The material here described has been received by the Imperial Institute of Entomology, and I am indebted to Sir Guy Marshall for the opportunity of studying it. The types have been presented to the British Museum (Natural History).

The following is a list of the more important insects collected in the Province of Mozambique (Portuguese East Africa) and which in some stage of their existence may be harmful to men or animals. During the writer's stay in Mozambique it was impossible to make a complete survey of that immense colony, but as much collecting was done as opportunity offered and this list may be considered a fairly representative one.

A small reclamation experiment staged in the coral rag thicket under unfavourable conditions proved successful in eradicating Glossina austeni and G. brevipalpis and in virtually eradicating G. pallidipes. Applied with adequate protective clearings, it is thought that the method may prove entirely successful in eradicating G. pallidipes as well as G. austeni and G. brevipalpis.

Under both dry and wet season conditions traps proved quite ineffective.

Experiments were carried out in West Bengal to ascertain whether the Paddy Stem Borer, Schoenobius incertulas (Wlk.) could be controlled by “Tetrax” 1, a systemic insecticide containing technical schradan equivalent to approximately 42 per cent, octamethyl pyrophosphoramide + approximately 25 per cent, triphosphoric acid pentadimethylamide.

In a preliminary experiment, treatment had little effect on the damage caused by the borer but the yield of grain was higher from a treated plot than from a control plot.

A further experiment was carried out, the following year, in which the seed was soaked in a 0·1 per cent, water solution of “Tetrax” 1 for eight hours before sowing in the seed beds. The seedlings were lifted about 2½ months later and steeped in 0·1 per cent. “Tetrax” 1 for eight hours before transplanting into two plots, each 32 ft. × 32 ft. About three weeks later the plants were sprayed with a solution of the same strength. Two plots of similar size, in which the paddy had received no treatment, were maintained as controls.

Again there was very little difference, between the treated and untreated plots, in the damage caused to the ear heads by the pest, but the treated plots produced 108·68 lb. of grain as against 77·27 lb. for the untreated plots. The increase was largely due to an increase in the number of ear heads per plant.

The incidence of the borer was too low in both experiments to determine whether “Tetrax” 1 exercised any appreciable control, but the treatment did give rise to a higher yield of grain under the conditions of the experiments.

Glossina pallidipes does not readily attack objects moving along the edge of vegetation forming its habitat; fewer tsetse attack under humid than Under dry conditions, but those that do seem to range further.

Parties of men moving out of heavily infested thicket did not carry tsetse far into the open. Few tsetses attached themselves to the men and these became gorged within a few yards of the thicket edge. Similar results were obtained when bait cattle were used.

Experimental catches in a glade showed, even during the humid season, an extraordinary reluctance on the part of G. pallidipes to approach a party moving through the glade even at so short a distance as 8 yards from the thicket, but further experiments showed that a party staying in the glade for a short time made a much larger catch.

Trilocha varians is one of the major pests of Ficus spp. Based on 19 bioclimatic variables provided by the Worldclim, our study analysed the suitable distribution areas of T. varians under current and future climate changes (SSP1-2.6, SSP2-4.5, SSP5-8.5) for two periods (the 2050s and 2090s) using the maximum entropy algorithm (MaxEnt) model. Key environmental variables affecting the geographic distribution of T. varians were also identified, and the changes in the area of suitable range under current and future climate changes were compared. The results showed that the key environmental variables affecting the distribution of T. varians were temperature and precipitation, comprising annual mean temperature (bio1), temperature seasonality (standard deviation × 100) (bio4), precipitation of driest month (bio14), and precipitation of driest quarter (bio17). Under the current climatic conditions, the suitable distribution area of T. varians is within the range of 92°13′E–122°08′E, 18°17′N–31°55′N. The current high, medium, and low suitable areas for T. varians predicted by the MaxEnt model are 14.00 × 104, 21.50 × 104, and 71.95 × 104 km2, of which the high suitable areas are mainly distributed in southern Guangdong, southwestern Guangxi, western Taiwan, Hong Kong, and Hainan. Under different future climatic conditions, some of the high, medium, and low suitability zones for T. varians increased and some decreased, but the mass centre did not migrate significantly. The Pearl River Basin is predicted to remain the main distribution area of T. varians.

Aldehyde oxidases (AOXs) are a group of metabolic enzymes that play critical roles in the degradation of xenobiotics and chemicals. However, the physiological function of this enzyme in insects remains poorly understood. In this study, three TcAOX genes (TcAOX1, TcAOX2, TcAOX3) were identified and characterized from Tribolium castaneum genome. Spatiotemporal expression profiling showed that TcAOX1 expression was most highly expressed at the early pupal stage and was predominantly expressed in the antennae of adults, indicating that TcAOX1 was involved in the degradation of chemical signals; TcAOX2 expression was most highly expressed at the late pupal stage and was mainly expressed in the fat body, epidermis of larvae and adults, respectively; and TcAOX3 expression was in all stages and was primarily expressed in the head of adults. Moreover, the transcripts of TcAOX2 and TcAOX3 were significantly induced after exposure to plant oil, and RNA interference (RNAi) targeting of each of them enhanced the susceptibility of beetles to this plant toxicant, suggesting that these two genes are associated with plant toxicant detoxification. Intriguingly, knockdown of the TcAOX1 led to reductions in female egg-laying but unchanged the hatchability and the development of genital organs, suggesting that this gene may mediate fecundity by effecting the inactivation of chemical signals in T. castaneum. Overall, these results shed new light on the function of AOX genes in insects, and could facilitate the development of research on pest control management.

The larvae and pupae of Elachiptereicus abessynicus Becker and of Pachylophus lugens Lw. are described and illustrated and those of the latter species are compared with those of Pachylophus beckeri Curr. A previous misidentification of P. beckeri is recorded and additional records of host plants and distribution are given for all three species.

Diabrotica speciosa is an important pest of several crops in South America, including soybeans. Adults cause severe defoliation in soybean plants, and damage is significant when cotyledons are attacked. This study evaluated feeding non-preference to D. speciosa adults using 10 soybean genotypes, testing (i) 15-day-old whole plants and (ii) leaf disks of 60-day-old plants, through assessments of soybean attractiveness and leaf area consumed (LAC). Foliar contents of flavonoids and nutrients, and leaf trichome density were quantified for potential correlations with soybean resistance to adult of D. speciosa. In the whole young-plant experiment, under free-choice conditions, the lowest LAC was observed in IAC 100 and PI 227687. In no-choice, PI 227687 and IGRA RA 626 RR showed lower LAC than the other genotypes. In the leaf disk test, in free-choice, the genotypes IAC 100, PI 274454, PI 227687, DM 339, and BR 16 were the least preferred by adult of D. speciosa. In no-choice, PI 274454 was one of the least preferred, similarly to IGRA RA 626 RR, Dowling, and PI 227687. In the whole plant experiment, a high rutin content and low amounts of zinc, calcium, sulfur and manganese were associated with less consumption of D. speciosa on leaves of resistant genotypes. In contrast, in the leaf disk test there was a significant influence of trichomes in soybean resistance to the pest. In conclusion, the PI lines herein assessed are also promising sources for developing cultivars resistant to D. speciosa.

Many plant bugs (Miridae) are generalist herbivores that feed on multiple host species. The reasons these bugs move across hosts and the behavioural mechanisms responsible for their retention at specific hosts remain elusive. Green mirids (Creontiades dilutus) are endemic to Australia. These insects are important pests of cotton (Gossypium hirsutum) and even in low numbers can cause substantial damage to crops. These bugs are also present in relatively much higher numbers on pigeon pea (Cajanus cajan) planted alongside cotton fields, and evidence shows they move across these crops in both directions. Observations of these highly mobile insects in the field are challenging, but indirect evidence suggests that they may be nocturnal. This study evaluated: (1) the diel (24 h) period in which C. dilutus adults were most active, (2) whether they respond to plant volatiles immediately prior to landing on host substrates, and (3) if their presence on a host is in response to attraction or arrestment cues. The results suggest that C. dilutus bugs are typically most active early in the evenings, after remaining motionless during the day (unless disturbed). Their movement (at night) was arrested by hosts prior to touching plant tissues. There was no evidence to suggest that these bugs are attracted by volatiles beyond 2 cm. These outcomes demonstrate that insect behaviours need to be investigated within their typical activity periods, and that arrestment cues possibly play a central role in the host finding process of generalist C. dilutus and probably, therefore, other mirid species.

In the Mediterranean and temperate regions, an increase in the frequency and intensity of drought events has been recorded, probably due to climate change. In consequence, trees will more frequently experience hydric stress, a condition that can be expected to affect insect–tree interactions, while adaptation mechanisms may be further in course. The effect of tree water stress on the performance of two allochronic populations of Thaumetopoea pityocampa was here studied. Namely, we compared a unique population of this insect, in which the larvae develop in the summer (SP), with the typical population having winter larval development (WP), to test the adaptation hypothesis to host plant status. Larvae of each population were fed on needles of young potted Pinus pinaster plants under two water supply regimes: (i) well-watered (control) and (ii) subjected to 3 months of drought stress. Compared to control, stressed plants had higher amounts of soluble sugars, phenols, and higher C/N ratio, whereas water content and chlorophylls concentrations were lower. In general, T. pityocampa larvae had lower performances on water-stressed plants, as shown by lower survival rates, lower needle consumption, and longer development times. Yet, the detrimental effects of tree stress were only significant for the WP larvae, while SP larvae were able to overcome such conditions. Results demonstrate that tree water stress can negatively affect T. pityocampa populations. Furthermore, the evidence is also provided that responses to the physiological condition of the host trees may occur at the population level, as a result of adaptation mechanisms driven by climate change.

The silkworm Bombyx mori (Lepidoptera: Bombycidae) is a lepidopteran model insect of great economic importance. The parasitoid Exorista sorbillans (Diptera, Tachinidae) is the major pest of B. mori and also a promising candidate for biological control. However, the molecular interactions between hosts and dipteran parasitoids have only partially been studied. Gene expression analysis by reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR) is indispensable to characterise their interactions. Accurate normalisation of RT-qPCR-based gene expression requires the use of reference genes that are constantly expressed irrespective of experimental conditions. In this study, the expression stability of 13 traditionally used reference genes was estimated by five statistical algorithms (ΔCt, geNorm, Normfinder, BestKeeper, and RefFinder) to determine the best reference genes for gene expression studies in different tissues of B. mori under E. sorbillans parasitism. Specifically, TATA-box-binding protein was the best reference gene in epidermis and testis, while elongation factor 1α was the most stable gene in prothoracic gland and midgut. Elongation factor 1γ, ribosomal protein L3, actin A1, ribosomal protein L40, glyceraldehyde-3-phosphate dehydrogenase and eukaryotic translation initiation factor 4A were the most suitable genes in head, silk gland, fat body, haemolymph, Malpighian tubule and ovary, respectively. Our study offers a set of suitable reference genes for gene expression normalisation in B. mori under the parasitic stress of E. sorbillans, which will benefit the in-depth exploration of host-dipteran parasitoid interactions, and also provide insights for further improvements of B. mori resistance against parasitoids and biocontrol efficacy of dipteran parasitoids.

Effects of host species, stage and size on clutch size and sex ratio of the gregarious, idiobiont ectoparasitoid Dibrachys boarmiae were investigated at 25±2°C and 70±5% relative humidity. The greater wax moth, Galleria mellonella, small wax moth, Achroia grisella, and early stage solitary larvae of the endoparasitoid, Apanteles galleriae, were used as hosts. Clutch size was greatest from prepupae of the largest host, Galleria mellonella, with a mean of 40.07 offspring per host versus 14.73 and 2.93 for Achroia grisella and Apanteles galleriae, respectively. The mean clutch size from pupae was lower than from prepupae, being 17.27, 10.73 and 2.89 for Galleria mellonella, Achroia grisella and Apanteles galleriae, respectively. Within each host species and stage, heavier hosts resulted in larger clutches. The sex ratio of offspring (proportion of male) was approximately 0.20, with only minor differences among host species, stages and sizes.

Decreased reliance on pesticides can be achieved through a clever use of eco-evolutionary knowledge via intercropping economically valuable crops with companion plants that can hamper pest outbreaks. We created a greenhouse multi-layered microcosm system to test two potato peach aphid clones, performing alone or in competition, on mixes of genetically variable cultivars of cabbage, with and without onion. The onion acted as a nuisance/disturbance for the pest, which was generally for the benefit of the cabbage albeit both plants sharing space and nutrients. The onion effect was context-specific and differed by aphid genotype. Onion variable nuisance negatively affected the numbers of one aphid genotype (green) across all contexts, while the other genotype (pink) numbers were decreased in two contexts only. However, the green performed better than the pink on all cases of cabbage di-mixes despite its numbers being capped when the onion was present. Further, there was also a general aphid propensity to wander off the plant along with a differential production of winged morphs to escape the onion-affected environments. Moreover, through a comparative increase in dry mass, which was subject to onion and aphid effects, a diversity effect was found where the cabbages of fully genetically variable microcosms sustained similar final dry mass compared with non-infested microcosms. Our findings provide fresh insights into the use of multi-layered contextual designs that not only allow disentangling the relative effects of genetic variation and modes of interaction, but also help integrate their benefits into pest management in view of companion planting.

Insects breathe using one or a combination of three gas exchange patterns; continuous, cyclic and discontinuous, which vary in their rates of exchange of oxygen, carbon dioxide and water. In general, there is a trade-off between lowering gas exchange using discontinuous exchange that limits water loss at the cost of lower metabolic rate. These patterns and hypotheses for the evolution of discontinuous exchange have been examined for relatively large insects (>20 mg) over relatively short periods (<4 h), but smaller insects and longer time periods have yet to be examined. We measured gas exchange patterns and metabolic rates for adults of a small insect pest of grain, the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), using flow-through respirometry in dry air for 48 h. All adults survived the desiccating measurement period; initially they used continuous gas exchange, then after 24 h switched to cyclic gas exchange with a 27% decrease in metabolic rate, and then after 48 h switched to discontinuous gas exchange with increased interburst duration and further decrease in metabolic rate. The successful use of the Qubit, a lower cost and so more common gas analyser, to measure respiration in the very small T. castaneum, may prompt more flow-through respirometry studies of small insects. Running such studies over long durations may help to better understand the evolution of respiration physiology and thus suggest new methods of pest management.

Aphidophagous hoverflies (Diptera, Syrphidae, Syrphinae) are common flower visitors and aphid predators in a range of flowering plants, including fruit crops. Here, we investigate whether aphid prey DNA can be detected in the gut contents of hoverfly larvae from a commercial strawberry field as a proof of concept that a molecular approach can be used to measure agricultural biocontrol. We used high-throughput sequencing (HTS) to target insect DNA and compared the resulting data to reference databases containing aphid and hoverfly DNA sequences. We explored what impact incorporating wildflowers within polythene-clad tunnels may have on aphid DNA detection rates in hoverfly larvae. In a randomized block experiment, coriander (Coriandrum sativum), field forget-me-not (Myosotis arvensis) and corn mint (Mentha arvensis) plants were inserted in rows of strawberries. Their effect on aphid DNA detection rates was assessed. Aphid DNA was found in 55 of 149 specimens (37%) validating the method in principle for measuring agricultural services provided by hoverflies. Interestingly, detection rates were higher near plots with forget-me-not than plots with coriander, though detection rates in control plots did not differ significantly from either wildflower species. These findings confirm that hoverflies predate aphids in UK strawberry fields, and that HTS is a viable method of identifying aphid DNA in predatory hoverflies. We comment on the need for further method development to narrow down identifications of both predator and prey. We furthermore provide some evidence that there is an effect of intercropping strawberry crops with wildflowers which may affect aphid consumption in hoverfly larvae.

Climate factors, pesticides, and landscape in coffee agroecosystems directly affect the populations of the coffee leaf miner and its parasitoids. This study aimed to investigate the effects of climate factors, insecticide use, and landscape on natural parasitism, parasitoid diversity, and infestation of L. coffeella in coffee plantations in the Planalto region, Bahia, Brazil. Mined leaves were collected monthly in six coffee plantations with varying edge density, vegetation cover, landscape diversity in scales of 500 to 3000 m of radius, insecticide use, and climate factors. Closterocerus coffeellae, and Proacrias coffeae (Eulophidae) predominated in the pest's natural parasitism. Our record is the first for the occurrence of Stiropius reticulatus, Neochrysocharis sp. 1, Neochrysocharis sp. 2, and Zagrammosoma sp. in Bahia. Higher temperature and larger forest cover increased the coffee leaf miner infestation. Higher rainfall values, insecticide use, and landscape diversity decreased the pest infestations. Natural parasitism and species diversity are favoured by increase in temperature, forest cover, and edge density, while increase in rainfall, insecticide use, and landscape diversity lead them to decrease.The natural parasitism and diversity of parasitoid species of the coffee leaf miner have been enhancing in the areas with greater forest cover and edge density associated with low use of insecticides. The areas composed of different lands with annual croplands surrounding the coffee plantations showed less natural parasitism and parasitoid species diversity. The ecosystem services provided by C. coffeellae and P. coffeae in coffee crops areas require conservation and these species are potential bioproducts for applied biological control programmes.

The water hyacinth grasshopper Cornops aquaticum (Bruner 1906) constitutes an appropriate model to assess phenotypic and karyotypic variability in the context of differentiation and adaptation of insect populations because it occurs over a wide latitudinal range. This study represents a general analysis of phenotype, karyotype and molecular variation in native populations of C. aquaticum in South America. This is also relevant because this insect is considered a promising biological control agent of water hyacinth, a native South American aquatic plant but a pest in South Africa. Along Paraná and Uruguay River Basins, body size correlated negatively with latitude, and positively so with temperature and rainfall in both sexes. To test whether the chromosomal and phenotypic patterns were adaptive, we compared them with neutral microsatellite loci variation in populations from the medium and lower course of the Paraná River. Firstly, the lack of pairwise association between karyotype and phenotype distance matrixes with that of neutral loci suggested non-neutrality. Secondly, phenotypic differentiation for all morphometric traits (PST) was significantly larger than molecular differentiation (FST), indicating a prevailing divergence selection effect on the observed phenotypic patterns. Finally, the phenotypic and genotypic spatial structures – inferred from Bayesian approaches – were discordant: neutral genetic structure clustered together most populations except for the two southernmost, downstream ones, whereas phenotypic spatial structure groups together all the deltaic populations and singles out the two northernmost ones. The results suggest directional selection leading to higher centric fusion frequencies in the downstream populations and favouring morphometric optimal differences in relation to the environment.

It is fitting that this, first, Guest Editorial to the new-format Bulletin should be devoted to stored-product entomology since 1990 celebrates 50 years of the formal establishment of stored-product insect research and control programmes in Britain. It was in 1940 that the Pest Infestation Laboratory was established at Slough under the, then, Department of Scientific and Industrial Research, consolidating the work begun some 15 years earlier under Professor J. W. Munro in the Entomology Department of Imperial College; almost at the same time, the Infestation Control Division of the Ministry of Food (now MAFF) was set up as an inspectorial and advisory body. Much has been achieved and many organisational changes have taken place since then. The original organisations have come together under the umbrella of the Ministry of Agriculture, Fisheries and Food (MAFF) whilst the group which was initiated at Slough in 1951 to address problems of storage in tropical areas is now the Storage Department of the Overseas Development Natural Resources Institute (ODNRI), the scientific unit of the Overseas Development Administration, UK (ODA). Slough has become synonymous with stored product research in Britain and beyond; sadly, however, the ‘Slough connection’ is destined to end—the ODNRI department will move this year to join its sister departments in the institute's new major laboratory development at Chatham, Kent, whilst plans are in hand for the eventual relocation of the MAFF laboratory as part of the Central Science Laboratory of the Agricultural Development and Advistory Service (ADAS).