The biology of seventeen common species of rain forest bark beetles was studied during a six month visit to Fiji in 1973. Geographical and altitude ranges, and host plants are given; breeding galleries and brood composition are described in detail, and the significance of competitors, associates, and parasites is noted. The biology of an Ozodendron sp. is described for the first time, and of Cryphalomorphus sp. for the first time outside Africa. Most Fijian bark beetles show strong host preferences, and some of the most common endemics, such as Cryphalomorphus grosse-punctatus Browne, Hypocryphalus laticollis Browne and Ozodendron fijianus (Schedl) are apparently host specific. Among dominant trees of the rain forest only Myrtaceae and conifers (Dacrydium, Podocarpus), which are thin barked, are apparently free of bark beetles. Of note among biological features is the habit, not previously recorded for tropical bark beetles, of packing the egg galleries with frass after egg-laying has finished. Five species are potential pests of pines—Cryphalus variolosus Schedl, Cyrtogenius granulifer (Beeson), Ozodendron fijianus (Schedl), Poecilips cyperi (Beeson), P. fijianus Schedl. All were taken in endemic Pinaceae, and some in Pinus plantations as well. Lying within the tropical hurricane belt, living coniferous exotics in Fiji are potentially vulnerable to bark beetle attack when trees are under stress, as often occurs in the dry season.

The effect of blood feeding on male sexual maturation in the tsetse flies Glossina morsitans Westwood and G. austeni Newstead was studied by comparing copulation and insemination performance of unfed and fed males during the first five days of adult life. These species differed conspicuously, both in the course of maturation and in the influence of blood feeding on it. G. morsitans males copulated before they could inseminate, and even fed flies did not all inseminate until day 3; unfed flies showed retarded insemination performance by day 2, before copulation performance declined. G. austeni males were less sexually responsive at first, but they nearly always inseminated when they did copulate, even on day 1. Unfed flies showed less increase in copulation performance by day 4, but no decline. Accessory glands were larger in G. austeni than G. morsitans at emergence, and in unfed flies of both species they ceased to grow after day 3. Both accessory gland size and copulation duration (beyond a minimum duration) were related to insemination success in a general way, though copulation duration was quite variable. Vertebrate blood apparently provides male tsetse with specific nutrients or stimuli which promote sexual performance, in addition to basic energy and water requirements. Feeding probably affects insemination in G. morsitans through accessory gland development, allowing more complete spermatophore formation and sperm transfer, but its mode of action on G. austeni sexual responsiveness is not evident.

A tortricid moth belonging to the subfamily Olethreutinae, reared from larvae feeding in seeds of Toona sureni (Meliaceae) in Papua New Guinea, is described and named Anathamna spermatophaga sp. n. Damage to the shoots was similar to that caused by larvae of the toon shoot and fruit boring pyralid moth Hypsipyla robusta (Moore).

The subgenus Synphlebotomus of Phlebotomus is reviewed, and an illustrated key is given for the six African and two non-African species. The status of P. rossi De Meillon & Lavoipierre, the suspected vector of dermal leishmaniasis among animals in South West Africa, is revised, and it is described and illustrated in detail.

Resting site preferences of adult Glossina morsitans morsitans Westw., the dominant species in the Republic of Zambia, were observed during the cool (May–August) and hot (September–October) dry seasons in 1974 at the Chakwenga Game Reserve. Tanglefoot was used to trap resting flies on boles, branches, bushes (undergrowth), canopies, fallen logs and in ant-bear holes.

All resting flies were collected below 4 m and there was an inverse relationship between numbers of resting flies and height of resting sites on boles, branches and canopies. Most flies were collected betwen 06.00 and 09.00 h, except in ant-bear holes, where no flies were found. No significant differences existed between numbers of flies collected from the four cardinal positions on boles. Although more flies were found on shaded than unshaded fallen logs and bushes, the differences were only statistically significant for fallen logs. Numbers of flies on various tree species were generally not significantly different. Boles, bushes and fallen logs were the most preferred sites.

The larval habitats of Culicoides species were determined by examining a total of 1 476 samples collected from different ecological environments in various parts of Kenya. Immature stages were collected from suspected breeding habitats and adults were reared. Adults were also captured in emergence traps and then identified. To determine species preferences, if any, the materials yielding Culicoides were analysed for pH, organic matter and water content.

Fifty-seven percent of the samples yielded a total of 26 species of Culicoides. Sites in which Culicoides occurred were classified into eleven habitats grouped into four major systems, namely, aquatic, transitional, terrestrial and general systems. Most species were found breeding over a wide pH range in sites which were wet at least part of the time. A few species appeared to select breeding habitats with a high organic content.

The four components of the synthesised sex pheromone of Diparopsis castanea Hmps. are dodecan-1-yl acetate (I); trans-9-dodecen-1-yl acetate (IIA); 11-dodecen-l-yl acetate (IIB); and trans-9,ll-dodecadien-l-yl acetate (IV). Increasing the proportion of IIA in a I/IIA/IIB/IV mixture progressively decreased male excitation in a laboratory bioassay, whilst in the absence of I all concentrations of IIA tested were equally inhibitory. The synthetic combination of 80% IV (93% trans: 7% cis) and 20% IIB (=dicastalure), was 485 times more potent in eliciting male activity than a female sex pheromone gland extract. Reduction in male response to crude extract occurred through exposure of males to glandular IIA and through reduced pheromone volatility caused by extracted triglycerides. Maximum quantities of pheromone were detected in the female sex pheromone gland 6–12 h into scotophase and for at least 30 min into photophase. Significantly greater bioassay responses were elicited by the optimal field combination of 80% IV and 20% IIB than for other ratios tested. Excitation and clasper extension were observed in response to the non-attractive IIB moiety and this indicates a role in close-range mating behaviour for this component. The threshold level of male response was estimated to occur in response to sex pheromone at an aerial concentration of 9·2 molecules IV mm3/s−1. This suggests that aerial concentrations of 102–103 times the male threshold response level may be sufficient to cause successful communication disruption in the field. The problems of relating the non-oriented responses in an assay of this type to directional responses in traps are briefly discussed.

D-glucoascorbic acid in 0·05–0·30% aqueous solution fed to adult males of Spodoptera littoralis (Boisd.) caused the production of deformed spermatophores. During mating the spermatophore corpus did not become inflated and permanent copulations were often observed. The inadequate moulding of the spermatophore was caused exclusively by oral uptake of D-glucoascorbic acid in male moths. This ascorbic acid analogue did not affect adult longevity, number of spermatophores or egg fecundity. Moths feeding on an aqueous diet of 0·3 % of this chemical were completely sterile. Bait-stations containing this material might possibly be used to induce sterility in the natural insect population.

The night resting sites of Glossina palpalis palpalis (R.-D.) were observed in a riverine swamp at Bara, Bauchi Emirate, northern Nigeria. The flies were marked with an ultra violet reflecting paint and released at dusk. They were detected with the aid of an ultra violet light beam. Most of the flies (72%) rest on leaves (50% on the upper sides) and on small twigs and creepers (20·2%). The average resting height was highest in the mid-rains (3·78 m), dropped in the late rains (2·95 m) and was lowest (1·52 m) in the dry season.

The resting site heights ranged from ground level up to 18 m. Females were found to rest slightly higher than males and when the moon shone both sexes had a tendency to perch higher. It was shown that the night resting behaviour of G. palpalis is favourable to the application of residual insecticide deposits from the air because most of the spray drops are deposited on leaves.

Large numbers of adult Austrosimulium pestilens Mack. & Mack, appear about a week after floods in permanent and temporary waterways and, because of the short period when stream flow remains suitable for oviposition, mating, feeding and egg maturation take place near the river where they breed. Most flies emerge early in an outbreak and fly to mating swarms at trees beside or near the river. After obtaining a blood meal from any of a number of mammal species nearby, females return to 1–5 m tall trees at the river's edge to mature their eggs in an unusually short time of 24 h. Although this species prefers rapidly flowing water, immatures also survived in trickles remaining after floods had passed, though the resulting adults took longer to develop and were smaller than normal. The closely related A. bancrofti (Tayl.) lives in more permanent waterways and disperses away from its breeding sites soon after emerging, concentrating in highest numbers on hills as far as 10 km or more from its nearest major breeding site. Catches in CO2-baited traps were influenced by temperature, wind, light intensity and rain. Although A. pestilens bit man and many mammals, A. bancrofti did not bite any vertebrate tested. In CO2-baited traps where man was present, there were large fluctuations in the catch of A. pestilens from minute to minute, while the catch of A. bancrofti decreased steadily.

A technique, based on the release and recapture of marked females, was used to measure the mating competitiveness of sterile males of Culex pipiens fatigans Wied. in villages in Delhi Union Territory, India. Experiments were carried out with chemosterilised and cytoplasmically incompatible translocated (IS-31B) males simultaneously with prolonged release trials with these two types of male. The fertile males in the tests were the indigenous population and the females used were in most cases of wild origin. With each type of male, one test was conducted with a moderate (ca. 13:1) ratio of released to wild males and the other tests used high (ca. 40:1) ratios. The estimated mean mating competitiveness of IS-31B males was somewhat higher than that of chemosterilised males, but the difference was found to be non-significant using a specially devised method of testing statistical significance. In the four experiments 77–94% of the egg rafts laid by recaptured females were sterile, indicating that both types of sterile male were sufficiently competitive to induce a high level of egg sterility in an isolated wild population.

The diurnal flight activity of Simulium griseicolle Becker was determined at Shambat, Khartoum, by means of a suction trap and a vehicle-mounted trap; and the biting activity by means of a chicken-baited trap. Only incidental observations of mammal-biting activity were made. The three trapping methods indicated two peaks of activity, one in the morning and the other late in the afternoon. Fly activity was lowest in the early afternoon when temperature and light intensity were highest, wind speed was moderate and relative humidity was least. Females outnumbered males in all the catches, except in the early morning when more males were sometimes recorded.

Ticks were collected from 2136 small mammals, comprising 5 bats (5 species), 14 elephant shrews (3 species), 84 Crocidura shrews (5 species), 25 hares (1 species), 10 small carnivores (3 species), 3 hyraxes (1 species) 1998 rodents (33 species), and from 41 birds (19 species) at various localities in Zambia. From these hosts 6568 ticks (4384 larvae, 1686 nymphs, 317 males and 181 females) were recovered. Twenty-three species were positively identified and nineteen other species were assigned to genus or species-group. Host and tick records are tabulated by regions collected and for each of the two regions with the largest collections, the records are tabulated by months. The ticks collected in the high montane area near the Malawi border differed significantly from collections in other areas studied, reflecting host and climate differences. In the two areas tabulated by month, most of the immature ticks were recovered in the cool dry winter months (April to August).

Adult behaviour and oviposition patterns of Cacoecimorpha pronubana (Hb.), Phlogophora meticulosa (L.), Autographa gamma (L.), Mamestra brassicae (L.) and Lacanobia oleracea (L.) were studied by introducing laboratory reared pupae into glasshouses. Adults emerging from these pupae were located by direct visual searching of chrysanthemum plants and of the greenhouse structures for up to three weeks after emergence.

In small houses (2·9×3·3×2·5 m), 49 adults of C. pronubana emerged. At least 15 stayed inside the house and laid 1 750 eggs. With P. meticulosa, A. gamma and L. oleracea, 262 adults emerged and escaped from the houses without laying eggs inside.

In a large glasshouse (9·8×13·1×5·1 m) with automatic ventilators, 840 adults of P. meticulosa, A. gamma and M. brassicae emerged and many were prevented from escaping when the ventilators were closed during the moths' flight period. Moths were inactive in daytime and most were found on the highest parts of the aluminium framework, mainly on the sides which received most external light overnight. None were found on the glass. Only 27·3% of the P. meticulosa were found on the plants. Moth distributions probably result from moths flying until they reach a barrier, which they then tend to follow, with directional responses to gravity, light, settling site, food plant and oviposition site superimposed in varying degrees on this basic pattern. About 30 470 eggs were laid, more in outer than in inner beds and more in the outer than in the inner rows of a bed. P. meticulosa and A. gamma laid eggs only on plants. M. brassicae laid about 1 854 eggs on the undersides of leaves and 2 972 on glass and framework, mainly in the direction of external light.

All five species can cause serious damage to crops. Initial infestations can be controlled by sprays of chemical insecticides or Bacillus thurin-giensis. Usually a few larvae survive a single spray and, in the absence of further control measures, they may produce a troublesome second generation, although in certain circumstances further control measures may not be required. If biological control of other tomato pests becomes widespread, steps should be taken to prevent L. oleracea again becoming an important pest.

The population dynamics of the desert locust, Schistocerca gregaria* (Forsk.), in Africa, the Middle East and Asia from 1966 to 1969 have been analysed to determine the causes of the beginning and the abrupt end of the plague of 1968. Evidence indicates that in 1966 there were no persistent sequences of breeding by gregarious populations, but in 1967 and early 1968 there were four sequences of breeding by initially solitary behaving locusts, each resulting in a substantial increase in numbers and density. These events led to a plague that ended by mid-1969.

The threshold rainfall requirement for successful breeding, defined as an increase in numbers from mature adults of the parent generation to filial fledglings, has been related to the rainfall required for the germination of ephemerals and their growth to sizes that can provide food and shelter for hoppers throughout their development. It is suggested that the minimum quantity of rainfall required initially over a large area is 25 mm. This requirement is usually met in the summer breeding areas. Rainfall in the winter-spring breeding areas is more variable, and falls exceeding the threshold are most commonly associated with deep troughs in the mid- and upper-tropospheric westerly winds in winter and spring. A season in which many such troughs occur may be essential for plague development. It is also suggested that the timing of successive periods of rainfall allowing successful breeding is critical in determining the occurrence of upsurges.

Control against non-gregarious infestations failed to contain the upsurge, but later control measures against hopper bands and swarms contributed to the plague decline. The most economical strategy for plague prevention might be one of upsurge elimination, that is to say control in selected areas against gregarious locusts only. The implications of adopting such a strategy are discussed.