Gas liquid chromatography (GC) was used to analyse the cuticular alkanes of 26 species and subspecies of tsetse flies (Glossina spp.). Unique interspecific and intraspecific (males vs. females) chromatographic patterns were observed. Solvent extraction of dried museum specimens and fresh specimens were equally successful, and left specimens undamaged. GC peaks were used as characters with one of five character states per peak, to show phenetic relationships among species by sex using a UPGMA algorithm, using 23 peaks for males and 40 peaks for females. Comparisons among species of the morsitans group often agreed with recognized morsitans group classification using morphological techniques, with G. austeni Newstead being somewhat aberrant. Glossina tachinoides Westwood was less closely related to others in the palpalis group than previously described using morphology. Eleven members of the rarely studied fusca group were also classified by this methodology.

In the North Block at Chungai, comprising about 11 sq. miles of thorn savannah and thicket in Central Province, Tanganyika, an Auster J5G aircraft was used between July 1959 and March 1960 to apply a 2·5 per cent. solution of dieldrin in oil at the rate of 0·125 gal. per acre in an attempt to eradicate Glossina morsitans Westw. and G. pallidipes Aust. Eight applications were made at approximately four-weekly intervals. Swath width was 55 yd., and the aircraft emitted the insecticide as a coarse aerosol of volume median diameter 50–60μ as it flew in both directions over the block.

The operation suffered delays, and three applications were incomplete to varying degrees. Kills of G. morsitans per application appeared to be 85 per cent. or higher, but the final reduction of 99·5 per cent. could theoretically have been attained with consecutive mortalities of only 65 per cent. It is suggested that this discrepancy may be due to the higher lethal dose required by pregnant females. G. pallidipes was also reduced by 99·5 per cent. Numbers of fly were reduced sufficiently for large-scale settlement with cattle, which should complete the work of exterminating the fly.

The experiment is compared with that of the previous year in the same block, using γBHC, which reduced fly catches by less than 50 per cent. It is concluded that a combination of reduced swath width, greater volume dosage, more lethal insecticide and smaller lethal drop, together with improved flying technique and the more reliable performance of the disseminating equipment, was responsible for the improved result. It is thought that without delays, interruptions, incomplete applications and reinfestation, even better results would be obtained.

This was the cheapest and one of the most successful aerial operations carried out against savannah tsetse. Costs actually over the ground were £301 per sq. mile; incidental costs due to the locality of operations were £66 per sq. mile. There is little chance of reducing the costs of flying directly, but economies are possible by the use of other insecticides or, more probably, by more efficient dispensing equipment.

This work was undertaken to unravel past confusion concerning the identity of certain economically important species of Cryptophlebia. It involved the study of several other species of the same genus and has resulted in the recognition of three new species and the transfer to Cryptophlebia of several species hitherto placed in other genera, mainly Argyroploce.

The three new species are described and 14 species are redescribed. The distribution of each is given and the food-plants are listed where known. The adult female and the male and female genitalia of each of the new species and certain others are illustrated.

In laboratories, the parasitism rate of Ostrinia furnacalis (Güenée) (Lepidoptera: Crambidae) eggs by Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) is low; however, efforts to control O. furnacalis with T. dendrolimi in the field have been successful. In this study, the effects of the number of attacks by T. dendrolimi against O. furnacalis eggs and diet of O. furnacalis larva on wasp development were investigated. The results indicated that more attacks increased significantly not only the successful parasitism rate of O. furnacalis eggs by T. dendrolimi, but also the percentage of host eggs that failed to develop into either O. furnacalis larvae or T. dendrolimi. Both the size and female proportion of T. dendrolimi offspring decreased as the number of attacks increased. The number of T. dendrolimi eggs laid in per host egg increased significantly as the ratio of wasps to host eggs increased from 1:5 to 3:5. Host diet also significantly affected the developmental time of immaturity and the emergence rate of adults of T. dendrolimi. These results illustrate how inundative releases of T. dendrolimi can successfully control O. furnacalis despite the fact that pest parasitism by the subsequent wasp generation decreases sharply in the field. The suitability of O. furnacalis eggs to T. dendrolimi and the superparasitism effects on offspring of T. dendrolimi are discussed.

The corn leaf aphid, Rhopalosiphum maidis (Fitch) (Hemiptera: Aphididae), is an important pest of corn, but no corn genotypes resistant to R. maidis are commercially available. Although the ability of silicon to induce plant resistance against some insects is known, the effect of silicon on R. maidis and in corn hybrids with different levels of constitutive resistance is still unknown. This study sought to determine the constitutive resistance of corn hybrids to R. maidis and silicon resistance induction in hybrids with different degrees of constitutive resistance. Field experiments with natural infestations of aphids were conducted in three locations in Brazil (Patos de Minas, Araguari, and Tupaciguara). Greenhouse trials were also used to evaluate the effect of varietal resistance on aphid population growth and identify resistant and susceptible genotypes. Aphid resistance induced by silicon was determined with resistant and susceptible corn hybrids. In the field, the corn hybrids BM8850, AS1625PRO, and DKB310PRO had the greatest proportion of plants infested by R. maidis in all three localities. The hybrids P30F53H, STATUS VIP, BM9288, DAS2B587HX, DKB175PRO, AS1633PRO, and DKB390PRO2 were the least infested in Patos de Minas and Araguari, and P30F53H was the least infested in Tupaciguara. When antibiosis effects were evaluated by aphid population growth, the hybrids AG7088PRO3 and DKB310PRO2 were susceptible, while P30F53YH was resistant. When natural aphid infestation was evaluated, wherein the effects of antibiosis and non-preference could not be discriminated, soil applications of silicon-induced resistance to R. maidis in both susceptible and constitutively resistant corn hybrids.

During the breeding seasons 1952 to 1955, samples of females of the Red Locust, Nomadacris septemfasciata (Serv.), were caught in the Rukwa Valley, Tanganyika Territory, and the ovaries classified according to egg length. Ovaries designated Class V were those regarded as containing eggs ready for oviposition. Population estimates and rainfall records were also taken.

The data suggested that the eggs in the ovaries develop very rapidly, becoming ready to be laid about seven days after the start of development.

The increase in weight of an individual female during ovary development is related to absolute size, and it was found that, during ovary development, the weight increases by approximately one-half.

The most important factor initiating ovarian development seemed to be a drop in daily maximum temperature to below 36°C. The factors of high humidity and rainfall were of less importance but their influence is not fully understood. The possibility of change in length of day being an important factor in the initiation of ovarian development is discussed.

The limiting factors for the number of egg-pods laid in a season are considered to be the dates of the drop in daily maximum temperature and of the drop or decline in parental population. The date of drop or decline in parental population seemed to be connected with the date of drop in daily maximum temperature.

The percentage of females laying more than one egg-pod was calculated, and the resuJts were found to vary considerably from year to year, although the average of 1 pods per female agreed with past estimates. Also, the average period of 16 days between successive egg-layings agreed with past work.

Drought, during the laying period, seemed to cause the females to retain their ripe eggs.

The evidence tended to confirm the possibility of a Red Locust population being able to increase 100-fold in a single year.

A general description of mass behaviour of the garden chafer, Phyllopertha horticola (L.), in the flight season was given earlier in this series (Milne, 1958). The outstanding features are two roughly equal and half-overlapping phases of activity: Phase 1, the swarming of the beetles over the grass sward, followed by Phase 2, the swarming on the surrounding bracken, hedges and trees. Investigation of sex proportions and mass reproductive state in the two phases permitted some deductions as to individual male and female behaviour (Milne, 1959a, b). In the present paper, further details of behaviour are given, and study of the flight season is concluded with a brief general discussion.

The stages of bush fly Musca vetustissima Walker, killed by the dung beetles, Onthophagus binodis Thunberg and Onitis alexis Klug, at low and high densities were measured in cattle dung of low nutritive value. A high level of M. vetustissima mortality occurred in the presence of Onitis alexis and Onthophagus binodis in experiments both in the laboratory at a constant 25°C, and exposed to summer fluctuating temperatures outside. The K values for total eggpuparia mortality increased curvilinearly with increasing log10 beetle numbers. The mortality of older larvae, k3, was most closely correlated with total mortality, K, where b = 0.720 and r2 = 0.931, while a lesser but significant correlation was obtained with mortality of young larvae, k2, where b = 0.291 and r2 = 0.645, but no correlation was obtained with egg mortality, k1, where b = −0.010 and r2 = 0.058. It is predicted that in unfavourable dung which occurs during summer, mortality of older bush fly larvae will be the key mortality caused by scarabaeine dung beetles.

The tachinid fly Exorista larvarum (L.) (Diptera: Tachinidae) is a polyphagous larval endoparasitoid that deposits its eggs on the host exoskeleton of lepidopteran and tenthredinid larvae. The attachment of larval E. larvarum and the formation of the respiratory funnel were studied during infestation in the last larval instar of the wax moth, Galleria mellonella (L.) (Lepidoptera: Pyralidae). The tachinid larvae burrow through the host integument after hatching, using their robust cephalopharyngeal skeleton, leaving a dark spot at the point of their penetration as a result of host cuticle melanization. Endoparasitoid penetration induces the host cellular defence, resulting in the formation of a haemocyte capsule consisting of multi-cellular sheaths. This enveloping capsule later undergoes melanization, which is mostly obvious towards the posterior part of the endoparasitoid. The endoparasitoid uses the host encapsulation response to build a respiratory funnel from the modified host integument, leading to the host surface. The encapsulated larva remains attached to the respiratory funnel via an anal hook and cuticular spines until fully developed. Additional immunohistochemical analyses were used to study host–parasitoid interactions. Indirect immunofluorescence showed no labelling of potential tachinid antigens and confirmed no effect on the surrounding host tissues. A simulated parasitization with coated polybead microspheres revealed the mortal impact of tachinid antigens to the host. Hosts injected with antigen-coated polybeads died as a consequence of an acute and extensive immunological response to the tachinid antigens and not due to the trauma caused by foreign objects inside their body.

A study has been made of the small moth-borers (Diatraea), the giant mothborer (Castnia), and the froghopper (Tomaspis) of sugar-cane, in their respective primitive environments, primarily with a view to finding new parasites for them and secondarily to obtain light on their ecology under agricultural conditions.

The original hosts of Diatraea saccharalis are shown to be certain aquatic and semi-aquatic grasses growing at the edge of forest creeks in the Orinoco Delta and of rivers flowing through the Venezuelan llanos, and in lakes of the Greater Antilles.

In the llano habitat D. busckella and D. impersonatella were found under indubitably primitive conditions.

The original host of D. canella, another destructive cane species include two forms of Paspalum millegrana, growing on the Trinidad littoral.

Variation in parasitism risk among hosts can arise from between-patch and within-patch factors, but considerably less information is known about the latter. This study investigated how distributions of the oriental fruit fly Bactrocera dorsalis influenced its parasitism by the pupal parasitoid Dirhinus giffardii in the laboratory. Because B. dorsalis larvae pupate underground, pupation depth was considered as an important factor that affects the risk of parasitism. When the density of B. dorsalis larvae was varied (1, 10, and 100 larvae per arena), average pupation depth increased with the density. When the depth of pupae was manipulated, the rate of parasitism differed by depths. Parasitism at 0 cm differed from the random parasitoid model expectation, but parasitism at 1 cm was not different from the model expectation. Few pupae at 2 cm were parasitized. In another experiment, when pupae were simultaneously presented at 0 cm and 1 cm depths, parasitism at 1 cm was weakened by the presence of puape at 0 cm. These results imply that the density of the host influences pupation depth as well as the distribution of parasitism and plays an important role in host-parasitoid dynamics.

The oriental fruit moth (OFM) Grapholita molesta (Lepidoptera: Tortricidae) is an important economic pest of stone and pome fruits worldwide. We sequenced the OFM genome using next-generation sequencing and characterized the microsatellite distribution. In total, 56,674 microsatellites were identified, with 11,584 loci suitable for primer design. Twenty-seven polymorphic microsatellites, including 24 loci with trinucleotide repeat and three with pentanucleotide repeat, were validated in 95 individuals from four natural populations. The allele numbers ranged from 4 to 40, with an average value of 13.7 per locus. A high frequency of null alleles was observed in most loci developed for the OFM. Three marker panels, all of the loci, nine loci with the lowest null allele frequencies, and nine loci with the highest null allele frequencies, were established for population genetics analyses. The null allele influenced estimations of genetic diversity parameters but not the OFM's genetic structure. Both a STRUCTURE analysis and a discriminant analysis of principal components, using the three marker panels, divided the four natural populations into three groups. However, more individuals were incorrectly assigned by the STRUCTURE analysis when the marker panel with the highest null allele frequency was used compared with the other two panels. Our study provides empirical research on the effects of null alleles on population genetics analyses. The microsatellites developed will be valuable markers for genetic studies of the OFM.

The survival of Oryzaephilus surinamensis (L.) and Sitophilus granarius (L.) adults at the surface and centre of two 40-tonne bins of wheat, each aerated at about 10 m3/h per tonne was studied in separate experiments over three successive years. In one bin, fan operation was controlled manually, but in the other an automatic differential thermostat was used. This switched on the fan when the centre of the bin was 2°C warmer than the ambient. O. surinamensis always survived better than S. granarius in the same bin and position. Both species survived better at the surface of each bin than at the centre, and both died quicker at the centre of the bin with aeration controlled with a differential thermostat, where the grain temperature was usually less than 4°C, than in the bin with aeration regulated manually, which was mainly above 6°C. However, there was no difference between bins in the survival of either species at the surface. S. granarius always died out in both positions in both bins, but O. surinamensis always survived at the surface of both bins, and in one year it survived at the centre of the bin with aeration controlled manually.

The tropical fire ant Solenopsis geminata (Fabricius) often nests very abundantly in the earthen banks (bunds) around irrigated rice fields in the tropics. Where some farmers habitually drain fields to the mud for about 3–4 days, the ants can quickly spread up to about 20 m into the fields where they collect food, including pest prey such as the eggs and young of the apple snail Pomacea caniculata (Lamarck) and insects such as lepidopterous larvae and hoppers, notably Nilaparvata lugens (Stäl) the brown planthopper (Bph) and green leafhoppers Nephotettix spp. Even in drained fields, the activity of S. geminata is restricted by rainfall in the wet season. The relatively few ant workers that forage characteristically into drained fields and on to the transplanted clumps of rice plants (hills) kill the normally few immigrant Bph adults but are initially slower acting than other species of the natural enemy complex. However, larger populations of Bph are fiercely attacked and effectively controlled by rapidly recruited ant workers; whereas, in the absence of the ant, the other natural enemies are inadequate. In normal circumstances, there is no ant recruitment in response to initially small populations of immigrant Bph and no evidence of incompatibility between ant foragers and other natural enemies such as spiders. However, when many ants are quickly and aggressively recruited to attack large populations of Bph, they temporarily displace some spiders from infested hills. It is concluded that, in suitable weather conditions and even when insecticides kill natural enemies within the rice field, periodic drainage that enables S. geminata to join the predator complex is valuable for ant-based control of pests such as snails and Lepidoptera, and especially against relatively large populations of Bph. Drainage practices to benefit ants are fully compatible with recent research, which shows that periodic drainage combats problems of ‘yield decline’ in intensively irrigated tropical rice and is also needed in South East Asia to make better use of seriously declining water supplies for irrigation.

House-resting Anopheles mosquitoes are targeted for vector control interventions; however, without proper species identification, the importance of these Anopheles to malaria transmission is unknown. Anopheles longipalpis, a non-vector species, has been found in significant numbers resting indoors in houses in southern Zambia, potentially impacting on the utilization of scarce resources for vector control. The identification of An. longipalpis is currently based on classical morphology using minor characteristics in the adult stage and major ones in the larval stage. The close similarity to the major malaria vector An. funestus led to investigations into the development of a molecular assay for identification of An. longipalpis. Molecular analysis of An. longipalpis from South Africa and Zambia revealed marked differences in size and nucleotide sequence in the second internal transcribed spacer (ITS2) region of ribosomal DNA between these two populations, leading to the conclusion that more than one species was being analysed. Phylogenetic analysis showed the Zambian samples aligned with An. funestus, An. vaneedeni and An. parensis, whereas the South African sample aligned with An. leesoni, a species that is considered to be more closely related to the Asian An. minimus subgroup than to the African An. funestus subgroup. Species-specific primers were designed to be used in a multiplex PCR assay to distinguish between these two cryptic species and members of the An. funestus subgroup for which there is already a multiplex PCR assay.

Achrysocharis diplosidis reared from galls of the Cecidomyiid Hyperdiplosis eupatorii Felt in Trinidad and Brazil is described, A. pulcherrima Kerrich is recorded from Pakistan, and a key separating these two gall-associated species of Achrysocharis Girault is given. Larval or pupal parasites of Promecotheca cumingii Baly (Hispidae) in Sri Lanka are described as Cotterellia lankensis, and of Promecotheca spp. in New Britain, Admiralty Is. and New Guinea Territory as C. insularis; C. podagrica Waterston is redescribed, and a key is given to the three species of Cotterellia Waterston ; the generic relatives of Cotterellia are discussed and a key separating this genus from Platocharis Kerrich and Schizocharis Kerrich is given. Rekabia Cameron is placed in synonymy with Euplectrus Westwood, and notes are given on material for a classification of the relatives of Stenomesius Westwood.

Observations have been made on the life-history and habits of C. cilicrura. The flies came to moist, freshly turned soil at all times from April to October, particularly in warm bright weather, but the number of flies seen on observation plots was affected by the area of damp and disturbed soil nearby. Both males and females were attracted and some females laid eggs within a few minutes of their capture. When isolated in phials and fed on dilute sugar solution, captured flies lived up to 79 days. Captured females spent varying periods up to 44 days before laying eggs. The eggs were usually laid in batches of less than ten at irregular intervals over periods extending up to 28 days, and 53 eggs per fly was the highest number recorded. Parasitism by the nematode, Heterotylenchus aberrans Bovien, occurred.

Eggs were found in soil crevices and on vegetation in contact with soil. The observed incubation period was 2–4 days according to the temperature.

The duration of the larval instars was affected by temperature; in captivity, the larval feeding period was 8–16 days in May-June and 15–24 days in October-November. The pupal stage lasted from 16–21 days in May-June and from five weeks to five months in autumn and winter. A few flies emerged during January and February in the insectary.

In captivity first-instar larvae found food buried at a depth of 6 ins. and they were able to reach maturity on fragments of vegetation buried in sand. It is suggested that they are primarily scavengers on organic matter in the soil.

Larvae of P. fugax have been found in the stems and crowns of turnips and swedes, and in cabbages, cauliflowers, lettuces and brussels sprouts. A study of their habitat shows that they occur in decomposing vegetation.

Eggs have been found about various brassicas. Their incubation period was 2–4 days. Larvae were reared in decomposing vegetation. Pupation takes place in the soil and in the feeding sites. Adults have been taken from May to October. The life-cycle from egg to adult occupied 4–5 weeks in spring and the winter was passed in the pupal stage.

The distribution of the larvae and pupae of Culicoides melleus (Coq.) in a natural beach habitat in an inlet on the Florida coast was studied in relation to tidal level and time of day. Larvae and pupae were confined to the intertidal zone and these distributions were unaffected by time of day or tidal level. Distributions of younger larval instars were displaced towards the inferred area of oviposition at higher elevations on the beach. Pupae were associated with the zone at and somewhat below high tide level. Differences in the vertical distribution of larvae between 0 and 2 in. deep between dark (pre-dawn)/low tide, morning/low tide and afternoon/low tide conditions were probably associated with larval response to light and heat.

In laboratory experiments with a temperature gradient, second- to fourth-instar larvae preferred the 18–25°C range, but the fourth instars were the least discriminating. Laboratory experiments with a simulated beach showed that pupae flooded on an incoming tide remained in their burrows and immediately buried themselves more deeply when waves were generated in the water; they were able to return to the surface if buried, and survived drowning for four days. Inundated areas were avoided as pupation sites. The orientation of pupae at the sand surface and their formation in burrows was related to negative phototactic responses of the pupating larvae.

Diaeretiella rapae is an aphid parasitoid with potential for use in biological control strategies. However, several recent genetic studies have challenged the long held view that it is a generalist parasitoid. We investigated its ecological specialization and ability to use resources in cultivated and uncultivated areas. Ecological specialization would reduce its ability to exploit the diversity of aphid species, particularly in uncultivated areas, and to control pest aphids. Four D. rapae strains were studied, three reared on pest aphids on Brassicaceae and one strain on a non-pest aphid on Chenopodiaceae. For each strain, we performed host-switching experiments, with a total of six aphid species, five of which D. rapae parasitizes in France. We tested cross-breeding ability between strains to detect potential reproductive isolation linked to aphid host species in D. rapae. The strain reared on non-pest aphids was able to develop on aphid species from both cultivated and uncultivated plants. The strains reared on pest aphids, however, exclusively parasitized aphid species on cultivated Brassicaceae. In addition, reproductive isolation was detected between strains from uncultivated and cultivated plants. Thus, the D. rapae populations examined here appear to be showing ecological specialization or they may even be composed of a complex of cryptic species related to the aphid hosts. The role of Chenopodium album as a reservoir for D. rapae, by providing a habitat for non-pest aphids on which it can feed, appears to be severely limited, and thus its efficiency to maintain local populations of D. rapae in the vicinity of crops is questionable.

We compare the pest status and age structure of bush fly,Musca vetustissima Walker, populations, and the abundance of native dung beetles at Uriarra, ACT, for five fly seasons before (1976–81) and three seasons after (1990–93) the exotic dung beetles Euoniticellus fulvus (Goeze) and Onthophagus taurus (Schreber) became established in the area during the late 1980s. Fly populations in all post-introduction seasons of 1990–93 were much older than in the pre-introduction seasons, indicating reduced levels of local fly breeding and higher proportions of immigrants. During the pre-introduction period, the fly annoyance index exceeded the ‘minimum discomfort’ threshold of 10.0 in parts of all seasons. The mean index was 11.3, and this did not differ significantly between seasons. The total dry weight of dung beetles at the time of the first influx of bush flies each year was consistently below 3 g/dung pad which was apparently too low to depress bush fly breeding below their replacement level of 3%. The mean annoyance index of 3.1 for the 1990–91 season was significantly lower than for the pre-introduction period and the total dry weight of beetles during November-December exceeded 3 g/dung pad on all sampling occasions. In the 1991–92 and 1992–93 seasons fly annoyance indices reverted to pre-introduction levels (seasonal means of 13.7 and 7.8 respectively) and total dry weight of beetles was again below 3 g/dung pad when the bush flies first appeared. Survival of immature bush flies in local dung pads remained below the replacement level of 3% during 1990–91, but exceeded 3% on two occasions during 1991–92. Apart from 1976–77, when mean catches of native dung beetles (O. australis and O. granulatus) were exceptionally high, mean catches of native dung beetles during pre- and post-introduction years were very similar, but the mean dung beetle biomass increased following the establishment of exotic species.