevin and the phosphoramidothioate decreased, and that of DDT increased, as the post-treatment temperature increased from 20 to 30°C. These effects of the post-treatment temperature were also found when treatment was by exposure to residues. When these effects were eliminated it was found that the contact toxicity of superficial deposits on plywood and of insecticides sorbed on dried soils increased as the temperature during the exposure period increased. A simple relationship between median lethal time and exposure temperature was indicated.
A new Eulophid egg-parasite associated with Tragocephala SPP. on cacao, with comparative notes on other species (Hym., Chalcidoidea)
Authors: Kerrich G. J.
Published: July 2009

A Chalcidoid egg-parasite of longhorn beetles of the genus Tragocephala, which damage shoots of cacao in West Africa, is attributed to the genus Aprostocetus Westw. (Eulophidae) and a new species, A. lamiicidus, is described for its reception. The morphological differences between this and some other African species of known economic importance are discussed and figured.
Preliminary studies on the biology of Orasema assectator Kerrich (Hym., Eucharitidae), parasitic on Pheidole and causing damage to leaves of tea in Assam
Authors: Das G. M.
Published: July 2009

The so-called ‘sewing blight ’ of tea in Assam is an effect of oviposition in the young leaves by two species of Eucharitid, Orasema initiator Kerrich and O. assectator Kerrich. The affected leaves develop brown spots round the oviposition punctures, wither prematurely and adversely affect the quality of the made tea. Normally only a small proportion of bushes is affected and these are associated with the presence of nests of an undetermined species of Pheidole.

An account is given of the life-history of O. assectator, and the developmental stages are briefly described. The eggs are laid singly in incisions made by the ovipositor on the underside of the leaf in parallel rows arranged lengthwise. The newly hatched larvae exist as free-living planidia on the leaf surface, whence they are carried by unknown means into the ants' nests in the soil beneath the tea bushes. Here the planidium transfers to the last-instar larva of the ant and penetrates its body. There it remains inactive until its host reaches the prepupal stage, whereupon endoparasitic feeding and development start. After the host pupa has formed, the parasite larva emerges, establishes itself below the thorax of its host, and remains there, feeding ectoparasitically, through two further instars, completely consuming the contents of its host. The mature larvae remain scattered in the ant's nest and pupate a few days later; both larvae and pupae are cared for by the worker ants.
An evaluation by bioassay of the persistence of DDT deposits on riverine vegetation in the Northern Guinea Savannah vegetation Zone of Nigeria and observations on the factors influencing the availability of deposits to Glossina palpalis (R.-D.)
Authors: Baldry D. A. T.
Published: July 2009

The persistence of DDT deposits, derived from dilutions of an emulsion concentrate, Arkotine D.25, on the leaves of riverine vegetation in the Northern Guinea Savannah vegetation zone of Nigeria was studied in the laboratory by a bioassay method using teneral females of Glossina palpalis (R.-D.) as test insects. Irrespective of whether sprayed in the dry or wet season, deposits derived from sprays containing 5.0 per cent. DDT produced by the Warley knapsack sprayer were still reasonably toxic one year after spraying. Deposits derived from sprays having a concentration of DDT varying from 1·25 to 5·0 per cent. DDT were equally toxic when young, but those from the lower concentrations were weathered much more rapidly than those from the 5·0 per cent, sprays. Young deposits produced by Warley and Motoblo sprayers were equally toxic, but deposits from the Motoblo deteriorated more rapidly than those of the Warley.

The toxicity of the DDT deposits on leaves varied regularly with the seasons. The various climatic factors that it is thought influenced the variations in toxicity are discussed. Accumulations of wind-blown dust on the leaves during the late dry season and low evaporation rates at the height of the rains appear to be responsible for reduced toxicity at those times; in the early wet season, the occasional violent storm probably washes off the leaves the dust accumulated during the dry season and makes the insecticidal deposits once more available. Heavy rainfall is important in removing the insecticidal deposits from the vegetation, and leaf decay and refoliation are important in reducing the availability of the deposits. The implications of these variations in toxicity and factors that reduce the availability of the deposits are discussed in relation to the eradication of riverine tsetse.

Great differences in the rates of foliage decay and refoliation occur between different riverine plants, and it is suggested that a thorough study of this feature in riverine plants and of resting sites favoured by tsetse flies might reveal information that would enable tsetse to be eradicated by selective spraying of certain plant species only.
Studies on the Dermestid beetle Trogoderma granarium Everts. VI.—Factors inducing diapause
Authors: Burges H. D.
Published: July 2009

The facultative larval diapause of the khapra beetle, Trogoderma granarium Everts, is initiated extrinsically by temperature, crowding, and very low or very high humidity. In crowded populations, in tubes of wheat, the proportion of diapause larvae varies from very low (2 to 3 per cent.) in the upper part of the insect's temperature range to 100 per cent, in the lower part. Diapause larvae become more frequent with increasing population density, the frequency becoming noticeable at a density of about ten larvae per gramme of wheat (about 10 times their minimum food requirements). Accumulation of faecal pellets is a factor that induces diapause in crowded conditions. Many larvae that are kept singly enter diapause when fed on old culture food from which pellets have been removed: possibly in the old culture the pellets impart to the food a substance that initiates diapause. The availability of a suitable refuge, in which larvae can cluster, has no consistent effect on the proportion of diapause larvae. Factors that induce diapause also slightly increase the developmental period of non-diapause larvae.

In malted barley, more larvae enter diapause than in wheat, probably due to the intensification of crowding by the confinement of larvae to a few malt grains.

The relative importance of the factors that induce diapause is discussed. These factors help to explain observations in stores and conflicting results in the literature. The main function of diapause seems to be in assisting the larvae to survive periods of food shortage; diapause may also improve the survival of larvae in a cold winter and synchronise the emergence of adults. Of the factors inducing diapause, accumulation of faecal pellets precedes food shortage and falling temperatures precede the cold of winter, but the role of high and low humidities in this connection is difficult to assess. Diapause larvae play a major part in the dispersal of the species. The diapause of T. granarium is compared with that of other arthropods.
Culturing Phlebotomus papatasii (Scopoli) in the laboratory
Authors: Hafez Mahmoud , Zein-el-Dine K.
Published: July 2009

An original method of breeding Phlebotomus papatasii (Scop.) in the laboratory in the Egyptian climate was evolved, whereby the development of a fungal growth, a well-known obstacle, was prevented by incorporating, in the larval feeding medium, living material from cultures of a bacterium, Alcaligenes viscosus, which had been found to be the predominant micro-organism in samples of soil collected from breeding places of P. papatasii in the field. Later, eight other Schizomycetes were also found to keep in check the development of mould. Certain fungicides also gave satisfactory results. Breeding pots made of unglazed earthenware were used. A layer of finely sieved sand (18 meshes) about 5 cm. deep was placed at the bottom of the pot and moistened with sterile water. To a mixture of one part dried, ground, sieved guineapig faeces (60 meshes) and two parts sieved dry earth (60 meshes), sufficient of a water suspension of the bacterium was added to impart a damp but friable condition. Granules of this larval feeding medium were then scattered over the sand in a loose layer about 1 cm. thick. Each breeding pot was stood in a petri dish of water and was placed in a small muslin cage to which adult insects were introduced. The females, which obtained their blood-meals from three-day-old white mice, oviposited within the pots, and no eggs were laid elsewhere. Development from egg to adult was completed successfully in this medium, and a healthy culture of the insect was maintained in the laboratory for several years.
The distribution of insects in stacks of bagged groundnuts in Northern Nigeria
Authors: Prevett P. F.
Published: July 2009

Decorticated groundnuts (Arachis) are stored in bags in pyramid-shaped stacks in Northern Nigeria over the period November to October. In Kano the dry season extends from October until March and is followed by a short hot season preceding the rainy season, which usually commences during May.

The seasonal distribution within such pyramids of the various insect species infesting groundnuts is considered in some detail, with particular reference to the primary pest Tribolium castaneum (Hbst.). This distribution is discussed in relation to temperature and moisture content of the kernels and to the effect on the environment of covering pyramids with tarpaulins, the normal practice for protection during the rainy season. T. castaneum is the only species present on groundnuts initially and throughout the storage season. It is concluded that the elimination, during storage, of other species also present initially, i.e., Cadra cautella (Wlk.), Plodia interpunctella (Hb.), Corcyra cephalonica (Stnt.) and Oryzaephihis mercator (Fauv.), and the ultimate concentration of infestation by T. castaneum within peripheral bags is the result of changes in physical conditions. It would appear that Cryptolestes ferrugineus (Steph.), which was not found until late in the storage season, is a pest of secondary importance.

The significance of the results obtained in relation to control measures is discussed, bearing in mind that all but one of the pests considered were found to be present on groundnuts when received at the Kano central storage area from buying stations. It is concluded that a programme of surface spraying of pyramids with insecticides is of little value and recommendations for the introduction of initial fumigation of pyramids have been put forward.
A study of the resting sites of Glossina swynnertoni Aust. in northern Tanganyika
Authors: Chadwick P. R.
Published: July 2009

Observations in three areas in northern Tanganyika on the day-time resting sites of adults of Glossina swynnertoni Aust. showed that the most important of these was the underside of branches of trees. The number of flies seen on this site represented about one-third of the total population as calculated from the apparent density, and about half of them were on branches 4–9 ft. above ground, 1–4 in. in diameter and at an angle of less than 35° from the horizontal. It is suggested that were an insecticide to be applied to branch sites within these limits, then, since any fly must make six or more flights in the first 18 days of its life, it would be expected to alight on a treated surface at least once in this period. Were a lethal deposit maintained for twice this period, plus the pupal period, control could be effected.
An analysis of the numbers of Anopheles gambiae Giles and A. Funestus Giles (Diptera, Culicidae) in huts in Northern Nigeria
Authors: Service M. W.
Published: July 2009

Pyrethrum spray-sheet collections in a small village in Northern Nigeria showed that there was no significant difference in the numbers of Anopheles gambiae Giles and A. funestus Giles caught at different times in the early morning. In this village, huts at the edge nearest to the only breeding site attracted considerably more adults than those further away from the edge, and some huts were consistently more attractive to mosquitos than others. There was a positive correlation between the numbers of A. gambiae and A. funestus in the huts. Although significant differences were found between numbers of mosquitos caught in the huts occupied by different numbers of people, no simple relationship could be discovered between the combined densities of the two species and the number of hut occupants. It is concluded that there is need for further investigations into the factors influencing densities of the Anophelines in village huts.
Populations of the leaf-miner Leucoptera meyricki Ghesq. and its parasites in sprayed and unsprayed coffee in Kenya
Authors: Bess Henry A.
Published: July 2009

Populations of the leaf-miner Leucoptera meyricki Ghesq. and its parasites, of which Zagrammosoma variegatum (Masi), Achrysocharella ritchiei Ferriére and Parahormius leucopterae Nixon were the most abundant, were studied for 40 consecutive weeks during 1960–61 in Kenya, in four experimental blocks of coffee (Coffea arabica), two of which received several applications of parathion sprays and the other two none. Each week eight different trees within each block were covered with a tent, pyrethrum spray was atomised within, and the adult moths and parasites were recovered from the polyethylene sheeting used as a floor to the tent. Fortnightly, counts of leaves, mined and unmined, and collections of leaves with leaf-miner larvae and parasites within them were made. These intensive studies were supplemented with two special spray tests, in which different dosages of insecticides were used, and with collections of leaves made periodically over a rather extensive area in Kenya, from which adult leaf-miners and parasites were reared to gain information on the parasite/host relationships over a wide range of ecological conditions.

Parathion used at 1 lb. 20 per cent, wettable powder in either 65 or 80 gal. water per acre appeared to kill all adult leaf-miners and parasites present. Possibly between 50 and 75 per cent, of the leaf-miner larvae, and appreciably fewer of the immature stages of the parasites within the mines, were killed. The sprays apparently had even less effect on the leaf-miner prepupae and pupae and the parasites within the cocoons, which are usually formed in the litter and in crevices in the soil.

Leaf-miner populations within the sprayed blocks were somewhat lower than those in the unsprayed blocks, but the fluctuations were remarkably similar. In general, this was also true for the parasites.

Assessment of the effects of the sprays on the efficiency of the parasites was made on the basis of the ratios of adult parasites to moths obtained from tented trees and from infested leaf samples held for adult emergence, as well as in terms of percentages of larvae parasitised in the samples dissected. It was found that the sprays killed a greater proportion of the leaf-miner larvae than of parasites within the mines, and thus increased the ratios of living parasites to leaf-miners immediately following the spray applications. During the period from October to January, when the sprays in the Eukera plots were synchronised with the peak populations of the moth, parasitisation was significantly higher in the sprayed plots than in the unsprayed plots. Furthermore, in the special spray tests, where different dosages of parathion and diazinon were used, parasitisation within the surviving populations was higher in the plots that received the higher dosages. These findings suggest that with proper timing of spray applications the efficiency of leaf-miner parasites may be improved.
Studies on Anopheles gambiae Giles and malaria transmission in the Umbugwe area of Tanganyika
Authors: Smith A.
Published: July 2009

The paper includes a description of studies on Anopheles gambiae Giles in the insecticide-free Umbugwe area of Tanganyika, and the results of dissections of A. gambiae and A. funestus Giles for sporozoite infections.

The densities of A. gambiae and A. funestus were assessed in houses by pyrethrum spray catches in 90 houses distributed in ten villages in the Umbugwe area between March 1960 and February 1962. A. gambiae was seasonally abundant, a sharp increase in density being associated with periods of rain. A. funestus type form was scarce in houses throughout the year, although a larval survey showed it to be the most common member of the complex of A. funestus in the area.

The average ratio of fed to gravid individuals of A. gambiae was 2·3:1 from June 1960 to November 1961, with peaks reaching 7:1 in March 1960 and 7·5:1 in January 1962. The peaks were attributed to rapid increase in production of adults during the limited period of the rainy seasons that followed very dry conditions.

Thirteen per cent, of recently fed individuals of A. gambiae were found in the exit window traps of experimental huts, having attempted to leave the huts on the night of feeding.

Two distinct types of huts are commonly found in the area, the tembe, which is large, divided into an average of five rooms by walls that are usually incomplete at the top, and accommodates large numbers of cattle as well as humans; and the banda, which is smaller, divided only into two rooms and seldom housing any domestic animals. Precipitin tests showed that whereas only 20 per cent, of individuals of A. gambiae taken in tembe had fed on man, in banda huts the percentage was 77. It was also shown that there was a dispersal of A. gambiae within a hut shortly after feeding. In a tembe. one-third of the individuals positive for man, and one-quarter of those positive for cattle had moved to rooms other than those in which they had fed.

A sporozoite rate of 1·47 per cent, was found among 3,746 specimens of A. gambiae dissected. Of the total number of 55 sporozoite-positive females of A. gambiae, 39 were found among the 424 individuals dissected in February 1962, thereby indicating unusually heavy transmission during the early part of 1962. A. funestus type form appeared to be of virtually no importance in malaria transmission in the Umbugwe area. Transmission by A. gambiae was highly seasonal, for although the percentage of gland-positive specimens was slightly higher in the long dry season than in the rainy season, the much larger mosquito population in the latter led to a higher number of infective bites in the rainy seasons. The highly seasonal transmission by A. gambiae was reflected in the results of examination of blood-films of people attending the Government dispensary.
Laboratory studies on dispersion behaviour of adult beetles in grain. VI.—Three-dimensional analysis of dispersion of five species in a uniform bulk
Authors: Surtees Gordon
Published: July 2009

The three-dimensional pattern of dispersion of five species of grain-infesting beetles was analysed in a 12-in.-cube bulk of wheat, kept in darkness at 25°C. and 14 per cent, moisture content, and built up of four layers, each of 16 three-in.-cube bags of Terylene net; the net retained the grain but allowed passage of insects. One hundred adults were placed in the centre of the upper surface of the topmost layer and after two weeks the entire bulk was broken down and the number of insects in each bag was determined. Five replicates were used for each species. More recoveries of Sitophilus granarius (L.), Tribolium castaneum (Hbst.), Rhyzopertha dominica (F.) and Cryptolestes ferrugineus (Steph.) were made from the top quarter of the bulk than from any of the lower layers. The vertical dispersion of Oryzaephilus surinamensis (L.) was homogeneous. Lateral dispersion was homogeneous with T. castaneum, R. dominica and C. ferrugineus, but with S. granarius and O. surinamensis relatively more recoveries were made from the corner units of the bulk than from elsewhere. The dispersion pattern assumed by a species in a uniform bulk is affected by locomotory activity, boundary response and intragroup stimulation. Thigmotaxis was demonstrated in S. granarius, persisting at relatively high densities; thus, following dispersal, individuals collect along habitat boundaries and then move up them as a result of intragroup stimulation. The positive response to boundaries shown by individuals of T. castaneum in isolation breaks down in crowded conditions, producing movement back into the bulk of grain and thus homogeneous lateral dispersion. O. surinamensis shows a positive response to habitat boundaries but no movement up them. Dispersal is slow in R. dominica, but the ultimate pattern of vertical dispersion is homogeneous. C. ferrugineus shows a tendency to form clumps, even in conditions free from marked physical gradients. The data are discussed in relation to ecology of the species, low-density populations, aggregation behaviour and a dynamic concept of population dispersion.
A new phytophagous termite from Saudi Arabia
Authors: Harris W. V.
Published: July 2009

Records of termites attacking growing crops in Saudi Arabia have so far referred to Microcerotermes diversus Silv., one of the subfamily Amitermitinae of the Termitidae (Ayoub, 1959). This termite is also known from the Yemen, the South Arabia Federation and Iraq.
Aircraft applications of insecticides in East Africa XIV.—Very-low-volume aerosols of dieldrin and isobenzan for the control of Glossina morsitans Westw
Authors: Burnett G. F. , Chadwick P. R. , Miller A. W. D. , Beesley J. S. S.
Published: July 2009

Two experiments were conducted simultaneously in 1962–63 at Chungai, in central Tanganyika, to test new equipment for disseminating insecticides from aircraft and a new insecticide, isobenzan (Telodrin), in the eradication of Glossina morsitans Westw. and G. pallidipes Aust. The new equipment consisted of an aerosol generator fitted to the exhaust of a Cessna 182E high-wing monoplane, and was used in both experiments. The isobenzan was compared with dieldrin, and the two insecticides were applied at rates inversely proportional to their toxicities to G. morsitans as previously determined in the laboratory.

Two blocks of woodland, each 11 sq. miles in area, were treated, one with a 12·3 per cent, solution of dieldrin at the rate of 0·0254 gal. per acre, giving a dosage of 0·5 oz. (14 g.) toxicant per acre, and the other with a 10 per cent, solution of isobenzan at the rate of 0·0124 gal. per acre, giving a dosage of 0·2 oz. (6 g.) per acre. The former block received eight treatments with dieldrin at approximately 3-week intervals, the fourth treatment being incomplete; the latter block received six treatments with isobenzan at intervals ranging from 20 to 45 days. The effects were assessed by means of fly-catches along fixed paths which continued for one year after treatments had ceased.

Both species of tsetse fly disappeared from the two blocks before the final treatments took place, and no more were caught until 11 months after spraying ended, when one example of G. morsitans was caught in each block; both were probably immigrants. None was found in the following month, and it is concluded that the flies were exterminated in both blocks. The fact that the blocks were unusually well isolated from sources of reinfestation probably contributed to the success of the operations.

The cost per sq. mile was £224 using dieldrin and £190 using isobenzan. These were the basic costs, independent of the locality in which spraying took place. Additional costs were incurred which would vary with local conditions; for the present experiments they were £34 and £30, respectively. It is considered that there is good scope for further reductions in costs, particularly with dieldrin, and that these might make dieldrin economically competitive with isobenzan. Owing to the low fly density in the block treated with isobenzan, the efficacy of this insecticide cannot be regarded as conclusively proved until further experiments have been carried out. It may then merit serious consideration as a toxicant for aerial spraying against tsetse flies.