Faecal pellet production by Tetranychus cinnabarinus (Boisd.) was recorded at different temperatures (19, 24, 30, 35°C) and relative humidities (0% to 100%); at all temperatures pellet production was greater under dry than under wet conditions. A feeding index based on faecal pellet production and the proportion of adults surviving each day showed that the optimal conditions for the mite were 24°C and 38% r.h. Pellet production increased under continuous light and, under any particular set of conditions, was closely correlated with the numbers of eggs laid. It is concluded that faecal pellet production can be used as a measure of feeding within a given set of conditions provided it is supplemented and checked by other data.

(1) Coal-tar phenols are useful intermediate solvents for making solutions of rotenone in both mineral and vegetable oils.

(2) Medium petroleum oil showed superiority to ground-nut oil as a carrier of rotenone in xylenol tested against Ornithodorus moubata.

(3) The solutions of rotenone in xylenol and oil showed no deterioration after storage in the dark at room temperature for six weeks.

(4) In these solutions rotenone proved far less toxic to Ornithodorus moubata than an equal weight of pyrethrin I in medium petroleum oil.

The two alpha-cyano pyrethroid insecticides lambda-cyhalothrin and alpha-cypermethrin were tested as bednet treatments at a target dose of 20 mg m-2. To establish their efficacy, female pyrethroid resistant and susceptible Anopheles stephensi Liston, and the F1-hybrids were allowed to fly freely in a room with a human subject under an impregnated net. Both treatments provided good personal protection by significantly reducing the number of blood fed mosquitoes compared to an untreated control net. Mortality after 24 h was significantly higher for the alpha-cypermethrin treated net when compared to lambda-cyhalothrin. For each insecticide there were no significant differences in the proportion of susceptible homozygotes and F1-hybrids found dead after a 24 h holding period, which suggests that there would be no selection for pyrethroid resistant heterozygotes by either of the insecticides.

Six soil samples from elephant-grass leys at Kawanda, Uganda, gave collections representing a population of 87,147 arthropods per sq. metre in the top 12 in. of soil.

Six samples from adjacent cultivated ground gave collections representing a population of 26,150 arthropods per sq. metre.

These numbers are compared with the population of arthropods found in the soil of grazed pastures in East Africa.

The greater population under elephant grass is attributed to the presence of a crumb structure and to the protection afforded by elephant grass against insolation.

It is suggested that the nitrogen contained in these soil arthropods, especially that locked up in the chitin and sclerotin of their skeletons, is part of the nitrate that becomes available some weeks or months after elephant-grass leys are cultivated.

The robber fly Mallophora ruficauda is one of the most important apicultural pests in the Pampas region of Argentina. This species is a parasitoid of scarab beetle larvae. Females lay eggs away from the host, and the larvae perform active search behaviour toward Cyclocephala signaticollis third instar larvae, parasitoid's preferred host. This behaviour is mediated by host-related chemical cues produced in hosts’ fermentation chamber. Also, C. signaticollis larvae are attracted to fermentation chamber extracts. As scarab larvae have microbe-rich fermentation chamber, it has been suggested that microorganisms could be involved in the production of these semiochemicals. The aims of this work were first to ascertain the presence of microorganisms in the fermentation chamber of C. signaticollis larvae and second to determine the role of microorganisms in the orientation response of parasitoid and host larvae. We found that microorganisms-free C. signaticollis larvae showed deterioration in their development and did not produce the attractive semiochemicals. Therefore, we isolated fermentation chamber microorganisms of host larvae by means of different cultures media, and then, assayed different microorganisms’ stimuli by binary choice tests. We were able to isolate microorganisms and determine that M. ruficauda larvae are attracted to semiochemicals from protein degradation in the fermentation chamber. However, C. signaticollis larvae were not attracted to any semiochemicals associated with microorganisms’ activity in the fermentation chamber. Although we were unable to elucidate the exact role of gut microorganisms in host behaviour, we discuss their relevance in parasitoid host-seeking behaviour and host conspecific interaction in M. ruficauda–C. signaticollis system.

The major component of aphid alarm pheromone is (E)-β-farnesene (EβF), but the molecular mechanisms of EβF synthesis are poorly understood. Here we established a biological model to study the modulation of EβF synthesis in the bird cherry-oat aphid Rhopalosiphum padi by using quantitative polymerase chain reaction, gas chromatography/mass spectrometry and RNA interference. Our results showed that the rearing conditions significantly affected the weight of adult and modulated EβF synthesis in a transgenerational manner. Specifically, the quantity of EβF per milligram of aphid was significantly reduced in the individually reared adult or 1st-instar nymphs derived from 1-day-old adult reared individually, but EβF in the nymph derived from 2-day-old adult that experienced collective conditions returned to normal. Further study revealed that the production of EβF started in embryo and was extended to early nymphal stage, which was modulated by farnesyl diphosphate synthase genes (RpFPPS1 and RpFPPS2) and rearing conditions. Knockdown of RpFPPS1 and RpFPPS2 confirmed the role played by FPPS in the biosynthesis of aphid alarm pheromone. Our results suggested that the production of EβF starts at the embryo stage and is modulated by FPPS and rearing conditions in R. padi, which sheds lights on the modulatory mechanisms of EβF in the aphid.

Cotton in Central Africa is subject to attack by numerous insect pests, and this has limited production. The pests include Diparopsis castanea Hmps., Heliothis armigera (Hb.), Earias spp. and Dysdercus spp. Methods of rearing these insects in the laboratory are described, preparatory to testing insecticides for their control. By means of an egg-dipping technique, the susceptibility of first-instar larvae of Diparopsis castanea to a wide range of insecticides was determined, and that of similar larvae of E. biplaga Wlk. to a smaller range. The most effective were methyl-parathion, carbaryl, menthyl-demeton, parathion, methiocarb, Zectran, isobenzan, endosulfan, BHC, endrin and phosphamidon. DDT was more effective against Earias than against Diparopsis, and toxaphene was relatively ineffective against both. Aftertakiing the mammalian toxicity of the insecticides and certain other factors into consideration, carbaryl, endosulfan, endrin and DDT were selected for further evaluation in the laboratory and the field.

Cryptolestes ferrugineus (Stephens, 1831) is an important insect pest of stored products. Due to its broad host range, short life cycle, and high reproductive capacity, this species has rapidly colonized temperate and tropical regions around the world. In this study, we isolated 18 novel polymorphic microsatellite loci from an enriched genomic library based on a biotin/streptavidin capture protocol. These loci will be useful tool to better understand the genetic structure and migration patterns of C. ferrugineus throughout the world. The genetic parameters were estimated based on 80 individual C. ferrugineus from two natural populations. The results revealed that 18 loci were different polymorphic levels. The numbers of alleles ranged from 3 to 12, and eleven loci demonstrated polymorphic information contents greater than 0.5. The observed (HO) and expected (HE) heterozygosities ranged from 0.051 to 0.883 and 0.173 to 0.815, respectively. Five locus/population combinations significantly deviated from Hardy–Weinberg equilibrium. We also demonstrated the potential utility of the C. ferrugineus microsatellites as population and species markers for four additional Cryptolestes species.

Prior to 1900–05 South Ankole was free from tsetse.

About 1906–07 Glossina morsitans crossed the Kagera northwards at three points: Kakitumba, Nyaruambu, and Kafunza (Tanganyika). Cattle in those areas were moved north on the advent of the fly, thus spreading it in small numbers, mainly northwards.

The epizootic recorded in Ngarama and Bukanga in 1910–11 was due to “direct” transmission following the introduction of infected cattle from the south.

The influx of man in 1914–15 through the Nyaruambu and Kafunza centres, chiefly the former, caused marked disturbances and rapid spread of the fly, principally along the line of communication to the north.

The sudden withdrawal of the human element resulted in marked diminution of fly density, and the advent of rinderpest in 1919 destroyed an important alternative food supply, thus giving further impetus to the reduction.

After a period of 27 years the tsetse had retired to those two points from which it had originally spread.

The Kakitumba centre had not suffered human invasion, as did the foregoing, and no great activity of Glossina has therefore been recorded.

The picture presented is that man himself has proved the greatest factor in that wide and rapid spread of Glossina which Ankole experienced during 1907–1917.

Glossina palpalis fuscipes Newst. was studied in lake-side forest in north-east Lake Victoria and in riverine forest on the Kuja river, which runs into Lake Victoria. Climatic records are given. Trees counts were made in fifty acres of lake-side forest.

Populations of G. palpalis exhibit long-term fluctuations which are not annual and not related to season. On the lake shore, the density of G. palpalis is roughly correlated with the width of the forest, being least where the forest is narrow. In a block 2,200 yeards along the shore by 100 yards wide (this was the widest forest studied) the population was 4,600 non-teneral males. The mean catch along the 2,200 yards of shore was 78 non-teneral males. Calculated on an area basis, this is more than ten times the population which would be inferred from the same catch of G. morsitans or G. swynnertoni. The mean death-rate in this isolated block was 26 per cent. per week, and the mean length of life was 27 days.

Analysis of catches indicates that riverine G. palpalis are always more hungry than those on the lake shore, for the percentages of tenerals, of females, and of males attacking, are all higher on the river. Catches from a boat produce more females but fewer males than land catches. Carrying a screen produced more females on some occasions, but not on others, the discrepancy being unexplained.

The Rutherglen bug is a well-known pest of fruit trees, vines and other crops in Australia, and has been recorded from every State in the Commonwealth, even Western Australia not being free from it.

The identity of this insect has been uncertain for some time past, although it has been assumed in economic literature that the species described by Bergroth in 1891 as Nystus vinitor is identical with the Rutherglen bug, since it is the only representative of the genus Nysius to have been described from Australia.

In 1927 Mr. R. Veitch, Chief Entomologist of the Department of Agriculture and Stock, Brisbane, sent a collection of Nysius spp. to the Imperial Bureau of Entomology for determination. They were handed over to Mr. W. E. China, of the British Museum, to whom I am indebted for the very considerable assistance given me in the preparation of this paper.

The collection, which consisted of a number of insects off different plants and from various localities, contained two distinct species, one of which agreed with Bergroth's very inadequate description of N. vinitor (I have not seen the type) ; the other turns out to be a new species, which I propose to name Nysius clevelandensis, since all the locality labels of this insect were marked Cleveland.

In undisturbed annual pasture in a Mediterranean-climate region of Australia adults of the whitefringed weevil, Graphognathus leucoloma (Boheman), were present from summer to early winter (December–June), with upsurge in numbers of first instar larvae only occurring after the rains began in April. The G. leucoloma population was predominantly first instar larvae in high abundance throughout the winter period (May–August). Larval growth, with high mortality, occurred in the spring period (September–January). The survival of eggs during the dry summer when adults were most abundant, although only at times of unseasonal rainfall, indicated that low larval recruitment at that time resulted primarily from the absence of high-quality legume food essential for oogenesis. It was inferred that most larvae arose from heavy oviposition by the few adults present in autumn when rainfall germinated annual legumes. A steady year-round abundance of late-instar larvae indicated that not all individuals completed their development in the one year.

Zeteticontus utilis sp. n., an encyrtid parasite of larvae of Carpophilus hemipterus (L.) and Urophorus humeralis (F.) in pineapple fields in Kenya and of C. hemipterus larvae in decaying fruit in Israel, is described. The parasite has been released in an attempt to control C. hemipterus in pineapple fields in Hawaii and is to be released against the same pest in Ohio.

The temperature-dependent development of Apanteles hemara (Nixon), a larval endoparasitoid of the devastating amaranth pest Spoladea recurvalis (F.) was studied in the laboratory at six constant temperatures (10, 15, 20, 25, 30 and 35 °C), a photoperiod of 12L:12D and a relative humidity of 60–70%. Developmental time decreased significantly with increasing temperature within the range of 15–30 °C. The parasitoid's pupal mortality, successful parasitism rate, adult emergence rate and longevity, sex ratio and fecundity were affected by temperature. The population of A. hemara failed to develop at 10 and 35 °C. The development threshold (Tmin) and the thermal constant (K) were calculated by the linear model while the lethal temperature (Tmax) was determined by the Lactin-1 model. The estimated values of Tmin, Tmax and K by the two models were 10.3 °C, 35.0 °C and 185.18 DD respectively for the total immature development. The estimated value of the optimum temperature using the Taylor model was 30.8 °C. This is the first study to report on the effect of temperature on the developmental parameters of A. hemara giving an insight into its biology. The implications of these findings for the use of A. hemara in biological control are discussed.

The classification of a Landsat Thematic Mapper satellite image helped demonstrate prevailing habitat types and land use intensity in the Volta basin of the Northern Region of Ghana. A geo-referenced data layer comprising the capture results of a cross-sectional survey of Glossina tachinoides Westwood was over-laid on a data layer of habitat types within 500 m of either bank of the Volta river and its tributaries. An evaluation of the relationship between habitat types and the capture results of G. tachinoides suggested a strong preference of G. tachinoides for woodland, followed by shrubland, grassland and flood plains. The findings were used to classify the suitability of habitat types for G. tachinoides as ‘high’, ‘medium’ and ‘low’ and a prediction map for the distribution of G. tachinoides in the entire river network was produced. The usefulness of this method in estimating the potential distribution of G. tachinoides in an area of increasing agricultural expansion is discussed.

This genus was recently described by Dr. Speiser and is a very characteristic one, on account of its elongate and slender body and bare 3rd longitudinal vein. The species belonging here, as long ago pointed out by Loew, have a great resemblance to those of the genus Elaphromyia, but they are at once distinguished by the thin and black occipital row, by the pointed lower angle of the anal cell and by the non-reticulate wing pattern. The genus is evidently allied to Ocneros, but has nothing to do with Rioxa. I will give here some additional details to the short description of Dr. Speiser

Information about the recorded distribution of the tick, Rhipicephalus sanguineus (Latr.) was accumulated in the same way as that gathered and mapped by Buxton (1941) for certain fleas. The search of the literature which was begun by Miss Benzian was continued by me to January, 1949. Besides the examination of original papers the following were consulted : Review of Applied Entomology, Series B, Tropical Diseases Bulletin and Zoological Record.

The emergence of resistance mechanisms to, and revocation of, many insecticides used in the control of the polyphagus aphid pest, Myzus persicae (Sulzer), has increased the pressure to develop novel approaches for the control of the pest in many crops. Kaolin-based particle films provide a physical barrier against insect pests and show considerable potential for controlling M. persicae. We conducted a series of laboratory experiments to investigate the mode of action of kaolin against aphids. The material appeared to have no direct effect on M. persicae; spraying adult aphids with aqueous kaolin suspension had no significant impact on their subsequent survival or reproduction on untreated plants. Similarly, when aphids were placed on kaolin-treated host-plants (Brassica oleracea), their performance (survival, growth rate and reproduction) was not significantly different from aphids on untreated plants. However, when M. persicae were given a choice between kaolin-treated and untreated (or water solvent-treated) leaf areas, both adults and nymphs exhibited a significant preference for non-kaolin-treated host-plant material. Rejection of kaolin-treated plant material occurred very rapidly (within 20 min) and this behavioural effect may be related to the efficacy of kaolin in controlling aphids under field conditions.

Pitfall traps baited with cattle dung are commonly used to characterize local assemblages of coprophilous insects. Baits can be made fresh or be prepared in advance and kept frozen until needed. Insect recoveries are expected to decline with the age of the bait and may be affected by the use of fresh vs. frozen baits. To assess the effect of these two factors on insect recoveries, we performed a pitfall trap experiment that was repeated in four trials spanning 2 years and two locations in southern Alberta, Canada. The experimental design allowed us to minimize the potential confounding effect of short-term weather events. For results combined across trials, baits aged >3 days were largely ineffective for attracting coprophilous species. Frozen baits attracted significantly more insects than did fresh dung for the first 3 days after placement in the field with no difference thereafter. Our findings suggest that insect recoveries in dung-baited pitfall traps can be maximized with the use of frozen baits with replacement every 3–4 days.

Mercury and tin amalgam were tried in mud bins, metallic bins and bamboo bins at different places in the Punjab. Mercury distributed throughout the bin at the rate of 3–4 tolas per maund of wheat proved effective in completely checking the increase of various stored grain pests. Mercury used at the bottom and top 10–12 in. layer of grains in the bin also proved fairly effective. Tin amalgam even with as high a dose as 13½ tolas per maund of wheat did not prove effective. Loss of mercury during use is very slight. Mercury has no deleterious effect on the germination or eating quality of wheat.

Mercury kills the fresh eggs of stored grain pests, but the eggs in an advanced stageof development are not adversely affected. It retards the growth but does not kill the larvae of T. granarium and Bruchus sp. It has no effect on the pupae, but affects the egg laying capacity of adults very slightly.