bluuebunny/crossref_metadata_2025 huggingface dataset:
Arthropod-induced mortality in immature stages of the bush fly, Musca vetustissima Walker (Diptera: Muscidae)
Authors: Tyndale-Biscoe M. , Wallace M. M. H. , Morton R.
Published: July 2009

Laboratory and field experiments were carried out in Australia to determine the effect of arthropods in cattle dung on the survival of the eggs and larvae of Musca vetustissima Wlk. They were tested in the numbers in which they came to dung pads near Canberra, during the 1978–79 and 1979–80 seasons. Laboratory tests indicated that the mite Macrocheles glaber (Müll.), the hydrophilid Cercyon sp. and the histerid Saprinus sp. were all very effective predators. The native dung beetles Onthophagus granulatus Boh. and O. australis Guér. exerted only a marginal controlling effect; and the staphylinid and aphodiine beetles were found to be largely ineffective. The control exerted by the total field fauna when brought into the laboratory was considerable when one or more of the three species of effective predators was present. In the field trials, the control of M. vetustissima was further enhanced by the adverse influence of weather.
Morphological and cytological separation ofAmphorophoraBuckton (Homoptera: Aphididae) feeding on European raspberry and blackberry (Rubusspp.)
Authors: Blackman R. L. , Eastop V. F. , Hills M.
Published: July 2009

Aphids of the genusAmphorophoracollected from European raspberry,Rubus idaeus, have a chromosome complement of 2n(♀)=18, whereasAmphorophorafromR. fruticosusagg. (blackberry, brambles) have a basic chromosome complement of 2n(♀)=20. Canonical variates analysis based on eight characters measured on numerous samples of apterous virginoparae showed thatAmphorophoraon EuropeanRubuscan be separated morphologically into two groups consistent with the differences in host plant and karyotype, and these two groups are concluded to be separate species. The correct name for the aphid on raspberry that is a vector of European raspberry viruses isAmphorophora idaei(Börn.), and the species on blackberry isA. rubi(Kalt.). Simple biometric methods of discriminating betweenA. idaeiandA. rubibased on pairs of variables are suggested, and their reliability is discussed. Taxonomic problems in the European and North AmericanRubus-feeding species ofAmphorophoraare considered with particular reference to their importance in applied entomology.
Morphology and abnormalities of the reproductive organs of the cabbage root fly,Delia brassicae(Wiedemann) (Diptera: Anthomyiidae)
Authors: Price Jean L.
Published: July 2009

The genitalia and reproductive organs of a normal and of an abnormal type of cabbage root fly (Delia brassicae(Wied.)) are described. The abnormal type, possessing incomplete genitalia, was found in the Welles-bourne laboratory culture. The abnormal females were sexually attractive to males but were unable to copulate or lay eggs, whereas the abnormal males copulated but did not inseminate females. The age of females at oviposition and both larval and adult diets influenced the number of abnormal flies in subsequent generations.
Effects of certain chemosterilants and biologically active substances on the adult Mediterranean flour moth,Ephestia kuehniellaZeller (Lepidoptera: Pyralidae)
Authors: Tan K. H. , Mordue W.
Published: July 2009

Of 11 chemosterilants tested on adult males ofEphestia kuehniellaZell., only tepa induced complete sterility. It also induced complete sterility in females ofE. kuehniella. Hempa showed weak sterilising activity against adult males and had no sterility effect against the females, even at dose levels that induced high mortality. Cycloheximide induced slight sterility in the males. Carbaryl was inactive as a sterilising agent but induced some of the males to produce spermatophore sacs without mating. The latter effect was also induced in a few males by injection of tri-, penta- or hexamethylmelamines, which also induced significant infertility in eggs of untreated females mated with treated males. No structure-activity relationship existed in this group of compounds. Hemel also induced two mating aberrations: permanent copulation and sterile mating. A juvenile hormone analogue (a mixture of 3 hydrochlorinated farnesoates with activity about 1% of that of natural juvenile hormone) induced significant sterility in adult females ofE. kuehniellawhen applied topically. It also caused 38–41% reduction in oviposition at 50–80 μg/adult. However, at 100 μg/adult, the analogue completely inhibited mating in the females. Injected doses of melatonin also caused significant reduction in oviposition. At 5·3 μg/adult, it induced most of the eggs laid to undergo incomplete development. The effects of these compounds are discussed. The sterility indices of tepa against adult male and femaleE. kuehniellawere 19·5 and 9·2, respectively; that for hemel against males was 1·4.
Field assessments of the impact of night-flying dung beetles (Coleoptera: Scarabaeidae) on the bush fly, Musca Vetustissima Walker (Diptera: Muscidae), in south-western Australia
Authors: Smith T. J. Ridsdill , Matthiessen J. N.
Published: July 2009

The effect of excluding the night-flying dung fauna, which included one abundant species of dung beetle (Scarabaeidae) in each of two areas, on the numbers of Musca vetustissima Wlk. emerging from cattle dung pads was studied in south-western Australia. Fresh dung pads were exposed to natural, daytime oviposition by M. vetustissima and half were covered at night. A test at one site before dung beetles emerged showed no effect of other nocturnal fauna on fly survival. In three experiments where Onthophagus ferox Har. was excluded, the numbers of flies emerging increased from 679 to 1019 per dung pad. In five experiments where Onitis alexis Klug was excluded, the number of flies emerging increased from 14 to 33 per dung pad. The mortality contributed by Onthophagus ferox was estimated to be around 27% and that by Onitis alexis around 15%.
Biological control of the floating fern Salvinia molesta in north-eastern Australia: plant-herbivore interactions
Authors: Forno I. W.
Published: July 2009

The curculionid Cyrtobagous salviniae Calder & Sands and the pyralid Samea multiplicalis Guenée were released in north-eastern Australia for the biological control of the floating fern Salvinia molesta. C. salviniae destroyed large areas of weed and was successful at coastal and elevated sites. At equilibrium, there was less than 1 adult/20 plants and only a few, very small plants at each site. The rate at which the weed was controlled varied with mat density. The moth did not reduce plant growth permanently at any site and did not interfere with the performance of the weevil.
Survey of enzyme variation in british populations of Myzus persicae (Sulzer) (Hemiptera: Aphididae) on crops and weed hosts
Authors: Brookes C. P. , Loxdale H. D.
Published: July 2009

Electrophoretic variation of eight enzymes (thirteen loci) including esterase-4 (EST-4, the enzyme conferring insecticide resistance) was studied in clones of Myzus persicae (Sulzer) from several localities in south-eastern England (major beet and rape growing areas) and from a site in mid-Scotland (a seed potato growing region). All loci except esterase-1/-2, which showed putative allelic variation with slow (EST-1) and fast (EST-2) bands, and EST-4, which occurred as three principal quantitative variants (susceptible (S), resistant (R1) and highly resistant (R2)), were found to be monomorphic. The occurrence of the insecticide-resistant variants is reported and shown to differ little from previous surveys, with frequencies of R1 aphids on rape in south-eastern England appearing close to fixation (>0·9), probably due to continued insecticide selective pressure. The general lack of qualitative (i.e. mobility) variation at the loci examined is thought to be due to the species having gone through tight population bottlenecks in the past, which have systematically eliminated the rarer alleles, driving the most common to fixation. Consequently, as the data suggest, only a small number of M. persicae genotypes may exist in Britain.
Phototactic response of Trioza erytreae (Del Guercio) (Hemiptera: Triozidae) to yellow-coloured surfaces, and an attempt at commercial suppression using yellow barriers and trap trees
Authors: Samways M. J.
Published: July 2009

Trioza erytreae (Del Guercio), the vector of the serious citrus greening disease, was found to be highly attracted to yellow surfaces, particularly fluorescent yellow-green (about 530 nm). The phototactic response was used to develop a monitoring trap using 3M Saturn Yellow self-adhesive tape adhering to a glass or Perspex sheet. Transparent PVC foils smeared with a thin layer of clear polybutene were clipped in position over the Saturn Yellow surface and acted as the sticky catchment surface. A spectroradiometric comparison of new and weathered traps indicated only a 10% decrease in reflectance after one year. The traps were a sensitive indicator of psylla abundance. Valencia orchards in the Transvaal, South Africa, supported higher population levels than did navel orchards. A mass-trapping experiment was also done, and involved a cordon of yellow sticky polyethylene strips (Gundle Flexipipe smeared with polybutene) placed around an orchard. This perimeter barrier was combined with aldicarb-treated trap trees within the orchard in an attempt to reduce further the already low psylla numbers. Inside the experimental area there was no statistically significant drop in psylla numbers compared with the control trees outside. These poor economic results making use of the flight response of T. erytreae suggest that carefully integrated biological and chemical suppression of the psylla vector is at present the most practical entomological method for containing greening disease on mature trees.
Immunological investigation of prey-predator relationships for Pieris rapae (L.) (Lepidoptera: Pieridae)
Authors: Kapuge Swarna Hewa , Danthanarayana W. , Hoogenraad Nicholas
Published: July 2009

An enzyme-linked immunosorbent assay (ELISA) was used to examine the digestive tracts of potential predators collected from an experimental cabbage plot in Victoria, Australia, for antigens of Pieris rapae (L.). The rabbit serum used in the study was made against an extract of all immature stages of the prey species and was shown to interact with proteins representing all immature stages. The serum was also shown not to react with antigens from other pest species collected from the experimental plot or with predators not exposed to the prey. The main predators found using the assay were the labidurids Nala lividipes (Dufour) and Labidura riparia truncata Kirby, the staphylinid Thyreocephalus cyanopterus (Erichson) and the eusparassid Olios diana (L. Koch). These results agree closely with laboratory observations on predation. The assay was sensitive, allowing 2000 assays to be performed per millilitre of serum and thus a single serum collection of 20 ml permitted about 40 000 assays.
Anemotactic strategy and optimum flight conditions for host-plant finding in the cabbage root fly, Delia radicum (L.) (Diptera: Anthomyiidae)
Authors: Nottingham S. F.
Published: July 2009

Hourly trap catches of Delia radicum (L.) from opposite sides of host-plant (cabbage) and non-host-plant (carrot) plots in eastern England were analysed with respect to local wind direction, wind speed, temperature and humidity. More females were caught around host- than non-host-plant plots. They predominantly approached host-plant plots by upwind movement, but equal upwind and downwind movement occurred to non-host-plant plots. A generalized linear model revealed that wind speed and humidity influenced the total trap catch of females, with wind speeds below 2 m/s and relative humidities above 65% being most favourable to fly activity, while wind speed was the only variable having a significant effect on the trap catches of flies moving upwind to host-plant plots.
The origin of sheep blowfly,Lucilia cuprina(Wiedemann) (Diptera: Calliphoridae), attractants in media infested with larvae
Authors: Eisemann C. H. , Rice M. J.
Published: July 2009

Laboratory bioassays with gravid females ofLucilia cuprina(Wiedemann) were used to isolate the source(s) of olfactory attractants emanating from larvae-infested media. Adults were not attracted by odours from axenic (micro-organism-free) larvae, but volatiles from xenic larvae were highly attractive. The attractants proved to be kairomones not pheromones, as odours from other species of calliphorids and a sarcophagid species were also attractive. Axenic, proteinaceous media produced a low level of attractive volatiles, which was increased by the activities of axenic larvae growing on the media. A greater degree of attraction occurred to odours from xenic media, and this too was much increased by the actions of growing larvae. The order of attractiveness of such volatiles is therefore: xenic with larvae >> xenic without larvae > axenic with larvae > axenic without larvae. It is concluded that larvae-infested media owe their great attractiveness to the volatiles produced by the action of micro-organisms, not to specific larval volatiles. Larval activity accentuates the output of attractive volatiles from both xenic and axenic proteinaceous media, possibly due to the effects of digestive enzymes, pH changes, mechanical mixing, warming or aeration or a combination of some or all of these factors.
The influence of larval phase on metabolic reserves, fecundity and lifespan of the african armyworm moth, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae)
Authors: Gunn A. , Gatehouse A. G.
Published: July 2009

Spodoptera exempta (Walker), in common with several noctuid moths, exhibits a density-dependent phase polyphenism. The abdominal glyceride contents of both sexes at emergence were 2·5 to 6·1 times greater in the gregaria than in the solitaria phase moths. Abdominal and thoracic total protein levels, haemolymph total protein, glyceride and carbohydrate, and the relative quantities of tri-, di- and monoglycerides were comparable in the two forms. Weight-related fecundity was strongly influenced by larval phase. Females from solitaria larvae produced approximately half the numbers of eggs laid by those reared in crowded conditions, but this difference was only evident in moths allowed distilled water. Moths having access to sucrose laid comparable numbers of eggs, irrespective of phase. There were no differences in the levels of metabolic reserves in the eggs. Differences in glyceride content, preoviposition period, fecundity and lifespan were apparent between laboratory strains. The implications of these differences for migratory flight and reproduction in the field are discussed.
Management of cereal aphid (Hemiptera: Aphididae) populations and their natural enemies in winter wheat by alternate strip spraying with a selective insecticide
Authors: Carter Nick
Published: July 2009

The effect on aphid population development of creating natural enemy refuges by spraying only alternate strips of winter wheat with the aphid-specific insecticide pirimicarb at 140 g a.i./ha was compared with those in an unsprayed and a completely sprayed block in south-eastern England. The numbers of Sitobion avenae (F.), Metopolophium dirhodum (Walker) and Rhopalosiphum padi (L.) increased rapidly in the unsprayed block and in the unsprayed strips to reach similar peak densities in early August. Natural enemy activity was similar in these two areas, indicating negligible movement of predators and parasitoids from the sprayed strips to the unsprayed strips. Instead, aphids re-colonized the sprayed strips more quickly than the sprayed block, and the peak density in the former was similar to those in the unsprayed areas.
On the Bionomics of a Eulophid (Trichospilus Pupivora, Ferr.) A Natural Enemy of the Coconut Caterpillar (Nephantis Serinopa, Meyr.) in South India
Authors: Anantanarayanan K. P.
Published: July 2009

The black-headed palm caterpillar (Nephantis serinopa, Meyr.) has been known to be a serious pest of coconut palms both in Ceylon and South India for many years past, and during the past ten years its appearance on a serious scale along the Malabar coast in South India has been attracting the attention of the Entomological Section of the Madras Agricultural Department. Among the different methods of control, the utilisation of the natural enemies of the pest has been tried to some extent. One of the more important natural enemies found to exert some appreciable influence on this pest was a Eulophid wasp, Trichospilus pupivora, Ferr. As one of the officers of the Entomological Section engaged in the work connected with this coconut pest, the author had opportunities of closely studying this parasite, and in this paper a brief account is attempted of the bionomics of this insect and of some methods employed in breeding it on a large scale.
The Developmental Stages of Bracon Tachardiae, Cam. (Hym.)
Authors: Glover P. M.
Published: July 2009

The egg, the five larval instars, cocoon, prepupa and pupa of Bracon tachardiae, Cameron, are described.

Two series of larvae, one male and one female, occur, these series overlap very considerably and it is only towards the maximum and minimum of the range that larvae are respectively entirely female or male.

It is shown that the five larval instars of B. tachardiae may be grouped by the widths of the head-capsule, and that an instar can be characterised by the head-width, particularly if only averages are considered. The actual range of head-width in each instar is rather large, and in some cases the extremes overlap. In actual practice head-width is a safe indication of the instar of a larva as the extremes rarely occur; the widths calculated on Dyar's principle also approximate sufficiently closely to the observed widths to preclude the chance of an ecdysis having been overlooked.

The length of the mandible is for practical purposes identical in a larva of any given instar and in its exuviae. The larval instars and their exuviae can be grouped by the lengths of the mandibles, particularly if averages are considered; the range for a given instar is wide but the extremes do not overlap. The lengths calculated on Dyar's head-width principle approximate closely with the observed lengths, sufficiently so to preclude the possibility of overlooking an ecdysis, and making possible the identification of the instar of fixed and mounted specimens of larvae or exuviae, for which purpose head-width is useless.

The factors of increase of head-width and mandibular length are fairly similar, falling near to 3 √2 =1.26, and for practical purposes one may be substituted for the other, the calculated widths and lengths so obtained still approximating to the observed widths and lengths.

Various uses of this fact are indicated. Preliminary investigations point to the fact that similar observations apply to Aphrastobracon flavipennis, Ashm., an ectoparasite of Eublemma scitula, Ramb. It is suggested that similar observations may be true for other ectoparasitic Braconids.

The growth of the body of the larva from instar to instar is independent of the growth of the head-capsule, larvae increasing in weight and in volume by a figure lying between 3 and 4 times from instar to instar. The actual figure obtained theoretically for volume increase was 3–6. The head-size increases by the usual double at each moult.
The Alimentary Canal, its Appendages, Salivary Glands and the Nervous System of the adult Female Lac Insect, Laccifer lacca, Kerr (Coccidae)
Authors: Negi P. S.
Published: July 2009

Owing to the deposition of resin, the females assume two shapes, one somewhat circular in which the mouth-parts are situated ventrally about the middle of the body, and the other pyriform, in which the mouth-parts are situated at the extreme anterior end. In the former type of females the mouth-parts are posteriorly directed and in the latter anteriorly. The rostrum lies outside the body cavity between the anterior pair of oral lobes. The rostralis opens into the pharynx which lies in the tentorium. The oesophagus is elongated and passes into the colo-rectum to be succeeded by the convoluted ventriculus. The ventriculus on leaving the colo-rectum leads into the intestine, which is marked into the mid and hind intestine by the junction of the ampulla of the Malpighian tubes. The intestine after forming a loop round the greater part of the colo-rectum re-enters it close to the point of its commencement from it and continues closely attached to the outer side of the ventriculus from its distal to its proximal end; after this it comes out of the colo-rectum and runs alongside it to open into it near the anterior third of its length. The convolutions inside the colo-rectum are comprised of the ventriculus and the part of the hind intestine running outer to it. The “colon caecum” is absent. The colo-rectum opens at the anus situated at the posterior end of the insect and is divided into colon and rectum by the opening of the intestine into it.

The salivary glands consist of two branches of ovoid and spherical bodies. The common duct of the salivary gland of each side runs close to the ventral ganglion and joins the opposite duct to form the terminal duct near its anterior end, which then opens into the pharynx.

The nervous system consists of a bilobed cerebral ganglion which lies anteriorly to the mouth-parts in females in which the tentorium is directed posteriorly, and either laterally or ventrally to it in females in which the tentorium is directed anteriorly and lies at the extreme anterior end. The cerebral ganglion is joined by a pair of connectives to the ventral ganglion, which lies dorsal to the tentorium in females in which it is directed posteriorly, and posterior to the tentorium in which it is directed anteriorly and lies at the extreme anterior end. The ventral ganglion is followed by the nerve chord, which varies in length in either type of female. The main nerves arising from the central nervous system are described.
Prediction of temperatures in cattle dung for estimating development times of coprophilous organisms
Authors: Matthiessen J. N. , Palmer M. J.
Published: July 2009

In studies in Western Australia, temperatures in air and one- and two-litre pads of cattle dung set out weekly and ranging from one to 20 days old were measured hourly for 438 days over all seasons, producing 1437 day x dung-pad observations. Daily maximum temperatures (and hence thermal accumulation) in cattle dung pads could not be accurately predicted using meteorological data alone. An accurate predictor of daily maximum dung temperature, using multiple regression analysis, required measurement of the following factors: maximum air temperature, hours of sunshine, rainfall, a seasonal factor (the day number derived from a linear interpolation of day number from day 0 at the winter solstice to day 182 at the preceding and following summer solstices) and a dung-pad age-specific intercept term, giving an equation that explained a 91·4% of the variation in maximum dung temperature. Daily maximum temperature in two-litre dung pads was 0·6°C cooler than in one-litre pads. Daily minimum dung temperature equalled minimum air temperature, and daily minimum dung temperatures occurred at 05.00 h and maximum temperatures at 14.00 h for one-litre and 14.30 h for two-litre pads. Thus, thermal summation in a dung pad above any threshold temperature can be computed using a skewed sine curve fitted to daily minimum air temperature and the calculated maximum dung temperature.
Habitat associations and seasonal abundance of coprophilous coleoptera (Staphylinidae, Hydrophilidae and Histeridae) in the Hluhluwe region of South Africa
Authors: Davis Adrian L. V. , Doube Bernard M. , McLennan Paul D.
Published: July 2009

A total of 134 species of Coleoptera (100 of staphylinids, 13 of hydrophilids and 21 of histerids) was extracted from pads of cattle dung placed in four contrasting habitats in both Hluhluwe Game Reserve, Natal, South Africa, and the surrounding pastoral regions. Pads were exposed to colonists for 24 h on eight occasions over one year. Forty-six species and species complexes were captured in numbers sufficient to permit analysis of their distribution patterns. Of 27 species significantly influenced by vegetation type, 22 were more abundant in unshaded situations and five more abundant in situations shaded by high profile vegetation. The total numbers of individual predatory staphylinids were evenly distributed between vegetation types, but members of coprophagous staphylinid and other predatory taxa were more numerous in unshaded situations. Of 13 species significantly influenced by soil type, six were more abundant on clay and seven more abundant on deep sand. The total numbers of individual coprophagous oxyteline staphylinids were greater on clay than on sand, but the members of predatory taxa, including staphylinids, were evenly distributed across soil types. Of 14 species showing significant seasonal changes in abundance, 13 were more abundant in hot wet months and one in cool dry months. The total numbers of hydrophilid individuals were greater in the cool dry season, but the other taxa were active predominantly in the rainy season. Most species were present in similar numbers in both the game reserve and pastoral regions. Enclosure of dung pads within wiremesh cones to exclude large dung-burying beetles resulted in reduced colonization by most beetle species regardless of their size.
Cardiochiles (Hymenoptera: Braconidae), a parasitoid of lepidopterous larvae, in the Sahel of Africa, with a review of the biology and host relationships of the genus
Authors: Huddleston T. , Walker Annette K.
Published: July 2009

In the ecologically sensitive Sahel of West Africa, two major crop pests, Helicoverpa armigera (Hübner) and Heliocheilus albipunctella (de Joannis), are attacked by Cardiochiles variegatus Szépligeti and C. sahelensis sp. n., respectively. The twelve Cardiochiles species present in the Sahel are revised, and a key is given for their identification. Five of these species (C. calvus sp. n., C. coelofrons sp. n., C. exiguurus sp. n., C. nixoni sp. n. and C. sahelensis sp. n.) are described, and C. striatus Brues is made a synonym of C. punctatus Szépligeti. Host relationships of the genus worldwide are discussed and the host records, principally involving Pyralidae and Noctuidae, collated. The known biology is summarized from the literature on the North American species C. nigriceps Viereck, and a comprehensive bibliography on the genus is given.

Dans la région écologiquement difficile du Sahel de l'Afrique de l'Ouest, on a découvert que deux importantes variétés d'insectes nuisibles à la culture, Helicoverpa armigera (Hübner) et Heliocheilus albipunctella (de Joannis), sont attaquées respectivement par Cardiochiles variegatus Szépligeti et C. sahelensis sp. n. Les douze espèces de Cardiochiles qui se trouvent dans la région du Sahel sont réétudiés, et une clé est formulée afin de les identifier. Cinq de ces espèces (C. calvus sp. n., C. coelofrons sp. n., C. exiguurus sp. n., C. nixoni sp. n. et C. sahelensis sp. n.) sont décrites, et C. striatus Brues devient synonyme du C. punctatus Szépligeti. Les rapports universels de ces genres d'hôtes sont discutés ainsi que la comparaison des rapports d'observation, principalement en ce qui concerne les pyralides et les noctuides. La biologie actuelle est resumée de la littérature sur l'espèce C. nigriceps Viereck nord américain et une vaste bibliographie du genre est présentée.
Influence of diet on the survival and wood consumption ofPorotermes adamsoni(Froggatt) (Isoptera: Termopsidae) at different temperatures
Authors: Lenz M. , Barrett R. A. , Williams E. R.
Published: July 2009

Survival and wood consumption were measured for laboratory groups ofPorotermes adamsoni(Frogg.) maintained over a range of constant temperatures from 8 to 29°C. The termites were fed on sound blocks ofPinus radiata, Eucalyptus regnans, decayedE. ?viminalis, and outer (sound) and inner (decayed) heartwood ofE. pauciflora. Above 21 °C, diet influenced the pattern of survival, wood consumption and wood consumption adjusted for survival, resulting in a significant temperature × timber interaction. In the upper range of the temperatures used, the termites survived in larger numbers or for longer periods on decayed than on sound wood and ate more of it. From the results, it is clear that difficulties arise when employing laboratory data to estimate feeding activity of termite populations in the field. Knowledge of the correlation between the performance of termites in laboratory groups with that of members of a field colony is still sparse.
Factors affecting uptake and loss of diflubenzuron in the tsetse flyGlossina morsitans morsitansWestwood (Diptera: Glossinidae)
Authors: Clarke L.
Published: July 2009

Interference with reproduction inGlossina morsitans morsitansWestw. by diflubenzuron depends on a variety of factors that influence its uptake and loss from the female fly. The duration of its eftect depends on the site and method of application to the fly as well as the amount of material applied. In nulliparous females, loss of diflubenzuron was by excretion, but as the fly aged approximately 50% of the material remaining within the fly was lost with each larviposition. Following injection, the rate of loss of diflubenzuron by excretion was twice that from flies treated topically, but in neither was it directly related to the amount of diflubenzuron within the fly. Loss to the in utero larva, however, was governed by the amount of material within the fly, at least 9 ng diflubenzuron being necessary for production of an abnormal offspring. In injected flies, the overall loss was twice that from flies treated topically on the dorsal thorax and similar to those treated topically on the ventral abdomen. This difference in the rate of loss from topically-treated flies seems to be related to the amount of material available on the surface of the fly, the cuticle apparently acting as a storage site from which there is a gradual release of diflubenzuron into the fly.
Survival and dispersal of young larvae of Chilo partellus (Swinhoe) (Lepi-doptera: Pyralidae) in two cultivars of sorghum
Authors: Chapman R. F. , Woodhead S. , Bernays E. A.
Published: July 2009

The establishment and survival of larvae of Chilo partellus (Swinh.) on two sorghum cultivars in the six days after hatching was investigated in the field in India. During this period relatively few larvae are present outside the whorls of the plants, and the numbers present six hours and three days after hatching are proportional to the numbers hatching. The number of larvae in the plants declines during these first three days, but subsequently is stable. Some dispersal to adjacent plants occurs during this period and, at the plant spacing used, approximately seven plants were infested by larvae from a single egg-mass of 40 eggs. The relative susceptibilities of the two cultivars, IS 1151 and IS 2205, altered with the age and size of the plants. This is a vulnerable period in the life-history of the insect and attention should be focused on it in developing resistant cultivars, but because the susceptibility of the plants changes with age it is important to decide the age at which protection would have the greatest economic value.
Possible sources of outbreaks of the armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae), in East Africa at the beginning of the season
Authors: Tucker M. R.
Published: July 2009

Possible sources of adults of Spodoptera exempta (Wlk.) giving rise to outbreaks in East Africa at the beginning of the season were estimated by assuming downwind displacement and using the technique of backtracking. The accuracy of backtracks was limited by the availability of suitable weather data, but they provided a reasonably objective means of analysis. Eastern Kenya and eastern Tanzania were found to be the most likely source areas for moths. Migration from Ethiopia was very unlikely. Immigration from southern Somalia into Kenya, and from Malawi, Zambia or northern Mozambique into southern Tanzania was possible in a few years. In most years, there were likely to be sources in Kenya or Tanzania, probably of low density and in places suitable for the larvae to survive the dry season.
Carbamate and organophosphate resistance inCulex pipiensL. (Diptera: Culicidae) in southern France and the significance ofEst-3A
Authors: Wood R. J. , Pasteur N. , Sinégre G.
Published: July 2009

Three French strains ofCulex pipiensL. were compared at the fourth larval instar for tolerance to organophosphate and carbamate insecticides, with and without the addition of synergists (the oxidase inhibitors piperonyl butoxide and CGA 84708) (a propynyl compound) and the carboxylesterase inhibitors triphenyl phosphate (TPP) andS,S,S-tributyl phosphorotrithioate (TBPT). The S54 strain was resistant to all the organophosphates tested (chlorpyrifos, malathion, monocrotophos and profenofos) compared to the susceptible LA VIS strain but only slightly tolerant to the two carbamates (carbaryl and naphthyl phenylcarbamate). The MAURIN strain was resistant to all the insecticides, including the carbamates, at a higher level. The action of chlorpyrifos and malathion on S54 was very strongly synergised by TBPT, less strongly by TPP and not at all by piperonyl butoxide. In fact, resistance was enhanced by piperonyl butoxide, as was resistance to monocrotophos and profenofos by CGA 84708. No synergist had much effect on the MAURIN strain, although TPP slightly increased the toxicity of malathion, and piperonyl butoxide and CGA 84708 slightly increased the toxicity of carbaryl. The toxic effect of carbaryl was also increased by the addition of extra acetone. Electrophoretic studies showed that the carboxylesterase enzyme coded by geneEst-20.64(which is in linkage disequilibrium withEst-3Aand acts as a marker for it) was absent from LA VIS but present in the resistant strains; but, whereas S54 was monomorphic for the gene, MAURIN was polymorphic (frequency 0·5). It is concluded that organophosphate resistance in S54 was due to detoxification by carboxylesterase wherease organophosphate and carbamate resistance in MAURIN had a strong non-metabolic component, possibly an insensitive acetylcholinesterase.
Studies of elemental composition as a biological marker in insects. II. The elemental composition of apterae of Rhopalosiphum padi (L.) and Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) from different soils and host-plants
Authors: Bowden J. , Sherlock P. L. , Digby P. G. N. , Fox J. S. , Rhodes J. A.
Published: July 2009

Energy-dispersive X-ray spectrometry was used to make quantitative determinations of the elemental composition of plasma-ashed apterous individuals of Rhopalosiphum padi (L.) and Metopolophium dirhodum (Walker). R. padi was reared on 24 plant–soil combinations and M. dirhodum on nine plant-soil combinations. Analyses were done for 12 elements: Na, Mg, Al, P, S, Cl, K, Ca, Mn, Fe, Cu and Zn. Principal components analyses of individuals showed no distinction, in either aphid species, between insects reared on any plant–soil combination, whether all elements, elemental sub-sets, soil sub-sets or host-plant sub-sets were considered. When group means (mean for all individuals from a particular plant-soil combination) were used in principal components analyses, five groups of R. padi could be distinguished from the other 19, although neither set could be further separated. Four of the five distinguishable groups were from plants that grew particularly poorly, and the fifth was from plants in a soil in which all host-plants grew less well than in other soils. There were no distinct separations between groups of M. dirhodum, though there were slight indications that soils were distinguishable. In both R. padi and M. dirhodum, elemental differences involved the minor elements, particularly Mn, Fe, Cu and Zn. The uniformity of elemental content in the apterae of both aphid species may be a consequence of genetic uniformity within clones of parthenogenetically reproducing species.
Electrophoretic study of enzymes from cereal aphid populations. III. Spatial and temporal genetic variation of populations ofSitobion avenae(F.) (Hemiptera: Aphididae)
Authors: Loxdale H. D. , Tarr I. J. , Weber C. P. , Brookes C. P. , Digby P. G. N. , Castañera P.
Published: July 2009

Ninety-two individuals ofSitobion avenae(F.) collected throughout Britain in 1979 and 1980, were cloned and investigated genetically by electrophoresis of 14 enzymes representing 26 loci. Percentage polymorphism (P) differed considerably between years, 64% (16/25 loci) in 1979 and 19% (5/26) in 1980, whereas average heterozygosity () was low (ca. 2%) in both years and confined mainly to one locus, EST-1. The prevalence of homozygous allozyme variation supports ecological findings suggestingS. avenaeto be largely anholocyclic in Britain. In 1981 and 1982, large populations, sampled from 11 sites in Britain and Spain, were examined at 13 loci.ranged from 2 to 7·6%, with heterozygosity restricted again mainly to EST-1. Some alleles were unique to certain geographical regions (including Britain or Spain); others showed significant spatial, and in two British populations examined in successive years, temporal frequency differences. Calculating Nei’s genetic identity (I) and distance (D) coefficients for each population pair mostly gaveI>0·8,D<0·2 with overall means (± s.e.m.) of 0·896 ± 0·006 and 0·111 ± 0·006, respectively, which are comparable with geographical population values for other insects.Dwas poorly correlated with geographical distance, although values were slightly greater (ca. 0·025) for international population comparisons and did not overlap on a principal coordinates plot. The overall population similarity suggests substantial inter-population gene flow; geographical barriers may have restricted movements but seemingly have not led to allopatric race formation. P andvalues resemble those for many other aphids, but H values are lower than typically found in other insects. Possible causes of this heterozygote deficiency are discussed.
The role of 1-octen-3-ol, acetone and carbon dioxide in the attraction of tsetse flies, Glossina spp. (Diptera: Glossinidae), to ox odour
Authors: Vale G. A. , Hall D. R.
Published: July 2009

In the Zambezi Valley of Zimbabwe, the numbers of Glossina morsitans morsitans Westwood and G. pallidipes Austen electrocuted on grids placed across their flight paths as they arrived at various natural and synthetic odour sources demonstrated that ox odour comprises two broad fractions of attractants. One fraction can be trapped by a charcoal filter and, in part, consists of 1-octen-3-ol. A more volatile fraction passes through the filter and, in part, consists of carbon dioxide and acetone. Levels of acetone and 1-octen-3-ol in ox odour varied considerably, up to maxima of 24 mg/h and 0·025 mg/h, respectively. Catches were roughly doubled when octenol at 0·5 mg/h was added to ox odour, but declined when the dose was increased to 50–500 mg/h. A synthetic odour consisting of 2 litres of carbon dioxide/mm, 5 mg of acetone/h and 0·05 mg of 1-octen-3-ol/h, was nearly as effective as ox odour for G. m. morsitans but only half as effective as ox odour for G. pallidipes. Increases to the doses of each attractant in the synthetic odour increased the catches, to roughly double those with ox odour. Data for other Diptera are also presented.
Theoretical models of the use of insecticide mixtures for the management of resistance
Authors: Curtis C. F.
Published: July 2009

Simple one- and multi-generation models are used to show the essential features of the dynamics of selection for resistance to one insecticide or two unrelated insecticides in insect populations, part of which are unexposed to either compound. The use of a mixture appears advantageous provided that resistance is not fully dominant, but, if it is, linkage disequilibrium builds up rapidly and nullifies the advantage of the mixture
Relationship between red scale, Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae), and its natural enemies in the upper and lower parts of citrus trees in South Africa
Authors: Samways M. J.
Published: July 2009

In mature Valencia orange trees at three sites in the Transvaal lowveld, there was a variable differential between levels of Aonidiella aurantii (Maskell) in the upper and lower parts of the trees. At one site there were high scale levels in the crowns of the trees as a result of past poor chemical spray procedure. In recent years, pest management has maximized on the use of natural enemies, especially Aphytis spp. However, the natural enemies have not been able to ameliorate the crown problem. At generally high levels of Aonidiella aurantii, the natural enemies were ableonly, more or less, to maintain the average overall level of the scale from one year to the next; they could not bring it down. This arose each year from too many scales escaping parasitism and reaching the relatively invincible adult stage early in the season. As the behaviour of the parasitoids was inversely density-dependent at these relatively high scale levels, this led to a greater increase in scale numbers, leading eventually to up to 90% of the population (excluding crawlers) being composed of adult females. The inverse density dependence was also partly because the majority of single scales escaped parasitoid attack. In the lowveld, it is a prerequisite that the density of A. aurantii first be lowered by an introduced natural enemy (e.g. the coccinellid Chilocorus nigritus (F.)) that attacks the adult stage and/ or by chemical means before maximal use is made of the regulatory influence of the existing natural enemies, particularly Aphytis spp.
The effect ofSitona discoideusGyllenhal (Coleoptera: Curculionidae) on lucerne yields in New Zealand
Authors: Goldson S. L. , Dyson C. B. , Proffitt J. R. , Frampton E. R. , Logan J. A.
Published: July 2009

The impact of injury by larvae and adults ofSitona discoideusGyllenhal on lucerne production was studied in two consecutive seasons at two adjacent sites near Christchurch, New Zealand. The root-feeding larvae were found to be more damaging than the adults; in the first cut in the 1982–83 season in a three-year-old stand, larvae reduced dry matter yield by 18%. In the wetter following season in a one-year-old stand, second and third cut losses of 43 and 30% dry matter production, respectively, were recorded. In both seasons, the lucerne had apparently substantially recovered from larval damage by the time of the last cuts. In the drier 1982–83 season, two cuts were taken compared with four in the 1983–84 season. Adult feeding was found to reduce second cut wet yields by 20–30% in the 1982–83 season but had no measurable effect in the 1983–84 season. In both seasons, manipulated ranges of larval densities showed that damage appeared only when larval populations were in excess of a distinct larval population density threshold. At larval densities less than this threshold, yield was unaffected; above the threshold, yield losses were independent of larval density. Such a yield response curve was found to be adequately described mathematically by a simple arctan model; this approach allowed the threshold to be further defined and overall estimates to be made of the yield losses arising from larval damage. The threshold occurred at about 1200 larvae/m2in the dry season and about 2100 larvae/m2in the wet season. This suggested moisture sensitivity and the possibility that the crop may enter a damage-induced dormancy related to that observed during a severe drought.
Meligethes heteropus Gerstaecker (Coleoptera: Nitidulidae), a new pest of bulrush millet in West Africa
Authors: Spriggs-Kirk A. H.
Published: July 2009

Vast populations of Meligethes heteropus Gerstaecker have recently been found on millet in Nigeria. The damage they cause is described and the previously unknown male is described and figured. The validity of characters previously used in the diagnosis of Meligethes is discussed.
An experimental evaluation of conventional control measures against the sheep tick,Ixodes ricinus(L.) (Acari: Ixodidae). I. A unimodal seasonal activity pattern
Authors: Steele Gordon M. , Randolph Sarah E.
Published: July 2009

Questing individuals ofIxodes ricinus(L.) on a naturally infested moorland in Wales were censused every fortnight from January 1981 to October 1982 by blanket-dragging, and feeding ticks were counted on the sheep hosts. The seasonal activity patterns for ticks in all three stages were unimodal, with nymphs and adults active between March and July, and larvae active between April and August. This unimodal, as opposed to the usually described bimodal, pattern is explained in terms of the long cold winters and short summers of this field site. The survival time of questing nymphs was calculated from an analysis of their changing lipid content during the activity season to be a maximum of four months, which is consistent with the other field observations. The precise identification of the pattern of activity, as well as being essential for the application of appropriately timed control procedures, is necessary for the interpretation of the tick-host interactions under various control regimes that were applied.
Spatial and temporal population patterns of Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) parasitoids (Hymenoptera: Aphelinidae and Encyrtidae) caught on yellow sticky traps in citrus
Authors: Samways M. J.
Published: July 2009

Parasitoids of Aonidiella aurantii (Maskell) on citrus in South Africa were monitored using two types of yellow sticky trap. One of these traps was highly efficient, being fluorescent with peak reflectance at about 530 nm. Aphytis spp. populations were low before February and high thereafter. Citrus surrounded by natural bush was an isolated reservoir of high host and parasitoid population levels. Aphytis spatial distribution within the orchard was extremely patchy, with over 100-fold differences in population levels over a distance of a few metres. This patchiness mirrored that of its host. This contagious spatial pattern was maintained despite 1000-fold seasonal changes in population levels. These temporal changes were characteristic and general throughout an orchard, and independent of patchiness. Initial Aphytis population levels did not dictate the final population level at the end of the season. Comperiella bifasciata Howard and its hyperparasitoid Marietta javensis (Howard) also showed clear seasonal population trends, but not of the same magnitude as those of Aphytis. There was no statistically significant correlation between the spatial distribution of one parasitoid with that of another, even between C. bifasciata and M. javensis. The patchiness of these two species was not correlated with overall host density. Aphytis and C. bifasciata were partially mutually exclusive. Aphytis was by far the most economically important of the parasitoids. Pest management practices, therefore, should aim at conserving the pool of Aphytis within the orchard as far as practicable.
The potency and effect of phytotoxins within yellow split-pea (Pisum sativum) and adzuki bean (Vigna angularis) on survival and reproductive potential of Sitophilus oryzae (L.) (Coleoptera: Curculionidae)
Authors: Holloway Graham J.
Published: July 2009

Sitophilus oryzae (L.) is a serious pest of stored cereal grains, but recently a few populations have been found able to feed and breed on certain legumes also. Legumes contain many toxic phytochemicals. A technique is described to generate data suitable for probit analysis, enabling a dose- response line to a toxic food to be constructed. The toxic effects of two legumes, yellow split-pea and adzuki bean, on adult survival and reproduction in three geographical strains of S. oryzae were examined. The strains were shown to vary in their abilities to tolerate legume phytotoxins, but there was no correlation between the abilities to survive on different legumes in the same strain. Yellow split-pea was shown to have residual effects on adult survival and reproduction, but performance was enhanced rather than impaired. It is suggested that improved performance results from induction of certain enzymes by substances within yellow split-pea. The use of legumes mixed with cereals as a control measure against S. oryzae is also discussed.