Glossina, tachinoides, Westwood, 1850, is a common tsetse fly and an important vector of trypanosomiasis in parts of West Africa.

This paper describes part of an extensive programme of research on new methods of controlling body lice carried out during 1940–1942. The work was initiated by Professor P. A. Buxton, F.R.S., with whom the writer was privileged to collaborate, and financed by grants by the Medical Research Council. The results proved for the first time the possibility of continuous protection against body lice over a period of several weeks after treatment. To some extent, the materials and methods of achieving this have now been improved or superseded; but it has seemed worth putting on record some details of technique and the results for their scientific interest.

Observations were made on crowded, laboratory-reared. 18–20-day-old males of Schistocerca gregaria (Forsk.) taking off in a wind tunnel. Depending upon the time of day, take-off, which was usually upwind, particularly at higher wind speeds, was related to food availability. Few locusts with full foreguts took off, especially at low air temperatures (20°C), while at high temperatures (35°C), 95% of ones starved for 6 h took off. At 30°C, there was little further increase with starvation for 24–30 h. Females containing large oocytes took off less readily than those with small ones. Take-off was also sometimes initiated by decreases in wind speed and light intensity, and sudden changes in air temperature. A distinct passing shadow stimulated take-off, but not the flickering shadows of other flying locusts. A period of flight immediately beforehand inhibited take-off. The results are discussed in relation to field observations.

We quantified the life table parameters and predation capacity of a generalist predatory mite, Typhlodromus bagdasarjani Wainstein and Arutunjan on five monotypic diets, including Tetranychus urticae Koch (TSSM) eggs in the presence (SW) and absence (SN) of webs, Trialeurodes vaporariorum Westwood (GHWF) eggs (G), honeydew (H), and maize pollen (M) as well as three mixed diets, including SN + M, SN + G, and G + M. Our results showed that the individuals fed on the mixed diets had a considerably shorter developmental time and pre-oviposition period (APOP), higher oviposition days, higher fecundity and population growth rate than those raised on the monotypic diets. Furthermore, we found that the mixed diet of TSSM and GHWF eggs was the most favorable diet, resulted in the highest fecundity and population growth rate, shortest developmental time and APOP. While TSSM eggs alone in the presence of webs and honeydew were the worst diets resulted in the longest developmental time, lower oviposition day, higher fecundity and population growth rate. Our data determined that TSSM has more nutritional benefits than GHWF for T. bagdasarjani. We observed the positive effects of pollen addition to prey on the predatory mite's immature and adult life-history characters; however, it reduced the predation rate. Overall, maize pollen could enhance ecosystem services provided against spider mites and whiteflies by positively impacting the increase of T. bagdasarjani population. This predator may be more effective when two prey species are available than when only one species is present.

Increasing evidence has demonstrated that the environmental conditions experienced by parents can shape offspring phenotypes. Here, we examined the effects of the photoperiod and temperature experienced by parents on the incidence of diapause in their progeny in the cabbage beetle, Colaphellus bowringi, using three experiments. The first experiment examined parental diapause incidence under different photoperiods at 25°C and the incidence of diapause in progeny from both non-diapausing and diapausing parents under the same rearing conditions. The results revealed that the incidence of diapause among progeny was exactly opposite to that of their parents, i.e., higher parental diapause incidence led to lower progeny diapause incidence, showing a negative relationship in diapause incidence between the parental generation and the progeny generation. The incidence of diapause among progeny produced by diapausing parents was higher than that in progeny produced by non-diapausing parents. The second experiment examined parental diapause incidence at different temperatures under LD 12:12 and the incidence of diapause in progeny from both non-diapausing and diapausing parents under the same rearing conditions. Similarly, the incidence of diapause in progeny was also opposite to that of their parents. However, the incidence of diapause in progeny produced by non-diapausing parents was different from that in progeny produced by diapausing parents. In the third experiment, naturally diapausing adults were maintained at a constant temperature of 9, 28°C or the mean daily summer temperature of 27.84°C under continuous darkness for 3 months of dormancy. After dormancy, the progeny of these post-diapause parents were reared under different photoperiods at 25°C. The results showed that the incidence of diapause among progeny was higher when their parents experienced high temperatures than when they experienced low temperatures. All results demonstrate that the photoperiod and temperature experienced by parents may significantly affect the diapause incidence among progeny.

In the course of general studies on control of Culex pipiens fatigans Wied. in British Guiana, the indigenous shrub Ryania speciosa, proven to possess insecticidal activity against certain agricultural pests, was investigated.

Aqueous extracts of the dried stem were shown to possess toxic properties against all larval stages of C. pipiens fatigans under clean laboratory conditions. Under conditions simulating a water-logged pit latrine, however, toxicity was greatly reduced by adsorption of the active agent ryanodine, rendering the crude stem relatively ineffective after 16 days. Because of the great bulk of unprocessed material required for even this limited result in pit latrines—which constitute an important local problem—Ryania was not considered of practical value in C. pipiens fatigans control.

Aqueous and alcoholic extracts of Ryania speciosa had no contact insecticidal properties against adults of this species.

The effect of a sub-sterilizing gamma radiation dose on Dacus ciliatus adults was investigated to assess the suitability of the sterile insect technique (SIT) as an alternative method to control this pest. Late pupae (48 h prior to adult emergence) from a laboratory strain were irradiated with 120 Gy of gamma rays emitted by a 60Co source. Following adult emergence, the mortality of irradiated and non-irradiated cohorts was recorded. Over a period of 50 days after emergence, no significant negative effects of irradiation upon the longevity of male or female laboratory flies were observed. A laboratory competitiveness study (Fried test), using irradiated laboratory and wild males at a ratio of 3:1 was conducted to assess the ability of irradiated males to reduce the egg hatch rates of a wild population. The overall competitiveness was found to be ca. 0.32, suggesting a reduced, but satisfactory, quality of irradiated laboratory as compared with wild males. Based on the above findings, we calculated and proposed effective male release ratios for field application of SIT against D. ciliatus.

The following descriptions and notes are based upon material received from H. Bennett Johnston, Assistant Government Entomologist, Wad Medani, Sudan, Africa.

Aponephus lentiformis, a new genus and species of Coccinellidae, is described from southern India and placed in the tribe Scymnini. It was found during searches for natural enemies of Rastrococcus spp.

Field trials were conducted to compare toxicity and residual activity on cattle of 18 acaricides against Rhipicephalus appendiculatus Neum., Amblyomma variegatum (F.), and Boophilus decoloratus (Koch). Ticks were counted one, four and seven days after the cattle were sprayed. Each of the seven experiments involved three sprayings at seven- to eight-day intervals.

Toxaphene at 0.25 per cent., included as a standard, was relatively slow acting compared to organophosphorous and carbamate acaricides, but was equal to or better than most of the new acaricides in residual activity and over-all effectiveness. Carbaryl, Mopham and toxaphene were tested at the highest concertration, 0.5 per cent., and found to have the maximum over-all effectiveness, including maximum residual activity. Nevertheless, even these treatments did not protexct cattle against tick attachment and engorgement for as long as seven days.

All acaricides tested were very effective against B. decoloratus and A. variegatum, but none completely prevented attachment of R. appendiculatus foe as long as four days, even though all were very toxic to this tick. The smallest number (1.8 per beast) of R. appendiculatus attaching in four days occurred on the cattle sprayed with 0.5 per cent. carbaryl, but by seven days after spraying there were many ticks attached and some were already partially engorged. The inference is that none of the compounds tested gave promise of prevention of tick-borne disease transmission when used on a seven-day schedule. No inference is made concerning tick-borne disease control by reduction of tick numbers on the pasture land.

Mortality among ticks on the cattle one day after treatment was greatest for 0.1 per cent. coumaphos, 0.25 per cent. Prolate, 0.05 per cent. Bayer 9053, 0.2 per cent. Geigy GS 13006, 0.2 per cent. and 0.5 percent. carbaryl, 0.1 per cent dioxathion, 0.05 per cent. Bayer 9037, 0.1 per cent. prothidathion, 0.1 per cent. Dursban, 0.2 per cent. and 0.5 per cent. Mobam, 0.025 per cent. and 0.05 percent. chlorfenvinphos, 0.2 per cent. fenitrithion and 0.1 per cent. ethion. Mortalities of 83.1 per cent. to 88.5 per cent. were given by 0.05 per cent. diazinon, 0.1 per cent. bromophos-ethyl, 0.025 per cent. Dursban, and 0.5 per cent. toxaphene. Mortality below 74 per cent. was caused by 0.25 per cent. toxaphene, 0.2 per cent. bromocyelen, and 0.1 per cent. carbophenothion.

Laboratory and field tests were made to investigate the toxicity, mode of action and persistence of technical DDT and γ BHC when applied to cacao in Ghana to control the Mirids, Distantiella theobroma (Dist.) and Sahlbergella singularis Hagl. The insecticides were tested at concentrations previously used in field trials. D. theobroma, S. singularis and Tribolium castaneum (Hbst.) were used as test insects. Preliminary tests with aldrin, chlordane and dieldrin were also made.

Cacao pods were sprayed to drip point with the test insecticides and the deposit was allowed to dry. Mirid nymphs were placed on the pods and the rate of knockdown and the mortality after exposure for a test period was recorded. These tests showed that BHC had a higher toxicity and acted much more quickly than DDT. BHC greatly reduced feeding.

Fumigant action was tested by spraying cacao leaves to drip point with the test insecticides, allowing the deposit to dry, and then exposing Mirid nymphs and adults over discs cut from the leaves. BHC had a powerful but transient fumigant action; adults, fifth- and second-instar nymphs were killed after, respectively, ½, 4 and 3 hours’ exposure at 28–30°C. over leaves treated with 0·25 per cent, γ BHC. No fumigant effect was observed after prolonged exposure over leaves treated with 2·5 per cent, technical DDT.

Persistence was studied by treating cacao leaves and pods growing under natural conditions and then testing the residual deposit at intervals. Tests with T. castaneum showed that when leaves were sprayed to drip point the residual toxicity of 1·25 and 2·5 per cent, technical DDT fell steadily and was negligible after an interval of three and six weeks, respectively; that of 0·25–2 per cent, γ BHC was negligible after 2–3 days. Corresponding tests with Mirids on pods were less consistent but suggested that 2·5 per cent, technical DDT was still effective against first-instar nymphs after three weeks; 0·25 per cent, γ BHC had a residual toxic effect for at least several days and depressed feeding greatly for at least a fortnight. It is suggested that BHC may have a local systemic action which persists after the surface deposit becomes ineffective.

Of the other insecticides tested, aldrin had a high toxicity and powerful fumigant action and appeared to be the most promising alternative to BHC.

It was concluded that BHC would be more effective than DDT when treating mature cacao because, in addition to its higher toxicity and quicker action, its fumigant action would compensate for incomplete coverage by low-volume spraying.

Species of Agonoscena (Hemiptera: Aphalaridae) are key pests of pistachio in all of the most important pistachio producing countries in the Old World. The efficiency and accuracy of DNA barcoding for the identification of Agonoscena species were tested using mitochondrial cytochrome c oxidase subunit 1 (mtCO1) and cytochrome b (cytb) gene sequences. Moreover, morphometric sexual dimorphism was studied. Finally, the potential geographical distribution of Agonoscena pistaciae, the most important pistachio pest, was calculated using the MaxEnt model. Similar relationships of clustering were found in the morphometric analysis and the molecular analyses with mtCO1 and cytb genes, with A. bimaculata and A. pistaciae being closely related, and A. pegani constituting their sister group. Although the results showed that the cytb gene is a better marker for barcoding in this group, the mtCO1 gene clearly separates the three psyllid species making mtCO1 suitable for diagnostic purposes. A geometric morphometric analysis showed that the distance between landmark number 7 (bifurcation of vein M) to the fore margin of the forewing, and the distance between landmarks number 6 (apex of vein Cu1b) and 11 (wing base), are the most important geometric characters for diagnosing the studied species. Moreover, the forewing shape of males vs females is similar in A. pistaciae and A. bimaculata but differs significantly in A. pegani. In the ecological niche modeling of the distribution of A. pistaciae, the most important contribution was made by the variable ‘minimum temperature of coldest period’. The most suitable areas for A. pistaciae are restricted to Eastern, Southern and some parts of Central Iran.

Mosquito surveillance programmes are essential to assess the risks of local vector-borne disease outbreaks as well as for early detection of mosquito invasion events. Surveys are usually performed with traditional sampling tools (i.e., ovitraps and dipping method for immature stages or light or decoy traps for adults). Over the past decade, numerous studies have highlighted that environmental DNA (eDNA) sampling can enhance invertebrate species detection and provide community composition metrics. However, the usefulness of eDNA for detection of mosquito species has, to date, been largely neglected. Here, we sampled water from potential larval breeding sites along a gradient of anthropogenic perturbations, from the core of an oil palm plantation to the rainforest on São Tomé Island (Gulf of Guinea, Africa). We showed that (i) species of mosquitoes could be detected via metabarcoding mostly when larvae were visible, (ii) larvae species richness was greater using eDNA than visual identification and (iii) new mosquito species were also detected by the eDNA approach. We provide a critical discussion of the pros and cons of eDNA metabarcoding for monitoring mosquito species diversity and recommendations for future research directions that could facilitate the adoption of eDNA as a tool for assessing insect vector communities.

Mahogany trees are attacked by two caterpillars which inflict a large amount of damage every year. One of these, Heteronygmiu leucogyna, Hmp. (Lymantriidae), eats the leaves, while the other, Mussidia albipartalis, Hmp. (Pyralidae), bores under the bark, causing much deformity of young trees and the formation of corky excrescences, accompanied by the exudation of resin.

In a series of notes and papers published in the last few years, the writer has attempted to apply simple mathematical methods to the study of the numerical increase of entomophagous parasites at the expense of their hosts. This work was undertaken mainly in the hope of bringing to light the general laws underlying parasitic interrelations, considered simply in their quantitative aspect. But since the publication of these papers the writer has frequently been questioned by entomologists as to the utility of the mathematical method in parasitological operations of the practical order.

The alarm behavior plays a key role in the ecology of aphids, but the site and molecular mechanism for the biosynthesis of aphid alarm pheromone are largely unknown. Farnesyl diphosphate synthase (FPPS) catalyzes the synthesis of FPP, providing the precursor for the alarm pheromone (E)-β-farnesene (EβF), and we speculate that FPPS is closely associated with the biosynthetic pathway of EβF. We firstly analyzed the spatiotemporal expression of FPPS genes by using quantitative reverse transcription-polymerase chain reaction, showing that they were expressed uninterruptedly from the embryonic stage to adult stage, with an obvious increasing trend from embryo to 4th-instar in the green peach aphid Myzus persicae, but FPPS1 had an overall significantly higher expression level than FPPS2; both FPPS1 and FPPS2 exhibited the highest expression in the cornicle area. This expression pattern was verified in Acyrthosiphon pisum, suggesting that FPPS1 may play a more important role in aphids and the cornicle area is most likely the site for EβF biosynthesis. We thus conducted a quantitative measurement of EβF in M. persicae by gas chromatography-mass spectrometry. The data obtained were used to perform an association analysis with the expression data, revealing that the content of EβF per aphid was significantly correlated with the mean weight per aphid (r = 0.8534, P = 0.0307) and the expression level of FPPS1 (r = 0.9134, P = 0.0109), but not with that of FPPS2 (r = 0.4113, P = 0.4179); the concentration of EβF per milligram of aphid was not correlated with the mean weight per aphid or the expression level of FPPS genes. These data suggest that FPPS1 may play a key role in the biosynthesis of aphid alarm pheromone.

Endoparasitoid species devoid of symbiotic viruses inject secretions derived from their reproductive glands into their hosts during parasitism in order to avoid various immune responses of their hosts. Pimpla turionellae L. (Hymenoptera: Ichneumonidae) is an endoparasitoid that lacks polydnaviruses, and its venom has previously been shown to paralyze the host Galleria mellonella (Lepidoptera: Pyralidae) and suppress its immune reactions to ensure the egg survival. The present study demonstrates that another female-injected factor calyx fluid extracted from the P. turionellae ovary is also responsible for the suppression of G. mellonella immunity. The total hemocyte counts of G. mellonella decrease after treatment with calyx fluid in a concentration-dependent manner. Significant reductions in cell viability are also observed at all calyx fluid doses both in vivo and in vitro. The analyses of the beads injected into the insects as encapsulation targets revealed that the number of encapsulated beads reduced significantly compared to controls post-calyx fluid injection. The injection of the highest calyx fluid dose (1 female equivalent calyx) is sufficient to completely inhibit the strong encapsulation and melanization reactions of the last instar larvae 24 h post-injection. These results demonstrate that P. turionellae calyx fluid is required to regulate host immunity for successful parasitization.

Radioactive (32P) and genetic (recessive eye-colour mutation) markers were used to estimate egg to pupal survival of Musca vetustissima Walker. Both marking techniques provided similar survival estimates under laboratory and field conditions in Australia. Egg to pupal survival rarely exceeded 10% in samples at intervals during spring and summer. Abiotic (dung quality and weather) and biotic (other dung fauna) mortality agents were both important in limiting the breeding success of M. vetustissima, being jointly responsible for a seasonal mean mortality of 93·8%.

A simple optical method for automatic recording and classification of a suction trap catch is described. The insects are illuminated against a dark background as they pass through a detection volume, and the amount of scattered light is used to measure insect size. The design centres on the detection volume, which is a volume through which the insects are made to pass, and within which they may be detected. The design is approached in four stages: 1. Delivery of insects to the detection volume. 2. Illumination of the detection volume. 3. Collection and detection of scattered light. 4. Signal analysis. The analysis could also be applied to related techniques. Results with a prototype demonstrate that classification into broad size categories is straight-forward (e.g. approximately three classes spanning body lengths of 2–7 mm), despite uncertainties of insect reflectivity, aspect and trajectory. Applications of the method are discussed, along with a brief mention of alternative techniques.

A method for physiological age determination in blackflies is described from studies on Simulium equinum (Linnaeus), S. ornatum Meigen, S. erythrocephalum (De Geer), and S. nigrum (Meigen) in Russia, and S. vittatum (Zetterstedt), and S.verecundum-venustum supercomplex in Canada. The method uses neutral red to stain the ovariolar structures which indicate preceding gonotrophic cycles. Two different processes can occur in the ovariole during the gonotrophic cycle: egg development with ovulation, or degeneration of a terminal follicle. Egg-sacs are resorbed and form zones of granulation which accumulate in the ovariole at each gonotrophic cycle. Following degeneration of the terminal follicle, a follicular relic (═gonotrophic dilatation) forms. The sum of zones of granulation plus follicular relics in each ovariole can indicate the number of completed gonotrophic cycles. However the number of follicular relics alone does not correspond to the number of preceding gonotrophic cycles and cannot reliably be used for determination of the parity of a female. Female flies collected in nature were categorized as: nulliparous; 1-parous; or multiparous. In multiparous females, most ovarioles have no more than two zones of granulation or a combination consisting of one zone of granulation and a follicular relic. Females in this category are considered to be 2-parous. In some ovarioles of parous females the germarium and terminal follicles were found to have disappeared.