bluuebunny/crossref_metadata_2025 huggingface dataset:
Population dynamics of Glossina morsitans submorsitans Newstead and G. tachinoides Westwood (Diptera: Glossinidae) in sub-Sudan savanna in northern Nigeria. I. Sampling methodology for adults and seasonal changes in numbers caught in different vegetation types
Authors: Dransfield R. D. , Brightwell R. , Onah J. , Okolo C. J.
Published: July 2009

An investigation was carried out into the use of water traps for sampling Glossina morsitans submorsitans Newst. and G. tachinoides Westw. in Yankari Game Reserve in sub-Sudan savanna in northern Nigeria. The traps consisted of coloured trays filled with water plus small quantities of formalin and detergent. Colour was thought to be the major factor attracting flies to the traps, white traps being most effective for G. m. submorsitans and black ones for G. tachinoides. Water traps were compared with biconical traps, and both methods showed similar changes in catches in different vegetation types over a year. Males and females of both species showed a marked expansion in distribution in the rains and a contraction to riverine woodland in the dry season, though females of G. m. submorsitans could be caught in the adverse deciduous woodland and open savanna all year round. Water traps are considered a very cheap and practicable sampling method for ecological studies on these species of Glossina, providing specimens well preserved upon capture for later morphometric and analytical studies.
The history of, and prospects for, the biological control of Chromolaena odorata (Compositae) by Pareuchaetes pseudoinsulata Rego Barros and allies (Lepidoptera: Arctiidae)
Authors: Cock M. J. W. , Holloway J. D.
Published: July 2009

Chromolaena odorata is a tropical American species of the Compositae that has become a serious problem in plantations in the tropics of Asia and Africa. The history of attempts to control it using the arctiid moth Pareuchaetes pseudoinsulata Rego Barros (misidentified in previous literature as Ammalo insulata (Wlk.)) is summarised. The taxonomy and distributions of the five species in Pareuchaetes are presented, together with keys based on genitalic characters, three new synonyms and one new combination. Information on the biogeography and ecology of the Pareuchaetes species is used to assess their potential as biological control agents.
Ticks (Acari: Ixodoidea) of the Yemen Arab Republic. I. Species infesting livestock
Authors: Pegram Rupert G. , Hoogstraal Harry , Wassef Hilda Y.
Published: July 2009

Data from surveys in 1951, 1972, 1973 and 1978–79 showed that tick numbers are generally low on the miniature breed of cattle in the Yemen Arab Republic and tick-borne diseases have not been recognised as a serious problem. This breed should be investigated for properties of resistance to tick bite. Each tick species commonly infesting livestock has been recorded as transmitting viruses (and some also rickettsiae) causing human illness in Africa and/or Eurasia. Between 1300 and 2000 m in altitude, Amblyomma variegatum (F.) is more abundant on camels than on cattle and Boophilus annulatus (Say) infests cattle. Below 1500 m, B. kohlsi Hoogst. & Kaiser is more abundant on goats than on sheep. Haemaphysails sulcata C. & F. infests sheep in certain highland areas. Hyalomma dromedarii Koch is the most prevalent and abundant tick of livestock. H. anatolicum excavatum Koch is next in abundance on camels. The numbers of H. anatolicum anatolicum Koch vary greatly in collections from different years. Few examples of H. erythraeum Tonelli-Rondelli were taken. H. impeltatum Schultze & Schlottke and H. marginatum rufipes Koch are widely distributed; the former is most abundant in coastal lowlands, the latter in humid habitats. H. arabica Pegram, Hoogst. & Wassef is recorded from goats, and also sheep, in southern hills. Immature examples of Hyalomma spp. are especially abundant on camels and hares. Rhipicephalus evertsi evertsi Neum. is common in the highlands, as is R. simus Koch below 2000 m. Species of the R. sanguineus (Latr.) group occur on some livestock.
Economic thresholds for cotton pest management in Sri Lanka
Authors: Keerthisinghe C. I.
Published: July 2009

Field experiments conducted on cotton in southern Sri Lanka, where the main pests were Heliothis armigera (Hb.), Earias vittella (F.) and Pectinophora gossypiella (Saund.), indicated that a damage action threshold of five squares and six bolls per 30 plants could be used for forecasting and early warning in pest management. A parallel sampling study indicated that a sample size of 30 plants would reduce the sampling error to acceptable levels as well as being a more convenient number in the field. An expression that corrects experimentally established thresholds for changes in the cost of control and the market price of the yield is given.
Incidence of yellows in sugar beet as affected by variation in plant density and arrangement
Authors: Johnstone G. R. , Koen T. B. , Conley H. L.
Published: July 2009

Aphid species found infesting sugar-beet in Tasmania were Aphis craccivora Koch, Aulacorthum solani (Kalt), Macrosiphum euphorbiae (Thos.) and Myzus persicae (Sulz.). The activity of infective alatae over plots of sugar-beet established by sowing at different densities and arrangements to produce 12 treatments was gauged by recording the numbers of plants which became affected with virus yellows symptoms. The incidence of yellows increased as plant density decreased and as plant arrangement altered from rectangular to more square patterns. A regression equation of the form: where a, b, c and d were constants and x and y the intra- and interrow spacings, respectively, accounted for 92% of the variation produced by the 12 treatments. These results indicate that the incidence of virus infection in row crops resulting from aphid flight activity may be manipulated through altering plant density and arrangement.
Studies on the flight of black-flies (Diptera: Simuliidae). I. Flight performance ofSimulium ornatumMeigen
Authors: Cooter R. J.
Published: July 2009

The flight performance ofSimulium ornatumMg. s.l. was measured under laboratory conditions using a simple flight mill. Males and unmated females were flown and the duration, distance and average speed of flight were recorded for adults fed on water only, sucrose, blood & water, or blood & sucrose. On 91% of all test occasions sucrose-fed insects flew but 25% of those on water only did not fly. Feeding flies on 10% sucrose solution markedly improved both willingness to fly and flight performance, and under these conditions maximum duration, distance and average speed recorded were 4.9 h, 4·2 km and 2·84 km/h, respectively. The ratio of average to maximum speed was 0·631 for females and 0·610 for males, with absolute maximum speeds of 3·19 and 2·99 km/h, respectively. Duration and distance flown were well-correlated, speed being the least variable aspect of flight performance measured. The distributions of flight duration and distance flown were skewed such that few insects made long flights. Mean flight performance at different ages was measured; unmated females appeared to retain a high level of willingness to fly throughout the age-range tested (up to 33 days). The longest recorded flight (5·3 h) was made by a female during an overnight experiment. The implications for long-range flight movements by simuliids are discussed.
The development of resistance to certain organophosphorus and carbamate ixodicides by the blue tick, Boophilus decoloratus (Koch) (Acarina, Ixodidae), in Rhodesia
Authors: Matthewson M. D. , Wilson R. G. , Hammant C. A.
Published: July 2009

Eight strains of Boophilus decoloratus (Koch) are described from farms in the High veld area of Rhodesia. All eight strains showed resistance to a number of organophosphorus ixodicides and four showed additional resistance to the carbamate, carbaryl. This is the first recorded resistance to these two groups of ixodicides in Rhodesia.

Biochemical studies on the Alicedale West Farm strain indicated a level of resistance between that of the Berlin strain of B. decoloratus and the Biarra strain of B. microplus (Can.).
The genetic basis for organophosphorus resistance in the Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera, Calliphoridae)
Authors: Arnold J. T. A. , Whitten M. J.
Published: July 2009

Organophosphate resistance in Lucilia cuprina (Wied.) is shown, by the backcross and discriminating dose technique, to be controlled by two major genetic loci on chromosomes 4 and 6. Respectively designated Rop-1 and Rop-2, they are positioned on the known genetic map. Rop-1 has three resistance alleles and one of these, and the Rop-2 allele, demonstrated stable transmission and expression in the absence of insecticide. Expression of resistance was either intermediate or incompletely dominant depending on locus and stage of maturity. This, and interaction between the loci, suggests that they have different biochemical mechanisms.
Effects of human blood group, sweating and other factors on individual host selection by species A of the Anopheles gambiae complex (Diptera, Culicidae)
Authors: Thornton Christine , Doré Caroline J. , Willson J. O. C. , Hubbard Judith L.
Published: July 2009

The suggestion that mosquitoes can discriminate ABO blood group status in man was re-examined and an attempt made to determine recognition mechanisms.

Host choice was assessed in the laboratory by recording landings on and blood-meals taken from the forearms of pairs of human volunteers in a 10-min exposure to 20 females of species A of the Anopheles gambiae complex, and an alternative procedure, which did not involve mosquitoes probing the host's skin, was developed and evaluated. The presence of weals on the host's skin was found to be an unreliable indicator of probing or feeding activity by mosquitoes. The effect of thermally induced sweating was also investigated.

No effect of ABO blood group status on host choice was found. Mosquitoes did, however, show a highly significant preference to land and feed on a subject when thermogenic sweating was induced. Secretor substances in the sweat did not influence host selection.

The predictive value of host variables such as MN blood group, skin temperature and humidity, skin colour and forearm hair density in determining host choice was examined. Very little of the observed variation in mosquito activity could be accounted for by these host variables within the ranges used.
Biology and ecology of Stomoxys nigra Macquart and Stomoxys calcitrans (L.) (Diptera, Muscidae) in Mauritius
Authors: Kunz S. E. , Monty J.
Published: July 2009

The distribution and seasonal abundance of Stomoxys nigra nigra Macq. and S. calcitrans (L.) in Mauritius was determined by field surveys in 1973–74. S. nigra, the species of major importance, is most common throughout the wetter, higher elevations where it becomes a major pest of cattle. S. calcitrans occurs throughout the island to a much lesser extent. Coastal areas with less than 60 inches of rain are generally free of damaging infestations of both species. Seasonal infestation levels were determined by making counts of flies feeding on animals and of flies on resting surfaces. Populations of up to 200 S. nigra per animal were highest during the warm, wet, sugar-cane cropping season but declined to generally non-damaging levels during the cool season. S. calcitrans increased up to 145 flies/animal during the cool, drier season and virtually disappeared during the wet season. S. nigra accounted for up to 98% of the total Stomoxys infestation with S. calcitrans making up 62 % of the total at one study site during the study.

Sugar-cane debris in fields was found to be the primary breeding source for 5. nigra, whereas decaying manure and organic matter provided the source for S. calcitrans. Generation-to-generation increases were usually below five-fold for both species. Both species exhibit two feeding peaks throughout the day at temperatures of 14°C or above.
Descriptions ofTachinobiagen. n. and three new species of Tetrastichinae (Hymenoptera: Eulophidae), with a tentative key to genera
Authors: Bouček Z.
Published: July 2009

Tachinobiagen. n. is defined andT. repandasp. n. andT. gradwellisp. n., both of which are parasites of Taohinidae, are described and illustrated.Kocourekia clavigerasp. n., a parasite ofMegachile, is also described. A tentative illustrated key to 17 genera of Tetrastichinae is given, with notes on all genera and details of hosts and geographical distribution for included species. One species,Quadrastichodella eucalypti, is probably phytophagous and is widely distributed on cultivated eucalypts.
Development of Gryon gnidus (Nixon) (Hymenoptera: Scelionidae) in eggs of Acanthomia tomentosicollis (Stål) (Hemiptera: Coreidae) killed either by gamma irradiation or by freezing
Authors: Egwuatu R. I. , Ajibola Taylor T.
Published: July 2009

The effects of host quality on the development of Gryon gnidus (Nixon), a scelionid egg-parasite of Acanthomia tomentosicollis (Stål), are reported. A minimum exposure period of 24 h at —4°C or an irradiation dose of 1000 rads from a cobalt-60 source killed 98–99% of freshly-deposited, fertile eggs of A. tomentosicollis. Sub-lethal periods of exposure delayed hatching in both treatments and the incubation period was increased from 4 days to 5–7 days in eggs exposed to freezing temperature and 4–7 days in irradiated eggs. About 44% of the fertile, untreated eggs hatched normally while 56% were parasitised by G. gnidus. The irradiated or frozen eggs did not hatch and were not parasitised by G. gnidus, thus indicating that G. gnidus would not parasitise dead eggs of A. tomentosicollis. The significance of these results is discussed.
Effects of gamma radiation on the stable fly, Stomoxys nigra Macquart (Diptera: Muscidae)
Authors: Ramsamy M
Published: July 2009

Freshly formed (less than 1-day-old) pupae of Stomoxys nigra Macq. treated with gamma rays showed a linear-regression mortality-response with radiation exposure. Mature 5-day-old pupae did not show this effect and were considered more suitable for sterility studies. Flies emerging from both groups of treated pupae showed no deviation from a 1:1 sex ratio. Radiation inhibited fecundity. An exposure dose of 1000 R halved egg production and a dose of 2000 R almost stopped oviposition. Females from pupae exposed to 3000 R produced no eggs. Complete sterility of males was not achieved within the range of tested dosage; exposures of 3000 R and 4000 R induced 98–8 and 99–7% male sterility, respectively. Radiation reduced the longevity of both males and females. A dose of 3000 R did not impair either male mating ability or sexual competitiveness in small-scale laboratory tests.
Observations on the biology ofCerambyx duxFaldermann in the Maltese Islands
Authors: Saliba L. J.
Published: July 2009

The distribution and host-range ofCerambyx duxFald. are summarised, and the detailed life-history in Malta, where the hosts are apple and pear, is described. Collections of various stages from host material indicate that the duration of the complete life-cycle is three years, including a 26–28 month larval period. The number of larval instars is estimated at six. Egg survival is dependent on high humidity. The early months of larval activity are confined to the superficial regions of the trunk and main branches of the host, penetration of the sapwood and heartwood occurring later. No special air-holes appear to be constructed by the larva. No exit gallery is constructed, and the emerging adult makes use of the existing burrows, finally gnawing its way to the exterior. The period of emergence is short (8–10 days) and may be stimulated by rain. Adult life lasts about one month. The average number of eggs laid per female is approximately 13. The main predator onC. duxlarvae is the larva ofZeuzera pyrina(L.). This is confined to the lesser limbs of trees in Malta, but extends throughout the trees in Gozo, and has practically eliminatedC. duxfrom this island.
Large-scale rearing of tsetse flies (Glossina spp.) in the absence of a living host
Authors: Mews A. R. , Langley P. A. , Pimley R. W. , FLOOD M. E. T.
Published: July 2009

A successful technique for feeding colonies of Glossina morsitans morsitans Westw. and G. austeni Newst. in the absence of living hosts is described. Insects are fed through membranes made of silicone rubber or of agar and Parafilm, overlying blood pools poured onto grooved glass plates. The diet employed is fresh pig blood, collected at slaughter, and aseptic procedures are adopted at every stage of diet preparation and presentation. The reproductive performance of these in vitro-fed colonies in terms of adult survival, fecundity, and offspring size, is the same as that of colonies fed on living hosts, when compared over a long period of time. The fact that the technique is successful when used with a diet of pig blood, but is not successful when used with cow blood prepared in the same way, suggests that the technique per se is adequate to elicit a normal feeding response from these tsetse species. The nature of the nutritional superiority of pig blood is not understood.
Ecological studies of ixodid ticks (Acari: Ixodidae) in Zambia. III. Seasonal activity and attachment sites on cattle, with notes on other hosts
Authors: MacLeod J. , Colbo M. H. , Madbouly M. H. , Mwanaumo B.
Published: July 2009

The seasonal activity of the adults of 13 tick species was studied on cattle herds in the Central Province of Zambia from 1969 to 1972. The six main species, Boophilus decoloratus (Koch), Hyalomma marginatum rufipes Koch, H. truncatum Koch, Amblyomma variegatum (F.), Rhipicephalus appendiculatus Neum., and R. evertsi Neum. behaved as previously described for the Southern Province. R. compositus Neum. appeared from August, with peak numbers in September–October. R. simus Koch and R. tricuspis Dön. appeared from October, for seven months and three months respectively. R. supertritus Neum. and Ixodes cavipalpus Nutt. & Warb. had a brief activity season from November to January, and R. pravus gp. and R. sanguineus gp. were active from December to July. The distribution of ticks over the body of cattle was determined by fractionised collections, which gave reliable quantitative information for nine of the species. A limited number of collections from sheep, goats and dogs are analysed in relation to season. Collections from 127 wild animals, mainly along the escarpment and riverine bush of the Zambesi, are recorded.
Seasonal fluctuations of Culicoides species (Diptera: Ceratopogonidae) in Kenya
Authors: Walker Alan R.
Published: July 2009

Light-traps were used to collect adult Culicoides from 61 sites throughout Kenya and to sample long-term population fluctuations at six sites. Activity patterns were recorded with a suction trap and larval habitats were sampled with laboratory emergence traps. Culicoides cornutus De Medllon, C. milnei Aust., C. pallidipennis C, I. & M., C. schultzei (End.) gp. and C. zuluensis De Meillon were found widespread and also concentrated at livestock pens. Their seasonal population fluctuations did not correlate clearly with rainfall but all these species persist throughout the year. The activity of C. pallidipennis and C. schultzei gp. extends over the whole night and is inhibited by winds in excess of 3 m/s and stimulated by high temperatures and relative humidity. Larval habitats were mainly in mud mixed with detritus or dung; larvae of C. pallidipennis and C. schultzei gp. were both found in swamp mud but not in dung pats. The significance of these findings is discussed in relation to the epidemiology of bluetongue virus disease of sheep and ephemeral fever virus disease of cattle.
The influence of climatic factors on catches of the red bollwonn Diparopsis castanea Hampson (Lepidoptera: Noctuidae) in sex pheromone traps
Authors: Marks R. J.
Published: July 2009

Males of Diparopsis castanea Hmps. were caught in a water trap baited with sex pheromone sited 2·0 m above ground level in a cotton field in the Lower Shire Valley, Malawi. Analysis of catches for 21 nights between 8.iii.75 and 3.vi.75 showed that optimal catches of males occurred at wind speeds of 1·0−2·5 m s−1. Wind speeds in excess of 3–4 m s−1 depressed activity. Regression analysis revealed an optimal relative humidity for flight of 60−70%. Inclusion of humidity in a multiple regression analysis with wind speed and temperature failed to improve significantly the relationship with catch provided by a model that considered wind speed and temperature only. No simple relationship existed between temperature and moth abundance, and wind speed clearly exerted the greatest independent effect on catch. Male Diparopsis nevertheless exhibited a temperature-related pheromone responsiveness, with peak catches occurring earlier in scotophase during periods of cool weather. Analysis of data gathered during the 1973 and 1974 seasons indicated a slight, but significant, positive correlation between night rainfall and moth catch. However, none of the various independent and joint relationships established between moth catch and climatic factors could be reliably used for forcasting moth abundance.
Studies on the biology and taxonomy of someChilocorusspp. (Coleoptera: Coccinellidae) preying onAulacaspisspp. (Hemiptera: Diaspididae) in East Africa, with the description of a new species
Authors: Greathead D. J. , Pope R. D.
Published: July 2009

Field studies of predators onAulacaspis tegalensis(Zhnt.) and laboratory breeding experiments, supplemented by taxonomic studies, showed thatChilocorus discoideusCrotch andC. bilineataKorsch. are junior synonyms ofC. schioedteiMuls. and that two other forms, originally described as ‘aberrations’, may also belong to this species. Similarly,C. erythrocephalusMuls. andC. solitusWeise are junior synonyms ofC. distigma(Klug).C. rufoplagiatussp. n., allied toC. distigma, is described from the shores of Lake Victoria, and the Oriental speciesC. nigritus(F.) is recorded from the African mainland for the first time.C. distigmais found in the savanna and steppe areas of Africa andC. schioedteiin the forest and adjoining zones. Comparative studies suggest that, althoughC. schioedteihas a higher fecundity, it is not displaced byC. distigmaas, unlike the latter, it is unable to breed under hot dry conditions. Comparison of host records for these two species show thatC. distigmais not restricted to feeding on Diaspididae, as isC. schioedtei, but that otherwise the range of hosts and associated plants is similar for both species. The potential of these species andC. nigritusfor use in biological control is discussed and it is suggested thatC. schioedteiis only suitable for trial in tropical areas without a dry season, but thatC. distigmaandC. nigritusmay be useful under a wider range of conditions.
A New species of Exaeretopus Newstead (Homoptera: Coccidae) attacking wheat in Iraq
Authors: Williams D. J.
Published: July 2009

Exaeretopus tritici sp. n. is described and illustrated from specimens collected in the Ninevah and Arbil Provinces of Iraq. In 1975, it was present in considerable numbers on the stems and inner surfaces of the leaves of wheat. Triticum aestivum, and the infestations reduced ear and grain size.
The flight of tsetse flies (Diptera : Glossinidae) to and from a stationary ox
Authors: Vale G. A.
Published: July 2009

Glossina morsitans morsitans Westw. and G. pallidipes Aust. flying to and from a stationary ox were captured by a wall of electrocuting netting at distances ranging from 45 m upwind of the ox to 120 m downwind. The pattern of catches at each distance suggested that most flies not recently fed were attracted to the ox from downwind, from distances up to about 90 m. Most flies leaving the ox flew downwind. This was most marked for flies that had fed on the ox, some of which travelled 120 m within about 30 min of engorging.
The immature stages ofElachiptereicus abessynicusBecker andPachylophus lugensLoew (Diptera: Chloropidae)
Authors: Deeming J. C.
Published: July 2009

The larvae and pupae ofElachiptereicus abessynicusBecker and ofPachylophus lugensLw. are described and illustrated and those of the latter species are compared with those ofPachylophus beckeriCurr. A previous misidentification ofP. beckeriis recorded and additional records of host plants and distribution are given for all three species.
Population dynamics of Xyleborus fornicatus Eichhoff (Coleoptera: Scoly-tidae) in relation to yield trends in tea
Authors: Sivapalan P.
Published: July 2009

A highly significant negative linear correlation (r=– 0·911, P=0·001) was observed between Xyleborus fornicatus Eichh. population levels in tea plants and the crop size in the preceding month. A highly significant negative linear correlation (r=– 0·858, P=0·001) was also observed between Xyleborus population levels and the percentage of healed galleries of the respective samples. Cambial activity, which has a direct relationship with crop size, determines the rate of healing of brood galleries, and this seems to be the critical factor that regulates population size within a pruning cycle. Since the population has an inverse relationship to crop size and as the latter could be predicted in advance using weather parameters, it should be possible to predict population levels of Xyleborus in advance.
A critical review of procedures for sampling populations of adult mosquitoes
Authors: Service M. W.
Published: July 2009

A critical review is presented of the many and varied procedures for sampling adult mosquitoes. All sampling methods are subject to bias, but human-bait collections are probably the most reliable single method for detecting and monitoring populations of anthropophilic species. The estimation of realistic man-biting rates, however, remains difficult. The recent advances in computer technology have generated considerable interest in population modelling, with the aim of getting a better insight into the complexities of population dynamics, mosquito control and disease transmission. Although such approaches may be informative, it is stressed that models should be based on meaningful values of the critical parameters and that these are best obtained from field populations. The difficulties of interpreting mosquito collections in both attractant traps, such as animal-baited traps, carbon-dioxide-baited traps and light-traps, and in non-attractant ones, such as Malaise traps, sticky traps, ramp traps, rotary traps, suction traps and vehicle-mounted traps, are described. Suction traps probably provide the least biased catches of aerial populations of mosquitoes, but, if populations as a whole are to be considered, then resting adults also must be adequately sampled, and this may prove difficult. It is emphasised that different trapping techniques usually sample different components of a population, and that the choice of sampling methods depends much on the type and quality of information required. The limitations of using mark-recapture techniques to study adult dispersal and obtain absolute population estimates are discussed, together with the advantages and disadvantages of applying simple and more complex mathematical procedures for analysing recapture data.
Sensory receptors on the ovipositor of the carrot fly (Psila rosae (F.)) Diptera: Psilidae and the cabbage root fly (Delia brassicae) (Wiedemann) (Diptera: Anthomyiidae)
Authors: Behan Mary , Ryan M. F.
Published: July 2009

The ovipositor of Psila rosae (F.) comprises abdominal segments seven, eight and nine, the latter with well-defined tergite, sternite and anal cerci. Approximately 110 trichoid sensilla are located on the ovipositor. The ovipositor of Delia brassicae (Wied.), comprising abdominal segments six, seven, eight and nine, has a well-defined sternite on segment eight, with a tergite, sternite and cerci on segment nine. Approximately 245 trichoid sensilla are located on the ovipositor, in addition to 20 styloconic-type and four basiconic-type sensilla. These extra sensilla may enhance chemical discrimination, and thus host-finding, by D. brassicae. Transmission electron microscopy was used to reconstruct a trichoid sensillum, probably a mechanoreceptor, on the cerci of D. brassicae.
Field trials of the synthetic sex pheromones of the striped rice borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae), and of related compounds
Authors: Beevor P. S. , Hall D. R. , Nesbitt Brenda F. , Dyck V. A. , Arida G. , Lippold P. C. , Oloumi-Sadeghi H.
Published: July 2009

The female sex pheromones of Chilo suppressalis (Wlk.) were previously identified as (Z)-11-hexadecenal and (Z)-13-octadecenal. This paper describes field trials of the synthetic pheromones carried out in the Philippines, Korea and Iran during 1975 and 1976. These trials established that the two pheromones in their naturally occurring ratio are attractive to male C. suppressalis in the field. Both pheromones are necessary for efficient attraction, and ratios of the two pheromones close to the naturally occurring ratio are the most attractive. The rate of release of the pheromones was found to be critical in order to obtain an attractant source comparable with the virgin female moth. The bisulphite adducts of the pheromones showed some promise as a slow-release source of attractant material with a long field life.

Preliminary experiments were carried out to assess the potential use of the two natural pheromones and of two pheromone “mimics”. (Z)-9-tetradecenyl formate and (Z)-11-hexadecenyl formate, as mating disruptants. All four compounds were shown to interfere with pheromonal communication between the sexes
Factors affecting resistance to insecticides in house-flies, Musca domestica L. (Diptera: Muscidae). II. Close linkage on autosome 2 between an esterase and resistance to trichlorphon and pyrethroids
Authors: Sawicki R. M. , Devonshire A. L. , Farnham A. W. , O'Dell Kate E. , Moores G. D. , Denholm I.
Published: July 2009

Widespread slight pyrethroid-resistance in Musca domestica L. on animal farms in southern England was correlated with strong resistance to trichlorphon and to malathion, and with the presence of an esterase, E0·39, detected by electrophoresis. In the laboratory, the frequency of E0·39 increased in response to selection with either pyrethroids or trichlorphon. Genetic analysis confirmed that this esterase, controlled by a gene on autosome 2, was closely linked with moderate resistance to trichlorphon and malathion and weak resistance to pyrethroids. When autosome 2 with the gene for E0·39 was introduced into a strain homozygous for the resistance mechanism super-kdr, resistance to pyrethroids increased by a factor equivalent to the weak resistance conferred by autosome 2 with E0·39 alone. Homozygosity for both mechanisms of resistance, and E0·39, was obtained by selecting the progeny of this cross with permethrin alone, permethrin and trichlorphon, or DDT and trichlorphon, demonstrating that very strong pyrethroid resistance can be achieved through the use of non-pyrethroid insecticides. E0·39 was absent from insecticide-resistant strains of M. domestica from Denmark but was present in several multi-resistant strains from other European countries.
Reproductive abnormality and loss in natural populations ofGlossina pallidipesAusten (Diptera: Glossinidae) in Kenya
Authors: Turner D. A. , Snow W. F.
Published: July 2009

The nature, frequency and causes of reproductive loss were investigated in populations ofGlossina pallidipesAust. in western and coastal localities in Kenya. Daily collections from biconical traps in which females were trapped for varying periods up to 30 h were followed by a series of hourly captures which gave less biased data. Ovarian abnormalities and insemination failure were rare, and abortion was the only major source of loss of fecundity. Total reproductive loss was within the range 1·60–1·97% (0·23% ovarian loss plus 1·37% abortions or 1·74% total empty uteri) in western Kenya (Lambwe Valley) and 0·99–1·71% from less comprehensive data at the coast. The incidence of empty uteri was higher in daily than in hourly collections, due mainly to premature parturitions brought about by the stressful effects of prolonged confinement in traps and handling. Abortions were significantly more frequent in females which had ovulated but were not yet parous than in older, parous flies. No relationship between the frequency of abortion and climate, tsetse density or pathogen or parasite infection could be demonstrated.
The winter development, reproduction and lifespan of viviparae of Sitobion avenae (F.) (Hemiptera: Aphididae) on wheat in England
Authors: Williams C. T. , Wratten S. D.
Published: July 2009

Viviparae of Sitobion avenae (F.) in clip-cages on winter wheat in field plots in southern England were monitored throughout the 1980–81 winter to determine characteristics of development, reproduction and lifespan under winter conditions. Rate-temperature relationships for development and reproduction were well described by straight lines when temperatures were measured above 3°C. A simple thermal-time scale could therefore be used for both processes. The parental morph and the time of year modified thermal-time requirements for the production of an adult's first 20 nymphs but did not affect those for development. For both alatae and apterae, nymph production per day-degree was greater than at higher temperatures and the relationship between reproductive rate and age was different. The minimum temperature experienced by the aphids was −7°C; survival was good, with little low temperature mortality. Total fecundity of apterae was usually greater than at higher temperatures, though some apterae and alatae that were deposited in October had low fecundity, possibly because they were insufficiently acclimatized at the onset of cold winter weather. Overwintering alatae had lower development rates, reproductive rates and total fecundity than apterae and did not survive as long, but were restless as young adults and appeared ready to migrate. Oviparae were produced from late September to mid-October but not after this, suggesting that the clone used could ‘switch off’ sexual morph production in winter.
Comparison of the winter development, reproduction and lifespan of viviparae of Sitobion avenae (F.) and Rhopalosiphum padi (L.) (Hemiptera: Aphididae) on wheat and perennial rye grass in England
Authors: Williams C. T.
Published: July 2009

The mid-winter development, reproduction and survival of field-acclimatized viviparae of Sitobion avenae (F.) and Rhopalosiphum padi (L.) on leaves of tillering wheat and perennial ryegrass (Lolium perenne) plants at similar growth stages were compared by monitoring batches of aphids in clip-cages in field plots in southern England. For both aphid species, survival, total fecundity and reproductive rate were much higher on wheat than on L. perenne, and on both host-plants they were much higher for S. avenae than for R. padi. Development times (in day-degrees) were longer on L. perenne than on wheat, and on both host-plants were longer for R. padi than for S. avenae, though these differences were less marked. Comparison of the results with those of earlier studies suggests that large changes in cereal aphid performance occur between summer and winter and that these are both aphid-specific and host-plant-specific.
Two new species of Cicadulina China (Hemiptera: Euscelidae) from West Africa
Authors: Dabrowski Z. T.
Published: July 2009

Two new species of Cicadulina, C. ghaurii sp. n. and C. hartmansi sp. n., are described. Both occur over a wide area in Nigeria and Cameroon, and C. ghaurii has been shown to transmit maize streak virus.
Behavioural strategies of fruit flies of the genusDacus(Diptera: Tephritidae) significant in mating and host-plant relationships
Authors: Drew R. A. I.
Published: July 2009

Adults ofDacusspp. feed on plant surface bacteria. The responses ofD. tryoni(Froggatt) andD. cacuminatus(Hering) to some components of bacterial odours and to cue-lure were tested in a field-cage olfactometer, in studies in south-eastern Queensland. One component of bacterial emission, 2-butanone, attractedD. tryoni(a species responding to cue-lure) but notD. cacuminatus(a species responding to methyl eugenol) and is suggested as the attractive portion of the cue-lure molecule. Sexually mature males and immature females ofD. tryoniresponded to 2-butanone, cue-lure and bacterial odours in field-cage tests. Females fed on sugar and water required protein hydrolysate to produce eggs, but males were fertile with or without protein. These different nutrient requirements, and the fact that males and females possess different crop colour and bacterial contents when feeding in the same host-plant, indicate that the sexes feed on different substrates. Consequently, the strong bacterial attractant cues in the host-tree may be a feeding attractant to females and a sex attractant to males. It is proposed that 2-butanone is an important rendezvous stimulant in nature, bringing the mature male flies into the feeding and oviposition sites (host-trees) of the developing females for mating encounters.
Density independence of survival in myiasis breeding of Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae)
Authors: Dallwitz R.
Published: July 2009

Survival, size and development time were measured for larvae of Lucilia cuprina (Wiedemann) reared in artificially induced strikes on sheep. Between 477 and 18 000 eggs or larvae were implanted in the fleece of 42 sheep. Survival was found not to depend significantly on implant numbers. Size and development time were significantly but only weakly dependent on implant numbers. These results contrast markedly with L. cuprina's performance on carrion.
Food web of insects associated with the cassava mealybug,Phenacoccus manihotiMatile-Ferrero (Hemiptera: Pseudococcidae), and its introduced parasitoid,Epidinocarsis lopezi(De Santis) (Hymenoptera: Encyrtidae), in Africa
Authors: Neuenschwander P. , Hennessey R. D. , Herren H. R.
Published: July 2009

About 130 species of parasitoids and predators are reported, most of them for the first time, to be associated directly or indirectly with the cassava pestPhenacoccus manihotiMatile-Ferrero and its parasitoid,Epidinocarsis lopezi(De Santis), newly introduced into Africa as a biological control agent. About 20 species are common. The species are grouped in 11 guilds, which include the indigenous hyperparasitoids, which originally attacked parasitoids of other mealybugs, the predators with whichE. lopezicompetes for the same food source and their antagonists.
The strawberry aphid complex, Chaetosiphon (Pentatrichopus) spp. (Hemiptera: Aphididae): taxonomic significance of variations in karyotype, chaetotaxy and morphology
Authors: Blackman R. L. , Eastop V. F. , Frazer B. D. , Raworth D. A.
Published: July 2009

Holocyclic populations of aphids of the Chaetosiphon (Pentatrichopus) fragaefolii (Cockerell) group from Fragaria in British Columbia were found to have a homozygous 2n = 12 female karyotype, whereas samples from predominantly anholocyclic populations in Oregon, California, England and New Zealand have 13, 14, 15 or 17 chromosomes showing various degrees of structural heterozygosity. The 17-chromosome form is a morphologically recognizable taxon, C. jacobi Hille Ris Lambers. The other karyotypes apparently represent a series of parthenogenetic lineages derived from the 2n = 12 holocyclic form and carrying one, two or three autosome dissociations. The North American populations showed no correlation between karyotype and the number of submarginal setae, a character previously used in attempts to differentiate taxa within this species complex in western North America. Submarginal setal number varied greatly within and between clones and tended to increase in successive generations from the fundatrix, confirming that this character varies both genetically and seasonally and has little taxonomic value. Populations of the fragaefolii group from Rosa spp. in North America have a shorter rostrum than those from Fragaria. The name C. thomasi Hille Ris Lambers is assigned to this rose-feeding species, which is holocyclic on R. rugosa in British Columbia and colonizes Potentilla spp. (but apparently not P. anserina) as alternative hosts. Old World populations on Fragaria, presumably originating from North America, have longer siphunculi than North American populations of fragaefolii and few or no submarginal setae; these differences are probably due to founder effects. Both Old and New World populations of fragaefolii use P. anserina as an alternative host-plant.
Differential rate of selection for resistance by carbamate, organophosphorus and combined pyrethroid and organophosphorus insecticides in Myzus persicae (sulzer) (Hemiptera: Aphididae)
Authors: Ffrench-Constant R. H. , Devonshire A. L. , Clark S. J.
Published: July 2009

Field cages in southern England enclosing single rows of potatoes and infested with differing initial proportions of S (susceptible), R1 (moderately insecticide resistant) and R2 (very resistant) clones of Myzus persicae (Sulzer) were sprayed three times, at 14-day intervals, with pirimicarb (carbamate), demeton-S-methyl (organophosphorus) or a mixture of deltamethrin and heptenophos (pyrethroid and organophosphorus insecticides). The numbers of aphids on top, middle and basal leaves were counted, pre-treatment and one and eight days after each of the three sprays. The resistance genotype frequencies of the three variants were determined by an immunoplate assay which measures the amount of the carboxylesterase E4, the enzyme conferring resistance, in individual aphids. All three chemicals selected strongly for the very resistant variant. After three sprays, R2 aphid frequencies approached or equalled fixation (1·00) for both starting frequencies. However, the deltamethrin-heptenophos mixture selected for R2 aphids more rapidly than the other chemical treatments. Increasing the initial starting frequency of R2 aphids from 0·02 to 0·20 led to a more rapid increase of their frequencies towards 1·00 for all chemicals. The numbers of aphids on all treated plots were less than on the control. However, the more rapid increase in the proportion of R2's on plots treated with deltamethrin plus heptenophos, coupled with enhanced nymph production, resulted in a smaller reduction in numbers than was achieved by the other chemical treatments. The need for novel control methods is discussed in the light of the strong selection for R2 aphids exerted by all three insecticide classes.
Ecology of the maize stalk borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae)
Authors: Rensburg J. B. J. Van , Walters M. C. , Giliomee J. H.
Published: July 2009

New information on the intraseasonal progression of larval infestations of Busseola fusca (Fuller) in South Africa was obtained through repeated sampling in maize plantings of different planting dates over various seasons. Due to the occurrence of distinct periods of moth flight, variation in planting date had a marked influence on levels of larval infestation. Also, plants were found to be most attractive as sites for oviposition between three and five weeks after emergence, resulting in a definite pattern in the time distribution of different larval instars in different plant parts. In the pre-tassel stage of plant development, most larvae occurred in localized groups within the whorls, reaching maximum numbers eight weeks after plant emergence. The emergence of the tassel forced some larvae to migrate to adjacent plants, resulting in an increase of internally damaged plants without an increase in larval numbers. It is shown that scouting for eggs over a limited period of plant development can lead to better timing of spray applications and thus to more cost-effective control measures.
Observations on Anopheles gambiae Giles s.l. (Diptera: Culicidae) during a trial of permethrin-treated bed nets in The Gambia
Authors: Snow R. W. , Jawara M. , Curtis C. F.
Published: July 2009

In a Gambian village, the peak collections of females of the complex of Anopheles gambiae Giles occurred three months after the onset of the heaviest rains; 32% of these were A. melas Theobald, and 54% of blood-meals were identified as originating from man. Counts of A. gambiae s.l. in rooms containing permethrin-treated bed nets were compared with those in rooms containing placebo-treated nets. The numbers in the permethrin-treated nets were far lower than in placebo-treated nets. A higher rate of exophily was noted in rooms containing permethrin-treated nets. The numbers of unfed A. gambiae s.l. found inside the rooms with placebo-treated nets were significantly higher than those with permethrin-treated nets. However, the proportion fed and the mortality in the exit traps were not significantly affected by permethrin treatment. Three-minute bioassays conducted on four different fabric types impregnated at the same concentration showed that the toxicity varied between the fabrics. Handwashing severely reduced the toxicity and approximately halved the permethrin content. Bed nets are frequently washed in Gambian villages, and this could be a problem in the application of permethrin impregnation of bed nets for vector control. Methods are discussed to overcome this problem at the village level.
Estimation of egg to pupal survival of Musca vetustissima Walker (Diptera: Muscidae) in the field using genetic and radioactive markers
Authors: Vogt W. G. , Runko S. , Walker J. M.
Published: July 2009

Radioactive (32P) and genetic (recessive eye-colour mutation) markers were used to estimate egg to pupal survival of Musca vetustissima Walker. Both marking techniques provided similar survival estimates under laboratory and field conditions in Australia. Egg to pupal survival rarely exceeded 10% in samples at intervals during spring and summer. Abiotic (dung quality and weather) and biotic (other dung fauna) mortality agents were both important in limiting the breeding success of M. vetustissima, being jointly responsible for a seasonal mean mortality of 93·8%.
Effects of trap design on catches of grassland bibionidae (diptera: nematocera)
Authors: D'Arcy-Burt S. , Blackshaw R. P.
Published: July 2009

Bibionid flies were sampled in grassland in Northern Ireland from 4 April to 13 June 1985 using water and sticky traps with a range of characteristics. Nearly 70 000 bibionids were taken, of which 89·5% were males. Bibio johannis (L.) accounted for 96% of the catch, the rest comprising Dilophus febrilis (L.) (3%) and D. femoratus Meigen (1%). Trapping was carried out adjacent to a hedgerow and in the centre of the field. Differences in the abundance of the flies at these two locations occurred for all three species. Yellow was the best colour for maximizing catches. Greater numbers of B. johannis (63%) were taken in water than sticky traps, but over 76% of Dilophus spp. were caught on the latter. Increasing the diameter of water traps tended to enlarge the catch (principally B. johannis), but catch per unit area was relatively constant. The height of sticky traps above the ground affected the catch of all three species, indicating different flight levels.
A morphometric analysis of the Thrips hawaiiensis (Morgan) species-group (Thysanoptera: Thripidae)
Authors: Palmer J. M. , Wetton M. N.
Published: July 2009

The significance of morphological variation within the Thrips hawaiiensis (Morgan) species-group is examined. Multivariate analyses of four characters from 344 females and seven characters from 90 males show two distinct groups found throughout the Oriental, Pacific and American Regions, corresponding to T. hawaiiensis and T. florum Schmutz, and an intermediate group, exilicornis Hood, from Africa. The results are compared with previously published morphometric data concerning the separation of T. hawaiiensis and T. florum, and additional distinguishing characteristics are assessed. The distributions of the three forms as recognized in this study are summarized.
Two new species of Encarsia Foerster (Hymenoptera: Aphelinidae) from pakistan, associated with the cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae)
Authors: Lopez-Avila A.
Published: July 2009

The aphelinids Encarsia adrianae sp. n. and E. cibcensis sp. n. are described from material in culture ex Bemisia tabaci (Gennadius) on beans at the C·A·B International Institute of Biological Control, Ascot, UK. They are descendants of material collected in Rawalpindi, Pakistan, from B. tabaci on Lantana camara.