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.

A new genus and species of Ichneumonidae, Sliochia bala, reared from a pod husk miner (Acrocercops sp.) of cacao is described and compared with related genera in the Macrini.

The third-stage larva of Chalcosoma atlas (L.) collected in Malaysia is described, with illustrations, and a key is provided to distinguish larvae of this species from those of Oryctes rhinoceros (L.) and Xylotrupes gideon beckeri Schaufuss, all of which occur in similar breeding sites.

Eight strains of Boophilus decoloratus (Koch) are described from farms in the High veld area of Rhodesia. All eight strains showed resistance to a number of organophosphorus ixodicides and four showed additional resistance to the carbamate, carbaryl. This is the first recorded resistance to these two groups of ixodicides in Rhodesia.

Biochemical studies on the Alicedale West Farm strain indicated a level of resistance between that of the Berlin strain of B. decoloratus and the Biarra strain of B. microplus (Can.).

Organophosphate resistance in Lucilia cuprina (Wied.) is shown, by the backcross and discriminating dose technique, to be controlled by two major genetic loci on chromosomes 4 and 6. Respectively designated Rop-1 and Rop-2, they are positioned on the known genetic map. Rop-1 has three resistance alleles and one of these, and the Rop-2 allele, demonstrated stable transmission and expression in the absence of insecticide. Expression of resistance was either intermediate or incompletely dominant depending on locus and stage of maturity. This, and interaction between the loci, suggests that they have different biochemical mechanisms.

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.

The eggs, three larval instars and puparia of Chrysomya bezziana Villeneuve are described and illustrated in detail by scanning electron micrographs. Particular attention is paid to the extent and nature of the median strip in the eggs and the spine bands and spiracular structures in the larvae and puparia.

Eggs and third-instar larvae of five other species of Chrysomya, C. nigripes Aubertin, C. varipes (Macquart), C. rufifacies (Macquart), C. saffranea (Bigot) and C. megacephala (F.), are illustrated, described and compared with C. bezziana and each other by means of keys, which also permit their identification. In addition, notes on the puparia of these species are provided.

Mosquitoes flying at low levels over open farmland were sampled by means of electrical suction traps. These were set up at nine levels from ground level up to 6 m. From the vertical profiles obtained it was possible to recognise three patterns of behaviour: (1) a low-flying group with relatively very high densities below 1 m, comprising Mansonia (Man-sonioides) spp., Aedes spp. and some species of Anopheles; (2) an intermediate group with densities rather evenly distributed at the lower levels but declining above 2–4 m, comprising A. funestus Giles, A. gambiae Giles and Culex neavei Theo.; (3) a high-flying group with catches at 6 m greater, or much greater, than at 1 m, composed of C. antennatus (Becker), C. thalassius Theo. and C. poicilipes (Theo.). For all species, catches after 23.00 h showed an increase in the proportion of mosquitoes taken in traps at the lower levels, this being most marked at ground level and 0·5 m. No influence of either moonlight or wind speed could be detected to account for this. Biting catches on human baits showed a generally similar pattern to suction-trap catches, although differences between baits at 1-m intervals at the higher levels were less than with unbaited traps.

Under simulated natural conditions the anal orifice of the larva of Glossina morsitans morsitans Westw. appears to open either at or soon after parturition. The larva burrows on average within two minutes of deposition; pupariation is completed 10–15 min later. Using methods that prevent burrowing and prolong the crawling period, certain larval movements were related to the pre-pupariation anal discharges and to the rapid spread of the fluid. Although the anus is not generally thought to be connected with the hind gut during the whole of larval life, the presence of uric acid in the discharges indicates that the fluid is a product of Malpighian tubule excretion. In a two-choice chamber in an incubator, flies larviposited significantly more often in the experimental pot if it contained a water- or ether-soluble extract of larval excretion in addition to any pupariating larvae. This points to the presence of a larval phero-mone which may attract gravid females to a breeding site.

Laboratory evaluation of alternative insecticides to replace persistent organochlorines in leaf-cutting ant baits is described, based on tests of 40 candidate compounds which were bioassayed with Atta cephalotes (L.) and Acromyrmex octospinosus (Reich). Insecticides having a suitable delayed killing action are listed, together with others which, although highly toxic to ants, had too rapid an action, but could feasibly be modified by using a controlled-release formulation.

A search was also made for alternative bait matrices to replace the expensive and often inadequate materials in current use. Horticultural grade vermiculite with sorbed orange juice as an arrestant was the best matrix tested, being at least as attractive as dried citrus pulp, which was the best previously known matrix.

Treatment of dried citrus pulp bait with propionic acid gave considerable protection against moulds, which spoil stored baits and baits placed in the field, and did not alter the attractiveness of these baits to ants.

Ingestion of radiolabelled plant juices from cut surfaces of leaves during foraging and during substrate preparation for the fungus garden was demonstrated for laboratory colonies of the leaf-cutting ants Atta cephalotes (L.) and Acromyrmex octospinosus (Reich). Using P32 isotope, up to one-third of the radioactivity in the leaves was taken in directly by the colony as a whole, but this was much less when C14 was used. Additional plant material was taken in by the ants via the fungus garden. Large numbers of ants spend time in investigating cut surfaces of leaves and also in cutting and crimping leaves. Ingestion of plant material during these processes could play an important nutritional role in the colony and this may explain why many ants return from foraging apparently unladen. Large ants obtained most of their plant juice intake during foraging and the medium and small ants took much of theirs during substrate preparation. Inhibitory chemicals did not affect cutting but they reduced drinking and also reduced the intake of P32 from leaves during substrate preparation. The ants also ingested different amounts of P32 from leaves of different acceptability. It is suggested that leaf-cutting ants use fungus culture as a means of ‘sidestepping’ plant inhibitors. Nutrients are ingested directly from leaves when these are palatable, and the less palatable components are made available to the ants via the fungus.

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).

Natural populations of four species of the Anopheles gambiae complex occurring in southern Africa were sampled and individuals identified using ovarian polytene chromosomes (19 species A, 190 species B, 140 species C and 54 A. merus Dön.). The genotypes of these same insects were scored for three loci coding for non-specific esterases, and one locus coding for tetrazolium oxidase, after electrophoresis. There is no intra-specific variation at the tetrazolium oxidase locus; species A, B and C share a common allozyme and A. merus is unique. The relative gene frequencies for the 16 allozymes of the three esterase loci for each species give a minimum probability of correct identification of 0·9533 under the worst conditions of sampling, i.e., where samples consist of equal mixtures of species. In practice, resort to such probabilities is necessary only in the discrimination between species A and C. This system of identification is superior to the chromosome method because all adults, whether male or female, and at whatever stage of the gono-tropic cycle, are identifiable.

The female sex pheromone gland of Diparopsis castanea Hmps. consists of modified intersegmental tissue between the eighth and ninth abdominal segments. Glands contain an average of 12·73 ×10–3 μg of pheromone consisting of 80·4±2·0% trans-9, 11-dodecadien-l-yl acetate (range 72·7–86·7%) and 19·6±2·0% 11-dodecen-l-yl acetate (range 13·3–27·3%). Although no significant correlation exists between female body weight and pheromone content of the gland, the duration of sex pheromone release over the lifespan of a female is positively correlated with its weight on emergence. Six behavioural steps may be recognised in the precopulatory behaviour of females but the frequency and duration of sex pheromone release is strongly influenced by both temperature and light intensity. At 25°C females typically ‘call’ on two or more occasions for 41–50% of the night, calling commencing earlier at cool (13·4°C) temperatures than at moderate (19·4°C) or warm (25·0°C) temperatures. Calling by mated females increases considerably from four to five nights after mating but is typically of shorter duration than for virgins. The dispersal flight of Diparopsis males in cotton crops commences almost immediately after sunset and before the end of dusk, with peak male catches in sex pheromone traps occurring earlier in the cooler months of May and June (20.00–22.00 h) than in November (02.00–04.00 h). The Diparopsis synthetic sex pheromone, dicastalure, traps a greater proportion of males and females both earlier and later in the night than virgin females and this ‘timing advantage’ may be important in a pheromone control programme based on disruption of communication between the sexes.

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.

Ten non-organochlorine insecticides which had shown promise in laboratory tests as formicides, because of their delayed toxic action, were field-tested in Brazil in experimental leaf-cutting ant baits and were compared with a mirex bait. Seven of these gave good control (similar to mirex) against Atta sexdens (L.) colonies. Several showed some success, at the concentrations used, against the larger Atta cephalotes (L.) colonies, but were not as good as mirex.

By microencapsulating some quick-acting and very potent insecticides it was shown that useful formicides could be produced, presumably because encapsulation delayed the toxic action.

Substituting vermiculite plus orange juice in place of dried citrus pulp as an attractive bait matrix gave successful results.

A light-trap separating hourly catches was operated on a pasture research station in south coastal Queensland for 18 months in 1972 and 1973. A total of 339 000 Noctuid moths was captured. Half of the catch comprised pest species. Weather and nocturnal illumination were recorded on the trapping site. Multiple regression analyses were performed on the raw data, and, for comparison, some pest species were reared under semi-field conditions for a year. Night temperature, night wind and nocturnal illumination, in that order, were the most important factors influencing catch. Temperature and wind were each responsible for about one-fifth of the variance in catch, nocturnal illumination for about one-tenth. Twenty per cent of the variance in catch cannot be ascribed to changes in local weather or illumination. Wind had a significantly stronger influence on males than on females all year round, temperature a significantly stronger one on females than on males in summer. This was probably due to differences in the vertical distribution of flight in the two sexes, females flying lower than males. Nocturnal illumination had a significantly stronger influence on females than on males; on females its influence was almost as strong as that of wind, increasing with rising temperature to be twice as strong in summer as in winter. Females were most abundant in the first part of the night, males in the second. Temperature, wind and moonlight maintain this nocturnal distribution which is probably endogenously controlled. Female flight is probably linked to oviposition, male flight to response to pheromone release from calling females. Heavy out-of-season rainfall had a negative effect on Noctuid populations in the area and strongly increased both larval and adult mortality. Temperatures and rainfall during the larval and adult periods equal to the corresponding long-term averages and totals create optimal conditions for the development of Noctuid populations. Strong indications of migration were found in autumn and spring of 1973. Many moths of different species probably entered the area during nights with wind convergence caused by the passage of cold fronts. Separate analyses on the most abundant pest species confirmed the results of the analyses on the total catch of Noctuids.

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 synthetic sex pheromone of Diparopsis castanea Hmps., dicastalure, is a 4:1 synergistic combination of 93% trans:7% cis-9,11-dodecadien-1-yl acetate (IV) and the unattractive compound 11-dodecen-1-yl acetate (IIB). Both cis and trans-9-dodecen-1-yl acetate (IIA), the latter occurring in the female pheromone gland, are potent inhibitors of male attraction, as little as 10–4 mg IIA significantly reducing the attractiveness of virgin females in pheromone traps for more than one month in the field. Inhibition is typically close range, although higher concentrations are inhibitory when placed at up to 1 m from the female. IV and IIB also reduce male catch in female-baited traps, but dicastalure does not. Recently mated females, confined with virgins, reduce male catch, thereby indicating release of an unknown inhibitor. When formulated in a suitable extender, such as corn-oil, dicastalure may be released from sealed polyethylene vials or from cellulose acetate cigarette filters, and inclusion of the antioxidant 2:6-di-tort-butyl-p-cresol (BHT) prolongs the attractiveness of 1 mg dicastalure formulations beyond 25–30 days. Release from polyethylene is more efficient than from either polypropylene or cellulose and moth catch over a five-week period is linearly related to the logarithm of pheromone concentration. Significant communication disruption, as measured by reduced trap catches of male Diparopsis, occurred when female-baited traps in 100 m2 cotton plots were surrounded by point sources of either dicastalure (synthetic females) or the inhibitory IIA acetate (anti-females). Since dicastalure is occasionally less attractive than virgin females, efforts are being made to improve pheromone slow release formulations.

Anopheles implexus (Theo.) was studied at the Zika Forest near Entebbe, Uganda, from 1966 to 1971, with central reference to biting activities and host selection. Seasonal fluctuations of populations appeared to be correlated with lake levels, not with local rainfall. Results of biting, resting and nectar-feeding catches at various points across the forest floor indicated that diel activity patterns of man-biting were related primarily to the proximity of resting female A. implexus and only secondarily to the influence of environmental variables. Latent effects of moon phase on day-time man-biting activity patterns support this view. Blood-meal identifications showed that the great majority of blood-fed females resting in forest had fed on cattle, indicating that they left the forest at night. This was confirmed by direct catching from cattle outside forest, while the virtual absence of A. implexus resting near these bait animals, together with the fact that man is very seldom attacked away from forest, indicated that different kinds of host selection strategy were involved. The diel activity pattern of biting on cattle taken into forest was then found to be very different from that on man. Age-grading studies helped to substantiate these differences. Hourly sampling of A. implexus arriving at representative resting sites in forest indicated an exodus of most of the adult mosquito population from forest at dusk and a return shortly after sunrise. The two basic host selection strategies evidently involved (a) active or (in effect) ‘hunting’ flight, mainly outside forest with a tendency to restrict choice to most strongly attractive hosts, and (b) passive or opportunistic attack from rest, in which some of the unfed females sheltering may be activated by the proximity of a host which need not be strongly attractive. The latter situation was investigated further through analysis of short-term day-time patterns of attack on man in forest which are postulated to be a function of mosquito response delay (involving both resident and incoming elements of the sheltering population), which in turn determines depletion rates (involving only the resident element available at the time of the host's arrival). In A. implexus the response delay appears to vary according to time of day. Anomalous results are finally re-considered and it is concluded that the different patterns of active and passive host selection could arise from a single circadian rhythm of responsiveness, with flight characteristics and day-time inhibition modulating responses to specific and non-specific host stimuli in different ways.