bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of instability in genetic sexing strains: effects of male recombination in association with other biological parameters
Authors: Busch-Petersen E. , Baumgartner H. 
Published: July 2009

AbstractGenetic systems have been developed in several insect species for separating males and females prior to releasing sterilized males in pest control programmes using the sterile insect technique. The systems generally depend on translocating a readily selectable gene onto the Y chromosome. A potential source of instability in such a system is genetic recombination in the male. Although such recombination was originally thought to be absent in most cyclorrhaphous Diptera, low levels have recently been found. We have developed a computer model which simulates the progression of instability in the presence of male recombination, which can be used to assess the influence of rate of recombination in combination with a range of associated genetic and biological parameters. Male recombination alone or fitness of the Y-linked translocation were found to contribute relatively little to the rate of progression of instability. By contrast reduced fitness or mating competitiveness associated with the selectable gene had a strong effect. The sex ratio and the ratio of carriers to non-carriers of the selectable gene showed patterns characteristic of the parameters modelled. The relevance of such data to the development of suitable strains for genetic sex-separation and the replacement of strains under mass rearing conditions are discussed.
Uscana lariophaga (Hymenoptera: Trichogrammatidae), an egg parasitoid of bruchid beetle (Coleoptera: Bruchidae) storage pests in West Africa: host-age and host-species selection
Authors: van Huis A. , Wijkamp M. G. , Lammers P. M. , Klein Goldewijk C. G. M. , van Seeters J. H. , Kaashoek N. K. 
Published: July 2009

AbstractUscana lariophaga Steffan is an egg parasitoid of bruchid species in West Africa. The hosts are Callosobrucbus maculatus (Fabricius) and Bruchidius atrolineatus Pic, insect pests of stored cowpea. Experiments were carried out to study the selection between hosts of different ages and of different species in choice and no-choice situations. Results were obtained through parasitization studies and by direct behavioural observations. A description of the parasitization behaviour of Uscana lariophaga is given. At 30°C, C. maculatus eggs of 0–2 day old are readily accepted for parasitization, but in a choice situation the 0 day old eggs are preferred. Of the older eggs only those of 3 days old are parasitized but significantly less than those of 0–2 days. At 30°C, B. atrolineatus eggs older than 24 hours are significantly less parasitized than younger eggs also in the no-choice situation. When eggs are older than one day, the time needed for penetrating the egg increases with host age. Both bruchid species are suitable hosts for U. lariophaga. In a choice situation B. atrolineatus is the preferred host and especially so when U. lariophaga has been reared on this species. However, in a no-choice situation the highest rate of successful parasitization is obtained on hosts of the species from which they have been reared. The higher parasitization rate of C. maculatus in the field in Niger can be explained by the difference in the susceptible period between the two host species.
Behavioural variation of Anopheles arabiensis (Diptera: Culicidae) populations in Natal, South Africa
Authors: Sharp Brian L. , le Sueur David 
Published: July 2009

AbstractAnopheles arabiensis Patton populations occur in those areas of Natal in which intra-domiciliary DDT is used for mosquito vector control and in the unsprayed areas. Indoor resting collections from the unsprayed area showed a human blood index >90%, in contrast to the indoor collections from the sprayed area where only 31% had fed on man. In exit trap collections from the sprayed area, 66% had fed on man. These trends of a high human blood index in the exit trap collections and a low human blood index in the indoor resting catches were unaffected, despite the close proximity of a cattle kraal to the majority of homesteads.
A Morphological Comparison of the Adults ofOryzaephilus surinamensis(L.) andO. mercator(Fauv.) (Col., Cucujidae).
Authors: Slow Joan M. 
Published: July 2009

The object of the work described in this paper was to compare adults ofOryzaephilus surinamensis(L.) and O.mercator(Fauv.) by morphological and biometric methods with a view to determining the status of the latter as either a variety ofO. surinamensisor as a separate species.There are some marked and constant differences between the two insects in the structure of the male genitalia. These are listed.The analysis of the biometric results shows a clear-cut difference between the two insects in the ratio of eye length to temple length. All the other ratios considered overlap, although the means may be widely different. Some of these ratios are illustrated by histograms.A cross-breeding experiment gave no offspring from the mixed pairs.It is concluded thatO. mercatoris a good species which can be recognised morphologically.
The Mating Behaviour of Females ofGlossina palpalis(R.-D.) in Captivity
Authors: Jordan A. M. 
Published: July 2009

Experiments were carried out in the laboratory with individually marked females ofGlossina palpalis(R.-D.); various aspects of their mating behaviour, when placed with virgin 7-day-old males, were studied.Using virgins, females 1–3 days old mated for an average period of about two hours, females 4–9 days old for about 75 minutes, and 10-day-old females for somewhat less than one hour.Using virgins, mating was found to be relatively infrequent in 1-day-old females, maximal in females 2 and 3 days old and thereafter decreased as the age of the females increased.Females up to 10 days of age were found to be willing to mate on a number of occasions; re-mating was more frequent among the younger flies. The number of older females ofG. palpaliswhich are prepared to re-mate is very small.Previously mated females ofG. palpaliswere shown to be less willing to mate than virgin females of the same age. It seems that this is due to a decrease in desire for mating by the females rather than a loss of attractiveness to males.The implication of these laboratory findings, in relation to fly behaviour in the field, is discussed. It is suggested that a considerable proportion of young females ofG. palpalisis prepared to re-mate in nature, on a number of occasions, but that the desire for mating is extinguished much sooner in life in mated females than it is in virgin females.
Biological Notes on the Tobacco Cricket, Brachytrupes membranaceus (Dru.) (Orthopt., Gryllidae), in Southern Rhodesia
Authors: Büttiker W. W. , Bünzli G. H. 
Published: July 2009

The Tobacco Cricket, Brachytrupes membranaceus (Dru.), is a pest of young plants of tobacco, maize and other field and garden crops in Southern Rhodesia. During the period of investigations, 1949–52, it was found to be widely distributed in the Territory, the heaviest attacks occurring in areas of light sandy soil of granitic origin. All stages are nocturnal and each individual excavates and inhabits a permanent burrow in the soil, that of an adult averaging 50 to 80 cm. in depth. The burrow has an enlarged chamber in which the cricket lives and stores food.There is one generation a year. Oviposition takes place in February and March, the average number of eggs per female, as shown by dissection, was 216. Incubation takes about 30 days and development of the young nymphs is at first rapid. From June to October, the period of dry and often scarce food, development is retarded but increases rapidly during the third and fourth (the last) nymphal stages in November. From November to May, when young and succulent food abounds, development is rapid. The adults start appearing early in December.The eggs are laid in the burrows and the young nymphs on hatching crawl away from the parent burrow, in all directions, in search of suitable places in which to start digging. The mandibles are used to excavate the soil which is thrown outwards by the forelegs, and the mounds formed by the time the adult stage is reached may attain a height of as much as 30 cm. When an adult is evicted from its burrow, as soon as it finds a suitable place to dig, it will disappear within the space of a minute.The burrows may be found in virgin land or in cultivated land, or along the borders of cultivated fields. The food consists of succulent or dry vegetable matter, according to the time of year, and is carried to and stored in chambers in the burrows. In the virgin veld it consists mainly of lush grasses, seedlings and root suckers of trees such as Brachystegia and Isoberlinia in the rainy season and of dried material of a similar nature during tha dry months. In cultivated land, tobacco, maize, field beans, garden vegetables, seedlings and young transplants are cut and stored.Although the food is compacted in chambers in the burrows it has not been found in a mouldy or fermenting condition. It is thought that it is conditioned before storage, the more succulent material being allowed to wilt before being taken into the burrow and the dry material when softened by dew.
Field Observations on Adults of the Wheat Bulb Fly (Leptohylemyia coarctata (Fall.)).
Authors: Long D. B. 
Published: July 2009

A study of adult populations of Wheat Bulb Ply, Leptohylemyia coarctata (Fall.), has been carried out in the field by routine sweeping at Rothamsted. It has been observed that the males emerge slightly before the females and that the emergence period may cover at least three weeks in late June and early July. Although the number of males may exceed the number of females at first, the females predominate later in the season due to the shorter life span of the males.The numbers of flies on the wheat have been found to fluctuate appreciably throughout the day. During the first week of the emergence period the number of flies taken increased steadily throughout the day. After the date of population peak, however, the maximum numbers occurred in the crop in the very early morning and the late evening, which suggested a daily flight dispersion followed by a general or localised return of the flies to the crop. Further study of the data showed that the daily temperature rhythm was only partly responsible for this daily flight dispersion, and that there appeared to be an active return flight to the crop in the evening. Generally the males were more active than the females and did not settle so deeply in the crop.The temperature threshold for flight was observed to be 12 to 13°C. Winds up to 8 m.p.h. did not appear to affect flight activity, but higher winds, e.g., 15 m.p.h., markedly reduced flight, the flies remaining deep in the crop near ground level. Gale-force winds, however, were observed to produce a permanent depletion in the number of flies infesting Broadbalk field, indicating that the population was probably localised.Although portions of the populations dispersed fairly rapidly from the emergence sites, recaptures of radioactive flies labelled with 32P indicated that the extent of the dispersions was not very great. The females dispersed more than the males, and were influenced to some extent by the occurrence of wheat in flower. Frequently the flies were found to have congregated on the lee edge of the crop, but other preferred regions have been observed which could not be attributed to the influence of the wind.
Some Mosquitos of the Blue Nile Valley in the Republic of the Sudan
Authors: Lewis D. J. 
Published: July 2009

The rainfall of the Blue Nile valley diminishes towards the north, and the number of mosquitos tends to do the same, but the natural state of affairs has been somewhat altered by irrigation works in the shape of the Sennar reservoir and the watering of cotton, sorghum and sunt trees (Acacia arabica, Willdenow), and will be further altered when the proposed dam at Roseires is constructed.The latter dam will form a large reservoir in the Kiri-Roseires area where conditions are likely to differ from those of the Sennar reservoir. Anopheles funestus Giles and many other species occurred in the stretch downstream between Roseires and Abu Hugar in which riverside basins, overgrown with sunt trees, were flooded when the river was high.Farther downstream, between Karkoj and Sennar, breeding conditions were affected by the Sennar dam, water at full storage level reaching different heights in the basins according to their distance from Sennar. Near Sennar the dualpurpose dam had a particular effect on the aquatic vegetation and the mosquitos.A. gambiae Giles bred among Najas pectinata (Parl.) Magnus which, however, only occupied a small area in the reservoir, A. rufipes (Gough) bred in small numbers in various places, and A. pharoensis Theo. in a large area of creeping grass growing on silt under conditions which caused it to form a raft that rose and fell with the water. Adults of A. pharoensis, which was by far the commonest Anopheline, rested near houses by day at certain times of the year. Control of the grass was difficult and liable, to favour more dangerous species of mosquitos. Differences between the Sennar and Jebel Auliya reservoirs are discussed.In the riverain area between Abu Geili and Soba, A. gambiae bred in residual pools in the river-bed in the dry season and in flooded sunt basins in the rains. Control of larvae was very difficult in these basins and much reliance was placed on residual sprays against adults in houses.Breeding conditions in the Gezira irrigated area are described with particular reference to the type of clay soil. There were many larvae of A. gambiae in field channels at the end of the rains when irrigation began, and in March when the summer started. The latter increase was not reflected by any increase in the number of adults, probably owing to the reduction in length of life of the latter in the very hot dry weather. A. rufipes was sometimes found in houses. Control measures are briefly described.Some mosquitos of Khartoum and a few other areas within the Blue Nile valley are briefly considered.
The relative Susceptibility to Pyrethrum in Oil of Coleoptera and Lepidoptera infesting Stored Products.
Authors: Lloyd C. J. , Hewlett P. S. 
Published: July 2009

With a view to providing information useful in practical control, the relative susceptibility to pyrethrins, and to pyrethrins plus piperonyl butoxide, of a series of stored product insects has been determined. Adult moths and beetles of 31 species were investigated, together with the larvae of 16 of these, and that of one other.The insects were treated with 1.3 per cent, pyrethrins, and 0.3 per cent, pyrethrins plus 3.0 per cent, piperonyl butoxide, in a heavy, highly refined mineral oil (Shell Risella 17). Both formulations were applied in two ways: insects were exposed on sprayed filter papers or were directly sprayed. Insects were also treated with the oil alone by both techniques. While confined on films, and after being sprayed, the insects were kept at 25°C. and 70 per cent. R.H.Large differences in susceptibility were encountered. The adult moths and Bruchids were susceptible, the adult Ptinids rather resistant, but otherwise susceptibility showed little correlation with systematic classification. The larva of a given species was usually more resistant than the adult. Among the adults of the different species, susceptibility to pyrethrum appeared to be correlated with high activity of the normal insect.On the whole, 1.3 per cent, pyrethrins and 0.3 per cent, pyrethrins plus 3.0 per cent, piperonyl butoxide were of about equal toxicity.
The Availability of Glossina morsitans Westw. in Ankole, Uganda
Authors: Harley J. M. B. 
Published: July 2009

SummaryTwo areas in Ankole, Uganda, were studied with a view to obtaining estimates of the standard availability of Glossina morsitans Westw. These estimates gave maximum and minimum fiducial limits of 2·0 and 0·19 per cent. These are considerably lower than the estimates, obtained by Jackson in Tanganyika, of approximately 10 per cent. This difference is of practical importance in that a single fly caught in Ankole indicates a much larger population, and this is the probable explanation of the trypanosomiasis problem round the edges of the flybelt, where routine catches showed flies to be scarce.
Laboratory Colonisation of the Mosquito, Eretmapodites chrysogaster Grah
Authors: Gillett J. D. 
Published: July 2009

SummaryA colony of Eretmapodites chrysogaster Grah., sensu stricto, was maintained successfully for over a year without any reinforcement.Identity of the mosquitos was established by starting the colony from a single batch of eggs laid by a single wild-caught female mosquito, and subsequent examination of the genitalia of the male progeny.Mating occurred regularly after the first blood-meal of the female. In fact the females would not accept the males until they had started, or had finished, their first blood-meal.Eggs were laid on the sterilised, water-filled bracts of banana flowers. Moist paper, moist cotton-wool or free water above paper or cotton-wool proved unsatisfactory as egg-laying media.Larvae fed largely on the substance of the banana bracts on which the eggs had been laid. The banana bract also provided cover and so reduced the incidence of cannibalism among larvae.
Studies on Aqueous Suspensions of Insecticides. Part VI. Further Notes on the Sorption of Insecticides by Soils
Authors: Barlow F. , Hadaway A. B. 
Published: July 2009

SummaryQuantitative measurements of the sorption of γ BHC and dieldrin in Uganda mud blocks have been made. Gamma BHC diffused more rapidly than dieldrin, and within a few weeks had achieved an almost uniform concentration throughout the sprayed blocks. Only when the uniform concentration had been reached did loss by evaporation from the blocks become marked. Increased dosages of γ BHC gave increases in biological activity which were roughly proportional to the dosages used. Sorption on to mud greatly prolonged the residual life of γ BHC as compared with similar deposits on glass.Dieldrin behaved in the same way as γ BHC although because of its slower rate of diffusion the distribution in the blocks had only reached in 48 weeks the stage reached by γ BHC in eight weeks. There was no appreciable loss of dieldrin during this time, whereas about 90 per cent. of the deposit on glass plates had been lost.Gamma BHC, dieldrin and DDT were recovered from the adsorbed state on mud and identified. Any decomposition is therefore likely to be negligible. Dieldrin was also recovered from two soils which had much higher “surface acidities” than the standard.Active mud can only sorb the portion of insecticide vapour from an evaporating deposit which happens to diffuse in its direction. This is to be expected, but the system has some peculiarities because the evaporation of γ BHC from filter papers over mud blocks is much faster than in the absence of the mud.Measurements of the distribution of DDT and dieldrin in soils less active than the standard Uganda one showed that both the initial adsorption and subsequent diffusion were very much slower.The activity of Uganda soil was not reduced by removal of material soluble in organic solvents, and was only partly reduced by complete extraction of iron compounds.Variation in temperature over the range 20 to 30°C. had only small effects on the diffusion of DDT and dieldrin within mud blocks.Repeated applications of DDT and dieldrin to the same blocks did not result in any observable slowing in the rate of disappearance. The concentration of insecticide in the successive layers of mud, did, of course, increase with successive sprayings.
The Groundnut Bruchid, Caryedon gonagra (F.)
Authors: Davey Pauline M. 
Published: July 2009

SummaryInformation on the world distribution and host-plants of the Groundnut Bruchid, Caryedon gonagra (F.), has been summarised from the literature. As a result of misidentification of the species that attacks groundnuts and of differing views about its generic assignment, this information has been given under several different names. The records brought together here are believed all to represent C. gonagra, and in a number of cases this has been confirmed by examination of the material concerned by Mr. B. J. Southgate.C. gonagra is widely distributed in the Old World tropics and sub-tropics, but it is absent from Australasia, and it has only a restricted distribution in the New World tropics. Almost all its host-plants belong to the Leguminosae, the principal one being the tamarind, Tamarindus indica, in the pod of which the beetle has been found to develop more quickly than in the groundnut.Data on the life-history and habits, and on the duration of pre-adult development and adult life, are summarised from the literature.Experiments are described to determine the optimum conditions for multiplication of C. gonagra, using groundnuts as food. When adult females were allowed to lay large numbers of eggs on shelled and unshelled nuts, only a small proportion of the resulting larvae completed their development, the number of adults that emerged averaging about 2·4 per kernel in shelled nuts and 3·2 in unshelled ones. The developmental period at 70 per cent. relative humidity was 42 days at 30°C. and 91–98 at 25°C.; the former figure is less than any recorded in the literature at higher or lower temperatures, and all subsequent experiments were therefore made at 30°C. and 70 per cent. relative humidity.Adults confined for three weeks, starting when four days old, at the rate of 25 pairs on 160 g. of a mixture of broken and intact kernels gave rise to some 314 F1 adults; this total was virtually unchanged when 50 pairs were used, but lower densities, though giving rise to greater yields per parent adult, gave much lower yields per weight of food. Emergence of adults began six weeks after the date of egg-laying and reached its peak from one to three weeks later.The yield from ten females on intact kernels was greater than from the same number on the mixture, but differed little whether the parent adults were left on for one week or three weeks, indicating that the majority of the eggs are laid in the first 11 days of adult life. The yield from unshelled nuts was nearly twice as great as that from shelled nuts, and also significantly larger than that from shelled nuts with ground shell added. Possible causes of this are discussed.The sexes can be distinguished in the adult stage by differences in the terminal abdominal segments.