bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population Studies of the Pea Aphid in East Anglia
Authors: Dunn J. A. , Wright D. W. 
Published: July 2009

Data on the populations of the Pea Aphid, Acyrthosiphon pisum (Harris), have been accumulated over four years on several leguminous crops in East Anglia. The populations on lucerne have provided the most extensive studies.Considerable annual variation was shown by the populations, but in spring the development of a peak in the numbers of Aphids occurred on lucerne, hop trefoil and sainfoin. On lucerne, which was periodically cut, the Aphids persisted throughout the growing season and a tendency towards the development of a peak in numbers in the autumn was also recorded.All the factors which affected the number of Aphids varied considerably in the influence they exerted. The probable reason for the more obvious trends in the populations have been given in fairly broad outline, but how the effect of these factors had been altered or predisposed by less apparent factors has been speculated upon only in certain instances.
Biology and host specificity of the Chondrilla gall mite Aceria chondrillae (G. Can.) (Acarina, Eriophyidae)
Authors: Caresche L. A. , Wapshere A. J. 
Published: July 2009

AbstractThe Eriophyid gall mite, Aceria chondrillae (G. Can.), which is distributed from south-east Russia to Portugal, was studied in the Mediterranean region as part of a biological control programme against skeleton weed (Chondrilla juncea) for Australia. The mite induces the vegetative and flower buds of Chondrilla to form leafy galls in which the full life-cycle is completed, causing stunting of the plant and reducing seeding. The mite overwinters in the rosettes of C. juncea without inducing gall development or reproducing. Populations decrease markedly during winter, recover in spring and infestations spread rapidly during summer. Reproduction is sexual and spermatophores are deposited by the males. Amblyseius sp. preys on A. chondrillae without marked effect. Tests made by placing fully developed galls of A. chondrillae on 75 species of plant including certain Cichoriaceae closely related to Chondrilla showed that the mite was highly specific to Chondrilla. Comparative tests with four geographical strains of A. chondrillae against six forms of C. juncea of various geographical origins indicated that the strains were specialised to their usual host form of the plant. A Greek strain of the mite readily attacked the main Australian form of C. juncea, and this strain has been introduced into Australia as a biological control agent for the weed.
Circadian flight activity in four sibling species of theAnopheles gambiaecomplex (Diptera, Culicidae)
Authors: Jones M. D. R. , Gubbins S. J. , Cubbin C. M. 
Published: July 2009

AbstractCircadian flight activity in the males and females ofAnopheles gambiaeGiles species A and B, A. melas (Theo.) and A. merus Dön. has been investigated using the acoustic actograph technique. In each species the pattern and timing of activity in males and females is almost identical. Cyclical activity continues in constant dark; the period of the cycle is approximately half-an-hour shorter inA. gambiaespecies A and half-an-hour longer inA. merusthan in the other two species. In alternating 12 h light: 12 h dark, both sexes are active during the dark period, with peaks of activity following light-off and light-on. After light-off, the species become active in the following order:A. gambiaespecies A,A. melas, A. gambiaespecies B,A. merus. A. merusis approximately 20 min later than species A.
Inversion polymorphism and circadian flight activity in the mosquitoAnopheles stephensiList. (Diptera, Culicidae)
Authors: Jones M. D. R. 
Published: July 2009

AbstractCircadian flight activity inAnopheles stephensiList. has been investigated using the acoustic aotograph technique. In alternating 12 h light: 12 h dark (50 or 200 lx), both sexes are active during the dark period, with peaks of activity following light-off and light-on. Cyclical activity persists in constant dark and is inhibited and reset by prolonging the light period. There are small differences between the carriers of the alternative chromosomal arrangements 2R+ ( +/+) and 2Rb (b/b) and between the sexes. In +/+ females the period of the cycle in constant dark is approximately half-an-hour longer and, in LD 12:12, there is less activity at light-on than in both sexes of b/b or in +/+ males. The +/+ males appear to be less susceptible to the inhibitory effect of prolonging the light period, although the cycle is reset.
Seasonal elimination of some size classes in males of Glossina morsitans morsitans Westw. (Diptera, Glossinidae)
Authors: Phelps R. J. , Clarke G. P. Y. 
Published: July 2009

AbstractSizes of young field-collected males of Glossina morsitans morsitans Westw. were compared with those of teneral males emerging in the laboratory from field-collected puparia. Based on the mean size, indications were that smaller flies in field populations were selected against for about seven months in the year. A method is described for estimating the proportion of flies lost in the field population, and for the calculation of standard deviations for the estimates. Estimates of the extent of elimination showed that up to 35·2% of the total fly population in the field was eliminated in the cool months and up to 75·5% in the hot dry months.
Comparative plague dynamics of tropicalLocusta(Orthoptera, Acrididae)
Authors: Farrow R. A. 
Published: July 2009

AbstractThe occurrence and causes of plagues of tropicalLocustaspp. are compared for the three major outbreak areas, Middle Niger of Mali (L. migratoria migratorioides(R. & F.)), south-west Madagascar (L. m. capito(Sauss.)), and Mindanao (Philippines) (L. m. manilensis(Meyen)). Multiplication and concentration are the two most important processes involved and may occur concurrently or sequentially depending on the outbreak area. In the Middle Niger and Madagascar heavy rainfall, through its effect of increasing multiplication, is the key density-disturbing factor, whereas on Mindanao the factor is drought leading to concentration of locusts. Variations in multiplication rates are determined by the response of eggs and hoppers to desiccation and by the density-dependent effects of fecundity and natural enemies. Concentration is caused by the restriction of favourable breeding habitats in relation to the seasonal population displacements and, because it occurs at different seasons in the three outbreak areas owing to their differing climates and geographies, profoundly modifies the timing of outbreaks. Man's modification of the environment, particularly in relation to the dry season survival ofLocusta, has caused outbreaks to occur in new areas. Long-term solutions to the problem of controlling such outbreaks lie in the field of management rather than in the continued use of insecticides because of the continued reinfestation from surrounding populations. The use of natural enemies does not as yet show any promise as a means of controlling outbreaks of tropicalLocusta.
The production of distribution maps of the incubation and hopper development periods of the desert locust Schistocerca gregaria (Forsk.) (Orthoptera, Acrididae)
Authors: Symmons P. M. , Green S. M. , Robertson R. A. , Wardhaugh K. G. 
Published: July 2009

AbstractThis paper describes the method used to produce maps of the incubation and hopper development periods of the desert locust Schistocerca gregaria (Forsk.). From these maps it is possible to calculate the likely development periods of eggs and hoppers for, respectively, laying and hatching on any date and at any place within the invasion area of the species. Maps could not be based on actual observations of development periods because such observations are few in number, irregular in distribution and are not for standard dates. Instead, expected mean development periods for laying and hatching on the first of each month were calculated for a large number of meteorological stations for which long-term mean temperatures were available, using relationships between the rates of development and mean daily screen temperatures. These relationships were, in the main, derived from earlier work by one of the authors (K.G.W.) and his associates. Some assessment has been made of the accuracy of development periods derived from the maps.
A Method for obtaining Samples of the Population of Collembola (Symphypleona) in Pastures
Authors: Davidson J. , Swan D. C. 
Published: July 2009

In our investigations on Smynthurus viridis, L., a study has been made of the population of this species, in an area of lucerne, at intervals of three and four days throughout the season.The density of the population of the species in a favourable pasture is markedly affected by the relative abundance of certain food-plants, especially leguminous species and particularly clovers such as subterranean clover (Trifolium subterraneum) and lucerne (Medicago sativa).The activity of the insect is intimately associated with the moisture of its environment, and the moisture content of the surface soil is one of the most important factors affecting the environmental conditions.Considering the habits of the insect, it was felt that the sweeping method would not give a reliable record of the total population in a given area of pasture. A sample obtained by sweeping with a net does not include individuals on or near to the surface of the soil. The relative proportion of individuals situated on or near the soil surface and those situated further up the plants varies considerably from time to time, according to the meteorological conditions, the growth of the herbage and the moisture content of the surface soil. It was necessary therefore to devise a simple method by means of which a more accurate record of the total population in a given area could be obtained.
Suppression of pink bollworm and effect on beneficial insects of a nectariless okra-leaf cotton germplasm line
Authors: Flint H.M. , Wilson F.D. , Parks N.J. , Reynoso R.Y. , Stapp B.R. , Szaro J.L. 
Published: July 2009

AbstractInfestations of pink bollworm, Pectinophora gossypiella (Saunders), (Lepidoptera: Gelechiidae), and numbers of beneficial insects in two cottons, Gossypium hirsutum, were compared at Maricopa, Arizona, and Brawley, California, during the 1986–1988 seasons. Plots (0.8 ha) of WC-12NL (nectariless, okraleaf, and early maturing) had significantly lower boll infestations than DPL-61 (nectaried, normal leaf, and later maturing) for each location and year. The three year average (range) PBW/100 bolls for WC-12NL and DPL-61 at Maricopa were 6.8 (5.7–10.7) compared to 11.2 (6.8–15.7), respectively. At Brawley the averages were 18.9 (9.3–27.6) compared to 39.2 (15.5–52.5), respectively. With the exception of 1986 at Maricopa, the percentage of bolls with eggs was significantly greater for DPL-61 (average 8.1, range 3.4–16.0) than for WC-12NL (average 4.2, range 1.1–12.1) for each location and year. Both cottons averaged about four eggs per oviposited boll; not significantly different. The numbers of Lygus spp. and three beneficial species of insects were not different in the two cottons. Collops vittatus (Say) (Coleoptera: Melyridae) was collected in significantly greater numbers in WC-12NL (1.0 per 50 sweeps compared to 0.9 for DPL-61), while Hippodamia convergens (Guérin-Ménéville) (Coleoptera: Coccinellidae) was collected in greater numbers in DPL-61 (0.6 per 50 sweeps compared to 0.3 for WC-12NL). WC-12NL is the culmination of a 20-year breeding programme for resistance to P. gossypiella and has characteristics attractive for cotton production in areas where a shorter growing season is desirable.
Dispersal of apterous aphids (Homoptera: Aphididae) from their host plant and its significance
Authors: Hodgson Chris 
Published: July 2009

AbstractDispersal of apterae from their natal plant was monitored for three aphid species (Myzus persicae (Sulzer), Brevicoryne brassicae (Linnaeus) and Megoura viciae Buckton), each on a different host plant. Some movement off the plant occurred even in the initial parental and second generations, when the plant appeared to be growing normally and when crowding was unlikely to be the cause. However, in most experiments the most marked increase in apterous dispersal coincided with a reduction or even cessation of plant growth. In nearly all the experiments this dispersal occurred when the population on the natal plant exceeded about 20 adults and their offspring per plant. The main emigrants were fourth instar apterae and prelarviposition adult apterae. The implications of this behaviour are discussed, and it is argued that apterous dispersal might be common in aphids, allowing a fuller utilization of the environment than would be likely by alate dispersal alone.
Clonal diversity in overwintering populations ofSchizaphis graminum(Homoptera: Aphididae)
Authors: Shufran Kevin A. , Wilde Gerald E. 
Published: July 2009

AbstractThe intergenic spacer region of the rRNA cistron was used as a molecular fingerprinting probe to study clonal diversity inSchizaphis graminum(Rondani). A high degree of clonal diversity was found in overwintering populations on wheat from Kansas, Texas and Oklahoma. Out of 184 individuals tested, 132 unique maternal lineages wereidentified. Overall, clonal diversity of overwintering populations was no less than in spring and summer populations. However, in some fields there were more instances where individuals of the same genotype were identified. By partitioning the total population diversity into various sampling components (fields, counties and states), 93.1% of the total diversity was found among individualS. graminumwithin fields. Overwintering of many genetically distinct clones as parthenogenetic morphs is one mechanism by which clonal diversity is maintained in populations ofS. graminum. The incidence of clonal diversity further substantiates the importance of theS. graminumholocycle for generating genetic heterogeneity in the USA.
Cross resistance spectra and effects of synergists in insecticide-resistant strains of Lucilia cuprina (Diptera: Calliphoridae)
Authors: Kotze A.C. , Sales N. 
Published: July 2009

AbstractCross-resistance spectra were determined in strains of the Australian sheep blowfly, Lucilia cuprina (Wiedemann), which had been pressured for several years in the laboratory with diflubenzuron, butacarb or deltamethrin. Each strain was highly resistant to its selecting chemical (resistance factors > 1000-fold), however, cross-resistance levels were variable and often low. In particular, strains selected with diflubenzuron and butacarb showed very little resistance to deltamethrin (resistance factors <7-fold). Each strain showed resistance levels to diazinon only slightly higher than the highest levels currently detected in field strain larvae. Piperonyl butoxide and triphenyl phosphate significantly synergized each pressured strain with its selecting chemical, suggesting the involvement of both monooxygenases and esterases in the observed resistances. Synergism ratios in each case were greater with piperonyl butoxide. The lack of any alteration in in vitro acetylcholinesterase sensitivity to butacarb inhibition in the butacarb-selected strain, and only low level resistance to DDT in the deltamethrin-selected strain, provided no evidence for target-site insensitivities in these strains. The low-moderate levels of cross-resistance therefore imply the existence of qualitative differences in the detoxification systems in each strain.
Evaluation of the chitin synthesis inhibitor triflumuron for controlling the tsetse Glossina morsitans morsitans (Diptera: Glossinidae)
Authors: Langley P.A. 
Published: July 2009

AbstractTopical doses of triflumuron in acetone as low as 0.05 μg per fly induced a significant reduction in the production of viable offspring by adult Glossina morsitans morsitans Westwood, the effect being greatest in the two reproductive cycles following treatment. A dose of 0.5 μg terminated successful reproduction for the life of the fly. A single dose was as effective as the same dose split into five separate treatments. Exposure of females by tarsal contact during passage through a cotton cloth cone treated with 3% suspension concentrate of triflumuron was sufficient to terminate successful reproduction for at least four reproductive cycles following treatment. Males exposed to treated surfaces for 5 minutes could transfer effective amounts of triflumuron to females during mating for at least 2 days after treatment. Target materials, treated with 1% triflumuron in acetone and exposed to field conditions in Zimbabwe for 6 months (April to September), retained their ability to induce a peak abortion rate of 60–70% (40–45% overall) among females exposed by brief tarsal contact in the laboratory.
Studies on Stenobracon deesae (Cam.), a Parasite of certain Lepidopterous Borers of graminaceous Crops in India
Authors: Narayanan E. S. , Chaudhuri R. P. 
Published: July 2009

Experiments were conducted to investigate oviposition and host selection by Stenobracon deesae (Cam.), a Braconid parasite of certain Lepidoperous borers of sugar-cane, maize and sorghum in India. The fecundity and sex-ratio of this parasite and the duration of its life-cycle were also studied.Chilo zonellus (Swinh.) and Corcyra cephalonica (Staint.) were used as hosts. The former is one of the principal hosts in the field, but the latter is not normally a host of this parasite.The femal Stenobracon normally avoids laying eggs on hosts that are already parasitised by its own kind when unparasitised hosts are available; but in the absence of healthy hosts or when these are too crowded, parasitised hosts are attacked by it.At a temperature of 26°C. and relative humidity of 75 per cent., the life-cycle of the parasite was completed, on an average, in 23·3 days, but under laboratory conditions at Delhi it took 14·1 days in June-July and 43·7 days in November-December. The average duration of adult life of females in June-February, mainly in ordinary laboratory conditions, was 35·7 days, and single females lived as long as 122 and 128 days. The adult male lived for 42·7 days on the average.In the laboratory, the female lays about 24 eggs on an average, but only about one-third of them yield adults.Males predominate. The sex-ratio appears to vary according to the host; among adults reared on Chilo larvae, 28·8 per cent. were females, but among others reared on Corcyra larvae, only 6·2 per cent. were females.The phenomena of discrimination between parasitised and unparasitised hosts and of the change of sex-ratio with change of host are discussed. It is suggested that the ovipositor enables the parasite to recognise the host and that the stimuli received by the ovipositor from the host influence the functioning of the spermatheca which in turn controls fertilisation and finally the sex of the progeny.
Muscidae of Medical Interest in the Anglo-Egyptian Sudan
Authors: Lewis D. J. 
Published: July 2009

The general distribution of theMuscidae(other thanGlossina) of medical interest in the Sudan is discussed, and brief notes are given on some Muscids in relation to trypanosmiasis.Eighty-six species of some medical interest, belonging to 22 genera, are listed, with records of their distribution and notes on the habits of several of them.
A trial of odour baited targets to control the tsetse fly, Glossina morsitans centralis (Diptera: Glossinidae) in west Zambia
Authors: Willemse L. P. M. 
Published: July 2009

AbstractTargets of black cloth with or without flanking netting panels (ca. 1 m tall × 1.7 m) baited with acetone (130 mg/h) and 1-octen-3-ol (0.5 mg/h), coated with deltamethrin suspension concentrate and deployed at 4/km2, produced a decline of 3% per day in the apparent density of the tsetse fly Glossina morsitans centralis Machado in 500 km2 of the Western Province of Zambia. Flies were eradicated in a year as evidenced by the absence of catches from flyrounds and traps and the elimination of the transmission of trypanosomiasis. The promise of the target technique is confirmed but the need for its further development is emphasized.
Target barriers for tsetse flies (Glossina spp.) (Diptera: Glossinidae): quick estimates of optimal target densities and barrier widths
Authors: Hargrove J. W 
Published: July 2009

AbstractThe probablity that tsetse flies (Glossina spp.) cross a barrier of odour-baited targets is calculated for barriers of different widths and target density, and for tsetse flies with varying natural rates of survival, daily step lengths (d) and probabilities of being killed by an odour-baited target. If the barrier is only as wide as d, and for a species which has a 2% natural daily mortality and a further 2% mortality due to each target per unit area, tsetse flies have probability (P) of ca. 0.1 of penetrating the barrier even if the target density is 64 per unit area. To ensure that P < 0.001 the barrier must be about 4d wide for target densities 32 per unit area; doubling the width to 8d means that target densities could be cut by about 75%, and total numbers of targets in the barrier by 50%. These biological considerations and the economic costs of different target barriers suggest that, for all tsetse fly species, a safe and relatively inexpensive barrier is achieved with barrier width 8d when the optimum target density is roughly the same as for normal operational areas. This has the important practical consequence that there is no need to treat barriers as a special case. Practical results from research and control operations in Zimbabwe are in accord with the theoretical findings, but further work is required to ascertain whether the safety margin, and hence costs, can be reduced.
Assessment of key factors responsible for the pest status of the bean flower thrips Megalurothrips sjostedti (Thysanoptera: Thripidae) in West Africa
Authors: Tamò M. , Baumgärtner J. , Delucchi V. , Herren H.R. 
Published: July 2009

AbstractMegalurothrips sjostedti (Trybom) is an important pest of cowpea (Vigna unguiculata) in West Africa. Three key factors assumed to be responsible for its pest status are analysed, the survival on alternative host-plants during the dry season, the inefficient biotic mortality factors regulating population growth, and the effect of larval feeding on the development of cowpea flower buds. Extensive surveys indicate clearly that M. sjostedti survives the dry season on a wide range of alternative hosts all belonging to the Leguminosae, where it can feed and reproduce. Different antagonists were observed attacking eggs and larvae of M. sjostedti; their impact, however, is low and cannot prevent pest outbreaks. Two undescribed Megaphragma spp., and one Oligosita sp., all trichogrammatid egg parasitoids, were recorded for the first time. The anthocorid Orius sp. was the most important larval predator. No hymenopterous parasitoids could be reared from larvae collected on cowpea and three major alternative hosts, whereas a low percentage of the larvae collected from the flowers of Tephrosia candida, an exotic shrub native to India, were parasitized by the eulophid Ceranisus menes (Walker), also recorded for the first time in Africa. The feeding activity of six larvae of Megalurothrips sjostedti during five days induced the shedding of all flower buds of a cowpea inflorescence. The results of the analysis shed new light on the M. sjostedti pest problem, and the ways to solve it. The lack of efficient antagonists, particularly larval parasitoids known from closely related south-east Asian Megalurothrips spp., and the high damage threshold, indicate that M. sjostedti is a potential target for biological control. However, further studies are needed to investigate the migration of M. sjostedti adults to and from alternative host-plants, in order to reinforce the action of biocontrol with cultural pratices.