Evaluation of the use of food-dye marking method for the study of sandfly behaviour was carried out in Baringo district, Kenya. A solution of sucrose and food dye was sprayed as bait on the vegetation around a selected source of flies in an animal burrow.

The extent of marking and distribution of coloured flies within a radius of 200 m was monitored for four nights. The species caught were Sergentomyia clydei, S. schwetzi, S. antennatus, S. squamipleuris, S. bedfordi, S. africanus S. ingrami and S. affinis and the number of coloured flies was 1017. Feeding on the dyed solution labelled 68.9% of the exiting flies near the burrow and 49.2% of the flies caught at the burrow's entrance. The total number of coloured flies caught at a distance of 50, 100, 150 and 200 m was similar toa linear distribution. The greater numbers of S. clydei caught at 200 m and the smaller numbers of S. squamipleuris and S. ingrami trapped between 50 and 200 m deviated from this pattern. These results are discussed as well as the possible application of the method.

This paper describes differences in reproductive and nutritional conditions that develop within 2 weeks of the transfer of wild-caught female Glossina pallidipes Austen to apparently ideal laboratory conditions. In order to investigate the relative sampling efficiency of baited NG2B traps for female G. pallidipes and the flies' changing feeding behaviour on different days of the pregnancy cycle, samples of female G. pallidipes taken directly from the field and those held in the laboratory for a known number of days after larviposition were subjected to both ovarian dissection (including the measurement of the uterine content and the two largest ovarioles) and fat and haematin analysis. Under the laboratory conditions of slightly lower mean temperature (buffered against diurnal fluctuations), lower activity and higher feeding frequency than in the field, the interlarval period was prolonged, the third larval instar was disproportionately prolonged, the ovarioles and larvae in utero showed differential growth rates, pupal size was increased and the fat reserves of post-partum females was depleted. It is concluded that tsetse are very responsive to the precise environmental conditions in which they find themselves and that absolute quantitative measurements made in the laboratory cannot be applied directly to the field situation.

Spraying of diflubenzuron at 100 g a.i./ha after spike emergence (10–15 cm from flag leaf) was more effective against early larval stages of millet spike worm, Heliocheilus (=Raghuva) albipunctella De Joannis, than spraying the crop at female flowering or at the milky grain stage.

Immune resistance to infestation by the brown ear tick, Rhipicephalus appendiculatus Neumann, was induced in rabbits by repeated tick feeding. Antibodies from the rabbits resistant to ticks were purified and used to isolate tick midgut antigens. Purified immunoglobulin G (IgGs) from rabbits immune to tick infestations demonstrated, by immunoblotting, nine protein subunits with molecular weights ranging from 12,000 to 92,000 daltons. Immuno-adsorption studies revealed an aggregated native protein with a molecular weight greater than 500,000 daltons as resolved by polyacrylamide gel electrophoresis (PAGE). Sodium dodecyl sulphate (SDS)-PAGE of this protein molecule revealed the presence of 14 protein subunits similar to some of those detected by the immunoblots. Their molecular weights ranged from 14,000 to 165,000 daltons. Sera from rabbits immunized with the 500,000 dalton molecule formed a weak precipitating arc in the immunodiffusion test, confirming its immunogenicity. The reproductive potential of ticks fed on rabbits immunized with the purified protein molecule was slightly affected compared to controls. The protein molecule also had the capacity to induce immediate and delayed type skin reactions when injected into rabbits resistant to adult R. appendiculatus, as opposed to control tick-naive rabbits.

The effects of endogenous and exogenous factors on mating behaviour were investigated to clarify the mechanisms of mating initiation, as one of the fundamental studies on the rice stem borer, Chilo suppressalis. The periodicity of mating behaviour is controlled basically by an endogenous circadian rhythm, and it is further affected by exogenous factors, such as temperature, day length, light intensity, light wave length and so on. Seasonal variations of mating behaviour can be observed under field conditions. The time of the onset of mating behaviour in August was delayed about 2 hours compared with that of June. Such variation of mating periodicity can be ascribed to the change in the hours of female calling and male pheromone response under different conditions among the seasons. Some of the important behavioural and physiological phenomena concerning mating initiation of Chilo suppressalis are discussed.

The effect of planting dates on beanfly infestation was investigated in successively planted bean plants during cropping seasons. The population tended to build up in the course of the season following the initial invasion by egg-laying females. Ophiomyia spencerella (Greathead) and Ophiomyia phaseoli (Tryon) were the species of beanflies infesting the bean plants in all seasons. The number of beanfly leaf punctures, eggs, larvae and puparia were more in late planted than early planted bean crop. The bean crop planted late in the season was severely damaged due to the generally higher population levels which had been building up in the course of the season.

Female sexual receptivity was studied in F1 laboratory-reared Glossina pallidipes Austen, 1903 originating from Nguruman in the Rift Valley of Kenya. Females mated as early as 6 days old but reached peak receptivity at 9–13 days old (60–80%). Females did not immediately mate with more than one male. The mean spermathecal value (MSV) was highest between 7 and 14 days of age, and declined thereafter. The duration of copulation was comparatively short (mean = 24 min), and did not vary significantly with age. High female receptivity corresponded with maturity of ovariole A, which reached maximum length at an age of 10 days. These results are discussed in relation to mass rearing of G. pallidipes.

The life cycles of two phycitid moths, Plodia interpunctella (Hubn.) and Ephestia cautella (Wik.) were studied under ambient laboratory conditions on groundnut, maize, sorghum, wheat and standard medium (maize/wheat/glycerol, 8:8:1, w/w). Egg hatchabilities were found to be 98.6 and 91.6% for P. interpunctella and E. cautella respectively. Five larval instars were recorded for each species based on head-capsule width measurements. The growth ratios of the larval head-capsule width ranged from 1.08–1.72 in P. interpunctella: and 1.33–1.57 in E. cautella. These ranges fall within the acceptable range in Dyar's rule. Mean fecundities ranged from 96.83 ± 0.31 on wheat to 190.87 ± 0.47 on standard medium for P. interpunctella; and 96.83 ± 0.31 on groundnut to 192 ± 1.33 on standard medium for E. cautella. Mean developmental periods of the two moths on the selected food media ranged from 25.65 days on standard medium to 46.11 days in broken wheat for P. interpunctella; and 26.95 days in broken sorghum to 40.14 days in ground maize for E. cautella.

Like most other insects, Chilo partellus requires sterols such as cholesterol in the diet. Freshly hatched larvae grown on a chemically defined diet take about 27 days to become adults. However, when an azasteroid, 25-azacholesterol is added to the diet in concentrations ranging from 0.5 ppm to 25 ppm, the time taken to become adults became 41 days at 5 ppm azasteroid. The maximum larval weight decreased to 76 mg from 140 mg as compared to the control insects. In larvae reared on a diet with 10 ppm azacholesterol, about 60% larvae died. The mortality was almost complete at a dose of 25 ppm. The larvae, pupae and adults reared on the chemically defined diet contained sitosterol, stigmasterol, cholesterol, compesterol and isofucosterol. No desmosterol was, however, detected in these insects. Inclusion of 25-azacholesterol in the diet led to the detection of desmosterol in these insects. It was observed that the cholesterol concentration decreased greatly, whereas sitosterol and stigmasterol concentration increased. This showed that the azacholesterol inhibited the dealkylation of C29 plant sterols to cholesterol, probably at the level of Δ-24-sterol reductase as evidenced by the accumulation of desmosterol. In some cases the adults were unable to separate themselves completely from the pupal cases. Some larval-pupal intermediates were also noted. It was further observed that the spermatogenesis was disturbed due to azacholesterol treatment. This may indicate that ecdysone biosynthesis is probably impaired. These results indicate that inhibition of steroid utilization may have the potential of being developed into a method for integrated pest management.

When 1, 2-dibenzoyl-1-tert-butylhydrazine was added to the diet at concentrations varying from 1 to 10 ppm, all the larvae died in all the concentrations tested, except 1 ppm. The larval weight was reduced to almost half due to the treatment and the larval duration increased as in case of 25-azacholesterol. However, the sterol composition of the insects did not change greatly.

This paper reports observations made on the sensory biology of Chilo partellus larvae and adults. The larval and adult antennae of this insect have hygro/thermosensitive sensilla equipped with receptor cells sensitive to minute changes in temperature. Inputs through those cells may partly be responsible for the light evasive and other light/temperature-dependent behaviour patterns. The grooved basiconic sensilla especially those found on the male antennae are sensitive to the female sex pheromone components of C. partellus. Host-plant odours are most likely perceived by one or two of the other antennal olfactory sensilla, namely the smooth-surfaced basiconica and coeloconica sensilla. Chilo partellus moths have a limited number of gustatory sensilla on the tarsi, ovipositor, antennae and the proboscis. Electrophysiological bioassays done on the ovipositor and tarsal sensilla are discussed. Similar tests on the larval maxillary styloconica sensilla showed that the lateral and medial sensilla differed in their sensitivity. Their taste receptor cells can detect differences between saps from susceptible and resistant host-plants.

Phenolic tsetse attractants in host urine were shown to form gradually from proattractants identified as a mixture of glucuronates and sulphates. The breakdown of proattractants is predominantly due to microbial activity. Of the eight bacteria isolated from buffalo urine three have demonstrated varying ability to give rise to free phenols the formation of which was monitored by observing the build-up of 4-cresol by means of gas chromatography. These observations may provide a useful biotechnological model for controlled release of these semiochemicals in the field.

Larvae of Maruca testulalis were found to be randomly dispersed on flowers of cowpea cultivar Vita 1. Three models based on Taylor's power law, Lloyd's mean crowding and the negative binomial were tested to find out the best fit for developing a sequential sampling plan for this pod borer. Taylor's power law model gave the best fit whilst the negative binomial gave the least. A sequential sampling plan and a table of optimum sample size for use in the field were therefore developed, based on the random distribution.

The susceptibility of head lice, Pediculus humanus capitis collected from children in Israel and that ofa laboratory colony of body lice, Pediculus humanus humanus to the insecticides malathion, deltamethrin, permethrin, fenitrothion and dieldrin has been evaluated using standard WHO papers. The LT50 and LT95 were established using different exposure times. Deltamethrin had the highest“knock-down”effect, followed by permethrinand malathion. All insecticidesexcept dieldrin gave higher mortality for body lice than for head lice. No differences in the susceptibility between adult and nymph lice could be observed.

Responses of tsetse Glossina morsitans morsitans and Glossina pallidipes (Diptera: Glossinidae) to host-derived phenolic kairomones were investigated using a wind tunnel. Activation behaviour of G. m. morsitans depended on the mixture of the phenols but not on the dose or ratio of the blend used. Up wind orientation behaviour and actual contact with the odour source depended on both the phenolic mixture and on the ratio of the phenols in the blend. In the present studies, a 4:1 blend of 4-cresol and 3-n-propylphenol, respectively, consistently induced more of the flies to fly upwind and contact the odour source as compared to any other combination of the phenols or even when these two crucial phenols were mixed in a ratio of 9:1; the ratio in which they are found in a typical sample of buffalo urine.

Comparison of the responses of the two species indicate that significantly fewer G. m. morsitans fly upwind and contact the odour source on stimulation with a blend of 4-cresol and 3-n-propylphenol as compared to G. pallidipes. This may explain why phenols only produce small improvements in the catches of G. m. morsitans as compared to G. pallidipes.

The simple wind tunnel developed, not only provides a useful tool for rapidly screening candidate attractants, but also a means to investigate how various compounds alone or in various combinations affect tsetse behaviour.

Several species of Chilo are serious pests of cereal crops. The important species attacking cereals are Chilo agamemnon, C. orichalcociliellus and C. partellus on maize and sorghum; C. auricilius and C. zacconius on sugar-cane, and rice; C. suppressalis on rice; and C. sacchariphagus indicus on sugar-cane. Insects are reared in the laboratory on natural and artificial diets for various purposes, namely for insecticide testing, hormone and pheromone manipulation, biological control, host-plant resistance, etc. Rearing of an insect in the laboratory requires rearing facilities, colony establishment, research and development of rearing techniques, resources, and maintenance of insect quality. All these aspects for rearing major Chilo spp. have been discussed. However, detailed information is available only for C. partellus and C. suppressalis. Techniques used for resistance screening and damage evaluation against spotted stem borer, C. partellus using naturally occurring population and artificial infestation are described.