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International Centre of Insect Physiology and Ecology

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Articles 901 - 930 of 1129

Full-Text Articles in Entomology

El Niño Causes Dramatic Outbreak Of Paederus Dermatitis In East Africa, Ingeborg M.C.J. Van Schayk, Ruben O. Agwanda, John I. Githure, John C. Beier, Bart G.J. Knols Jan 2005

El Niño Causes Dramatic Outbreak Of Paederus Dermatitis In East Africa, Ingeborg M.C.J. Van Schayk, Ruben O. Agwanda, John I. Githure, John C. Beier, Bart G.J. Knols

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An outbreak of Paederus sabaeus rove beetles in Kenya during the 1997-1998 El Niño resulted in a dramatic increase of vesicular dermatitis in its capital Nairobi. The beetle, popularly called ‘Nairobi Fly’, contains a potent toxic fluid that causes epidermolysis and acute conjunctivitis. A cross-sectional epidemiological study involving 1,208 Nairobi residents was conducted to determine the health impact of this outbreak. The results showed that one-third of the Nairobi population were infected during this period. The majority of the respondents reported lesions on exposed body parts above the shoulders. Disfiguring, painful blisters and skin rashes in and around the facial …

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The Presence Of Plasmodium Falciparum Gametocytes In Human Blood Increases The Gravidity Of Anopheles Gambiae Mosquitoes, Heather M. Ferguson, Louis C. Gouagna, Peter Obare, Andrew F. Read, Hamza Babiker, John Githure, John C. Beier Jan 2005

The Presence Of Plasmodium Falciparum Gametocytes In Human Blood Increases The Gravidity Of Anopheles Gambiae Mosquitoes, Heather M. Ferguson, Louis C. Gouagna, Peter Obare, Andrew F. Read, Hamza Babiker, John Githure, John C. Beier

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We conducted a field study in an area of endemic malaria transmission in western Kenya to determine whether mosquitoes that feed on gametocyte-infected blood but do not become infected have reduced or enhanced fecundity in comparison to mosquitoes fed on uninfected blood. Fifteen paired membrane-feeding experiments were conducted in which two strains of Anopheles gambiae mosquitoes were simultaneously fed on either Plasmodium falciparum-infected blood from children or uninfected control blood from adults. The presence of noninfecting gametocytes in blood increased the probability that An. gambiae would produce eggs after one blood meal by sixfold (odds ratio for control relative to …

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Functional Response Of Six Indigenous Trichogrammatid Egg Parasitoids (Hymenoptera: Trichogrammatidae) In Kenya: Influence Of Temperature And Relative Humidity, Andrew Kalyebi, W. A. Overholt, F. Schulthess, J. M. Mueke, S. A. Hassan, S. Sithanantham Jan 2005

Functional Response Of Six Indigenous Trichogrammatid Egg Parasitoids (Hymenoptera: Trichogrammatidae) In Kenya: Influence Of Temperature And Relative Humidity, Andrew Kalyebi, W. A. Overholt, F. Schulthess, J. M. Mueke, S. A. Hassan, S. Sithanantham

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Laboratory tests were conducted to evaluate the functional responses of six species/strains of native Kenyan trichogrammatids using the factitious pyralid host, Corcyra cephalonica, under different temperature and relative humidity regimes. The objective was to identify promising species/strains for controlling the noctuid Helicoverpa armigera, a serious pest of vegetables in Kenya. The six species/strains of Trichogramma and Trichogrammatoidea represented collections from low (<700 m), mid (between 700 and 1200 m) and high (>1200 m) altitude locations. They were compared for parasitisation rates at six temperatures (10, 15, 20, 25, 30 and 35°C) and two relative humidity levels (40-50% and 70-80%), at five host egg densities (6, 12, 18, 24, and …

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Laboratory Evaluation Of Some Eastern African Meliaceae As Sources Of Larvicidal Botanicals For Anopheles Gambiae, Mary Ndung'u, Baldwyn Torto, Bart G.J. Knols, Ahmed Hassanali Dec 2004

Laboratory Evaluation Of Some Eastern African Meliaceae As Sources Of Larvicidal Botanicals For Anopheles Gambiae, Mary Ndung'u, Baldwyn Torto, Bart G.J. Knols, Ahmed Hassanali

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Root bark extracts of five Meliaceae species (Turraea abyssinica Hochst., Turraea wakefeldii Oliv., Turraea mombassana Hiern ex C.DC., Trichilia roka (Forsk) Chiov. and Melia volkensii Guerke.) and different fractions thereof (following chloroform extraction and column chromatographic separation) were compared for their immediate toxicity and long-term effects on Anopheles gambiae Giles sensu stricto (Diptera: Culicidae). Larvicidal effects of the extracts appeared to be largely associated with limonoids of medium polarity with M. volkensii and T. mombassana extracts being more potent than those of the other Meliaceae. Long-term (6-8 days post-exposure) observations at lower doses showed that 100% cumulative mortality can be …

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Effect Of Agroecosystem Diversity On Natural Enemies Of Maize Stemborers In Coastal Kenya, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt Dec 2004

Effect Of Agroecosystem Diversity On Natural Enemies Of Maize Stemborers In Coastal Kenya, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt

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A study was conducted at Mtwapa in the northern coastal area of Kenya during the long and short rainy seasons of 1999 and 2000 to assess the benefits of agroecosystem diversification-through agroforestry and intercropping-on the activity of natural enemies of maize stemborers. Treatments consisted of maize and cowpea intercrops or maize monocrops planted within hedgerows of Leucaena leucocephala and Gliricidia sepium. The plots were mulched or unmulched and insecticide-treated or not. The maize stemborers encountered, in order of abundance, were Chilo partellus, Chilo orichalcociliellus and Sesamia calamistis. The egg parasitoids Trichogramma spp. and Telenomus spp. were recovered from stemborer eggs. …

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Phlebotomine Sandflies (Diptera: Psychodidae) Collected In Mukusu, Machakos District, Kenya And Their Nocturnal Flight Activity, Eiko Kan, Christopher O. Anjili, Rajindar K. Saini, Toshitaka Hidaka, John I. Githure Nov 2004

Phlebotomine Sandflies (Diptera: Psychodidae) Collected In Mukusu, Machakos District, Kenya And Their Nocturnal Flight Activity, Eiko Kan, Christopher O. Anjili, Rajindar K. Saini, Toshitaka Hidaka, John I. Githure

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This is the first report on the nocturnal flight activity of the phlebotomine sandflies in the field by trap collection in Mukusu, Masinga, the kala-azar (visceral leishmaniasis in humans) area in Kenya. A total of 514 sandflies were collected with three different types of traps (sticky traps, CDC light traps and a goat-baited trap), and seven species of two genera (Sergentomyia and Phlebotomus) were identified. The number of Sergentomyia bedfordi Newstead individuals captured was the largest among these seven species. This suggests that S. bedfordi is the most common among the seven species in Mukusu. The result of the sticky …

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Performance Of Cotesia Flavipes (Hymenoptera: Braconidae) In Parasitizing Chilo Partellus (Lepidoptera: Crambidae) As Affected By Temperature And Host Stage, Nanqing Jiang, Mamoudou Sétamou, Adèle J. Ngi-Song, Charles O. Omwega Oct 2004

Performance Of Cotesia Flavipes (Hymenoptera: Braconidae) In Parasitizing Chilo Partellus (Lepidoptera: Crambidae) As Affected By Temperature And Host Stage, Nanqing Jiang, Mamoudou Sétamou, Adèle J. Ngi-Song, Charles O. Omwega

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The braconid larval parasitoid, Cotesia flavipes, is used as a biological control agent against the crambid Chilo partellus, a serious pest of cereal crops in eastern and southern Africa. We examined the survival, development parameters, and body growth patterns of the host and its parasitoid at different temperatures (22, 26, and 30°C) using third and fourth instars of Ch. partellus. For non-parasitized hosts, larval mortality tended to be highest at lowest temperature and for parasitized at third host instars only at highest temperature. Development time of Co. flavipes immatures significantly decreased with host instar and with temperature. Sex ratio of …

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Repellency Of Essential Oils Of Some Kenyan Plants Against Anopheles Gambiae, Maurice O. Omolo, Denis Okinyo, Isaiah O. Ndiege, Wilber Lwande, Ahmed Hassanali Oct 2004

Repellency Of Essential Oils Of Some Kenyan Plants Against Anopheles Gambiae, Maurice O. Omolo, Denis Okinyo, Isaiah O. Ndiege, Wilber Lwande, Ahmed Hassanali

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Five mosquito repellents have been identified from the essential oils of 6 plants growing in Kenya. These include (S)-(-)-cis-perillyl alcohol, (S)-(-)-cis-verbenol, (S)-(-)-cis-carveol, (S)-(-)-perillaldehyde, caryophyllene oxide and (S)-(-)-cis-perillyl alcohol. (S)-(-)-cis-perillyl alcohol and (S)-(-)-cis-verbenol were the most potent. Essential oils of six plants growing in Kenya were screened for repellent activities against Anopheles gambiae sensu stricto. The oils of Conyza newii (Compositeae) and Plectranthus marrubioides (Labiateae) were the most repellent (RD 50 = 8.9 × 10 -5 mg cm -2, 95% CI) followed by Lippia javanica (Verbenaceae), Lippia ukambensis (Verbenaceae), Tetradenia riparia, (Iboza multiflora) (Labiateae) and Tarchonanthus camphoratus (Compositeae). Eight constituents of …

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The Development Of Plasmodium Falciparum In Experimentally Infected Anopheles Gambiae (Diptera: Culicidae) Under Ambient Microhabitat Temperature In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Elizabeth Walczak, Ephantus W. Kabiru, John C. Beier, Guiyun Yan, John I. Githure Oct 2004

The Development Of Plasmodium Falciparum In Experimentally Infected Anopheles Gambiae (Diptera: Culicidae) Under Ambient Microhabitat Temperature In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Elizabeth Walczak, Ephantus W. Kabiru, John C. Beier, Guiyun Yan, John I. Githure

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The effect of microhabitat temperature variation on the early development of Plasmodium falciparum in experimentally infected Anopheles gambiae s.s. (Diptera: Culicidae) was studied. Batches of mosquitoes were fed artificially on gametocyteamic blood obtained from human volunteers and then held in five environmental conditions described as: (1) incubator maintained at constant temperature of 28 ± 1°C as control; (2) temperature unregulated laboratory environment; (3) screen house; (4) grass thatched mud house and (5) corrugated iron roofed mud house. Both the grass and iron roofed mud houses were real houses found in the village communities around the ICIPE Research Centre in Mbita …

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Influence Of Indoor Microclimate And Diet On Survival Of Anopheles Gambiae S.S. (Diptera: Culicidae) In Village House Conditions In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Bart G.J. Knols, Ephantus W. Kabiru, Gerry F. Killeen, John C. Beier, Guiyun Yan, John I. Githure Sep 2004

Influence Of Indoor Microclimate And Diet On Survival Of Anopheles Gambiae S.S. (Diptera: Culicidae) In Village House Conditions In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Bart G.J. Knols, Ephantus W. Kabiru, Gerry F. Killeen, John C. Beier, Guiyun Yan, John I. Githure

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The survival of female Anopheles gambiae s.s. mosquitoes inside two village house types (grass-thatched and iron-roofed) was studied in relation to diet and ambient indoor microclimatic conditions. Two batches of 20-30, 1-day-old laboratory-bred mosquitoes were maintained inside cages in the grass-thatched (n = 2) and iron-roofed (n = 2) houses and fed daily, one group on 10% glucose and the other on human blood. Throughout the experiments, indoor temperature and relative humidity of the houses were recorded, and mortality of mosquitoes monitored daily until all had died. The experiments were replicated thrice. There was no significant variation in the overall …

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Multi-Trophic Level Interactions In A Cassava-Maize Mixed Cropping System In The Humid Tropics Of West Africa, F. Schulthess, A. Chabi-Olaye, S. Gounou Jun 2004

Multi-Trophic Level Interactions In A Cassava-Maize Mixed Cropping System In The Humid Tropics Of West Africa, F. Schulthess, A. Chabi-Olaye, S. Gounou

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Multi-trophic level interactions in a mixed crop, involving cassava and maize, were studied in derived-savanna in Benin, West Africa. Two trials were planted, one during the short rainy season two months before onset of the dry season and one during the long rainy season in spring. Key pests under study on maize were the noctuid Sesamia calamistis Hampson and the pyralids Eldana saccharina Walker and Mussidia nigrivenella Ragonot, and on cassava, the exotic mealybug, Phenacoccus manihoti Matile-Ferrero and its encyrtid parasitoid Apoanagyrus lopezi De Santis. Both crops received insecticide treatments to assess the crop loss by a pest species. On …

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Characterization Of Potential Larval Habitats For Anopheles Mosquitoes In Relation To Urban Land-Use In Melindi, Kenya, Joseph Keating, Kate Macintyre, Charles M. Mbogo, John I. Githure, John C. Beier May 2004

Characterization Of Potential Larval Habitats For Anopheles Mosquitoes In Relation To Urban Land-Use In Melindi, Kenya, Joseph Keating, Kate Macintyre, Charles M. Mbogo, John I. Githure, John C. Beier

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Background: This study characterized Anopheles mosquito larval habitats in relation to ecological attributes about the habitat and community-level drainage potential, and investigated whether agricultural activities within or around urban households increased the probability of water body occurrence. Malindi, a city on the coast of Kenya, was mapped using global positioning system (GPS) technology, and a geographic information system (GIS) was used to overlay a measured grid, which served as a sampling frame. Grid cells were stratified according to the level of drainage in the area, and 50 cells were randomly selected for the study. Cross-sectional household and entomological surveys were …

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Effect Of Constant Temperatures On Germination, Radial Growth And Virulence Of Metarhizium Anisopliae To Three Species Of African Tephritid Fruit Flies, Susan Dimbi, Nguya K. Maniania, Slawomir A. Lux, Jones M. Mueke Feb 2004

Effect Of Constant Temperatures On Germination, Radial Growth And Virulence Of Metarhizium Anisopliae To Three Species Of African Tephritid Fruit Flies, Susan Dimbi, Nguya K. Maniania, Slawomir A. Lux, Jones M. Mueke

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The effect of temperature on conidial germination, mycelial growth, and susceptibility of adults of three tephritid fruit flies, Ceratitis capitata (Wiedemann), C. fasciventris (Bezzi) and C. cosyra (Walker) to six isolates of Metarhizium anisopliae were studied in the laboratory. There were significant differences among the isolates in the effect of temperature on both germination and growth. Over 80% of conidia germinated at 20, 25 and 30°C, while between 26 and 67% conidia germinated at 35°C and less than 10% at 15°C within 24 hours. Radial growth was slow at 15°C and 35°C with all of the isolates. The optimum temperature …

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Host Suitability And Thermal Requirements Of Lathromeris Ovicida Risbec (Hymenoptera: Tricliogrammatidae), An Egg Parasitoid Of Cereal Stemborers In Africa, A. Chabi-Olaye, M. K. Fiaboe, F. Schulthess Jan 2004

Host Suitability And Thermal Requirements Of Lathromeris Ovicida Risbec (Hymenoptera: Tricliogrammatidae), An Egg Parasitoid Of Cereal Stemborers In Africa, A. Chabi-Olaye, M. K. Fiaboe, F. Schulthess

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Factors affecting the bionomics of the trichogrammatid egg parasitoid Lathromeris ovicida and its association with the two sympatric scelionid egg parasitoids Telenomus busseolae and Telenomus isis were studied in the laboratory. The potential host species employed were the noctuids Sesamia calamistis and Sesamia botanephaga, and the pyralids Eldana saccharina and Mussidia nigrivenella. Using eggs of S. calamistis Hampson as hosts, the lower and upper thresholds for development were estimated at 14.8 and 34°C, respectively. The percent parasitism, total progeny, and sex ratio decreased gradually from 42.0 to 10.2, from 56.4 to 10.8, and from 0.74 to 0.61, respectively, with host …

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Host Species, Age And Sex As Factors Affecting The Susceptibility Of The African Tephritid Fruit Fly Species, Ceratitis Capitata, C. Cosyra And C. Fasciventris To Infection By Metarhizium Anisopliae, S. Dimbi, N. K. Maniania, S. A. Lux, J. M. Mueke Oct 2003

Host Species, Age And Sex As Factors Affecting The Susceptibility Of The African Tephritid Fruit Fly Species, Ceratitis Capitata, C. Cosyra And C. Fasciventris To Infection By Metarhizium Anisopliae, S. Dimbi, N. K. Maniania, S. A. Lux, J. M. Mueke

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The effect of host age and sex on the susceptibility of 3 tephritid fruit fly species, Ceratitis capitata (Wiedemann), C. cosyra (Walker) and C. fasciventris (Bezzi) to the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin was studied in the laboratory. Three adult host ages, 0 (<1 day-old), 7-day-old and 14-day-old, were used. All 3 species were susceptible to fungal infection, although there were differences in the levels of susceptibility among the hosts. Age accounted for the largest variability in mortality followed by species, while sex had the lowest variability. Of the 3 host ages tested, the 0- and 7-day-old flies were more susceptible to fungal infection than the 14-day-old flies. Male and female C. fasciventris flies generally succumbed earlier to fungal infection than the other two species. Female flies of C. cosyra and C. fasciventris were also generally more susceptible to fungal infection than the males, although differences were apparent at 3 and 4 days after treatment but not 5 days after treatment. Age accounted for the largest variability in lethal time mortality values (LTs). Mean LT-values generally indicated that the speed of kill was faster among younger flies than the older flies. LT95 ranged between 3.9-4.9 days in the 0-day-old flies, 4.3-6.1 days in the 7-day-old flies and 4.6-6.1 days in 14-day-old flies in the different species and sexes. The implication of this study for the management of fruit flies is discussed.

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Responses Of Glossina Morsitans Morsitans To Blends Of Electroantennographically Active Compounds In The Odors Of Its Preferred (Buffalo And Ox) And Nonpreferred (Waterbuck) Hosts, Nicholas K. Gikonyo, Ahmed Hassanali, Peter G.N. Njagi, Rajinder K. Saini Oct 2003

Responses Of Glossina Morsitans Morsitans To Blends Of Electroantennographically Active Compounds In The Odors Of Its Preferred (Buffalo And Ox) And Nonpreferred (Waterbuck) Hosts, Nicholas K. Gikonyo, Ahmed Hassanali, Peter G.N. Njagi, Rajinder K. Saini

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In a previous study, comparison of the behavior of teneral Glossina morsitans morsitans on waterbuck, Kobus defassa (a refractory host), and on two preferred hosts, buffalo, Syncerus caffer, and ox, Bos indicus, suggested the presence of allomones in the waterbuck odor. Examination of the volatile odors by coupled gas chromatography-electroantennographic detection showed that the antennal receptors of the flies detected constituents common to the three bovids (phenols and aldehydes), as well as a series of compounds specific to waterbuck, including C8 - C13 methyl ketones, δ-octalactone, and phenols. In this study, behavioral respones of teneral G. m. morsitans to different …

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Parameter Estimation For Distributed Delay Based Population Models From Laboratory Data: Egg Hatching Of Oulema Duftschmidi Redthenbacher (Coleoptera, Chrysomelidae) As An Example, Maurizio Severini, Johann Baumgärtner, Lidia Limonta Sep 2003

Parameter Estimation For Distributed Delay Based Population Models From Laboratory Data: Egg Hatching Of Oulema Duftschmidi Redthenbacher (Coleoptera, Chrysomelidae) As An Example, Maurizio Severini, Johann Baumgärtner, Lidia Limonta

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The cohort development of poikilotherms under favorable temperature conditions may be described by the time-invariant distributed delay models that require three parameters, i.e. the thermal threshold T0, the thermal constant W and the variability parameter H representing distributed maturation times, also known as time distributed or stochastic development. Here, a parsimonious method is developed that uses stage-frequency matrices obtained under controlled conditions. The analysis of these matrices permits the estimation of the three parameters, while the incorporation of both developmental threshold and thermal constant into the time-invariant distributed delay model permits the representation of stochastic cohort development under constant temperatures. …

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Effect Of Soil Temperature And Moisture On Survival And Infectivity Of Metarhizium Anisopliae To Four Tephritid Fruit Fly Puparia, S. Ekesi, N. K. Maniania, S. A. Lux Jun 2003

Effect Of Soil Temperature And Moisture On Survival And Infectivity Of Metarhizium Anisopliae To Four Tephritid Fruit Fly Puparia, S. Ekesi, N. K. Maniania, S. A. Lux

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The infectivity of 4 isolates of Metarhizium anisopliae to puparia of Ceratitis capitata treated as late third-instar larvae in unsterilized soil was investigated in the laboratory under controlled temperature and moisture. At 20-30°C, mortality in puparia was highest at water potential of -0.1 and -0.01 mega Pascal (MPa) and lowest at water potential of -0.0055 and -0.0035 MPa in all the isolates. In wetter soil however, isolates ICIPE 20 and 60 caused significantly higher mortality than ICIPE 18 and 69. The survival of conidia in drier soil (-0.1 MPa) was not adversely affected at all temperatures. However, in wet soil …

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Prospects For Biological Control Of The Western Flower Thrips, Frankliniella Occidentalis, With The Entomopathogenic Fungus, Metarhizium Anisopliae, On Chrysanthemum, N. K. Maniania, S. Ekesi, B. Löhr, F. Mwangi May 2003

Prospects For Biological Control Of The Western Flower Thrips, Frankliniella Occidentalis, With The Entomopathogenic Fungus, Metarhizium Anisopliae, On Chrysanthemum, N. K. Maniania, S. Ekesi, B. Löhr, F. Mwangi

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The potential of Metarhizium anisopliae (Metsch.) Sorok. for the control of Frankliniella occidentalis (Pergande) on chrysanthemum cuttings was evaluated in greenhouse experiments. The fungus significantly reduced both the adult and larval populations of F. occidentalis, although the level of control of larval populations was much lower than for adults. Combined application of M. anisopliae and Methomyl (Lannate®), however, resulted in a significant reduction of both the larval and adult stages. The use of both control agents might be helpful in reducing the selection pressure for resistance to chemical insecticides, thereby delaying or preventing the build-up of resistant populations in greenhouses.

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Evidence Of The Establishment Of Cotesia Flavipes (Hymenoptera: Braconidae), A Parasitoid Of Cereal Stemborers, And Its Host Range Expansion In Ethiopia, E. Getu, W. A. Overholt, E. Kairu, C. O. Omwega Apr 2003

Evidence Of The Establishment Of Cotesia Flavipes (Hymenoptera: Braconidae), A Parasitoid Of Cereal Stemborers, And Its Host Range Expansion In Ethiopia, E. Getu, W. A. Overholt, E. Kairu, C. O. Omwega

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Three lepidopteran cereal stemborers, Chilo partellus (Swinhoe) (Crambidae), Busseola fusca Fuller, and Sesamia calamistis Hampson (Noctuidae) were collected from maize and sorghum in Ethiopia. The noctuid stemborers are indigenous to Africa while C. partellus is an introduced species from Asia. In 1999, the Asian stemborer parasitoid, Cotesia flavipes Cameron (Braconidae) was found to be widespread in Ethiopia, even though it had never been released in the country. In addition to attacking Chilo partellus, Cotesia flavipes was reared from B. fusca and S. calamistis. The origin of C. flavipes in Ethiopia may have been Somalia where it was released in 1997 …

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Effects Of Molasses Grass, Melinis Minutiflora Volatiles On The Foraging Behavior Of The Cereal Stemborer Parasitoid, Cotesia Sesamiae, Linnet S. Gohole, William A. Overholt, Zeyaur R. Khan, John A. Pickett, Louise E.M. Vet Mar 2003

Effects Of Molasses Grass, Melinis Minutiflora Volatiles On The Foraging Behavior Of The Cereal Stemborer Parasitoid, Cotesia Sesamiae, Linnet S. Gohole, William A. Overholt, Zeyaur R. Khan, John A. Pickett, Louise E.M. Vet

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Olfactory responses of the cereal stemborer parasitoid Cotesia sesamiae to volatiles emitted by gramineous host and nonhost plants of the stemborers were studied in a Y-tube olfactometer. The host plants were maize (Zea mays) and sorghum (Sorghum bicolor), while the nonhost plant was molasses grass (Melinis minutiflora). In single-choice tests, females of C. sesamiae chose volatiles from infested and uninfested host plants and molasses grass over volatiles from the control (soil). In dual-choice tests, the wasp preferred volatiles from infested host plants to those from uninfested host plants. There was no discrimination between molasses grass volatiles and those of uninfested …

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Incomplete Sexual Isolation In Sympatry Between Subspecies Of The Butterfly Danaus Chrysippus (L.) And The Creation Of A Hybrid Zone, G. Lushai, D. A.S. Smith, I. J. Gordon, D. Goulson, J. A. Allen, N. Maclean Mar 2003

Incomplete Sexual Isolation In Sympatry Between Subspecies Of The Butterfly Danaus Chrysippus (L.) And The Creation Of A Hybrid Zone, G. Lushai, D. A.S. Smith, I. J. Gordon, D. Goulson, J. A. Allen, N. Maclean

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Subspecies chrysippus, dorippus and alcippus of the butterfly Danaus chrysippus differ at three biallelic colour gene loci. They have partially vicariant distributions, but their ranges overlap over a substantial part of central and East Africa, where hybridism is commonplace. We now report that the West African subspecies alcippus differs from other subspecies, not only in nuclear genotype but also in mitochondrial haplotype in both allopatry and sympatry. The maintenance of concordant nuclear and cytoplasmic genetic differences in sympatry, and in the face of hybridisation, is prima facie evidence for sexual isolation. Other evidence that suggests alcippus may be isolated from …

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Comparative Analysis Of Microsatellite Loci In Four Fruit Fly Species Of The Genus Ceratitis (Diptera: Tephritidae), F. N. Baliraine, M. Bonizzoni, E. O. Osir, S. A. Lux, F. J. Mulaa, L. Zheng, L. M. Gomulski, G. Gasperi, A. R. Malacrida Feb 2003

Comparative Analysis Of Microsatellite Loci In Four Fruit Fly Species Of The Genus Ceratitis (Diptera: Tephritidae), F. N. Baliraine, M. Bonizzoni, E. O. Osir, S. A. Lux, F. J. Mulaa, L. Zheng, L. M. Gomulski, G. Gasperi, A. R. Malacrida

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The possibility to cross-species amplify microsatellites in fruit flies of the genus Ceratitis was tested with the polymerase chain reaction (PCR) by analysing 23 Ceratitis capitata (Wiedemann) microsatellite markers on the genomic DNA of three other economically important, congeneric species: C. rosa (Karsch), C. fasciventris (Bezzi) and C. cosyra (Walker). Twenty-two primer pairs produced amplification products in at least one of the three species tested. The majority of the products were similar, if not identical in size to those expected in C. capitata. The structures of the repeat motifs and their flanking sequences were examined for a total of 79 …

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Enrichment Of A Single Clone From A High Diversity Library Of Phage-Displayed Antibodies By Panning With Anopheles Gambiae (Diptera: Culicidae) Midgut Homogenate, G. F. Killeen, B. D. Foy, R. H. Frohn, D. Impoinvil, A. Williams, J. C. Beier Feb 2003

Enrichment Of A Single Clone From A High Diversity Library Of Phage-Displayed Antibodies By Panning With Anopheles Gambiae (Diptera: Culicidae) Midgut Homogenate, G. F. Killeen, B. D. Foy, R. H. Frohn, D. Impoinvil, A. Williams, J. C. Beier

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A high diversity library of recombinant human antibodies was selected on complex antigen mixtures from midguts of female Anopheles gambiae Giles. The library of phage-displayed single chain variable region fragment constructs, derived from β-lymphocyte mRNA of naïve human donors, was repeatedly selected and reamplified on the insoluble fraction of midgut homogenates. Five rounds of panning yielded only one midgut-specific clone, which predominated the resulting antibody panel. In A. gambiae, the epitope was found throughout the tissues of females but was absent from the midgut of males. The cognate antigen proved to be detergent soluble but very sensitive to denaturation and …

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Integrated Arthropod Pest Management Systems For Human Health Improvement In Africa, Johann Baumgärtner, Fritz Schulthess, Yunlong Xia Jan 2003

Integrated Arthropod Pest Management Systems For Human Health Improvement In Africa, Johann Baumgärtner, Fritz Schulthess, Yunlong Xia

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In a sub-Saharan African context, limited natural resources, infectious diseases, including those transmitted by arthropod vectors, and chronic exposure to food contaminated with mycotoxin-producing fungi which, among others, are vectored by insects, are among the major constraints to human health. Thus, pest control should be an important component in human health improvement projects. It appears that the advantages of preventive over curative methods are rarely recognised in Africa, with more emphasis being given to the search for the 'silver bullet' than to integrated control approaches. Integrated pest management (IPM) systems can be assigned to different decision-making levels as well as …

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Ring A-Seco Mosquito Larvicidal Limonoids From Turraea Wakefieldii, Mary Ndung'u, Ahmed Hassanali, Antony M. Hooper, Sumesh Chhabra, Thomas A. Miller, Rowena L. Paul, Baldwyn Torto Jan 2003

Ring A-Seco Mosquito Larvicidal Limonoids From Turraea Wakefieldii, Mary Ndung'u, Ahmed Hassanali, Antony M. Hooper, Sumesh Chhabra, Thomas A. Miller, Rowena L. Paul, Baldwyn Torto

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Five novel limonoids, 1-5, were isolated from the root bark of Turraea wakefieldii and were characterized as tecleaninoid derivatives. This is the first report of the natural occurrence of tecleanin-type limonoids with a five-membered-ring A-seco structure for which we propose the name neotecleanins. The relative stereochemical structures of compounds 1-5 were established on the basis of NMR spectroscopy. The absolute stereochemical structure of 5 was confirmed by X-ray diffraction methods. In mosquito larvicidal assays, compounds 1, 2 and 4 showed dose-dependent larvicidal activity against larvae of Anopheles gambiae s.s. © 2003 Elsevier Ltd. All rights reserved.

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Evidence For The Involvement Of A Tsetse Midgut Lectin-Trypsin Complex In Differentiation Of Bloodstream-Form Trypanosomes, L. U. Abubakar, G. Zimba, C. Wells, F. Mulaa, E. O. Osir Jan 2003

Evidence For The Involvement Of A Tsetse Midgut Lectin-Trypsin Complex In Differentiation Of Bloodstream-Form Trypanosomes, L. U. Abubakar, G. Zimba, C. Wells, F. Mulaa, E. O. Osir

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We have previously described a bloodmeal-induced molecule (lectin-trypsin complex) from the midgut of the tsetse fly, Glossina longipennis, with both lectin and trypsin activities (Osir et al., 1995). In this paper, we report on the isolation of a similar molecule from the midguts of Glossina fuscipes fuscipes and provide direct evidence for its involvement in the development of African trypanosomes. The molecule (native Mr ∼65,700) has two non-covalently linked subunits, Mr ∼28,800 and Mr ∼35,700. The native molecule was found to be capable of inducing differentiation of bloodstream-form trypanosomes into procyclic (midgut forms) in vitro. In the assays, specific antibodies …

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High Seasonal Variation In Entomologic Inoculation Rates In Eritrea, A Semi-Arid Region Of Unstable Malaria In Africa, Josephat Shililu, Tewolde Ghebremeskel, Solomon Mengistu, Helen Fekadu, Mehari Zerom, Charles Mbogo, John Githure, Robert Novak, Eugene Brantly, John C. Beier Jan 2003

High Seasonal Variation In Entomologic Inoculation Rates In Eritrea, A Semi-Arid Region Of Unstable Malaria In Africa, Josephat Shililu, Tewolde Ghebremeskel, Solomon Mengistu, Helen Fekadu, Mehari Zerom, Charles Mbogo, John Githure, Robert Novak, Eugene Brantly, John C. Beier

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Entomologic studies were conducted in eight villages to investigate the patterns of malaria transmission in different ecologic zones in Eritrea. Mosquito collections were conducted for 24 months between September 1999 and January 2002. The biting rates of Anopheles arabiensis were highly seasonal, with activity concentrated in the wet season between June and October in the highlands and western lowlands, and between December and March in the coastal region. The biting rates in the western lowlands were twice as high as in the western escarpment and 20 times higher than in the coastal region. Sporozoite rates were not significantly different among …

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Geographic Differences In Host Acceptance And Suitability Of Two Cotesia Sesamiae Populations In Zimbabwe, P. Chinwada, W. A. Overholt, C. O. Omwega, J. M. Mueke Jan 2003

Geographic Differences In Host Acceptance And Suitability Of Two Cotesia Sesamiae Populations In Zimbabwe, P. Chinwada, W. A. Overholt, C. O. Omwega, J. M. Mueke

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Three lepidopteran stemborers, Busseola fusca Fuller (Noctuidae), Sesamia calamistis Hampson (Noctuidae), and Chilo partellus (Swinhoe) (Crambidae), were evaluated for their acceptability for oviposition and suitability for development by two populations of the larval endoparasitoid Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) occurring in the highveld (>1200m) and lowveld (<600 m) regions of Zimbabwe. Mating studies were also conducted to determine reproductive compatibility between the populations. Both C. sesamiae populations preferred the noctuids to C. partellus for oviposition. possibly reflecting differences in evolutionary history. Although B. fusca was partially suitable for development of lowveld C. sesamiae, all three hosts were suitable for development of the highveld population. Crosses between highveld and lowveld C. sesamiae were compatible, and were generally not different from the intra-population crosses in developmental time, % adult emergence and sex ratio. However, broods were much larger when highveld males were used in the mating combinations. We conclude that although there is host overlap and probably a considerable degree of outbreeding between the two C. sesamiae populations, there are still significant genetic differences between them. Within Zimbabwe, it is unlikely that the deliberate introduction of either population outside its region of occurrence will give meaningful stemborer control. © 2003 Elsevier Science (USA). All rights reserved.

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Olfactory Responses Of Cotesia Flavipes (Hymenoptera: Braconidae) To Target And Non-Target Lepidoptera And Their Host Plants, Bekele Jembere, Adele J. Ngi-Song, W. Overholt Jan 2003

Olfactory Responses Of Cotesia Flavipes (Hymenoptera: Braconidae) To Target And Non-Target Lepidoptera And Their Host Plants, Bekele Jembere, Adele J. Ngi-Song, W. Overholt

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The attraction of Cotesia flavipes Cameron to volatiles from a range of non-target lepidopteran larvae and their host plants (grasses and trees) or food substrate (honeycomb) was evaluated using a Y-tube olfactometer. The non-target host larvae used in the study included Galleria mellonella (L.), Charaxes cithaeron Felder, Bombyx mori L., and Eldana saccharina Walker. The target insects, Chilo partellus (Swinhoe) and Chilo orichalcociliellus (Strand), were used as controls. Host plants included Afzelia quanzensis Welw., Morus alba L., Cyperus papyrus L., Pennisetum purpureum Schumach, and Zea mays L. The response of C. flavipes to volatiles from the non-target larvae and their …

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