1. An examination has been made of all specimens labelled Leucoptera daricella (Meyr.), standing in the collections of the British Museum and of the late E. Meyrick.

2. Crobylophora staterias, Meyr., and Crobylophora onychotis, Meyr., two species previously regarded as synonymous with Leucoptera daricella, are thought to be good species. The specimens of the former, which were bred from Plumbago, have been received from India and Ceylon ; the latter is an Indian species.

3. A new African species, Leucoptera caffeina, Washbn., is described, which causes damage to coffee trees.

4. Records of Leucoptera daricella have been investigated, and, as a result, the writer is of the opinion that this species has not yet been recorded outside Australia, and that records from Africa, India and Burma, prove unsubstantiated.

5. Lectotypes are cited of the species Leucoptera daricella (Meyr.), Crobylophora staterias, Meyr., Crobylophora onychotis, Meyr., and these are in the British Museum (Natural History), London.

An experimental control project against Simulium damnosum Theo. in Northern Nigeria using DDT in diesel oil as a larvicide is described. A description, together with a map, is given of the project area, some 1,200 sq. miles in extent, with a population of 32,000 persons, and it is emphasised that this was selected to provide information on the feasibility of control in an area not isolated from other fly foci.

Methods used in applying the larvicide to the rivers, which had rocky beds with rapids and falls, and assessing the effects of treatment are discussed. Applications were made at prearranged treatment points, weekly, for a period of 12 weeks in the dry season of two successive years, 1956 and 1957, and the post-treatment density of adult fly was assessed and compared in a Table and in histograms, with that existing in the year prior to treatment.

In the first year, a mean dosage per application of 1·4 p.p.m. of p,p′DDT applied over 30 minutes (S.D. = 0·5 p.p.m.) at each of four treatment points resulted in the clearance of all breeding for a distance of 15–23 miles below these points, and a reduction of adult fly density in the area of 96 per cent. as compared with pre-treatment density. But reinfestation of cleared breeding grounds was found to be rapid, these becoming repopulated with immature stages within six months in spite of a mean wet-season fly density of only 0·35 flies per boy-hour.

In the second year, with application of 1 p.p.m. of p,p′DDT for 30 minutes, results were less successful than in the first, although three additional treatment points were used with the aim of controlling a greater distance than in the first year, adult density being only reduced by an estimated 82 per cent. of that before treatment in the first year. The reasons for this are discussed, and the lower degree of control is attributed to the partial failure of the insecticide to reach the breeding sites owing to the exceptionally low state of the rivers.

The fly-rounds used in assessing adult density and the pre-treatment breeding sites and the positions of the treatment points are shown on maps. Detailed data from the fly-rounds are given in an Appendix.

With the exception of slight mortality among fish, thought to be due to accidental impediments to tbfi free downstream flow of the larvicide, no toxic effects on other organisms were observed.

The cost of treatment is given, and the results are discussed briefly in relation to the existing knowledge on control of S. damnosum. It is suggested that control by the application of larvicides in non-isolated foci is a practicable possibility, but that annual treatment might be necessary because of rapid re-establishment in cleared areas. The effect of control, of the degree obtained in this work, on the incidence of human onchocerciasis cannot yet be determined.

Field studies on the biting habits of Culicoides furens (Poey) were made near Montego Bay, Jamaica, during 1959 and 1960. Details of the experimental design and analysis have been given in the preceding article of this series. C. furens was collected in eight experiments, six on Florida beach, one at East Florida and one at White Bay. Four of the experiments were conducted at sunset, three at dawn and one in the night.

Malaya: Teluk Anson, 1 ♀, iii.1923 (G. H. Corbett), 3 ♀♀, 1 ♂, 18.iv.1930; Serdang, 1 ♀, 1 ♂, 17.i.1925 (G. H. Corbett); Kuala Lumpur, 1 ♀, 10.vii.1928 (G. H. Corbett & B. A. R. Gater).

Host. The three more recent series were bred from larvae of the Limacodid moth, Setora nitens, Walk.

The banana weevil (BW), Cosmopolites sordidus (Coleoptera: Curculionidae), is one of the most important insect pests of bananas and plantains. The mobility and the origin of BW infestations at the Canary Islands (Tenerife, La Gomera and La Palma) have been analysed using Random Amplified Polymorphic DNA (RAPD) as molecular markers. Populations from Costa Rica, Colombia, Uganda and Madeira were also included for comparison. One hundred and fifteen reproducible bands from eight primers were obtained. The level of polymorphism in the populations from the Canary Islands (40–62%) was in the range of those found in other populations. Nei's genetic distances, pair-wise fixation index (FST) values indicate that the closest populations are Tenerife populations among themselves (Nei's genetic distance=0.054–0.100; FST=0.091–0.157) and Costa Rica and Colombia populations (Nei's genetic distance=0.049; FST=0.113). Our results indicate the existence of BW local biotypes with limited gene flow and affected by genetic drift. These results are compatible with a unique event of colonization at Tenerife; whereas, the outbreaks in La Gomera and La Palma may come from independent introductions. The Madeira population is phylogenetically and geographically closer to the Canary Islands populations, suggesting that it is the most likely source of the insects introduced in the Canary Islands.

1. Flies of 9–10 and 16–19 days old were more susceptible to DDT than 4–5-day-old flies. Female flies were less susceptible than males, and large flies less susceptible than small flies to residual deposits of DDT. It is clearly important that flies used in comparative toxicity tests should be standardised for age, sex and size.

2. The strain Torre in Pietra was 3·6 times more resistant to dry deposits of DDT on Essex board than the Roma strain, but this resistance declined after culturing the strain in the laboratory for 22 generations.

3. The DDT-resistant strain (Torre in Pietra) was as susceptible as the non-resistant (Roma) strain to deposits of γ BHC on Essex board but was slightly resistant to pyrethrins.

4. The DDT resistance of the Torre in Pietra strain was increased readily by selection, yet a similar selection with DDT on the Roma strain was unsuccessful. This failure in the Roma strain may be due to the purity of the stock.

Two types of population history shown by Lasioderma serricorne (F.) are described, one when the food was renewed at regular intervals, the other when there was no food renewal. Initially, both of these populations increased together to a high level, the former continuing at this level until the observations were discontinued, the latter declining and eventually becoming extinct. Stage-specific properties, which relate the numbers in each stage to those a unit of time previously and which are functions of the survival, developmental and fecundity rates, were estimated for each type of population; they are compared as between the two types and with the corresponding properties of a population given effectively unlimited space and food. It is shown that the effect of the limiting conditions produced a decrease in survival, developmental and fecundity rates. From this, together with other evidence, it appears that food shortage, not space shortage, was the primary cause. After the initial increase in numbers, the stage-specific properties shown by the species in both populations imply that there was a regular oscillation in the developmental, survival or fecundity rates, which would result in corresponding fluctuations in numbers.

Bemisia tabaci biotype B is one of three genetic groups able to induce silverleafing in squash. Several earlier studies had observed that this physiological change was induced only through the feeding of juvenile whiteflies. This study uses adult males only to show that after 11 days the adult males were able to begin to induce silverleafing. Further, the response was density dependant with 120 adults inducing the first signs of silverleafing in 11 days, 90 adults in 13 days and 60 adults in 15 days.

A method of marking adult locusts, particularly useful when numbers are low and hand marking would be difficult, is described. It involves the use of a small hand spray gun from which a jet of paint can be directed at the locusts in spurts at ranges up to about 15 ft. The paints tested consisted of suspensions of pigments in light oil.

The paints are of low toxicity and the marks remain visible for many weeks. By the use of this method far more locusts can be marked in a given time than could be marked by hand. The efficiency of the method is reduced by high winds and dense vegetation, and it is more costly than hand marking. Most of the marked locusts cannot be recognised as such without being captured.

Some results obtained with this method in the French Sudan are given. In two months more than 50,000 locusts, Locusta migratoria migratorioides (R. & F.), were marked with a red paint; four were recovered 60 kilometres or more from the area in which they were marked, and the paint was clearly visible after five weeks.

Ways of improving the technique, and other possible methods of marking, are discussed.

Although some novel antimicrobial peptides (AMP) have been successfully isolated from Bactrocera dorsalis Hendel, the mechanisms underlying the induction of these peptides are still elusive. The homolog of NF-κB transcription factor Relish, designated as BdRelish, was cloned from B. dorsalis. The full length cDNA of BdRelish is 3954 bp with an open reading frame that encodes 1013 amino acids. Similar to Drosophila Relish and the mammalian p100, it is a compound protein containing a conserved Rel homology domain, an IPT (Ig-like, plexins, transcription factors) domain and an IκB-like domain (four ankyrin repeats), the nuclear localization signal RKRRR is also detected at the residues 449–453, suggesting that it has homology to Relish and it is a member of the Rel family of transcription activator proteins. Reverse transcription quantitative polymerase chain reaction analysis reveals that BdRelish mRNAs are detected in different quantities from various tissues and the highest transcription level of BdRelish is determined in fat body. The injection challenge of Escherichia coli and Staphylococcus aureas significantly upregulated the expression of BdRelish. The injection of BdRelish dsRNA markedly reduced the expression of BdRelish and decreased the transcription magnitude of antimicrobial peptides. Individuals injected BdRelish dsRNA died at a significantly faster rate compared with the control groups. Therefore, BdRelish is vital for the transcription of AMPs to attack the invading bacteria.

It is suggested that the attachment of the immature stages of certain species of Simulidae to mayfly larvae and to crabs is primarily an adaptation whereby the immobile Simulium pupa can obtain protection against disorientation with respect to the current, and against damage, in an environment where available inorganic substrata are liable to be displaced by violent water movement.

The principal evidence for this is that these associations typically occur in fast-flowing streams or rivers, and that the attached stages of Simulium include a disproportionately high number of pupae and large larvae. Any direct benefit the Simulium larvae themselves may derive from the association is regarded as a secondary feature of it.

Certain responses to physical factors, which might be expected in simulium larvae achieving successful attachment, are briefly discussed.

Sexual interaction is an important activity that determines the reproductive schedule of organisms and can ultimately influence the fitness traits of both sexes. Although the influence of sexual interaction on the fitness of females has been extensively determined, little is known about the effects on males, which often have different mating strategies and optimal mating regimes from those of females. To understand how mating regimes (timing and frequency) modulate the fitness in both sexes, we used spider mite (Tetranychus urticae) to investigate the influence of delayed mating and repeated mating on the fitness of male and female. For females, the unmated and the delayed mating females outlived those mated immediately after adult emergence. The repeated mating shortened the lifespan of females that mated at 1-day-old, but not that mated 7-day-old. However, no significant variation in lifespan was observed for males across different mating regimes. We found although delayed mating significantly reduced the daily reproductive rate of the females, there was no significant difference in lifetime reproduction of females across treatments because the delayed mating females increased their reproductive lifespan as a compensation. Our study highlighted that the time and frequency of sexual interaction showed a sex-specific consequence on male and female spider mites, indicating that sexual interaction incurs a higher cost to females which have a much lower optimal mating frequency than males.

An investigation using modified Manitoba traps on a forest track in Scotland showed that carbon dioxide, coloured spheres, movement, heat, Haematopota pluvialis (L.) and a swarm of other adults of Hydrotaea irritans (Fall.) were attractive. Traps with coloured spheres attracted more flies than traps without spheres. Matt black, shiny black and shiny red spheres attracted more males and females than did shiny green, white or yellow spheres. Significant increases in the number of flies caught did not occur when carbon dioxide was released from a trap at rates above 2 litres/min. Carbon dioxide seems to act as a long-range attractant, with vision becoming important near the host. Manitoba traps were also used with three repellents for H. irritans in order to evaluate the trap's potential for testing repellents.

Records of braconid parasitoids attacking bees (Apidae) are reviewed and their biology is discussed. The adult of Syntretomorpha szaboi Papp (Braconidae) is redescribed, the female for the first time. The final-instar larva is also described for the first time and the implications of interpreting larval characters are discussed. The Oriental honey bee, Apis cerana Fabricius, is recorded here for the first time as the host of S. szaboi.

Panonychus citri (McGregor) is the most common pest in citrus-producing regions. Special low-toxicity acaricides, such as spirocyclic tetronic acids and mite growth inhibitors, have been used for a long time in China. However, pesticide resistance in mites is a growing problem due to the lack of new acaricide development. Wide-spectrum insecticides, such as amitraz have gained acceptance among fruit growers. An amitraz-resistant strain of P. citri was obtained by indoor screening to examine field resistance monitoring of mites to acaricides and to explore the resistant mechanism of mites against amitraz. The amitraz-resistant strain of P. citri had an LC50 value of 2361.45 mg l−1. The resistance ratio was 81.35 times higher in the resistant strain of P. citri compared with the sensitive strain. Crossing experiments between the sensitive and resistant strains of P. citri were conducted, resulting in a D value of 0.11 for F1 SS♀×RS♂ and 0.06 for F1 RS♀×SS♂. Reciprocal cross experiments showed that the dose–mortality curves for the F1 generations coincided, indicating that the resistance trait was not affected by cytoplasmic inheritance. The dose–expected response relationship was evaluated in the backcross generation and a significant difference was observed compared with the actual value. The above results indicate that the inheritance of resistance trait was incompletely dominant, governed by polygenes on the chromosome. Synergism studies demonstrated that cytochrome P450s and esterase may play important roles in the detoxification of amitraz. Based on differential gene analysis, 23 metabolism-related genes of P. citri were identified, consistent with the results of synergism studies. Real-time PCR verification implied that P450s, ABC transporters, and acetylcholinesterase might influence the detoxification of amitraz by P. citri. These results provide the genetic and molecular foundation for the management of pest mite resistance.

The present study was conducted to appraise the ontogenic radio-sensitivity of a serious tropical pest, Spodoptera litura (Fabr.). The molecular responses pertaining to the phenoloxidase (PO) pathway and an anti-oxidant defense mechanism were evaluated in order to understand its implication in pest control at pre-harvest and post-harvest intervals. Irradiation exhibited an inverse relationship with age with respect to impact on developmental and transcriptional responses. Transcript abundance of PO cascade enzymes, prophenoloxidase (slppo-2), its activating enzyme (slppae-1) and free-radical scavenging enzymes, superoxide dismutase (slsod) and catalase (slcat) was evaluated upon gamma irradiation alone and the dual-stress of radiation plus microbial challenge. The slppo-2, slppae-1, slsod and slcat transcripts were significantly up-regulated in F1 L6 larvae (6th-instar) resulting from 100 Gy sub-sterilized male adults and unirradiated female moths. The extent of upregulation was relatively higher in comparison with L6 survivors (6th-instar larvae) developed from irradiated neonates (L1) treated with 100 Gy. Upon Photorhabdus challenge, the transcripts were down-regulated in irradiated L1 suggesting increased larval susceptibility to bacterial infections. Radioresistance increased with the age of the insect, and molecular responses (transcript abundance) of insect defense mechanism were less influenced when older age (F1 progeny) were irradiated. These findings will help to optimize the gamma dose to be employed in inherited sterility technique for (pre-harvest) pest suppression and (post-harvest) phytosanitation and quarantine, and suggest compatible integration of biorational tactics including nuclear technology.

The Asian subterranean termite Coptotermes gestroi is a worldwide structural pest, although its reproductive biology has been poorly investigated due to a cryptic habit and occurrence of polycalic nests. In this study, we investigated ovarian development and oogenesis in different-aged females of C. gestroi: fourth-instar nymphs, non-functional neotenics, alates, and functional queens. We show that the ovaries develop gradually according to their age and functionality, as younger individuals possess immature oocytes, whereas alates and functional queens always undergo vitellogenesis. Oocytes were classified into previtellogenic (stages I, II, and III) or vitellogenic (stages IV, V, and VI). Ovary development varied among non-functional neotenics, and a rapid differentiation and/or the presence of primary reproductives are believed to influence such a maturation. Immature oocyte stages were shared between fourth-instar nymphs and neotenics. These characteristics, together with other neotenic features (wing buds, body pigmentation, and eye color), should be evaluated in detail aiming to clarify which nymphal instars differentiate into secondary reproductives. Oogenesis was not uniform among alate females, and cross-sectional area of terminal oocytes was significantly smaller in alates when compared to functional queens, suggesting different degrees of maturation in swarming individuals. Functional queens always had mature terminal oocytes (stage VI). Ovariole number and oocyte maturation in C. gestroi relies on several factors and may therefore differ among individuals of the same caste. Future studies should take into account these reproductive features to evaluate how they impact colony development.

The hemlock woolly adelgid (Hemiptera: Adelgidae: Adelges tsugae Annand) is an invasive insect, introduced from Japan to eastern North America, where it causes decline and death of hemlock trees. There is a closely related lineage of A. tsugae native to western North America. To inform classical biological control of A. tsugae in the eastern USA, the density and phenology of three native western adelgid specialist predators, Leucopis argenticollis (Zetterstedt), Le. piniperda (Malloch) (Diptera: Chamaemyiidae), and Laricobius nigrinus Fender (Coleoptera: Derodontidae), were quantified in the Pacific Northwest. Infested branches were collected from western hemlock (Pinaceae: Tsuga heterophylla (Raf.) Sarg.) at four sites around the Puget Sound, Washington and three sites in Oregon. Immature Leucopis were identified to species using DNA barcodes. Leucopis argenticollis was roughly twice as abundant as Le. piniperda. Laricobius nigrinus larvae were more abundant than the two species of Leucopis during the egg stage of the first adelgid generation, but Leucopis were present as feeding larvae during the second adelgid generation when La. nigrinus was aestivating in the soil, resulting in Leucopis being more abundant than La. nigrinus across the entire sampling period. Adelges tsugae and La. nigrinus densities were not correlated, while A. tsugae and Leucopis spp. densities were positively correlated. Leucopis spp. and La. nigrinus densities were negatively correlated. These results support the complementary use of La. nigrinus and the two Leucopis species for biological control of A. tsugae in the eastern USA, and point to the need for further investigation of spatial and temporal niche partitioning among the three predator species.

Irradiation is a physical, environmentally friendly treatment which does not leave any residues in the product. It is increasingly used as an alternative to methyl bromide and other chemical fumigants for disinfestation of insect pest in stored grains. In this research, we try to evaluate the effect of low gamma irradiation doses in the range of 50–1200 Gy on the different stages of Callosobruchus maculatus. It was found that no adults emerged after irradiation of eggs at 450 Gy. No emerging adults (F1 generation) have been shown when larvae or pupae were exposed to 650 Gy. Also, no emerging adult has been shown from the parental C. maculatus adults irradiated with 650 Gy. When suppression of F1 generation was used for the measuring effective irradiation dose and phytosanitary efficacy, 650 Gy was required for disinfestation of cowpea seed weevils. The irradiation dose level of 650 Gy was used for the large-scale confirmatory tests applied to 27,754 adults of C. maculatus in cowpea seeds resulting in non F1 adults' production with a confidence level of 93.77%. All the physical and chemical characteristics of cowpea seeds were non-significantly (P ≤ 0.05) affected by the irradiation dose of 650 Gy. Meanwhile, this irradiation dose very slightly reduced the microbial load of cowpea seeds. We recommend the generic dose 650 Gy as the phytosanitary irradiation dose for the cowpea seed weevil.

Field studies in Zimbabwe of the orientation of males of Glossina morsitans morsitans Westwood to decoy ‘females’ (9 × 3-mm rectangles of 2-mm thick brushed nylon, baited with sex pheromone, 15,19,23-trimethyl-heptatriacontane, and placed on a vertical, 1-m2 black cloth screen) demonstrated that (1) no olfactory response to air-borne pheromone was involved in the orientation of males to decoys, (2) the presence of decoys on a stationary screen did not increase the numbers of males landing on the screen, but they directed landings onto the decoys or the adjacent screen surface, (3) males did not differentiate between black or brown decoys, (4) males were more attracted to vertically oriented decoys on the screen surface than to decoys held away from the surface, and (5) males were more attracted to decoys at the centre of the screen than to decoys near the top or bottom edges. Points 1, 2 and 4 also applied in the case of G. pallidipes Austen using decoys dosed with its pheromone (13,23-dimethylpentatriacontane), but this species preferred black to brown decoys and showed less overt sexual activity than G. m. morsitans. Males of G. m. morsitans each removed 1–2μg of pheromone by contact with a decoy, leading to a gradual loss of the decoy's stimulatory power.