bluuebunny/crossref_metadata_2025 huggingface dataset:
Field evaluation of gossyplure, the synthetic sex pheromone of Pectinophora gossypiella (saund.) (Lepidoptera, Gelechiidae) in Malawi
Authors: Marks R. J.
Published: July 2009

The synthetic sex attractant of the pink bollworm of cotton, Pectinophora gossypiella (Saund.) (Lepidoptera, Gelechiidae), is a mixture of (Z, Z) and (Z, E)-7, 11-hexadecadien-l-ol acetate, referred to as gossyplure (Hummel et al., 1973). Field trials in the Lower Shire Valley, Malawi, have shown that of various mixtures tested, 55–60% of the (Z,Z) isomer in a mixture of the two acetates gives maximum field attraction. The catches of both pink bollworm males and males of the red bollworm of cotton, Diparopsis castanea Hmps., in pheromone traps are not affected by the release of mixtures of the pheromones of both species together. Dual-purpose sex pheromone traps may therefore be used to monitor both pest species at the same time. A simple omnidirectional flat disc trap is as efficient in trapping pink bollworm males as more complex designs. Release of gossyplure from a sealed 2·5 ml polyethylene vial or from a Zoecon beem-polyethylene vial is more efficient than from narrow-bore teflon capillary. Presence of the antioxidant 2,6-di-tert-butyl-P-cresol at 8·4% w/w gossyplure does not increase the attractive life of the pheromone in the field. Considerable numbers of the Angoumois grain moth Sitotroga cerealella (Ol.) (Tineidae), together with a new species of gelechiid, were occasionally caught by gossyplure lures in cotton fields. Catches of pink bollworm are not influenced by moonlight or trap colour but are significantly influenced by trap area. Maximum catches of males occur between midnight and 04.00 h in June and between 01.00 and 05.00 h in August.
The influence of behaviour modifying chemicals on mating success of the red bollworm Diparopsis castanea Hmps. (Lepidoptera, Noctuidae) in Malawi
Authors: Marks R. J.
Published: July 2009

The synthetic sex pheromone (dicastalure) of the red bollworm of cotton, Diparopsis castanea Hmps., in Central and Southern Africa, and an inhibitor of male sexual attraction (trans-9-dodecenyl acetate,=IIA), were used in an enclosed 0·2 ha cotton field-cage to reduce successful female matings. Over one month dicastalure at 21·0 and 42·3 g/ha produced average reductions in mating of 47·9% and 72·5% respectively and 37·9 g IIA/ha produced an overall reduction in mating of 71·5%, or 79·5% in released moth populations, over the same period. The proportion of virgin females present in disruption situations was significantly greater than in untreated populations and was density-independent for moth populations of up to 2 200/ha. The proportion of fertile eggs in disruption situations was correspondingly reduced to 30·2% from an average of 67·9% in control cycles. Reduction in sex pheromone trap catches is an unsatisfactory indicator of the extent to which males are prevented from inseminating females and considerably over-estimates the true degree of disruption. This is the first time that a naturally occurring inhibitor has been used successfully to disrupt mating in a field population of insects and it indicates the potential of the method for the control of high density pest populations in cotton. However, use of polyethylene dispensing mechanisms similar to those used in the field-cage disruption experiments would be unsuitable as a practical method of dispensing behaviour modifying chemicals and it is suggested that, for suitably controlled release of such chemicals, currently available microencapsulation technology offers the best prospects.
Effects of groundnut crop density on the population dynamics of Aphis craccivora Koch (Hemiptera, Aphididae) in Malawi
Authors: Farrell J. A. K.
Published: July 2009

Three plant spacings, 30 cm, 7·5 cm and 2·5 cm within rows 90 cm apart, equivalent to about 36, 143 and 430 thousand plants/ha respectively, were used in three field trials on the population dynamics of Aphis craccivora Koch on groundnuts at Chitedze, Malawi in 1964–1967. Aphid density per infested plant was consistently higher, while numbers of aphid-infested plants per unit area were consistently lower, in 30 cm than in 2·5 cm spacing. Aphid numbers per unit area increased to similar levels at all spacings in crops under 40–50 days old, but subsequently aphid density was consistently lower in 2·5 cm than in 30 cm spacing. This effect could not be related to the intensity of fungus disease infection, parasitism, predation, the availability of feeding sites or the rate of emigration. Aphid groups were, however, consistently smaller in 2·5 cm than in 30 cm spacing in one trial. The potential rate of increase was studied in two trials using the methods of Hughes (1962), and was found to be consistently lower in 2·5 cm than in 30 cm spacing. The rate of plant growth was relatively depressed in 2·5 cm spacing, particularly after 40 days. The effect of spacing on aphid numbers was attributed to the effect of host-plant condition on the potential rate of increase.
Effects of intersowing with beans on the spread of groundnut rosette virus by Aphis craccivora Koch (Hemiptera, Aphididae) in Malawi
Authors: Farrell J. A. K.
Published: July 2009

In two trials, at Chitedze, Malawi, in 1966–1967, the spread of rosette virus disease in groundnuts (Arachis hypogaea) intersown with field beans (Phaseolus vulgaris) was less than the spread in groundnut monocultures comprising plant populations equivalent to the number of groundnut plants and to the total number of plants in the intersown crop. In one trial, numbers of early rosette transmissions were related to numbers of alate Aphis craccivora Koch, the vector of the virus, found on groundnut plants. Immigrant alate A. craccivora settling on the intersown crop were trapped by the hooked epidermal hairs of the bean plants and the observed reduction of rosette infection in the intersown crop was attributed to this effect. Inter-sowing with beans is considered less effective than early-sown, high-density monoculture as a method of reducing groundnut rosette infections and yields of groundnuts from inter-sown crops may be lower than those obtained from high-density monoculture.
Resting sites of Glossina morsitans morsitans Westwood (Diptera, Glossinidae) during the dry season in the Republic of Zambia
Authors: Okiwelu S. N.
Published: July 2009

Resting site preferences of adult Glossina morsitans morsitans Westw., the dominant species in the Republic of Zambia, were observed during the cool (May–August) and hot (September–October) dry seasons in 1974 at the Chakwenga Game Reserve. Tanglefoot was used to trap resting flies on boles, branches, bushes (undergrowth), canopies, fallen logs and in ant-bear holes.

All resting flies were collected below 4 m and there was an inverse relationship between numbers of resting flies and height of resting sites on boles, branches and canopies. Most flies were collected betwen 06.00 and 09.00 h, except in ant-bear holes, where no flies were found. No significant differences existed between numbers of flies collected from the four cardinal positions on boles. Although more flies were found on shaded than unshaded fallen logs and bushes, the differences were only statistically significant for fallen logs. Numbers of flies on various tree species were generally not significantly different. Boles, bushes and fallen logs were the most preferred sites.
The night resting sites of the tsetse fly Glossina palpalis palpalis (Robineau-Desvoidy) (Diptera, Glossinidae) in northern Nigeria
Authors: Scholz E. , Spielberger U. , Ali J.
Published: July 2009

The night resting sites of Glossina palpalis palpalis (R.-D.) were observed in a riverine swamp at Bara, Bauchi Emirate, northern Nigeria. The flies were marked with an ultra violet reflecting paint and released at dusk. They were detected with the aid of an ultra violet light beam. Most of the flies (72%) rest on leaves (50% on the upper sides) and on small twigs and creepers (20·2%). The average resting height was highest in the mid-rains (3·78 m), dropped in the late rains (2·95 m) and was lowest (1·52 m) in the dry season.

The resting site heights ranged from ground level up to 18 m. Females were found to rest slightly higher than males and when the moon shone both sexes had a tendency to perch higher. It was shown that the night resting behaviour of G. palpalis is favourable to the application of residual insecticide deposits from the air because most of the spray drops are deposited on leaves.
Comparative bionomics of adult austrostmulium pestilens Mackerras & Mackerras and A. bancrofti (Taylor) (Diptera, Simuliidae)
Authors: Hunter D. M. , Moorhouse D. E.
Published: July 2009

Large numbers of adult Austrosimulium pestilens Mack. & Mack, appear about a week after floods in permanent and temporary waterways and, because of the short period when stream flow remains suitable for oviposition, mating, feeding and egg maturation take place near the river where they breed. Most flies emerge early in an outbreak and fly to mating swarms at trees beside or near the river. After obtaining a blood meal from any of a number of mammal species nearby, females return to 1–5 m tall trees at the river's edge to mature their eggs in an unusually short time of 24 h. Although this species prefers rapidly flowing water, immatures also survived in trickles remaining after floods had passed, though the resulting adults took longer to develop and were smaller than normal. The closely related A. bancrofti (Tayl.) lives in more permanent waterways and disperses away from its breeding sites soon after emerging, concentrating in highest numbers on hills as far as 10 km or more from its nearest major breeding site. Catches in CO2-baited traps were influenced by temperature, wind, light intensity and rain. Although A. pestilens bit man and many mammals, A. bancrofti did not bite any vertebrate tested. In CO2-baited traps where man was present, there were large fluctuations in the catch of A. pestilens from minute to minute, while the catch of A. bancrofti decreased steadily.
Competitiveness of chemosterilised males and cytoplasmically incompatible translocated males of Culex pipiens fatigans wiedemann (Diptera, Culicidae) in the field
Authors: Grover K. K. , Curtis C. F. , Sharma V. P. , Singh K. R. P. , Dietz K. , Agarwal H. V. , Razdan R. K. , Vaidyanathan V.
Published: July 2009

A technique, based on the release and recapture of marked females, was used to measure the mating competitiveness of sterile males of Culex pipiens fatigans Wied. in villages in Delhi Union Territory, India. Experiments were carried out with chemosterilised and cytoplasmically incompatible translocated (IS-31B) males simultaneously with prolonged release trials with these two types of male. The fertile males in the tests were the indigenous population and the females used were in most cases of wild origin. With each type of male, one test was conducted with a moderate (ca. 13:1) ratio of released to wild males and the other tests used high (ca. 40:1) ratios. The estimated mean mating competitiveness of IS-31B males was somewhat higher than that of chemosterilised males, but the difference was found to be non-significant using a specially devised method of testing statistical significance. In the four experiments 77–94% of the egg rafts laid by recaptured females were sterile, indicating that both types of sterile male were sufficiently competitive to induce a high level of egg sterility in an isolated wild population.
Assessment of the use of sex pheromone traps to time chemical control of red bollworm, Diparopsis castanea Hampson (Lepidoptera: Noctuidae) in Malawi
Authors: Marks R. J.
Published: July 2009

Experiments in Malawi over several seasons indicated that use of sex pheromone baited traps would be an unsatisfactory method for the more efficient timing of insecticide applications against Diparopsis castanea Hmps. Excessive temporal and spatial variation between catches of male moths in pheromone traps and corresponding oviposition by females on cotton renders the method unreliable. Experiments indicated, however, that fewer sprays of insecticide against Diparopsis could be applied without significant loss of yield or quality by spraying when the numbers of eggs of Diparopsis reached 0·25/plant. It is suggested that modification of the existing method of egg scouting on plants offers the best prospect for efficient control of Diparopsis concomitant with the increasing demand by farmers for reduced spraying.
A revision of the genus Chaetanaphothrips Priesner (Thysanoptera: Thripidae)
Authors: Pltkin B. R.
Published: July 2009

The genus Chaetanaphothrips Priesner, comprising seven species and including pests of bananas, tea and orchids, is revised, and a key is provided for their identification. The host preferences and distribution of each species are discussed briefly.
Feeding responses of tsetse flies (Diptera: Glossinidae) to stationary hosts
Authors: Vale G. A.
Published: July 2009

An incomplete ring of electrocuting nets was placed round various mammals stationed singly in woodland infested with Glossina morsitans morsitans Westw. and G. pallidipes Aust. in the Zambezi Valley in Rhodesia. Catches of fed and unfed flies made on the inside and outside faces of the nets were used to estimate the number and nutritional status of flies travelling to and from the baits. The validity of these assessments was investigated by studying the responses of the flies to the netting frame, and the effects of different heights and arrangements of nets. The percentages of recently fed flies in samples leaving various mammals were: ox 33–61, donkey 51, sedated ox 42, kudu 41, washed ox 34, warthog 19, sedated goat 15, ox with three men 12, bushpig 8, buffalo 5, ox sprayed with repellent 4, bushbuck 2, goat 1, sheep 1, impala 0. With the ox, the proportion of fed flies fell by one-third when the number of tsetse attracted to the ox increased 4·5-fold to the point where the ox became intolerant. Effects of time of day and season on the proportion of flies feeding are discussed.
Metabolism of U-14C-phenylalanine and U-14C-tyrosine by females of Glossina morsitans Westwood (Diptera: Glossinidae) during pregnancy
Authors: Moloo S. K.
Published: July 2009

After injections of U-14C-phenylalanine into the haemolymph of female Glossina morsitans Westw. during late pregnancy, radioactivity was detected in the post-parturient female and its larval offspring in the injected material and in lipids, a range of non-essential amino acids and tyrosine. After intrahaemocoelic administration of U-14C-tyrosine, radio-activity was detected in the adult and larva in all these nutriments except phenylalanine. The level of radioactivity in the larva was higher than that remaining in the female parent, and in both radioactivity was greater in amino acids than in the lipid fraction. Radiometric analysis of the oocyte and the infra-uterine larva 24 h after injection of labelled phenylalanine or tyrosine on different days of the pregnancy cycle revealed patterns of radioactivity relative to their respective growth characteristics. The rate of phenylalanine utilisation by the pregnant female for nourishment of the in-utero third-instar larva was significantly higher than the rate of tyrosine utilisation. For both labelled materials, there was a significantly higher utilisation for energy during early than during late pregnancy, but at both physiological ages tyrosine was metabolised for energy to a relatively greater degree. Uric acid is the main nitrogenous waste product of aromatic amino acid metabolism in this insect, though a very low level of activity was also detected in the amino acid fractions of the excreta from females in early and late pregnancy.
Foraging and grass selection by the grass-cutting ant Acromyrmex landolti fracticornis (Forel) (Hymenoptera: Formicidae) in habitats of introduced forage grasses in Paraguay
Authors: Fowler H. G. , Robinson S. W.
Published: July 2009

Colony densities of Acromyrmex landolti fracticornis (Forel) were found to vary in habitats of introduced forage grasses in central Paraguay. Colony densities were found to be positively correlated with basal grass coverage and the amount of grazing damage. The ants preferentially harvested tender grass blades that showed little or no previous damage by other invertebrates. Colony densities and the amount of grazing damage by the ants showed negative correlations with the amount of grazing damage by other invertebrates. Preferences were determined for 13 species of exotic forage grasses. In both laboratory and field tests, Digitaria smutsii and Panicum maximum were selected significantly more often than other species, and Pennisetum purpureum, P. ciliare and Brachiaria decumbens were selected significantly less often. The preferences observed in the laboratory were also observed in field colonies. The importance of these factors in determining colony density and their practical implications on the Paraguayan cattle industry are discussed.
Tests of pyrethroid vaporising mats against Aedes aegypti (L.) (Diptera: Culicidae)
Authors: Chadwick P. R. , Lord C. J.
Published: July 2009

Vaporising mats are used to volatilise small amounts of pyrethroid to prevent mosquito nuisance within houses. A small absorbent mat containing pyrethroid is placed on a 5- to 6-W electric heater. The mat surface temperature is about 125°C. Pyrethroid is released for several hours at a slowly diminishing rate. In tests, no evidence of degradation of bioallethrin was obtained. Vapour from mats inhibited biting by female Aedes aegypti (L.) and caused knockdown and kill. A commercial mat containing 88 mg allethrin was as effective as a mosquito coil containing 0·25% allethrin. In laboratory-made mats, 40 mg bioallethrin or 19 mg S-bioallethrin gave equal or better action than allethrin. Additives, such as piperonyl butoxide, mineral oil or antioxidant slightly reduced the rate of emission of pyrethroid and diminished the bite inhibitory and knockdown effects.
Mathematical model of the survival rates of female bushflies (Musca vetustissima Walker) (Diptera: Muscidae) as inferred from field populations
Authors: Sands P. , Hughes R. D.
Published: July 2009

The survival rate of the females of Musca vetustissima Wlk., the Australian bushfly, was determined as a function of age and size from an analysis of the age-size distribution of 11 530 females caught over a period of four years at three sites in south-eastern Australia. The mean length of life of the largest female flies commonly observed in the field was about 15·5 egg-stage periods, as compared to 8·5 for the smallest flies commonly observed. Over the same range of sizes, the breeding potential of a female varied by a factor of 22 to 1. It was found that the attractiveness of a human observer as a bait to female flies varied with the flies' reproductive state; taking the attractiveness to newly emerged flies to be unity, the attractiveness of the observer to flies that had just laid eggs was 1·22, and to flies in the pre-gravid stage 0·15. The mathematical model presented in this paper is appropriate for use in an overall model of bushfly population dynamics.
Varietal differences in the susceptibility of cowpea to larvae of the seed moth, Cydia ptychora (Meyrick) (Lepidoptera: Tortricidae)
Authors: Perrin R. M.
Published: July 2009

Glasshouse and field screening showed that several varieties of cowpea (Vigna unguiculata) in the germplasm collection at the International Institute of Tropical Agriculture at Ibadan, Nigeria, had promising levels of resistance to damage by larvae of Cydia ptychora (Meyr.). There was no preference between varieties for oviposition in the glasshouse, but varietal differences in damage to pods and seeds occurred due to differences in the pod-boring and seed-feeding success of larvae. Large numbers of seeds per pod in some varieties diluted the effects of a given larval density and resulted in low percentages of damaged seed. A measure of relative susceptibility was devised that overcame the problem of chance escape from attack by certain pods. Resistance in glasshouse screening was not necessarily related to resistance in the field, where plant growth habits and the ecological requirements of the adult moths are more fully expressed and play an important role in determining the outcome of the plant-insect interaction. The most resistant variety in the glasshouse, Vita-3, was least resistant in the field, partly because it was partially photosensitive and produced few flowers and pods in the early growing season in Ibadan. Two varieties, TVu 946 and TVu 2994, may have escaped severe attack by maturing quickly. The former is small-leaved, non-vigorous, carries its pods on long peduncles well above the foliage and consequently constitutes an unsuitable habitat for daytime sheltering by adults. It was the least damaged variety in the field trial. The latter was most attacked by other pod-feeding pests, and the consequent reduction in seed weight and quality appeared to enhance the level of damage caused by C. ptychora.
Larval release method for genetic control of the Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae).
Authors: Foster G. G. , Whitten M. J. , Vogt W. G. , Woodburn T. L. , Arnold J. T.
Published: July 2009

A method for releasing genetically altered strains of Lucilia cuprina (Wied.) as free-falling larvae from aircraft was tested. Full-fed genetically marked third-instar larvae were released from aircraft flying at a height of 150 m and speeds of 120 or 220 km/h. Progeny tests of adult flies trapped subsequently indicated that released male larvae survived to the adult stage and were competitive with wild males for females.
Enzyme variation in theAnopheles gambiaeGiles group of species (Diptera: Culicidae)
Authors: Miles S. J.
Published: July 2009

The genotypes of chromosomally-identified individuals from natural populations of the known species of the group ofAnopheles gambiaeGiles were scored for the enzyme protein structural loci coding for adenylate kinase (Adk), α-naphthyl acetate esterase (Est-1, Est-2, Est-3), glutamic-oxaloacetic transaminase (Got), α-glycerophosphate dehydrogenase (αGpd), hexokinase (Hk), isocitric dehydrogenase (Idh), lactic dehydrogenase (Ldh), ‘leucine’ aminopeptidase (Lap-2), malic enzyme (Me), octanol dehydrogenase (Odh), phosphoglucomutase (Pgm-1, Pgm-2), 6-phosphogluconic dehydrogenase (6-Pgd), phosphohexose isomerase (Phi) and superoxide dismutase (Sod), following starch gel electrophoresis. In the material examined,Est-1, Est-2, Est-3, Got, ldh, Lap-2, Odh, Pgm-1, Pgm-2andSodwere segregating for two or more alleles; unique alleles at theEst-1, GotandSodloci produced species-specific phenotypes inA. melas(Theo.), species C and species D, respectively. The further sampling ofA. merusDön, populations supported the presence of a unique SOD phenotype by which this species can also be identified. Of the other enzyme systems examined, no activity following electrophoresis was detected for aldolase and fructose-1,6-diphosphatase, and the resolution of acid and alkaline phosphatase, glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, malic dehydrogenase and xanthine dehydrogenase was too poor under the particular electrophoretic conditions for genetic analyses of the enzyme phenotypes.
Evaluation of a new technique for recording the direction of flight of mosquitoes (Diptera: Culicidae) in the field
Authors: Gillies M. T. , Jones M. D. R. , Wilkes T. J.
Published: July 2009

In a study in the Gambia on the relationship between wind direction and the direction of flight of mosquitoes, high-voltage electric grids were used as screens in conjunction with suction traps. Mosquitoes contacting or attempting to fly through the grids were electrocuted. The screening efficiency of the grids was estimated to be 75–80%, and the grids had no demonstrable effect on wind speed. The traps were set up in pairs with their mouths at ground level, one trap in each pair being screened on the upwind and the other on the downwind side. In this way, the mosquitoes could be segregated into those that were flying predominantly upwind and predominantly downwind, respectively. The results indicated that some 64% were flying upwind at this level, but this proportion varied considerably over a period of days, with nightly extremes of 87 and 43%; there was little difference between species. This variation was not correlated with wind speed, but there was some evidence that the presence of moonlight led to a greater degree of upwind flight.
Courtship and mating behaviour of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae)
Authors: Khasimuddin Syed
Published: July 2009

Laboratory-bred males of Spodoptera exempta (Wlk.) required at least 48 h after emergence before responding to females, whereas wild-caught males matured in 24 to 36 h; laboratory-bred females took 60 h, whereas wild-caught females were sexually attractive to males 48 h after emergence. Mating only occurred between 00.30 and 03.00 h. Females exhibited a courtship behaviour involving ‘calling’, and the males exhibited a series of pre-mating behavioural responses, probably characteristic of physiological levels of excitement by the female's ‘calling’. Experiments showed that a male can mate with and inseminate only one female each night. The number of females inseminated by any male was related to the male's life-span and was very variable. The fertility of eggs laid by a female was not affected by the age of the male she mated with. A single mating was sufficient for the fertilisation of a life-time's production of eggs by a female.
Physiological age-grading in females of the dung beetle Euoniticellus intermedius (Reiche) (Coleoptera: Scarabaeidae)
Authors: Tyndale-Biscoe Marina
Published: July 2009

Newly emerged females of Euoniticellus intermedius (Reiche) have no differentiated oocytes in their single ovariole. The eggs mature sequentially during the maturation period, and at 27°C the first egg is laid 4–8 days after emergence. The rate of oviposition increases with temperature between 18 and 32°C. The threshold for oviposition is 19·6°C, and one egg is produced for every four day-degrees above this threshold. Most females can be sorted into the nulliparous or one of three parous categories, covering the period from emergence to the time when between 75 and 127 eggs have been deposited, on the basis of the quantity of yellow body in the ovariole. The hardness of the cuticle, the degree of oocyte development, and the presence or absence of fat-body in the abdomen can be used to subdivide the nulliparous category into three parts and to recognise old or ‘spent’ beetles. The degree of wear on the tibial teeth gives an age estimate that is independent of nutritionally induced delays and with which the ovarian age can be compared. Actual age cannot be estimated in field-caught-beetles, however, since many factors besides temperature alter the rate of brood production.
Wing dimorphism and flight in Zonocerus variegatus (L.) (Orthoptera: Pyrgomorphidae)
Authors: Chapman R. F. , Cook A. G. , Mitchell G. A. , Page W. W.
Published: July 2009

Adults of Zonocerus variegatus (L.) from the dry-season population in southern Nigeria were shown to exist in two forms, one with relatively long wings and the other with relatively short wings. The wet-season population normally existed as the short-winged form, but the insects had the capacity to develop long wings. Long-winged insects had welldeveloped flight muscles and were capable of flight. Flight in the field occurred before sexual maturation and may have led to downwind displacement of individuals over considerable distances.
Estimation of age of females in field populations ofLucilia cuprina(Wiedemann) (Diptera: Calliphoridae) using ambient temperature and solar radiation
Authors: Woodburn T. L. , Vogt W. G. , Kitching R. L.
Published: July 2009

A previously published method for determining the physiological age of femaleLucilia cuprina(Wied.), based on a linear relationship between their rates of ovarian development and temperature, was tested under field-cage conditions. It was found that ovarian development was more rapid than that predicted by thermal summation based on ambient temperature. A re-examination of the rate of development-ambient temperature relationship, over a wider temperature range that that used previously, showed that the development threshold temperature was 8·2°C rather than 11·3°C. Thermal summation using the revised threshold also fell short of the observed day-degree totals. An effective temperature for ovarian development (ambient temperature plus a temperature excess proportional to the incoming solar radiation intensity) was fitted to the data from the field cage. This relationship gave accurate predictions of ovarian development (±8%) for flies that were released into the field.
Description of the developmental stages of Sosylus spp. (Coleoptera: Colydiidae) from New Guinea, parasites and predators of ambrosia beetles (Coleoptera: Platypodidae)
Authors: Roberts Hywel
Published: July 2009

A description is given of some of the developmental stages of Sosylus vicinus (Grouv.), S. silius Hinton and S. reflexus Pope from Papua New Guinea. At least three instars are recognised in all species, and the first or primary instar is of the triungulin type. A triungulin is also reported as the primary instar of another colydiid, Asosylus rhysodoides (Pasc.). This is the first time triungulins have been found in the coleopterous family Colydiidae. Differences in the triungulin of the three species of Sosylus are recognised, based on the form and arrangement of segmental spines. The structure of the different instars with regard to their habits on the host is discussed, and a brief comparison is made with larvae of Meloidae and Rhipiphoridae, the only two other families of Coleoptera with triungulin first-instar larvae.
Andaspis dasi Williams identical with A. numerata Brimblecombe (Hemiptera: Diaspididae), a species found on tea and associated with the fungus Septobasidium
Authors: Williams D. J.
Published: July 2009

Andaspis dasi Williams, which was described from India, is made a synonym of A. numerata Brimblecombe, which was described from Australia. The species is now known from several localities and host-plants in the Pacific area and is often found on tea. A short account is given of its association with the fungus Septobasidium in Papua New Guinea.
Observations on scale insects (Homoptera: Coccoidea) of the Middle East*
Authors: Ben-Dov Y.
Published: July 2009

Observations on the taxonomy, distribution and host-plants of scale insects of several taxa in the Middle East are reported. A lectotype is designated for Bodenheimera rachelae (Bodenh.). Coccus capparidis (Green) is recorded for the first time from Israel and the Mediterranean region. C. arens Hodgson is a new synonym of C. capparidis. C. pseudo-magnoliarum (Kuw.) is recorded from Israel and France. The genus Paralecanopsis is regarded as a subjective synonym of Lecanopsis. Archaspis is synonymised with Quadraspidiotus and Archaspis ephedrae Bodenh. with Quadraspidiotus cecconii (Leonardi). The identity of Diaspis capparidis Bodenh. is established, the species is transferred to Rungaspis, and R. trabuti Balachowsky synonymised with it. R. macrolobis Kaussari is redescribed and a lectoype designated; it is recorded from Israel. A key is given to the three species of Rungaspis, and Sinaidiaspis is synonymised with this. Pseudococcus lindingeri Bodenh. is transferred to Planococcus, and Planococcus variabilis (Hall) synonymised with it. Trionymus internodii (Hall) is recorded for the first time from pineapple and from Israel.
Flight as a factor in the host-finding behaviour of tsetse flies (Diptera: Glossinidae)
Authors: Vale G. A.
Published: July 2009

The numbers of Glossina pallidipes Aust. and G. morsitans morsitans Westw. flying in and out of a large clearing in Zimbabwe were estimated from catches on unbaited electrified nets placed on the perimeter of the clearing. By estimating the numbers of flies that would encounter visual and olfactory attractants in the middle of the clearing, and from measurements of the numbers caught responding and estimates of the efficiency with which responding flies were caught, it was calculated that 80–100% of flying tsetse responded to stimuli they encountered. The importance of flight as a means of encountering host stimuli in woodland and open areas, and with mobile and stationary baits, is discussed.
Life-cycle studies on Paulinia acuminata (DeGeer) (Orthoptera: Pauliniidae) with particular reference to the effects of constant temperature
Authors: Thomas P. A.
Published: July 2009

The effects were examined of constant temperature on the life-cycle of Paulinia acuminata (Deg.), a potential biological control agent for Salvinia molesta. Over the range of temperatures tested (25–36°C), the duration of the life-cycle varied from approximately 85 days to 38 days. Egg development was most rapid at 33–36°C, but percentage hatch was greatest at 33–34°C. The duration of the nymphal period continued to decrease up to 36°C. The optimum temperature for nymphal development appeared to be higher than for eggs since temperature did not significantly affect nymphal mortality, which was about 50%. There were sometimes five and sometimes six instars, six being rather more common at lower than at higher temperatures. Crowded nymphs developed more slowly than isolated ones. Population growth rate statistics were calculated by combining data from several series of experiments. In an attempt to predict the results of a release of Paulinia at Lake Kariba between Zambia and Zimbabwe, these statistics were related to the mean annual temperature on the lake. It was estimated that P. acuminata would undergo three generations a year, with the population increasing by a factor of 8000 per annum.
Hybridisation studies on sibling species of the Anopheles gambiae Giles complex (Diptera: Culicidae) in the laboratory
Authors: Okereke T. A
Published: July 2009

Assortative mating amongst species of the complex of Anopheles gambiae Giles that occur sympatrically in West Africa was investigated in laboratory mating-choice experiments using dieldrin resistance and hybrid sterility as genetic markers. In competition experiments involving A. gambiae and A. arabiensis Patt., mating was found to be assortative. No effect of cage volume was observed on the operation of the specific mate-recognition system. On the other hand, experiments in which A. gambiae and A. arabiensis were caged separately with A. melas Theo. failed to show the presence of mating barriers known to operate in nature. Similar cage experiments conducted with two different strains of A. gambiae showed that there was no marked mating barrier between the strains. Other experiments showed that hybrid females from the cross between A. gambiae females and A. arabiensis males and the reciprocal cross would mate with both parental types as well as their own males in cages.
Release and establishment of the baculovirus disease of Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae) in Papua New Guinea
Authors: Gorick B. D.
Published: July 2009

Oryctes rhinoceros (L.) is a major pest of coconut palms in Papua New Guinea but has a limited distribution within the country. Pre-release monitoring showed that no baculovirus disease was present in the country prior to its importation. A consignment of O. rhinoceros larvae infected with a baculovirus disease was imported into Papua New Guinea from Western Samoa in 1977. The virus proved highly infectious to both larvae and adults of the local population of O. rhinoceros. During 1978 and 1979, adults were perorally infected with the baculovirus and released at nine sites on Manus Island, four sites on New Ireland and twelve sites on the Gazelle Peninsula of East New Britain. The infected adults were active disseminators of the virus into the field population, and the virus became established at nearly all the release sites. The shortest time between virus release and recapture of newly infected adults from a release site was eight weeks. Three different examples indicated the virus spread at approximately 1 km/month. During a fourteen-week period in the early establishment phase, significantly more females than males were collected in traps but a significantly higher percentage of the males was infected.
Population dynamics of pine woolly aphid, Pineus pini (Gmelin) (Hemiptera: Adelgidae), in Kenya
Authors: Mailu A. M. , Khamala C. P. M. , Rose D. J. W.
Published: July 2009

The population dynamics of Pineus pini (Gmel.) was examined in two locations in the Kenya Highlands where the mean annual precipitation ranges from 620 to 1400 mm. Variations in population densities were related to rainfall. Generally, there was a marked decrease in population during the three months of heavy rainfall in March to May and a significant increase during dry weather from August to October. This was followed by a slight decrease in the rate of population build-up, until the long rains in April again resulted in another population collapse. Nine species of predatory insects were identified, and population fluctuations of the most common of these, Exochomus spp., was studied. Predators seemed to remove about 12% of the aphid population. Other mortality factors included heat and crawler dispersion. The greatest mortality occurred early in the life-cycle and was mainly due to eggs and crawlers being washed off the host-tree by rain.
Seasonal changes in mite (Acari) and fungal populations in aerated and unaerated wheat stored for three years
Authors: Hurlock E. T. , Armitage D. M. , Llewellin B. E.
Published: July 2009

In experiments at Slough, southern England, one hundred tonnes of wheat at about 14% moisture content were divided between six similar metal bins, three of which were aerated during the winter. Observations were made on the mite and fungal populations and physical conditions for an uninterrupted storage period of three years. During the winter, the wheat in the aerated bins was 2–4°C cooler than that in the unaerated bins and it always had a moisture content 0·5–1% higher, except at the surface where it was usually drier. Aeration appeared to delay the increase of Acarus siro L. and Lepidoglyphus destructor (Schr.) for 4–6 months after harvest, but few individuals survived into the second year of storage in any bin. Cheyletus eruditus (Schr.) and Tydeus interruptus Thor were present after one year and were most numerous in the aerated bins. The distribution within the bins of the different species of mites varied with season. A greater increase in storage fungi occurred in the aerated bins than the unaerated. Members of the Aspergillus glaucus and A. restrictus groups, Penicillium spp. and Wallemia sebi were the commonest fungi.
The age-structure and biting behaviour of Stomoxys calcitrans (L.) (Diptera: Muscidae) from Manaus, Brazil
Authors: Charlwood J. D. , Lopes J.
Published: July 2009

The physiological age of female Stomoxys calcitrans (L.) caught biting horses during seven all-day catches and 20 catches in the morning or afternoon during the rainy season (January-July) in Manaus, Amazonas, Brazil, was determined by examination of their ovaries. Males and unmated females with undeveloped ovaries had similar biting patterns, with peaks of activity in the early morning and late afternoon, when the relative humidity was between 50 and 80%. Nulliparous inseminated females with ovaries at Stages II to V attacked throughout the day, with no pronounced peaks, whereas parous females showed a peak of biting in the late morning and early afternoon. The majority of parous flies had oviposited less than four times and had distended overiolar sacs, indicative of recent oviposition.
Forty generations of inbreeding of Glossina morsitans morsitans Westwood (Diptera: Glossinidae)
Authors: Jordan A. M.
Published: July 2009

A single male and female were removed from a well-established laboratory colony of Glossina morsitans morsitans Westw. and became the parents of an inbred stock. In general, each subsequent generation comprised ten randomly selected females mated to one of three randomly selected males, both sexes being offspring of the preceding generation. The inbred stock was fed on the ears of rabbits for 40 generations, over a period of almost eight years. Performance, in terms of length of female life, female fecundity, number and weight of puparia produced, effective emergence rate from puparia and sex ratio of emerged flies showed little variation between generations. By generation 40, the inbreeding coefficient was 0·9347; over the same eight years, the inbreeding coefficient of the parent colony of G. m. morsitans was less than 0·0303. It is concluded that the risks of inbreeding having deleterious effects on laboratory colonies of Glossina are slight.
Field studies of the responses of tsetse flies (Glossinidae) and other Diptera to carbon dioxide, acetone and other chemicals
Authors: Vale G. A.
Published: July 2009

In studies in the Zambesi Valley, Zimbabwe, carbon dioxide alone dispensed at 2·5 to 15 litres/min, or acetone alone dispensed at 0·3 to 300 g·h, increased by up to six times the catches of Glossina morsitans morsitans Westw, and G. pallidipes Aust. from stationary biconical traps, stationary electrocuting traps used with and without a visual target, and a mobile party of hand-net catchers. Catches were increased further when the chemicals were dispensed together. Carbon dioxide at 2·5 litres/min plus acetone at 15 g/h was about half as effective as ox odour for enhancing the catches from an electrocuting trap plus target; the efficacy of carbon dioxide at 15 litres/min plus acetone at 300 g/h was not significantly different from that of ox odour. Several short-chain ketones, and also formaldehyde and propionaldehyde, were attractive. Several long-chain ketones, and also heptaldehyde and caproic acid, were repellent. Carbon dioxide was attractive for Tabanidae, Stomoxyinae and non-biting Muscidae. Acetic acid was repellent for Stomoxyinae and non-biting Muscidae.
Catches of Glossina morsitans morsitans Westwood and G. pallidipes Austen (Diptera: Glossinidae) in odour-baited traps in riverine and deciduous woodlands in the Zambesi Valley of Zimbabwe
Authors: Hargrove J. W. , Vale G. A.
Published: July 2009

Catches of Glossina morsitans morsitans Westw. and G. pallidipes Aust. were made on electric nets baited with the odour of one ox, in deciduous and riverine woodland in the Zambesi Valley of Zimbabwe. Catches of teneral and mature flies of both sexes and species declined sharply during the hot dry season (September to November) in the deciduous woodland. In the riverine woodland, catches of mature G. m. morsitans increased during this period; catches of mature G. pallidipes rose rapidly to a high level in June (early in the cool dry season), which was maintained for most of the dry season. Catches of teneral flies in the riverine woodland were fairly constant from June to September (the cool dry season and start of the hot dry season) and then declined, though not as sharply as in the deciduous woodland. The percentage of tenerals in the catch showed a minimum at the end of the hot dry season (October–November); at that time there was also a dramatic rise in the female: male ratio in the deciduous woodland, but no such change occurred in the riverine area.
Occurrence of the grasshopper pest Zonocerus variegatus (L.) (Orthoptera: Pyrgomorphidae) in south-western Nigeria in relation to the wet and dry seasons
Authors: Page W. W.
Published: July 2009

An investigation into the seasonal abundance of Zonocerus variegatus (L.) around Ibadan, Nigeria, showed that hatching occurs between October and March and peak abundance is in late November. Adults occur almost throughout the year. Oviposition takes place between March and October or possibly November, with a peak in April. Eggs laid in March and April hatch in October and November after a diapause, while those laid from June onwards do not appear to enter diapause. Thus eggs laid in June and July hatch at the same time as those laid in March and April. Parasitism by the sargophagid fly Blaesoxipha filipjevi (Rod.) during March and April results in a rapid decline in adult numbers which may be followed by a secondary peak in adult numbers when nymphs, which are present at the same time and are rarely parasitised, reach adult stage. Oviposition resulting from such a peak does not produce a secondary peak in hatching as this coincides with hatching from earlier layings. The fungus Entomophthora grylli plays an important role in controlling the abundance of nymphs and adults during the dry season despite the intermittent nature of the attacks. During the wet season, the fungus is able to germinate and disperse more readily, thus keeping the numbers of the insects low. It is concluded that there is one generation of Z. variegatus a year, with a peak in population coinciding with the dry season (November-March). It is suggested from the results that the grasshopper may have originated in the semi-arid zones of the north.
The effects of temperature and photoperiod on the induction of diapause in eggs of the Australian plague locust,Chortoicetes terminifera(Walker) (Orthoptera: Acrididae)
Authors: Wardhaugh K. G.
Published: July 2009

Photoperiod was shown to be the principal factor regulating the induction of a facultative egg-diapause inChortoicetes terminifera(Wlk.). All developmental stages from first-instar nymphs to immature adults were sensitive to photoperiod. At constant photophases, the insect exhibited a short-day—long-day response, with the upper and lower critical photo-periods for induction approximating to LD 15·5: 8·5 and 11:13, respectively. These correspond to the range of photoperiods experienced by the insect under natural conditions. The maximum inductive response occurred at about the mid-point of this range, i.e. LD 13·5: 10·5. In experiments in which insects experienced a change in photophase at the end of the nymphal stage, the incidence of diapause varied with the direction of change (long to short or short to long) and indicated that diapause induction was prevented by an increase in photophase but enhanced when the photophase was reduced. The size of the inductive response associated with a decrease in photophase appeared to depend less on the size of the decrease than on its position within the inductive range, such that the maximum effects were observed when the sequence of light regimes were close to or spanned the most inductive constant photophase. Temperature was also important in determining the induction of diapause. In the upper portion of the inductive range (15·5 to 12·5 h light), insects subjected to high temperatures or to an increase in temperature during development showed a lower incidence of diapause than those subjected to low temperatures or to a decrease in temperature. In the lower portion of the inductive range, the effects of temperature were reversed, with high temperature or an increase in temperature being more inductive than low temperature or a decrease in temperature.
Sexual competitiveness of males of the Mediterranean fruitfly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), carrying a Y-chromosome translocation
Authors: Rössler Y.
Published: July 2009

The sexual competitiveness of males of Ceratitis capitata (Wied.) carrying a chromosomal translocation and a morphological mutation was compared to that of a wild-type strain. The competitiveness was evaluated by calculating from progeny data the proportion of females that mated with each male type. Males were introduced into the test population in varying proportions. The chromosomal translocation did not affect the competitiveness of the males. The presence of an eye-colour mutation (apricot) reduced the sexual competitiveness of the males bearing the translocation. The results showed evidence for a minority effect (an inverse relation between genotype frequency and mating success). The genetic background of the females in the test populations influenced the competitiveness of the participating males.