Thirty-five species of mosquitoes (10 782 adults) were caught in modified CDC light-traps during the 27-week rice cultivation cycle at Ahero, Kenya, in the period September 1972 to March 1973. Only 0·8% were blood-fed and 5·1% gravid, indicating that the traps were sampling newly emerged adults. During weeks 1–7, before rice seedlings were transplanted, catches were small, but increased markedly from then until harvest (week 20). Two groups of mosquito species were recognised: the first, including Mansonia uniformis (Theo.), M. africana (Theo.) and Mimomyia splendens Theo., bred throughout the rice cycle; the second, including Anopheles gambiae s.l., A. pharoensis Theo., A. ziemanni Grünb., Culex poicilipes (Theo.) and C. antennatus (Becker), were affected by water depth and height of the rice crop. The slurry of shallow muddy pools which follows transplanting stimulated intense breeding of A. gambiae and A. pharoensis. Once the young plants were established, reflooding of the fields and subsequent growth of water plants and algae favoured the breeding of A. ziemanni and C. poicilipes. Towards the end of the rice cycle large numbers of C. antennatus were caught. It is concluded that mosquito control by means of insecticides or by irrigation management would be possible.

The biting activity of Culex (Melanoconion) portesi Senevet & Abonnenc and C. (M.) taeniopus D. & K. in a secondary seasonal marsh forest in Trinidad was studied by means of catches by six mouse-baited suction traps, and a single light-trap. The traps were cleared at hourly intervals between 17.00 h and 07.00 h on nights which approximated to the new, first quarter, full and last quarter phases of the moon. The catches were compared with illumination at canopy and ground level which was estimated by selenium photocells whose output was recorded on the continuous chart of a servo-potentiometer. Humidity, rainfall, temperature and cloud cover were also recorded. In the suction traps both species showed peaks of activity at evening and dawn twilight at new moon, although the dawn peak was not very pronounced with C. taeniopus, but this pattern was modified on other nights in a manner which was consistent with moon age. At full moon the evening and dawn peaks were replaced by increased activity during moonrise and the middle of the night. The light-traps failed to show the evening and dawn activity and did not always duplicate the baited traps during darkness. Two hypotheses based on either a permissive range of illumination or an underlying circadian rhythm are discussed; neither fully explains the observed biting activity. Although an association between moonlight and biting activity does exist, an understanding of its nature will require more experimental data.

The performance of native and laboratory-bred Glossina morsitans morsitans Westw. was observed in Kariba, Rhodesia, the original natural habitat of the colonised Langford strain. After two years in captivity, the Langford strain was similar to the native strain in survival, dispersal, and rate of recovery in the field. No differences were detected in laboratory studies of the mating behaviour of the two strains. Native-strain males sterilised in the pupal stage with tepa were similar to untreated males in dispersal, survival, and rate of recovery. Also, both the released laboratory-bred flies and the released native strain flies compared favourably with the native population.

Nearly 2000 Phlebotomine sandflies collected in caves in Belize were examined for flagellate infections in the gut. Infections were found in 4% of Lutzomyia trinidadensis (Newst.) and in 42% of L. beltrani (Belize form). The two species of sandflies were infected with different species of parasites. The sources of infections in L. trinidadensis were not established, but females probably became infected when taking blood-meals on a vertebrate. One specimen of L. trinidadensis infected with flagellates was also infected with filaria worms. Circumstantial evidence suggests that L. beltrani is the insect host of Trypanosoma leonidasdeanei, a parasite in the blood of insectivorous bats. An account is given of the physiological condition of infected and uninfected L. beltrani, of the distribution of flagellates in the gut and of differences in the incidence of infections. The presence of the parasites in the gut disturbs some physiological processes in the fly and it is suggested that the presumed Chiroptera/T. leonidasdeanei/L. beltrani association is a recent evolutionary development. A model of population structure for a community of New World Phlebotominae, derived from observations on L. beltrani, is presented.

Larvicide tests were conducted on five species of mosquitoes, each of which had one or more DDT-resistant strains. The high potencies of DDT and, to a large degree, of DDD were completely lost by resistance. Other compounds were affected in different degrees according to the resistance mechanisms present, as indicated by resistance spectra and the effects of synergists. DDT-resistant strains of Culex pipiens fatigans Wied., Anopheles quadrimaculatus Say and A. stephensi List, showed highly specific resistance to DDT, probably dependent on a dehydrochlorination mechanism. DDT-resistance in Aedes aegypti (L.) and A. gambiae was also high, but there was definite evidence of cross-resistance to biodegradable DDT-analogues (about ×4 and ×10, respectively). This low-level, but definite, cross-resistance extended to a number of other compounds, notably pyrethroids, insect development inhibitors, amines, etc. The presence of synergistic action by piperonyl butoxide suggested that this depended on a microsomal oxidation system.

Isotopically labelled (14C) DDT and malathion were used to study pick-up and penetration of these insecticides by larvae of normal and resistant Ae. aegypti. Both the actual and the percentage penetration of DDT were greater in the resistant than in the normal strain. Whatever the reason for this, it disposes of the possibility of reduced pick-up and penetration as a factor in DDT-resistance. With malathion, the percentage penetration was always higher in the susceptible strain than in the resistant one, though in some cases the actual amount was less.

Fresh defibrinated bovine blood was superior to either haemolysed or freeze-dried defibrinated bovine blood when fed in vitro to female Glossina morsitans morsitans Westw. The presence of adenosine-5′-triphosphate (ATP) or other additives did not improve reproductive performance. The flies were able to compensate for considerable dilution of the blood with both serum and saline. Both parental and F1 female size affected the weight of the F2 puparia produced. The feeding of females on rabbits' ears on one day and in vitro on five days per week prevented any deterioration in performance over successive generations compared with a purely in vitro regime. A colony was established using this technique and results over a 13-month period were compared with those from a colony fed without rabbit supplement and another fed on rabbits only. The reproductive performance of females in the all-membrane-fed colony deteriorated from generation to generation, while those in the rabbit supplement colony performed similarly to those of the rabbit-fed colony except that survival was better but fecundity was poorer and the puparia produced were smaller.

The action of smoke from smouldering mosquito coils against Aedes aegypti(L.), Anopheles stephensi List. and Culex pipiens fatigans Wied. was studied. Smokes from lindane or DDT coils did not inhibit biting of guinea-pigs by Ae. aegypti or A. stephensi nor did they cause knockdown. The pyrethroids (allethrin, pyrethrins, bioallethrin and S-bioallethrin in that order) were increasingly effective in knocking down and killing C. p. fatigans and Ae. aegypti, and their bite-inhibiting activity on Ae. aegypti and A. stephensi increased in the same sequence. Pyrethrins were inferior to allethrin for knockdown of A. stephensi. Smoke from a bioallethrin coil inhibited Ae. aegypti from probing and taking blood from man. Tests in a cylinder of 0·034 m3 and a room of 25 m3 suggested approximate relative potencies of 1:2:4 for allethrin, bioallethrin and S-bioallethrin, the bite-inhibitory and knockdown actions being closely associated. Use of gauze-ended test cages reduced the range of relative potencies. The discussion suggests that the sequence of effects exerted by smoke on a mosquito entering a room is deterrency, expellency, interference with host finding, bite inhibition, knockdown and, eventually, death.

Using the inverse square law, estimates can be made of the distances at which illumination from a light-trap is equal to that from background sources. From these distances an index of trap radius can be constructed which can be considered as a measure of trap potential. Between new moon and full moon trap radii vary, depending upon the times of the night at which the trap may be operating, in ratios from about 10:1 to 15:1. A comparable index of light-trap catches can be calculated which allows catches to be examined in relation to changing radius of the trap. Analysis of a series of catches in Uganda and Ghana shows that many species are more abundant than expected in periods of moonlight, particularly at and near full moon, the biggest difference between new moon and full moon being about 10:1 for Marasmia trapezalis (Gn.), whereas the Isoptera, Bostrychidae and Spodoptera triturata (Wlk.) are 3–4 times more frequent at full moon. The ratios between catch at new moon and catch at full moon suggest that the primary determinant of catch is the frequency with which insects cross the boundary of a region of influence whose size is determined by a radius of equal energy. Deductions about the pattern of insect activity through a lunation, and nightly, and the general agreement between curves describing the change in radius of the trap and those of trap catches suggest that changes in catch over a lunation can be explained by changes in the effectiveness of the trap. When corrections are made to allow for such changes, all taxa show some increase in numbers in moonlit periods and in many taxa this increase is substantial. Correction of catches should take account of flight periodicity and this periodicity should, if possible, be confirmed by methods independent of light-traps.

Field trials were undertaken in Victoria and New South Wales, Australia, to discover whether synthetic sex pheromone, cis-8-dodecenyl acetate, could be used to control the oriental fruit moth, Cydia molesta (Busck), in peach orchards by the disruption technique. When pheromone was released at rates exceeding 5 mg/ha h from polyethylene capillary tubes males were generally unable to locate synthetic pheromone sources or live virgin females. By maintaining a constant rate of release per unit area it was possible to reduce the number of dispensers from one per 50 m2 to one per 400 m2. There was no significant difference in disruption when pheromone was released from tree crowns at 3·5 m or lower down at 1·5 m. Shoot and fruit damage from trials in commercial orchards suggested that pheromone treatments were as effective as a full seasonal schedule of insecticide applications in reducing damage.

A laboratory-reared British strain of Myzus persicae (Sulz.) did not readily accept the artificial diet that has been used to maintain North American strains. All components of this diet were re-tested in factorial tests and a modified diet was developed which contained increased amounts of alanine, leucine, phenylalanine, serine, folic acid, calcium pantothenate and pyridoxine, while omitting arginine, glutamic acid, histidine, tryptophan, valine, ascorbic acid, choline chloride, nicotinic acid and riboflavin. This diet, although less adequate nutritionally than the original diet, could maintain M. persicae for several weeks and more than two generations. It was readily accepted by aphids with few deaths in the first generation, so that it should be more suitable than the Californian diet for bioassay of systemic insecticides and for studies on substances that might influence aphid behaviour.

The Indian species of Trichomma Wesmael (Anomaloninae) are revised. A new species parasitising Dioryctria abietella (Denis & Schiffermtüller) (Pyralidae) and Eucosma pylonitis Meyrick (Tortricidae) is described as T. dioryctri, and two known species, T. nigricans Cameron and T. decorum (Cameron), are redescribed and briefly compared with other species in the genus. Short notes on the host ranges of the species are included. The cephalic capsules of the final-instar larvae of two species are described.

In 1968–70 adults of Oryctes rhinoceros (L.) and Scapanes australis grossepunctatus Sternb. were counted and removed weekly from two one-acre plots in separate plantings of 3–5-year-old coconuts in the Gazelle Peninsula of New Britain. For O. rhinoceros the immigration rate (average 3 adults/acre (60 palms) 4 weeks) showed no annual cycle or overall trend with time but was reduced by rain; the beetles occurred singly on the palms, but certain palms were more frequently attacked than would be expected by chance; the sex ratio (♂/♀) averaged 0·91, five out of nine females being mated and one having mature eggs. For S. a. grossepunctatus the immigration rate (average 4 adults / acre 4 weeks) decreased with time but was not affected by rain; females were usually accompanied by males, the female being deeper in the feeding hole, and 92% were mated, 15% with mature eggs; the high ♂/♀ sex ratio (3·69), differing from that in reared material, is attributed to females spending much time searching for ovi-position sites.

The effects on the emerging adult of topical application of 14C-dieldrin to third-instar larvae of Musca domestica L., and the distribution of the insecticide in the fly, the puparial case, and the holding medium, were examined. The dose ranged from 0·04 to ca 13 μg/larva. All flies emerging after treatments of 1 μg and above showed symptoms of poisoning some time after emergence. With the larger doses an increasing number of flies, although they escaped the puparium, were unable to reach the surface of the holding medium. With the two top doses some were unable to escape fully from the puparial case. These flies contained amounts of dieldrin well in excess of the LD99 dose. However, even the highest dose allowed some flies to emerge normally. None of the treatments affected metamorphosis and all flies appeared morphologically normal. The data provided evidence that the transfer of dieldrin to the adult via the pupal stage accounts for the effects in the newly emerged fly.

Nesodiprion biremis (Konow) is a potential pest of pine nurseries and plantations in northern Thailand, attacking both native and exotic species. The eggs are laid in an aggregated pattern on fairly young or mature needles. There are normally six larval instars in both sexes. The larvae feed almost entirely on mature foliage unless food is short, and show little preference for particular species of pine. They are not markedly gregarious. Larval defence mechanisms are discussed. Cocoons are spun among the bases of living needles close to the stem. The life-cycle takes at least six weeks at 25–30°C, and there are probably 5–6 broadly overlapping generations each year. Egg mortality is normally low, but mortality of first-instar larvae due to inability to initiate a feeding site is high. Two parasites attack the larvae and at least four more species the cocoons. Shortage of food leads to the production of smaller adults with a reduced fecundity. Possible control strategies are discussed.

The development of an outbreak of the woodwasp, Sirex noctilio F., in a 30-year-old population of Pinus radiata in Tasmania was traced by growth ring analysis of killed trees. The outbreak probably developed from small foci; it reached its peak when the trees were 18–19 years old and then declined rapidly. Attack per tree was directly related to the density of emergents from trees killed in the previous season and the intensity of oviposition drilling was modified by the rainfall during the emergence season; the frequency of treble oviposition drills was directly related to summer rainfall. Survival of insects within trees declined with the years; this was related to the greater vigour and resistance of the surviving trees, but was apparently modified by spring rainfall. Resinosis and polyphenols associated with growth rings in stems living in 1964 indicated an increase in the proportion of trees resisting attack during the outbreak. The growth patterns of attacked and unattacked trees, and the obvious susceptibility of the weaker understorey trees, are discussed and due attention to site quality and plantation management are recommended to reduce Sirex attack in future.

The dispersion and density of brood galleries of the wood-boring ambrosia beetle, Xyleborus fornicatus Eichh., in the tea plant depends on the type of branch (primary, secondary and tertiary) and not on the total available length of branch nor on branch thickness. Within the different branch types, branch lengths and the numbers of galleries contained in them are directly related. Significantly more galleries are formed in the primary branches than in the secondaries, which themselves carry more than the tertiaries. For precise estimation of Xyleborus population density, a stratified sampling system, representing the different branch classes, will be required.

Aphytis melinus DeBach was introduced to South Australia, reared in the laboratory, and then released against Aonidiella aurantii (Mask.) on citrus. In tests in nine citrus orchards, 100 adults of Aphytis melinus ensured colonisation during summer and early autumn, 1000 during late autumn, but even that number was insufficient during winter. Colonisation was equally successful whether Aonidiella aurantii was very abundant or very rare. The most efficient method for colonisation was therefore to release 100 adult parasites during summer and early autumn into small populations of A. aurantii. The parasite had dispersed at least three trees from each summer release site after five months, but much less following autumn releases. Ten months after summer release into nine trees of a total of 3330 adults, Aphytis melinus was recovered from 286 out of 354 (80%) trees in one orchard. In a further experiment, numbers of Aonidiella aurantii were reduced from 300–1000 per 150 leaves on five trees to less than 10 per 150 leaves 18 months after the release of Aphytis melinus, whereas on a control tree they increased from 550 to 1450 per 150 leaves over nine of those months.

A self-supporting colony of Glossina morsitans morsitans Westw. fed through Agar/Parafilm membranes upon haemolysed bovine blood for five days and upon the ears of living rabbits for one day each week (M5R1) is reported. This colony produced offspring intermediate in weight between those produced by adults fed exclusively upon living hosts (R6) and those fed exclusively through membranes (M6). Life span and fecundity of M5R1 adult females was close to that of R6 females and superior to that of M6 females whose reproductive performance was inadequate to maintain a colony. The different regimes did not affect feeding frequency, although adult nutrient intake was lower in M6 than in R6 females, and M5R1 females were intermediate. Larval growth as measured by dry weight increase and total nitrogen content at 24-h intervals throughout the second reproductive cycle showed that growth rates of all three instars were lower with M6 than with R6 feeding regimes, while the M5R1 regime produced an intermediate effect. There was a linear relationship between dry weight and total nitrogen content for all developmental stages from egg to fully grown third-instar larva, and this was unaltered by the feeding regime, suggesting that gross nutrient composition remained constant and was unaffected by the adult diet. Evidence is presented that a large critical blood-meal ingested on or about the fifth day of a nine-day interlarval period provides the bulk of nutrient for larval growth. Histological examination of the adult uterine glands showed that the greatest secretory activity was coincident with a waning of cell size and that nutrient secretion is a continuous process from the time of hatching of the first-instar larva until parturition. It is concluded that poor reproductive performance of adults maintained on in vitro feeding regimes is due mainly to quantitative aspects of feeding rather than qualitative deficiencies in the diet.

The nature and age dependence of behaviour of Culicoides melleus (Coq.) during and immediately after separation from copulation has been examined. Differences in the timing of events during separation, and consequent retention of the spermatophore, were ascribed to interplay of three factors: (i) the existence of age-dependent physiological mechanisms in both male and female that ‘time’ the course of copulation, (ii) female kicking behaviour which acts as a stimulus causing the male to release his claspers, and (iii) after clasper release, the separatory kicking performance of the female and simultaneous attempts by the male to free the spermatophore's capsule lodged in his genitalia. Post-separatory behaviour of both male and female was age-dependent, but only that of the male was influenced by the presence of the spermatophore. A retained spermatophore caused abdominal grooming to be initiated significantly more frequently as the first action after separation, and to occupy the insect for a substantially larger proportion of its time for the first two minutes after separation. In insects of both sexes, abdominal grooming was the dominant activity after separation giving way to grooming of other bodily parts and locomotory activity. Both young and old males and old females removed a retained spermatophore usually within 40 s of separation. Only very young females performed poorly in this respect, with spermatophores kept usually for at least several minutes and, in some instances, several hours.