bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the ecology and biology of a cocoa pollinator,Forcipomyia squamipennisI. & M. (Diptera, Ceratopogonidae), in Ghana
Authors: Kaufmann T.
Published: July 2009

From field observations and laboratory rearings, the biology ofForcipomyia squamipennisI. & M. in cocoa plantations in Ghana was established as follows. Adult midges are found between buttresses of large shade trees, in crevices of decayed old logs, in hollow tree stumps and cocoa husk heaps. Swarming takes place at any time during the day in or around the resting place, while dispersal occurs in the early morning and in the late afternoon, the normal flight range being 5–6 m. The largest populations occur in the rainy season. Eggs are laid on moist decomposing wood, cocoa husks and other plant debris in batches of 40–90; the larvae hatch in 2–3 days and pupate after four moults, when about 12 days old; the pupal stage lasts 2–3 days. Adult females require liquid plant food for survival and oviposition, although the maturation of ova is independent of adult food intake or mating; unfertilised eggs do not develop. The maximum adult life span for both sexes is eight days in captivity.F. squamipennisundergoes at least 12 generations a year. Due to its abundance and continuous breeding in cocoa plantations,F. squamipennisis probably the most important Ceratopogonid cocoa pollinator in Ghana. Both sexes are efficient pollinators, but four times more males than females visit cocoa flowers.
The vertical distribution of flying mosquitoes (diptera, culicidae) in west african savanna
Authors: Snow W. F.
Published: July 2009

The vertical distribution of mosquitoes was investigated at Keneba in The Gambia, using flight traps and suction traps set up over open ground. Flight traps were used to sample three levels, ground to 1·37 m, 1·45–2·82 m, and 2·90–4·27 m. Suction traps were mounted in two series of experiments at three levels, 0·68, 2·13 and 3·51 m, and in a third series at four levels, 0·91, 305, 6·10 and 9·15 m. Most species, including Anopheles melas Theo., A. squamosus Theo., Aedes punctothoracis (Theo.), the Culex decens group, C. tritaeniorhynchus Giles, Mansonia africana (Theo.) and M. uniformis (Theo.), were most common near the ground, with catches declining progressively with height. C. thalassius Theo. was frequent at all levels, although the largest catches were taken at 9·15 m. Only C. neavei Theo. and C. weschei Edw. were more common in the higher traps. Although larger catches of A. melas and C. tritaeniorhynchus were taken during moonless periods, the numbers of other species were unaffected by lunar phase. In general, the presence or absence of moonlight had little effect on vertical distribution. However, C. thalassius and the C. decens group were shown to be more attracted to flight traps in moonlight, and it is concluded that visual responses were involved. A limited series of four-level, human-bait catches, with the catchers stationed at the same heights as the suction traps of the third series, produced results similar to those of the suction trap collections.
The succession of mosquito species (Diptera, Culicidae) in rice fields in the Kisumu area of Kenya, and their possible control
Authors: Chandler J. A. , Highton R. B.
Published: July 2009

Thirty-five species of mosquitoes (10 782 adults) were caught in modified CDC light-traps during the 27-week rice cultivation cycle at Ahero, Kenya, in the period September 1972 to March 1973. Only 0·8% were blood-fed and 5·1% gravid, indicating that the traps were sampling newly emerged adults. During weeks 1–7, before rice seedlings were transplanted, catches were small, but increased markedly from then until harvest (week 20). Two groups of mosquito species were recognised: the first, including Mansonia uniformis (Theo.), M. africana (Theo.) and Mimomyia splendens Theo., bred throughout the rice cycle; the second, including Anopheles gambiae s.l., A. pharoensis Theo., A. ziemanni Grünb., Culex poicilipes (Theo.) and C. antennatus (Becker), were affected by water depth and height of the rice crop. The slurry of shallow muddy pools which follows transplanting stimulated intense breeding of A. gambiae and A. pharoensis. Once the young plants were established, reflooding of the fields and subsequent growth of water plants and algae favoured the breeding of A. ziemanni and C. poicilipes. Towards the end of the rice cycle large numbers of C. antennatus were caught. It is concluded that mosquito control by means of insecticides or by irrigation management would be possible.
Biology of the carob midge complex,Asphondyliaspp. (Diptera, Cecidomyiidae), in Cyprus
Authors: Orphanides G. M.
Published: July 2009

In Cyprus, the pods of the carob tree (Ceratonia siliqua) are infested by three races or sibling species of midges: the pepper, caper and squill midge (Asphondyliaspp.). This classification has been made on the basis of secondary host-plant preferences. Tests in cages revealed that secondary host-plants which are attacked by these midges during spring, summer and autumn, taken together, are: pepper (Capsicum annuum), potato (Solanum tuberosum), caper (Capparis spinosa), garden rocket (Eruca sativa), mustard (Sinapisspp.), sea squill (Urginea maritima), asphodel (Asphodelus fistulosus), and St Johnswort (Hypericum crispum). The carob midge complex overwinters as young larvae in carob pods and may have a maximum of six or seven generations per year according to the location. The emergence pattern of the overwintering generation varied between locations. The adult sex ratio was 42 ♂ : 100 ♀ and the mean longevity under laboratory conditions was 55 h. Some major morphological characteristics of all developmental stages are also presented. The larval stage is divided into three instars. Sex identification has been determined at the pupal stage.
Cross-resistance in DDT-resistant strains of various mosquitoes (Diptera, Culicidae)
Authors: Rongsriyam Y. , Busvine J. R.
Published: July 2009

Larvicide tests were conducted on five species of mosquitoes, each of which had one or more DDT-resistant strains. The high potencies of DDT and, to a large degree, of DDD were completely lost by resistance. Other compounds were affected in different degrees according to the resistance mechanisms present, as indicated by resistance spectra and the effects of synergists. DDT-resistant strains of Culex pipiens fatigans Wied., Anopheles quadrimaculatus Say and A. stephensi List, showed highly specific resistance to DDT, probably dependent on a dehydrochlorination mechanism. DDT-resistance in Aedes aegypti (L.) and A. gambiae was also high, but there was definite evidence of cross-resistance to biodegradable DDT-analogues (about ×4 and ×10, respectively). This low-level, but definite, cross-resistance extended to a number of other compounds, notably pyrethroids, insect development inhibitors, amines, etc. The presence of synergistic action by piperonyl butoxide suggested that this depended on a microsomal oxidation system.

Isotopically labelled (14C) DDT and malathion were used to study pick-up and penetration of these insecticides by larvae of normal and resistant Ae. aegypti. Both the actual and the percentage penetration of DDT were greater in the resistant than in the normal strain. Whatever the reason for this, it disposes of the possibility of reduced pick-up and penetration as a factor in DDT-resistance. With malathion, the percentage penetration was always higher in the susceptible strain than in the resistant one, though in some cases the actual amount was less.
An analysis of an outbreak of the woodwasp, Sirex noctilio F. (Hymenoptera, Siricidae), in Pinus radiata
Authors: Madden J. L.
Published: July 2009

The development of an outbreak of the woodwasp, Sirex noctilio F., in a 30-year-old population of Pinus radiata in Tasmania was traced by growth ring analysis of killed trees. The outbreak probably developed from small foci; it reached its peak when the trees were 18–19 years old and then declined rapidly. Attack per tree was directly related to the density of emergents from trees killed in the previous season and the intensity of oviposition drilling was modified by the rainfall during the emergence season; the frequency of treble oviposition drills was directly related to summer rainfall. Survival of insects within trees declined with the years; this was related to the greater vigour and resistance of the surviving trees, but was apparently modified by spring rainfall. Resinosis and polyphenols associated with growth rings in stems living in 1964 indicated an increase in the proportion of trees resisting attack during the outbreak. The growth patterns of attacked and unattacked trees, and the obvious susceptibility of the weaker understorey trees, are discussed and due attention to site quality and plantation management are recommended to reduce Sirex attack in future.
Field trials with a nuclear polyhedrosis virus and Bacillus thuringiensis against larvae of Heliothis armigera (Hb.) (Lepidoptera, Noctuidae) on sorghum and cotton in Botswana
Authors: Roome R. E.
Published: July 2009

Six trials with an unpurified suspension of Heliothis armigera nuclear polyhedrosis virus (NPV) against Heliothis armigera (Hb.) larvae on sorghum (five trials) and on cotton (one trial) during 1971–73 are described. Commercial preparations of H. zea NPV and of Bacillus thuringiensis were included in two of the trials. H. armigera NPV was as successful as a standard insecticide in preventing losses of sorghum in one trial. Lowering the rate of NPV reduced the control of H. armigera larvae. There was no difference in control achieved by spraying in the morning or in the evening. Spraying every second or every third row (relying on natural spread of the virus) reduced control. Low concentrations of molasses (0·6%) made control by 100 larval equivalents (L.E.) per hectare as good as that by 200 L.E. per hectare without molasses. Neither the commercial H. zea NPV nor the Bacillus preparation was as effective as the local virus. The local virus was reasonably effective against H. armigera on cotton at very high rates and with molasses. It was not as damaging as carbaryl to populations of egg parasites and predators, but the predators did not control damaging populations of aphid and Jassid on the virus-sprayed plots.
Activity of adult Heliothis armigera (Hb.) (Lepidoptera, Noctuidae) with reference to the flowering of sorghum and maize in Botswana
Authors: Roome R. E.
Published: July 2009

Night-time observations on adults of Heliothis armigera (Hb.), and data from light-trap and hand net catches in irrigated and dryland crops, showed that both sexes flew and fed and females oviposited between 20.00 and 23.00 h. From then until 02.00 h both sexes were inactive, but. from 02.00 to 04.00 h the males flew above the crop in a ‘purposeful’ manner, while the females were stationary and releasing pheromone. During this period of high male and low female activity, copulation in cages, assembly of males to females in cages and copulating pairs on crop plants were all observed. Inseminated female H. armigera were collected in crops which were at a stage suitable for oviposition, while traps away from crops or near mature crops collected mainly virgin females. It is suggested that susceptible crops attract H. armigera adults and that, once within the crop, inseminated females are ‘trapped’ by suitable physiological cues from the plants. Identification of such cues could assist in the breeding of crop varieties resistant to H. armigera attack.
Description of a new genus of Ichneumonidae (Hymenoptera) of economic importance from Sabah
Authors: Gauld I. D.
Published: July 2009

A new genus and species of Ichneumonidae, Sliochia bala, reared from a pod husk miner (Acrocercops sp.) of cacao is described and compared with related genera in the Macrini.
Observations on the free larval stage of Glossina morsitans morsitans Westw. (Diptera, Glossinidae): the possibility of a larval pheromone
Authors: Nash T. A. M. , Trewern M. A. , Moloo S. K.
Published: July 2009

Under simulated natural conditions the anal orifice of the larva of Glossina morsitans morsitans Westw. appears to open either at or soon after parturition. The larva burrows on average within two minutes of deposition; pupariation is completed 10–15 min later. Using methods that prevent burrowing and prolong the crawling period, certain larval movements were related to the pre-pupariation anal discharges and to the rapid spread of the fluid. Although the anus is not generally thought to be connected with the hind gut during the whole of larval life, the presence of uric acid in the discharges indicates that the fluid is a product of Malpighian tubule excretion. In a two-choice chamber in an incubator, flies larviposited significantly more often in the experimental pot if it contained a water- or ether-soluble extract of larval excretion in addition to any pupariating larvae. This points to the presence of a larval phero-mone which may attract gravid females to a breeding site.
Ecological studies of ixodid ticks (Acari, Ixodidae) in Zambia. I. Cattle as hosts of the larvae ofAmblyomma variegatum(F.) andRhipicephalus appendiculatusneum.
Authors: MacLeod John , Colbo M. H.
Published: July 2009

The roles of cattle and alternative hosts in maintaining the immature stages ofAmblyomma variegatum(F.) andRhipicephalus appendiculatusNeum. are unknown. Weekly collections of ticks from cattle in two herds in Zambia indicated an apparently higher nymph-adult ratio in the annual totals forA. variegatumthan forR. appendiculatus. The larva-nymph ratios for these herds were estimated by a patch-sampling method in which all larvae and nymphs on 100 cm2areas on the cheek, neck, dewlap, shoulder, ribs, abdomen and lower-foreleg were collected. The overall annual ratios of larvae to nymphs on the two herds were:A. variegatum5:1 and 14:1,R. appendiculatus1·5:1 in both herds. The ratios suggest that cattle themselves feed larvae ofA. variegatumin sufficient numbers to maintain their nymphal infestation level. The numbers of cattle-fed larvae ofR. appendiculatusmay not be adequate for this, and alternative hosts may play an important part in maintaining the population at existing levels. There was negligible evidence of significant shift of distribution of the immature stages over the body with advancing season, and it is suggested that patch-sampling affords a method of quantitative comparison of the relative infestations by the immature stages of ticks.
Diapause of the southwestern corn borer,Diatraea grandiosellaDyar (Lepidoptera, Pyralidae): effects of a juvenile hormone mimic
Authors: Chippendale G. M. , Yin C.-M.
Published: July 2009

Topical applications of a juvenile hormone (JH) mimic induced and prolonged the mature larval diapause of the southwestern corn borer,Diatraea grandiosellaDyar. The onset of this diapause is marked by an ecdysis from a spotted to an immaculate morph. A high percentage of spotted non-diapause larvae treated with a single dose of a JH mimic moulted into the immaculate morph and became dormant. Similar treatments of diapause larvae led to a reversion to the spotted morph, but the larvae remained dormant. These results imply that diapause larvae contain an intermediate JH titre. A use for JH mimics in disrupting the seasonal phenology of pest insects with larval dormancies is suggested.
Experimental observations of food-aversive responses in larvae of Spodoptera exempta (Wlk.) (Lepidoptera, Noctuidae)
Authors: Ma Wei-Chun
Published: July 2009

The oligophagy of the African armyworm, Spodoptera exempta (Wlk.), was investigated experimentally. The resistance to feeding on cassava, a non-food plant, declined at a faster rate if the larvae had been reared on artificial diet. If diet-reared larvae were allowed to feed on maize for increasing periods of time the subsequent rejection of cassava increased accordingly. This effect could still be induced after removing the labral or palpal sensilla but not after removing both pairs of stylo-conic sensilla. The left and right pair of styloconic sensilla are supplementary to each other. In so far as aversive responses to non-food plants are concerned, the rearing on artificial diet can be considered as a case of pseudomaxillectomy. It is suggested that during feeding on maize the larva receives a specific input pattern which influences central acceptance-rejection decisions in a time-dependent manner. This specific information is absent from artificial diet and can no longer be perceived by larvae without styloconic sensilla.
Studies on some ornithophilic mosquitoes (Diptera, Culicidae) of the Kano Plain, Kenya
Authors: Chandler J. A. , Highton R. B. , Boreham P. F. L.
Published: July 2009

During 1972–74, 13 865 female mosquitoes of 25 species from eight genera were collected at the Kisumu heronry using light-traps, chicken-baited traps and battery-driven aspirators. A total of 3298 of these were engorged and 2169 were subjected to precipitin testing in order to determine their food sources. A high percentage of feeds on birds was recorded for Coquillettidia karandalaensis (Wolfs) (96%), Culex poicilipes (Theo.) (82%), and C. univittatus gp (65%); Mansonia uniformis (Theo.), M. africana (Theo.) and C. antennatus (Becker) were found to feed on birds occasionally. Results from catches in CDC light-traps set at various heights in trees with nesting birds indicated that C. univittatus gp, C. poicilipes and Aedomyia africana Nev.-Lem. were active in the upper levels of the canopy. Further analysis of blood-meals from birds indicated that C. univittatus gp mosquitoes were feeding principally on ciconiiform birds. Any mosquito which feeds regularly on birds and man must be considered as a potential vector of arboviruses; the results indicate that the most important vectors at Kisumu are probably C. univittatus gp mosquitoes.
Effects of groundnut sowing date and plant spacing on rosette virus disease in Malawi
Authors: Farrell J. A. K.
Published: July 2009

In a series of field trials at Chitedze, Malawi, groundnuts were sown at spacings of 30 cm, 7·5 cm and 2·5 cm within rows 90 cm apart. Contrasting sowing dates were approximately 1 December and 1 January. Immigration of alatae of Aphis craccivora Koch, monitored on observation plots, commenced 5–6 weeks after the emergence of early-sown groundnuts. Numbers of immigrant alatae were significantly greater on late-sown or open-spaced than on early-sown or close-spaced groundnuts, and were correlated with numbers of randomly distributed primary rosette virus infections. During observations, more alatae landed on 56–60-day-old plants than on 85–112-day-old plants. Similar numbers landed on 11–26-day-old plants at 30-cm and 2·5-cm spacing, but significantly more aphids settled on 30-cm spacing. The incubation period of rosette virus was consistently longer in 2·5-cm than in 30-cm spacing, and increased with plant age at inoculation. The virus was transmitted from a low proportion of infected plants before the appearance of rosette symptoms, and from a high proportion of plants snowing symptoms. The rate of spread of virus transmissions from inoculated sources within the crop varied significantly with spacing as 30 cm > 7·5 cm > 2·5 cm. Secondary spread of rosette varied, approximately, with the numbers of aphids per infected plant.
Description of the larva of Chalcosoma atlas (L.) (Coleoptera, Scarabaeidae, Dynastinae) from Malaysia
Authors: Bedford G. O.
Published: July 2009

The third-stage larva of Chalcosoma atlas (L.) collected in Malaysia is described, with illustrations, and a key is provided to distinguish larvae of this species from those of Oryctes rhinoceros (L.) and Xylotrupes gideon beckeri Schaufuss, all of which occur in similar breeding sites.
The immature stages of the Old-World screw-worm fly, Chrysomya bezziana villeneuve, with comparative notes on other australasian species of Chrysomya (Diptera, Calliphoridae)
Authors: Kitching R. L.
Published: July 2009

The eggs, three larval instars and puparia of Chrysomya bezziana Villeneuve are described and illustrated in detail by scanning electron micrographs. Particular attention is paid to the extent and nature of the median strip in the eggs and the spine bands and spiracular structures in the larvae and puparia.

Eggs and third-instar larvae of five other species of Chrysomya, C. nigripes Aubertin, C. varipes (Macquart), C. rufifacies (Macquart), C. saffranea (Bigot) and C. megacephala (F.), are illustrated, described and compared with C. bezziana and each other by means of keys, which also permit their identification. In addition, notes on the puparia of these species are provided.
The effects of temperature and relative humidity on the development ofRhipicephalus appendiculatusNeumann (Acarina, Ixodidae)
Authors: Tukahirwa E. M.
Published: July 2009

Variation in temperature affected the developmental periods of eggs, larvae and nymphs ofRhipicephalus appendiculatusNeum. and developmental periods were shortest at an optimum of 30°C. The periods increased as temperatures diverged from the optimum until upper and lower temperature limits were reached, when metabolism ceased. These limits were 16°C and 34°C for eggs, and 12°C and 41°C for larvae and nymphs.

Generally, relative humidity did not affect the rate of development. It did, however, critically affect survival, particularly of eggs and larvae. The relative humidity range of 60–70% was critical, and below this range survival of the eggs and larvae was very limited. Nymphs and adults were more resistant, and natural tick populations probably survive hot and dry seasons in these stages.

It was found that in a habitat with thick vegetation, temperature and humidity fluctuations were smaller than in one with sparse vegetation, and the former therefore supported a greater tick population. Denying cattle access to this thick vegetation or getting rid of it altogether seem to be possible methods of reducing the tick load of cattle in the area studied.
Effects of hempa on the gonads of Locusta Migratoria (L.) (Orthoptera, Acrididae)
Authors: Nath Vishwa , Mittal P. K. , Sheikher Chander
Published: July 2009

Only a very strong dose of 0·5 mg of hempa caused necrosis in testes of Locusta migratoria (L.). The apical cells, spermatogonia and primary spermatocytes became pycnotic and the germ cells were disorganised. Multinucleated cells also developed, due to failure of spindle formation, and a few hypertrophied spermatids occurred. In ovaries the chromatin of the follicular epithelial cell nuclei was abnormally fragmented; nuclei of the follicular epithelial cells became pycnotic; germinal vesicle was badly damaged; cytoplasm of the follicular epithelial cells was drawn into the peripheral empty space formed by the contraction of the ooplasm; the follicular epithelium degenerated later; and yolk formation was inhibited. With increased doses and post-treatment periods necrosis became more marked. Hempa was more effective in the ovary than in the testes of L. migratoria.
Communication disruption of adult Egyptian cotton leafworm Spodoptera littoralis (Boisd.) (Lepidoptera, Noctuidae) in Crete using synthetic pheromones applied by microencapsulation and dispenser techniques
Authors: Campion D. G. , McVeigh L. J. , Murlis J. , Hall D. R. , Lester R. , Nesbitt Brenda F. , Marrs G. J.
Published: July 2009

Communication between adult male and female Spodoptera littoralis (Boisd.) was disrupted by spraying microencapsulated formulations of pheromone inhibitor (IIA) (Z)-9-tetradecen-1-yl-acetate on lucerne plots in north-west Crete. Polyurea-based microcapsules applied at the rate of 100 g/ha active ingredient caused a 97% disruption for a period of seven days, as measured by the reduction of catches in the treated area in traps baited with the pheromone attractant (III) (Z)-9, (E)-11-tetradecadien-1-yl acetate, compared with catches in control areas. At lower rates of application both the level of disruption after seven days and the subsequent persistence of the effect were reduced. When applied at a rate of 100 g/ha active ingredient, disruption of 80% and above was achieved for a period of three weeks. Slower release microcapsules containing IIA based on polyurea/polyamide appeared more effective in that a level of disruption was achieved at one-tenth the amount of active ingredient required for the polyurea-based formulations.

III dispensed in polythene vials caused 97% disruption when distributed at the rate of one vial per 9 m2, with lower levels of disruption at distributions of one vial per 25 m2 or 50 m2. IIA was much less effective in causing communication disruption at the same rates of distribution and no clear dose/response relationship was established.

Inside enclosures of 10 100 and 1 000 m2 fenced by single-strand polythene impregnated with IIA at the rate of 1 mg/5 cm and maintained at a height of 0·5 m, a high level of disruption in excess of 93% was achieved for the first five days. The effect persisted in the smaller enclosures in that disruption in excess of 80% was maintained for a period of 40 days. In the 1 000 m2 enclosure the effect declined much more quickly.

When IIA and III were dispensed together in WT traps the inhibitory effect persisted for at least 60 days. Similarly the polyurea-based microcapsules containing IIA together with III in WT traps maintained an inhibitory action for periods of 30–40 days. Polyurea/polyamide formulations of IIA were generally less effective, probably because loss from these slow releasing formulations became too low. Small numbers of mostly unmated female moths were attracted to the traps when IIA was exposed together with III, either when dispensed in the polythene vials or in microencapsulated formulations.
Ticks (Acarina, Ixodoidea) of the northern regions of the Somali Democratic Republic
Authors: Pegram R. G.
Published: July 2009

In this survey of distribution and prevalence of adult ticks (Acarina, Ixodoidea) parasitising domestic animals in the northern regions of the Somali Democratic Republic, 26 species were identified. The ten most common species were widely distributed withHyalomma anatolicum anatolicumKoch,H. dromedariiKoch,H. erythraeumTonelli-Rondelli,H. impeltatumSchulze & Schlottke andRhipicephalus sanguineusgroup more common in the drier vegetation zones, andH. marginatum rufipesKoch,H. truncatumKoch,R. e. evertsiNeum.,R. pravusDön. andR. pulchellus(Gerst.) more common in the wetter woodland, evergreen and forested zones. Four species,Amblyomma gemmaDön.,A. variegatum(F.),Boophilus decoloratusKoch andR. simusKoch, were confined to the wooded zones above 1200 m altitude. Species collected less frequently wereArgas persicus(Oken),Amblyomma falsomarmoreumTonelli-Rondelli,H. anatolicum excavatumKoch,H. m. marginatumKoch,H. m. turanicumPom.,H. puntHoogst., Kaiser & Pedersen,Ornithodoros savignyi(Aud.),R. armatusPocock andR. longicoxatusNeum.Ambylomma lepidumDön. was represented only by a few specimens introduced on nomadic livestock.

Nearly 60% of the total number of ticks collected wereR. pulchellus. This species is considered to be the main vector of Nairobi sheep disease (NSD) virus in northern Somalia. NSD is the most important tickborne disease in sheep and goats and causes considerable economic losses to the Somali livestock industry.A. gemmaandA. variegatumare probably the vectors ofCowdria ruminantium(heartwater) in sheep and goats in the western highlands. These two ticks are also incriminated in the spread ofDermatophilus congolensisinfection (streptothricosis).R. e. evertsimay be the vector ofBabesia motasiin sheep and goats.Boophilus decoloratusis probably the vector ofBabesia bigeminain cattle in the western highlands. Various tick species may be associated with bacterial abscesses of feet and lymph nodes in sheep and goats.
Rate of linear advance by Glossina morsitans submorsitans newst. (Diptera, Glossinidae) on a trade cattle route in south-western Nigeria
Authors: Riordan K.
Published: July 2009

Indigenous cattle are trekked, along well defined routes, from the north of Nigeria to markets in the south of the country. A major route crosses the River Niger at Jebba and proceeds south through Ilorin, Ogbomosho and Oyo towns. In 1912 the tsetse fly Glossina morsitans submorsitans Newst. was absent from this route south of Jebba. The species appeared mid-way between Jebba and Ilorin in about 1935, reached Ilorin by about 1950 and Oyo by, or before, 1967. The rate of southwards advance, if linear, was about 5·4 km per year or 104 m per week.

The Jebba-Oyo infestation may have originated, not as a southwards extension of a fly belt north of the River Niger at Jebba (now termed Belt 24), as generally believed, but by immigration of flies from Eastern Ilorin Province, known to be heavily infested as early as 1912. Several cattle routes from that area converged north of Ilorin before the present route became predominant.

G. m. submorsitans was eradicated from the route south of Ogbomosho by insecticide spraying in January 1970. The rate of re-invasion of this section was measured for the next three years and found to be about 5·13 km per year or 99 m per week, proceeding faster during dry than during wet seasons.

The calculated rates of advance, both long and short term, were about half the figure (180 m per week) proposed by other workers as the dispersal rate of individual flies, which is believed to determine rates of advance. The relative slowness of the present advance was probably related to the equability of the climate, in which seasonal increases and decreases in fly population were slight.
Larval habitats of common Culicoides Latreille (Diptera, Ceratopogonidae) in Kenya
Authors: Lubega R. , Khamala C. P. M.
Published: July 2009

The larval habitats of Culicoides species were determined by examining a total of 1 476 samples collected from different ecological environments in various parts of Kenya. Immature stages were collected from suspected breeding habitats and adults were reared. Adults were also captured in emergence traps and then identified. To determine species preferences, if any, the materials yielding Culicoides were analysed for pH, organic matter and water content.

Fifty-seven percent of the samples yielded a total of 26 species of Culicoides. Sites in which Culicoides occurred were classified into eleven habitats grouped into four major systems, namely, aquatic, transitional, terrestrial and general systems. Most species were found breeding over a wide pH range in sites which were wet at least part of the time. A few species appeared to select breeding habitats with a high organic content.
Laboratory evaluation of the sex pheromone and mating inhibitor of the red bollworm Diparopsis castanea Hampson (Lepidoptera, Noctuidae)
Authors: Marks R. J.
Published: July 2009

The four components of the synthesised sex pheromone of Diparopsis castanea Hmps. are dodecan-1-yl acetate (I); trans-9-dodecen-1-yl acetate (IIA); 11-dodecen-l-yl acetate (IIB); and trans-9,ll-dodecadien-l-yl acetate (IV). Increasing the proportion of IIA in a I/IIA/IIB/IV mixture progressively decreased male excitation in a laboratory bioassay, whilst in the absence of I all concentrations of IIA tested were equally inhibitory. The synthetic combination of 80% IV (93% trans: 7% cis) and 20% IIB (=dicastalure), was 485 times more potent in eliciting male activity than a female sex pheromone gland extract. Reduction in male response to crude extract occurred through exposure of males to glandular IIA and through reduced pheromone volatility caused by extracted triglycerides. Maximum quantities of pheromone were detected in the female sex pheromone gland 6–12 h into scotophase and for at least 30 min into photophase. Significantly greater bioassay responses were elicited by the optimal field combination of 80% IV and 20% IIB than for other ratios tested. Excitation and clasper extension were observed in response to the non-attractive IIB moiety and this indicates a role in close-range mating behaviour for this component. The threshold level of male response was estimated to occur in response to sex pheromone at an aerial concentration of 9·2 molecules IV mm3/s−1. This suggests that aerial concentrations of 102–103 times the male threshold response level may be sufficient to cause successful communication disruption in the field. The problems of relating the non-oriented responses in an assay of this type to directional responses in traps are briefly discussed.
The diurnal activity of the chicken-biting black fly,Simulium griseicolleBecker (Diptera, Simuliidae) in Northern Sudan
Authors: El Bashir S. , El Jack M. H. , El Hadi H. M.
Published: July 2009

The diurnal flight activity ofSimulium griseicolleBecker was determined at Shambat, Khartoum, by means of a suction trap and a vehicle-mounted trap; and the biting activity by means of a chicken-baited trap. Only incidental observations of mammal-biting activity were made. The three trapping methods indicated two peaks of activity, one in the morning and the other late in the afternoon. Fly activity was lowest in the early afternoon when temperature and light intensity were highest, wind speed was moderate and relative humidity was least. Females outnumbered males in all the catches, except in the early morning when more males were sometimes recorded.
The development and termination of the 1968 plague of the desert locust,Schistocerca gregaria(Forskål) (Orthoptera, Acrididae)
Authors: Bennett L. V.
Published: July 2009

The population dynamics of the desert locust,Schistocerca gregaria*(Forsk.), in Africa, the Middle East and Asia from 1966 to 1969 have been analysed to determine the causes of the beginning and the abrupt end of the plague of 1968. Evidence indicates that in 1966 there were no persistent sequences of breeding by gregarious populations, but in 1967 and early 1968 there were four sequences of breeding by initially solitary behaving locusts, each resulting in a substantial increase in numbers and density. These events led to a plague that ended by mid-1969.

The threshold rainfall requirement for successful breeding, defined as an increase in numbers from mature adults of the parent generation to filial fledglings, has been related to the rainfall required for the germination of ephemerals and their growth to sizes that can provide food and shelter for hoppers throughout their development. It is suggested that the minimum quantity of rainfall required initially over a large area is 25 mm. This requirement is usually met in the summer breeding areas. Rainfall in the winter-spring breeding areas is more variable, and falls exceeding the threshold are most commonly associated with deep troughs in the mid- and upper-tropospheric westerly winds in winter and spring. A season in which many such troughs occur may be essential for plague development. It is also suggested that the timing of successive periods of rainfall allowing successful breeding is critical in determining the occurrence of upsurges.

Control against non-gregarious infestations failed to contain the upsurge, but later control measures against hopper bands and swarms contributed to the plague decline. The most economical strategy for plague prevention might be one of upsurge elimination, that is to say control in selected areas against gregarious locusts only. The implications of adopting such a strategy are discussed.
Tsetse (Diptera: Glossinidae) eradication by aerial (helicopter) spraying of persistent insecticides in Nigeria
Authors: Spielberger U. , Na'isa B. K. , Abdurrahim U.
Published: July 2009

The technique of applying persistent insecticides (largely dieldrin or endosulfan) from the air by helicopter against Glossina spp. in northern Nigeria is described. In the Guinea savanna vegetation zone, a high degree of discrimination was practised. Where the riverine species G. tachinoides Westw. and G. palpalis palpalis (R.-D.) only were present, spraying was confined to the fringing forest vegetation along drainage lines and in flood plains. Where the savanna species G. morsitans submorsitans Newst. was also present, Isoberlinia woodlands were also sprayed in swaths along the outside edges and penetrating swaths at maximum intervals of 200 m; the denser vegetation encircling the many flat-topped hills was also sprayed, as well as the main tracks and cattle routes. The more undifferentiated woodlands in the southern Guinea savanna zone were sprayed as a grid with swaths at intervals of 150 to 200 m. The degree of discrimination varied according to the fly species and density of the vegetation; usually 5 to 16% of the totally infested area was actually sprayed. So far, approximately 10 000 km2 have been reclaimed from tsetse by this technique. The degree of reinvasion encountered per annum was approximately 25% of each project area. All reinfested areas have been successfully resprayed. Costs averaged approximately 18 Naira/ha actually sprayed or 2 Naira/ha of reclaimed area in the northern Guinea savanna zone. In the southern Guinea savanna zone, the reclaimed area averaged 3 Naira/ha. The ultra-low-volume spraying technique was introduced in 1972, and this has gradually replaced the conventional spraying technique using emulsion concentrates and booms and nozzles. The ULVA-Bals single-disc atomisers were modified and improved so that droplet sizes within a range of 70 to 200 μm volume median diameter can be produced as required. Many insecticides have been tested in the laboratory, preliminary tests on permethrin indicate; that it may prove to be a useful alternative to dieldrin and endosulfan.
Biology and host specificity of the Chondrilla crown moth, Oporopsamma wertheimsteini (Rebel) (Lepidoptera: Tortricidae)
Authors: Hasan S. , Wapshere A. J.
Published: July 2009

The tortricid moth Oporopsamma wertheimsteini (Rebel) is a potential biological control agent of Chondrilla juncea, which is a serious introduced weed in Australia. The biology of the moth was studied on wild C. juncea growing in Azerbaidzhan (Iran). It has one generation per year and undergoes two periods of diapause, aestivating as a pupa and hibernating as an egg. The larvae live in cases attached to and feeding on the collar region of C. juncea and may destroy plants with thin stems. Larval infestations are common on C. juncea growing in sandy soils. The braconid Chelonus asiaticus Telenga was recorded as a larval parasite. Host specificity assessment by laboratory tests in France, in which trimmed crowns of various Compositae were exposed to late-instar larvae, suggested that they had a broader host range within that plant family than would be desirable in an organism to be used for biological control. However, tests under both field and glasshouse conditions in Iran indicated that the first-instar larvae select only Chondrilla juncea as hosts. The species was therefore introduced into Australia under quarantine for further host-safety studies.
The biology and host specificity of the Echium leaf miner Dialectica scalariella (Zeller) (Lepidoptera: Gracillariidae)
Authors: Wapshere A. J. , Kirk A. A.
Published: July 2009

The gracillariid leaf miner Dialectica scalariella (Zell.), which occurs in Mediterranean Europe, North Africa, the Middle East and the Canaries, is a potential biological control agent for the weed Echium plantagineum in Australia. The moth has a high fecundity and oviposits on the leaves of Echium spp. and other Boraginaceae. The larvae destroy the leaves by forming large bulbous blotch mines. There are 5-7 generations per year. Host restriction of D. scalariella to Boraginaceae was tested by exposing a wide range of cultivated plants considered to be most at risk from it because of their close relation to Boraginaceae, because they were of Australian or non-European origin, because they did not occur in the same ecoclimatic region as D. scalariella, because their entomological fauna was poorly known, and because they or related plants were known to be attacked by insects closely related to D. scalariella. The host restriction of the moth was confirmed as only boraginaceous plants were attacked. It was concluded that both in terms of effectiveness and specificity D. scalariella could serve as a biological control agent in Australia for E. plantagineum.
Radiolsotopes as metabolic labels forGlossina(Diptera: Glossinidae). I. Laboratory determination of the relationship between radioisotope metabolism, respiration and temperature
Authors: Taylor P.
Published: July 2009

The turnover of the radioisotope137Cs is shown to be of a one-component nature and to be positively correlated with temperature for males of bothGlossina morsitansWestw. andG. pallidipesAust. A direct correlation with oxygen consumption is also demonstrated, and the relation for both species may be described by the same regression line. The feasibility of using137Cs as a metabolic label for tsetse is therefore confirmed, and it is suggested that the predictive nature of the relationship between radioisotope turnover and metabolism may extend beyond closely related species.
Mating disruption of the red bollworm of cotton Diparopsis castanea Hampson (Lepidoptera: Noctuidae) by ultra-low-volume spraying with a micro-encapsulated inhibitor of mating
Authors: Marks R. J. , Nesbitt B. F. , Hall D. R. , Lester R.
Published: July 2009

Communication between adult male and female Diparopsis castanea Hmps. was disrupted by ultra-low-volume spraying of cotton in a 0·2-ha field cage and in an open-field plot in Malawi with a polyurea-based microencapsulated formulation of the mating inhibitor 80% (E)- and 20% (Z)-9-dodecenyl acetate (IIA). When sprays containing 38·7 or 105·3 g IIA/ha were applied at 6-day intervals within the cage, reductions in mating of 62–66% and in oviposition of 72–78% resulted. Larval infestation was reduced by an average of 61% over a 52-day period. Effective release rates during these experiments were 4–19 mg/IIA/ha. Spraying at 6-day intervals with 15·9 g IIA/ha, however, had no significant effect on mating, and applications of 25·8 g of IIA/ha at 12–14 day intervals in the presence of high moth populations produced a reduction in female mating of only 19% despite a release rate of 4·4–53·0 mg/ha/h. Physical and chemical evaluations of microcapsule deposition on cotton plants indicated a low application efficiency, with an ‘effective’ spray deposition on plants of only 3·25–20·05% between pre-flowering and maturity. In an open-field spraying trial, applications of 38·7 g IIA/ha at 14–15 day intervals reduced oviposition by 75% from expected levels. Application of 15·7 g IIA/ha, however, had no disruptive effect in the field. Gas-liquid chromatographic analysis revealed no chemical interaction or marked effect on the release rate of IIA when carbaryl and IIA were sprayed in combination. Indirect evidence indicated that the microencapsulated formulations used possessed a considerable ability to withstand rain when applied to plants.
The influence of pheromone trap design and placement on catch of the red bollworm of cotton Diparopsis castanea Hampson (Lepidoptera: Noctuidae)
Authors: Marks R. J.
Published: July 2009

Three suitable sex pheromone trap designs for trapping the red bofiworm of cotton, Diparopsis castanea Hmps., including a simple omnidirectional monitoring trap, are described. In trials in Malawi, Diparopsis was more readily trapped on open horizontal trapping surfaces (water or adhesive) than in enclosed types of traps. The presence of a roof above the trapping surface, at spacings of up to 20 cm, significantly reduced catches. White traps, or unpainted traps in the case of vane traps constructed from galvanised metal, caught more moths than traps of other colours. Catches were greatest when monitoring traps in cotton were placed at ground level or at a height of 0·5 m and, when dicastalure was released from polyethylene vials, by employing a trap 60 cm in diameter. Evidence was obtained that competition may exist between female-baited traps spaced up to 73 m apart, although catches in traps baited with dicastalure were not significantly different when traps were 40–60 m apart. The greatest catches of moths in cotton were in traps located in insecticide-sprayed fields, but moths were also trapped in considerable numbers in other crops and to a reduced extent in open areas 4·8 km from the nearest cotton. From about the end of February, catches in maize, groundnut and fallow areas frequently exceeded the catches recorded within cotton fields, which may indicate an increased dispersal flight from cotton by adult moths later in the season. Weekly replacement in monitoring traps of polyethylene vials containing dicastalure produced maximum moth catches, but there was no significant difference in catch between traps in which pheromone was replaced at intervals of 2, 3, 4 or 6 weeks.
A revision of Tachinaephagus Ashmead (Hymenoptera: Encyrtidae) with descriptions of four new species
Authors: Subba Rao B. R.
Published: July 2009

The encyrtid genus Tachinaephagus is revised, and a key to species presented. Four species are described and illustrated: T. stomoxicida sp. n., a very important parasite of Stomoxys nigra Macq. from Uganda and Mauritius; T. malayensis sp. n. from Malaysia; T. javensis sp. n. from Indonesia; and T. congoensis sp. n. from Zaïre. A lectotype is designated for T. zealandicus Ashm., the type-species of Tachinaephagus, and this genus as defined here is restricted to larval and pupal parasites of Diptera. Zeteticontus, which is superficially similar, is in fact distinct, and characters separating the two genera are tabulated.
Laboratory observations on the bionomics of Aedes fluviatilis (Lutz) (Diptera: Culicidae)
Authors: Cônsoli R. A. G. B. , Williams Paul
Published: July 2009

A laboratory colony of Aedes fluviatilis (Lutz) was established in ambient conditions in Brazil in which temperature varied from 22 to 31°C and relative humidity from 61 to 73%. Females laid eggs 3–13 days (mean 5·6 days) after a blood-meal and produced, on average, 64·3 eggs per batch. Eggs were usually deposited directly on the surface of water and preferentially on water that had previously contained fourth-instar larvae. The eggs proved to have little resistance to desiccation, hatching rates being reduced when eggs were kept on dry filter paper for only 1–3 days. Hatching took place following the detachment of a cap-like portion of the anterior end or through an irregular longitudinal split along the side of the egg. In different experiments, about 10–20% of eggs failed to hatch. Eggs usually hatched 2 days after oviposition. The average length of larval life was 10·2 days, and the highest proportion of larvae pupated on day 9. The duration of the successive immature stages increased geometrically with age. Mortality was 1–2% in each of the first 3 larval instars but rose to about 10% in the fourth. In the larval stage, males developed more rapidly than females. Crowding lengthened the duration of the larval stage, reduced the numbers surviving to pupate and resulted in a disparate sex ratio with emergent males much more abundant than females. Pupation occurred throughout the day and night with a slight peak at 05.00–06.00 h. The pupal stage lasted 1–3 days, usually 2 days, and was the same in both sexes.
Effects of host spectra on feeding behaviour and reproduction of soft ticks (Acari: Argasidae)
Authors: Galun Rachel , Sternberg S. , Mango Christine
Published: July 2009

Argas persicus (Oken) fed readily on avian hosts and consumed more blood and produced more eggs than on mammalian hosts. Ornithodoros tholozani (Lab. & Mégn.) fed equally well on chicken and various laboratory animals and converted the blood of all hosts into eggs at equal rates. O. moubata (Murr.) was intermediate, feeding more readily on chicken, rabbit and guineapig than on mouse, rat or hamster, and showing greater utilisation of blood of chicken and rabbit than of the other hosts. The relation of these phenomena to the natural host spectra of the 3 tick species is discussed.