Soil-dwelling tenebrionid larvae have developed in three evolutionary lines and are pests in all faunal regions. Description of and keys to most of the important species are available. However, revisional studies, on both adult and larval characters, are needed in many groups. The basic number of non-sex chromosomes appears to be 18, but the number and type of sex chromosomes are variable. Host ranges of both larvae and adults are usually extensive but usually only include plants. Development rates are related mainly to temperature, with life-cycles of one, two or three years. Larval development periods are rather long, and adults are long-lived. The number of instars is high, often above ten and frequently variable within a species. Sampling is best carried out by direct counts and pitfall trapping. In the species studied, mating follows a regular pattern and pheromones are involved. Species show definite temperature, moisture and soil-type preferences and these influence both spatial and temporal distribution. Recorded parasitoids include Diptera (mainly tachinids), Hymenoptera, mites, bacteria and fungi. Birds, carabids and a variety of other vertebrates are the main predators, but abdominal secretions and postural mechanisms provide some defence. Cultural control was formerly widely practised but has given way to chemical control.

The effects were examined of constant temperature on the life-cycle of Paulinia acuminata (Deg.), a potential biological control agent for Salvinia molesta. Over the range of temperatures tested (25–36°C), the duration of the life-cycle varied from approximately 85 days to 38 days. Egg development was most rapid at 33–36°C, but percentage hatch was greatest at 33–34°C. The duration of the nymphal period continued to decrease up to 36°C. The optimum temperature for nymphal development appeared to be higher than for eggs since temperature did not significantly affect nymphal mortality, which was about 50%. There were sometimes five and sometimes six instars, six being rather more common at lower than at higher temperatures. Crowded nymphs developed more slowly than isolated ones. Population growth rate statistics were calculated by combining data from several series of experiments. In an attempt to predict the results of a release of Paulinia at Lake Kariba between Zambia and Zimbabwe, these statistics were related to the mean annual temperature on the lake. It was estimated that P. acuminata would undergo three generations a year, with the population increasing by a factor of 8000 per annum.

Assortative mating amongst species of the complex of Anopheles gambiae Giles that occur sympatrically in West Africa was investigated in laboratory mating-choice experiments using dieldrin resistance and hybrid sterility as genetic markers. In competition experiments involving A. gambiae and A. arabiensis Patt., mating was found to be assortative. No effect of cage volume was observed on the operation of the specific mate-recognition system. On the other hand, experiments in which A. gambiae and A. arabiensis were caged separately with A. melas Theo. failed to show the presence of mating barriers known to operate in nature. Similar cage experiments conducted with two different strains of A. gambiae showed that there was no marked mating barrier between the strains. Other experiments showed that hybrid females from the cross between A. gambiae females and A. arabiensis males and the reciprocal cross would mate with both parental types as well as their own males in cages.

The cossid moth Azygophleps albovittata Bethune-Baker is recorded for the first time as a pest of groundnuts in northern Nigeria. This is the first food-plant record for the species and, as groundnuts were only introduced into Africa 400 to 500 years ago, there must be at least one indigenous host-plant. The larval, pupal and imaginal stages are described and figured. Attacks by larvae of this moth appear to be confined to crops on sandy and gravelly soils, as groundnuts grown on lateritic soils at Samaru are not affected. Larvae cause massive damage to the crown of the plant, but attacks are highly localised and never affect more than 20% of plants. As larvae diapause throughout the dry season, crop rotation may prove to be an effective means of control.

Sixty-seven per cent of parasitoid mummies which developed from Metopolophium dirhodum (Wlk.) collected in wheat fields at Rothamsted, southern England, in 1979 were of Toxares deltiger (Hal.), a species previously unrecorded from cereal aphids. T. deltiger formed only 1% of samples when parasitoid mummies were collected directly from cereals in the field. Laboratory observations of the parasitoid indicate that affected aphids probably leave the host-plant prior to death and mummy formation.

Specimens of a leafhopper from Jamaica, previously thought to be Osbornellus bimarginatus (DeLong) and which is suspected of being the vector of lethal yellowing disease of coconut, were found to belong to a new species. This is described as O. dabeki sp.n. and compared with related species. Genitalia of the male of Caribovia intensa (Wlk.), hitherto unknown, is described, and this species is compared with and shown to be distinct from C. coffeacola (Doz.).

Known components of the female sex pheromone of Spodoptera littoralis (Boisd.), tetradecyl acetate (I), (Z)-9-tetradecenyl acetate (IIA), (Z,E)-9, 11-tetradecadienyl acetate (III) and (Z,E)-9, 12-tetradecadienyl acetate (IV), and related compounds dispensed from polyethylene vials were used to bait water traps and funnel traps in lucerne fields in Crete. In comparison with the catches of males in traps baited with the primary component (III) alone, catches were increased by the addition of 1–100% of I in relation to the amounts of III, decreased by the addition of 5% or more of IIA and decreased by the addition of more than 5% of IV. The diene III was more attractive than any of the other three geometric isomers, although combining the Z,Z isomer (V) or the E,E isomer (VI) with III increased catches while the addition of the E,Z isomer (VII) decreased catches. The alcohols VIII and IX corresponding to the acetates III and IIA were not attractive but caused a marked reduction in trap catch when combined with III. The homologue of III (Z,E)-11-methyl–9, 11-tetradecadienyl acetate (X), was unattractive to males but increased trap catches when combined with III. 9-Tetradecynyl acetate (XI) exhibited neither attractant nor inhibitory activity, and similar results were obtained with ethyl cyclohexane carboxylate (XII) and 2-nonynal dimethyl acetal (XIII), compounds which have similar far-infrared spectra to that of diene III. The distributions of males landing on sticky board traps 70 cm in diameter baited with III or mixtures of III with I, IIA or IV showed that a greater percentage of the moths landed at the periphery of the traps baited with certain combinations of III with I and IV than on traps baited with III alone. Collection and analysis of the volatiles emitted by virgin females of different origins indicated that those from Crete produced I and III only, those from Israel produced I, III and IV, while those from Egypt produced I, III, IV and IIA and/or (E)-11-tetradecenyl acetate (IIB). The results are discussed in relation to previous work on S. littoralis and current theories on insect communication, and also in terms of their relevance to the practical field usage of pheromones in control of this pest.

The identity of Lecanium krugeri Zhnt. is established, and the species is redescribed in a new genus Saccharolecanium. Originally known from Java, the species is now recorded from India and West Malaysia on sugar-cane.

In tests in Nigeria with its principal host-plant, cowpea, Cydia ptychora (Meyr.) showed distinct oviposition preferences. Most of the eggs were laid on the sepals (including their remains on pods) in screenhouse tests involving four varieties. There were distinct differences in the number of eggs laid on different varieties in both no-choice tests with four or five varieties and free-choice tests with 17 varieties in the field. Vita-3 was the preferred variety in the laboratory tests and H 13–1 in the larger comparisons in the field. Fewest eggs were deposited on Tvu 2994 in all tests.

Oryctes rhinoceros (L.) is a major pest of coconut palms in Papua New Guinea but has a limited distribution within the country. Pre-release monitoring showed that no baculovirus disease was present in the country prior to its importation. A consignment of O. rhinoceros larvae infected with a baculovirus disease was imported into Papua New Guinea from Western Samoa in 1977. The virus proved highly infectious to both larvae and adults of the local population of O. rhinoceros. During 1978 and 1979, adults were perorally infected with the baculovirus and released at nine sites on Manus Island, four sites on New Ireland and twelve sites on the Gazelle Peninsula of East New Britain. The infected adults were active disseminators of the virus into the field population, and the virus became established at nearly all the release sites. The shortest time between virus release and recapture of newly infected adults from a release site was eight weeks. Three different examples indicated the virus spread at approximately 1 km/month. During a fourteen-week period in the early establishment phase, significantly more females than males were collected in traps but a significantly higher percentage of the males was infected.

Large electrocuting nets were used at different seasons near a big tree in Zimbabwe to capture tsetse flies at different heights, distances from the bole and times of day. Some differences were found between species and sexes, but most flies were caught within 3·3 m of the ground and in the late afternoon. In the cool and wet seasons, Glossina pallidipes Aust. was less confined to lower levels than was G. morsitans morsitans Westw. Flies, especially fed males of G. pallidipes near the bole of the tree, were recorded in the greatest numbers in the midday period. Diurnal variations occurred in the relative proportions of females of the two species caught at different points. Releasing ox odour through an electrocuting net suspended at different heights confirmed that most flies were flying near the ground, especially in the hot dry season. Comparison of samples from the large electrocuting nets with those caught by other methods operated contemporaneously showed that the large nets gave samples which compared well with those from an electrocuting screen used in conjunction with a ventilated pit. Methods involving fly-capture by people gave very distorted results for all catch parameters examined. No method used gave consistently representative samples of replete flies or of newly emerged flies.

Interspecies attraction studies in four species of bruchids (Callosobruchus analis (F.), C. chinensis (L.), C. maculatus (F.) and Zabrotes subfasciatus (Boh.)) showed that only males were attracted by the females of other species except in C. maculatus, the males of which were also attracted by males of Z. subfasciatus. C. chinensis showed no attraction towards any other species and none was attracted to it. On the other hand, C. maculatus males were attracted by females of C. analis and Z. subfasciatus and vice versa. C. analis and Z. subfasciatus showed no attraction towards each other.

The population dynamics of the leafhopper Neoaliturus fenestratus (H.-S.) was studied at two temperatures (20 and 25°C) and on a summer host-plant (safflower) and a winter host-plant (Chrysanthemum segetum).

The life-span, reproduction and computed rates of increase were established, and it was found that the leafhopper performed best on safflower at 25°C. Delayed mating induced longer survival in both sexes. C. segetum, the winter host-plant, enabled long maintenance of the insect, although markedly reducing its rate of reproduction. The implication of these findings for the seasonal cycle of the leafhopper is discussed.

Egg-batches of Spodoptera littoralis (Boisd.) collected in Crete showed an abnormal sex ratio; 24% yielded predominantly female adults. The field data and data from nine generations of a laboratory strain, which also produced predominantly female offspring, showed that this abnormal condition was transmitted between generations by the females. The mean percentage hatch of egg-batches collected from the field which produced females only was 59·6, and the mean percentage hatch of the eggs of the laboratory strain was 58·8. These results suggest that the production of females only is a result of the mortality of the male embryos. Occasionally, abnormal females from the laboratory strain reverted to producing offspring of both sexes. This recovery from the abnormal condition became more common as successive generations were bred in the laboratory. One female of a normal strain produced all-female offspring and descendants of this female were similarly affected. The females of the unisexual laboratory strain were similar in appearance to normal females but laid significantly smaller egg-batches.

The population dynamics of Pineus pini (Gmel.) was examined in two locations in the Kenya Highlands where the mean annual precipitation ranges from 620 to 1400 mm. Variations in population densities were related to rainfall. Generally, there was a marked decrease in population during the three months of heavy rainfall in March to May and a significant increase during dry weather from August to October. This was followed by a slight decrease in the rate of population build-up, until the long rains in April again resulted in another population collapse. Nine species of predatory insects were identified, and population fluctuations of the most common of these, Exochomus spp., was studied. Predators seemed to remove about 12% of the aphid population. Other mortality factors included heat and crawler dispersion. The greatest mortality occurred early in the life-cycle and was mainly due to eggs and crawlers being washed off the host-tree by rain.

A suction trap for sampling small insects in areas without mains electricity is described. The traps were operated from two 25-ampere-hour 12-V batteries connected in parallel, giving an average airflow of 329–355 m3/h over a 12-h period. The trap was used successfully to catch first-instar larvae of Cryptococcus fagisuga Ldgr. in a beech forest in England.

Quantitative observations on the biting activities of Simulium simplicicolor Lutz and S. sanguineum Knab s.1. at Aripuanã, Mato Grosso, Brazil, and S. guianense Wise and S. sanguineum s.1. at Uru´, Par´, were made during the wet and dry seasons between June 1978 and August 1979. The species demonstrated characteristic attacking patterns regardless of abundance or environmental conditions. S. simplicicolor, S. guianense and S. sanguineum s.1. at Uruá demonstrated bimodal biting patterns with early morning and late afternoon peaks. S. sanguineum s.1. at Aripuanã, however, bit throughout the day with three peaks of activity. Evidence is presented for circadian control of the biting patterns which are subject to modification by exogenous factors outside of an optimal range. S. simplicicolor seemed to be most affected by light intensity, whereas the other species were affected by variable combinations of light, temperature and humidity depending on the species and population. Physiological age sometimes also modified biting activity in S. simplicicolor. This variable was not studied in the other species. S. simplicicolor and S. guianense preferred biting man on the legs and S. sanguineum s.1. at Uruá preferred the upper torso, but S. sanguineum s.1. at. Aripuanã did not demonstrate a consistent preference for sites above or below the waist. Average engorgement times for all of the populations except the Uruá population of S. sanguineum s.1. were between 4·3 and 5·3 min.

Observations are reported on diapause and laboratory breeding of Phlebotomus perniciosus Newst. and P. ariasi Tonnoir, the two phlebotomine sandflies incriminated as vectors of visceral leishmaniasis in southern France. Previous field studies had suggested that both species are univoltine in southern France, but the present laboratory investigations showed that diapause is obligatory for neither species. Temperature (both species) and photoperiod (P. perniciosus) were found to affect diapause-induction, and diapause was commonly determined before the overwintering stage (the fourth-instar larva). The results showed that P. perniciosus can be mass-reared for at least three uninterrupted generations each year if it is maintained at 28°C in LD 17:7. Further investigations are needed if P. ariasi is also to be bred in sufficient numbers for epidemiological experiments; its colonisation was prevented primarily by low fertility, and attempts at forced insemination were unsuccessful.