The turnover of the radioisotope 137Cs is shown to be of a one-component nature and to be positively correlated with temperature for males of both Glossina morsitans Westw. and G. pallidipes Aust. A direct correlation with oxygen consumption is also demonstrated, and the relation for both species may be described by the same regression line. The feasibility of using 137Cs as a metabolic label for tsetse is therefore confirmed, and it is suggested that the predictive nature of the relationship between radioisotope turnover and metabolism may extend beyond closely related species.

Communication between adult male and female Diparopsis castanea Hmps. was disrupted by ultra-low-volume spraying of cotton in a 0·2-ha field cage and in an open-field plot in Malawi with a polyurea-based microencapsulated formulation of the mating inhibitor 80% (E)- and 20% (Z)-9-dodecenyl acetate (IIA). When sprays containing 38·7 or 105·3 g IIA/ha were applied at 6-day intervals within the cage, reductions in mating of 62–66% and in oviposition of 72–78% resulted. Larval infestation was reduced by an average of 61% over a 52-day period. Effective release rates during these experiments were 4–19 mg/IIA/ha. Spraying at 6-day intervals with 15·9 g IIA/ha, however, had no significant effect on mating, and applications of 25·8 g of IIA/ha at 12–14 day intervals in the presence of high moth populations produced a reduction in female mating of only 19% despite a release rate of 4·4–53·0 mg/ha/h. Physical and chemical evaluations of microcapsule deposition on cotton plants indicated a low application efficiency, with an ‘effective’ spray deposition on plants of only 3·25–20·05% between pre-flowering and maturity. In an open-field spraying trial, applications of 38·7 g IIA/ha at 14–15 day intervals reduced oviposition by 75% from expected levels. Application of 15·7 g IIA/ha, however, had no disruptive effect in the field. Gas-liquid chromatographic analysis revealed no chemical interaction or marked effect on the release rate of IIA when carbaryl and IIA were sprayed in combination. Indirect evidence indicated that the microencapsulated formulations used possessed a considerable ability to withstand rain when applied to plants.

Three suitable sex pheromone trap designs for trapping the red bofiworm of cotton, Diparopsis castanea Hmps., including a simple omnidirectional monitoring trap, are described. In trials in Malawi, Diparopsis was more readily trapped on open horizontal trapping surfaces (water or adhesive) than in enclosed types of traps. The presence of a roof above the trapping surface, at spacings of up to 20 cm, significantly reduced catches. White traps, or unpainted traps in the case of vane traps constructed from galvanised metal, caught more moths than traps of other colours. Catches were greatest when monitoring traps in cotton were placed at ground level or at a height of 0·5 m and, when dicastalure was released from polyethylene vials, by employing a trap 60 cm in diameter. Evidence was obtained that competition may exist between female-baited traps spaced up to 73 m apart, although catches in traps baited with dicastalure were not significantly different when traps were 40–60 m apart. The greatest catches of moths in cotton were in traps located in insecticide-sprayed fields, but moths were also trapped in considerable numbers in other crops and to a reduced extent in open areas 4·8 km from the nearest cotton. From about the end of February, catches in maize, groundnut and fallow areas frequently exceeded the catches recorded within cotton fields, which may indicate an increased dispersal flight from cotton by adult moths later in the season. Weekly replacement in monitoring traps of polyethylene vials containing dicastalure produced maximum moth catches, but there was no significant difference in catch between traps in which pheromone was replaced at intervals of 2, 3, 4 or 6 weeks.

Glasshouse and field screening showed that several varieties of cowpea (Vigna unguiculata) in the germplasm collection at the International Institute of Tropical Agriculture at Ibadan, Nigeria, had promising levels of resistance to damage by larvae of Cydia ptychora (Meyr.). There was no preference between varieties for oviposition in the glasshouse, but varietal differences in damage to pods and seeds occurred due to differences in the pod-boring and seed-feeding success of larvae. Large numbers of seeds per pod in some varieties diluted the effects of a given larval density and resulted in low percentages of damaged seed. A measure of relative susceptibility was devised that overcame the problem of chance escape from attack by certain pods. Resistance in glasshouse screening was not necessarily related to resistance in the field, where plant growth habits and the ecological requirements of the adult moths are more fully expressed and play an important role in determining the outcome of the plant-insect interaction. The most resistant variety in the glasshouse, Vita-3, was least resistant in the field, partly because it was partially photosensitive and produced few flowers and pods in the early growing season in Ibadan. Two varieties, TVu 946 and TVu 2994, may have escaped severe attack by maturing quickly. The former is small-leaved, non-vigorous, carries its pods on long peduncles well above the foliage and consequently constitutes an unsuitable habitat for daytime sheltering by adults. It was the least damaged variety in the field trial. The latter was most attacked by other pod-feeding pests, and the consequent reduction in seed weight and quality appeared to enhance the level of damage caused by C. ptychora.

In studies in Nigeria, survival and weight increase of the larvae of Cydia ptychora (Meyr.) were affected by the variety of cowpea (Vigna unguiculata) on which they fed. The weights of fifth-instar larvae immediately prior to pupation and the amount of fresh food ingested were similar on three varieties when loose seeds were fed, but in a more natural situation, larvae appeared to face a manoeuvrability problem in small pods, which resulted in reduced weight gain. Differences in weight due to diet were less pronounced in emerging adults. Larval mortality was greatest on two varieties with large pods and may have been related to the nutritional quality of mature seeds or the presence of toxic chemicals. Some first-instar larvae died during the pod-boring process, particularly in the variety Vita-5. Two known susceptible varieties produced a moderate-to-small degree of mortality and large females. Significantly greater weight was attained when larvae fed for five days on 10-day-old seed followed by 15-day-old seed, or on 15-day-old seed throughout, than on 15-day-old seed followed by dried seed, or on 10-day-old seed throughout. Ovipositing females seemingly select pods of an age that minimises exposure of young larvae to drying or fully dried seed, which is a relatively unsuitable diet.

The encyrtid genus Tachinaephagus is revised, and a key to species presented. Four species are described and illustrated: T. stomoxicida sp. n., a very important parasite of Stomoxys nigra Macq. from Uganda and Mauritius; T. malayensis sp. n. from Malaysia; T. javensis sp. n. from Indonesia; and T. congoensis sp. n. from Zaïre. A lectotype is designated for T. zealandicus Ashm., the type-species of Tachinaephagus, and this genus as defined here is restricted to larval and pupal parasites of Diptera. Zeteticontus, which is superficially similar, is in fact distinct, and characters separating the two genera are tabulated.

A method for releasing genetically altered strains of Lucilia cuprina (Wied.) as free-falling larvae from aircraft was tested. Full-fed genetically marked third-instar larvae were released from aircraft flying at a height of 150 m and speeds of 120 or 220 km/h. Progeny tests of adult flies trapped subsequently indicated that released male larvae survived to the adult stage and were competitive with wild males for females.

The genotypes of chromosomally-identified individuals from natural populations of the known species of the group of Anopheles gambiae Giles were scored for the enzyme protein structural loci coding for adenylate kinase (Adk), α-naphthyl acetate esterase (Est-1, Est-2, Est-3), glutamic-oxaloacetic transaminase (Got), α-glycerophosphate dehydrogenase (αGpd), hexokinase (Hk), isocitric dehydrogenase (Idh), lactic dehydrogenase (Ldh), ‘leucine’ aminopeptidase (Lap-2), malic enzyme (Me), octanol dehydrogenase (Odh), phosphoglucomutase (Pgm-1, Pgm-2), 6-phosphogluconic dehydrogenase (6-Pgd), phosphohexose isomerase (Phi) and superoxide dismutase (Sod), following starch gel electrophoresis. In the material examined, Est-1, Est-2, Est-3, Got, ldh, Lap-2, Odh, Pgm-1, Pgm-2 and Sod were segregating for two or more alleles; unique alleles at the Est-1, Got and Sod loci produced species-specific phenotypes in A. melas (Theo.), species C and species D, respectively. The further sampling of A. merus Dön, populations supported the presence of a unique SOD phenotype by which this species can also be identified. Of the other enzyme systems examined, no activity following electrophoresis was detected for aldolase and fructose-1,6-diphosphatase, and the resolution of acid and alkaline phosphatase, glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, malic dehydrogenase and xanthine dehydrogenase was too poor under the particular electrophoretic conditions for genetic analyses of the enzyme phenotypes.

Sticky traps baited with (Funemone cis-8-dodecenyl acetate or (Codlemone trans-8,trans-10 dodecadien-1-ol) were operated in plum orchards in Cambridgeshire, England, from 1974 to 1976. In addition to large numbers of the target species Cydia funebrana (Treitschke), males of 24 other tortricids were captured. These included species of Cnephasia, Celypha, Epiblema, Pammene and Cydia. As an aid to the correct identification and interpretation of trap catches, details are given of the more important species attracted by the pheromone baits.

Following a demonstration of the role of ants in the dissemination of Phytophthora pod rot and an intensive study of the ant mosaic on cocoa at the Cocoa Research Institute of Nigeria, there was a need for a wide-scale assessment of the relative importance of different species of ant on cocoa farms in the major growing area of western Nigeria. Between 19 January and 6 February 1976, 50 trees were examined on each of 76 cocoa farms and all ant species visible from the ground were recorded. Sixteen species, or species-groups, of ants occurred on more than 1% of the trees, and their geographical distribution, habitat requirements and inter-specific relations were examined. The last of these were elucidated using principal components analysis, and the results are compared with earlier work on the ant mosiac. Any one cocoa farm only rarely provided a suitable habitat for more than one or two of the dominant species, and a diagram summarising the habitats is given. The potential usefulness of ant population manipulation is thought to be restricted in Nigeria by the undesirable effects of co-dominant and associated species found with the dominant species, Oecophylla longinoda (Latr.) and Tetramorium aculeatum (Mayr), which are regarded as beneficial in Ghana. The most important of the undesirable co-dominants is Pheidole megacephala (F.).

A laboratory colony of Aedes fluviatilis (Lutz) was established in ambient conditions in Brazil in which temperature varied from 22 to 31°C and relative humidity from 61 to 73%. Females laid eggs 3–13 days (mean 5·6 days) after a blood-meal and produced, on average, 64·3 eggs per batch. Eggs were usually deposited directly on the surface of water and preferentially on water that had previously contained fourth-instar larvae. The eggs proved to have little resistance to desiccation, hatching rates being reduced when eggs were kept on dry filter paper for only 1–3 days. Hatching took place following the detachment of a cap-like portion of the anterior end or through an irregular longitudinal split along the side of the egg. In different experiments, about 10–20% of eggs failed to hatch. Eggs usually hatched 2 days after oviposition. The average length of larval life was 10·2 days, and the highest proportion of larvae pupated on day 9. The duration of the successive immature stages increased geometrically with age. Mortality was 1–2% in each of the first 3 larval instars but rose to about 10% in the fourth. In the larval stage, males developed more rapidly than females. Crowding lengthened the duration of the larval stage, reduced the numbers surviving to pupate and resulted in a disparate sex ratio with emergent males much more abundant than females. Pupation occurred throughout the day and night with a slight peak at 05.00–06.00 h. The pupal stage lasted 1–3 days, usually 2 days, and was the same in both sexes.

The night resting sites of Glossina tachinoides Westw. were observed in riverine forest at Bara, Bauchi State, northern Nigeria. The flies were marked with an ultraviolet-reflecting paint and released at dusk. They were detected with the aid of an ultraviolet lamp. Most of the flies (84·6%) rested on leaves (68·3% on the upper sides) and on small twigs and creepers (11·5%). The resting heights ranged from ground level up to 6·8 m. The average resting height was highest (2·6 m) in the mid-rains at 20.00–24.00 h; however, at 24.00–04.00 h at the same season the mean height was only 1·6 m. Resting height was lowest (1·3 m) in the early rains. Females were found to rest slightly higher than males and, in moonlit periods, both sexes had a tendency to perch higher. The night resting behaviour of G. tachinoides is compared with that of G. palpalis palpalis (R.-D.), which was investigated in an earlier study at the same location. There is much similarity in the behaviour of the two species, but G. tachinoides selects lower resting sites, and a slightly higher proportion of this species is found to rest on leaves as opposed to small twigs

In a study in the Gambia on the relationship between wind direction and the direction of flight of mosquitoes, high-voltage electric grids were used as screens in conjunction with suction traps. Mosquitoes contacting or attempting to fly through the grids were electrocuted. The screening efficiency of the grids was estimated to be 75–80%, and the grids had no demonstrable effect on wind speed. The traps were set up in pairs with their mouths at ground level, one trap in each pair being screened on the upwind and the other on the downwind side. In this way, the mosquitoes could be segregated into those that were flying predominantly upwind and predominantly downwind, respectively. The results indicated that some 64% were flying upwind at this level, but this proportion varied considerably over a period of days, with nightly extremes of 87 and 43%; there was little difference between species. This variation was not correlated with wind speed, but there was some evidence that the presence of moonlight led to a greater degree of upwind flight.

Argas persicus (Oken) fed readily on avian hosts and consumed more blood and produced more eggs than on mammalian hosts. Ornithodoros tholozani (Lab. & Mégn.) fed equally well on chicken and various laboratory animals and converted the blood of all hosts into eggs at equal rates. O. moubata (Murr.) was intermediate, feeding more readily on chicken, rabbit and guineapig than on mouse, rat or hamster, and showing greater utilisation of blood of chicken and rabbit than of the other hosts. The relation of these phenomena to the natural host spectra of the 3 tick species is discussed.

A trail pheromone, methyl 4-methylpyrrole-2-carboxylate (M4MP2C), of Atta texana (Buckley) was tested in the laboratory as a possible component of attractive poison bait for the leaf-cutting ants A. cephalotes (L.), A. sexdens (L.) and Acromyrmex octospinosus (Reich). For all three species, M4MP2C when impregnated onto paper discs increased pick-up of the discs. It also increased pick-up by Atta sexdens of a citrus-pulp bait. The addition of M4MP2C made them easier to find, although at high concentrations it was repellent. It did not affect the average number of ant investigations before the bait was picked up. The pheromone remained on citrus-pulp bait in active concentrations for approximately four days. To test -the effect of M4MP2C as a foraging stimulant for A. cephalotes, an apparatus was constructed in which the ants passed in single file over a transparent section of the trail where they were counted with a photoelectric cell. When bait impregnated with M4MP2C was placed on the foraging table, large increases in activity were recorded away from the nest but only small increases were recorded in the nest and at the nest entrance. When air containing M4MP2C vapour was injected into the fungus chamber, an increase in activity was recorded at the nest entrance, but this increase was not repeated when known amounts of the pheromone impregnated onto baits of filter-paper discs were added directly to the fungus chamber. It is suggested that factors other than M4MP2C are also involved in the stimulation of foraging activity. The experiments suggest that M4MP2C could play some part in the formulation of an attractive bait for the control of leaf-cutting ants.