Single-species and mixed-species populations of Tribolium castaneum (Hbst.) and T. confusum Duv. were followed in two experiments. Food (flour) was renewed at various intervals between 30 days and 180 days or was not renewed at all. As the interval between food renewals lengthened, single-species populations of T. confusum became extinct later than populations of T. castaneum, the survivor in mixed-species populations changed from T. castaneum to T. confusum, and the mixed-species populations became extinct later than the single-species populations. When resource is limited, therefore, populations of the two species may persist longer if they compete than if they are husbanded as single species.

Adult males of Locusta migratoria migratorioides (R. & F.) had an oxygen consumption of 120 mm3 g-1 h-1 at 15°C and 988 mm3 g-1 h-1 at 37°C, although respiratory quotient in fed insects (0.83) did not alter over this temperature range. Starvation or starvation and desiccation reduced the respiratory quotient from 0.83 to 0.77 indicating a shift in metabolism from carbohydrates towards fats. It is shown that the amount of biologically useful energy produced (in the form of ATP) remains the same, and that a shift from carbohydrate to fat metabolism requires the depletion of a smaller weight of food reserve. The shift is counterproductive in terms of metabolic water production, as only 0.28 mg g-1 h-1 water is produced in starved or desiccated locusts compared with 0.35 mg g-1 h-1 in fed animals.

Hylurdrectonus araucariae Schedl is a major pest in hoop pine (Araucaria cunninghamii) plantations at Bulolo and Wau in Papua New Guinea, establishing itself in nests inside the branchlets. The length of the excavation is proportional to the age of the nest. Colour changes in infested branchlets reflect changes in colony composition and in excavation activity as the colony ages; the branchlet eventually dies and falls off and severely infested trees lose much of their foliage. Data from field observations between 1967 and 1972 show that there are 5–10 overlapping generations of H. araucariae in a year. The life-cycle takes place wholly within the branchlet, except for a brief period of flight or walking by the adult when seeking new nesting sites. The eggs incubate for 5–15 days, larvae take 10–25 days, pupae 10–15 days, and the immature adult 2–10 days; the adult may live 60 days or more. The colony composition is fairly stable in heavily infested areas throughout the year, except during drought. Colony composition and size vary from branchlet to branchlet or from tree to tree, but are more similar on trees with a similar stage of infestation. No significant natural enemies were found.

In laboratory colonies of Atta cephalotes (L.) and Acromyrmex octospinosus (Reich) pick-up responses to paper discs impregnated with arrestant and inhibitory solutions and feeding responses to measured amounts of these solutions were progressively increased by increasing the concentration of arrestants and decreasing the concentration of inhibitor; the inhibitor had a much greater effect on feeding than on pick-up. Both species picked up paper discs impregnated with arrestants and Acromyrmex readily incorporated these into the fungus garden, while Atta did this less readily. Foraging of arrestive paper discs presented regularly for several days was maintained by Acromyrmex but declined in Atta. Both species were less selective during periods of high foraging activity and during a shortage of suitable substrate. Incoming foragers did not seem to influence the preferences of the outgoing ants, but different colonies showed different preferences. Initially little preference was shown for new materials but on subsequent encounters widely fluctuating preferences emerged, which stabilised within two weeks. Over longer time periods further changes in preferences occurred. The ants' pick-up, cutting or feeding response to a particular material is determined by its chemical and physical nature, the amount of chemical information which the ants obtain, and the threshold of their response. This threshold is modified by such factors as the genetic composition of the colony, the previous quantitative and qualitative availability of the substrate, and the general level of foraging activity. Practical implications of these findings for toxic bait production are discussed.

A description is given of a simple moveable platform which enables workers using stereoscopic microscopes to focus their work accurately without the need to remove their hands from the specimen or work area.

The taxonomic status of the Chondrilla gall midge, Cystiphora schmidti (Rübsaamen), is discussed and new generic and specific synonymy is established in the genus Cystiphora. Male, female and larval characters of C. schmidti are described and illustrated on the basis of specimens made available from recent studies of this species in Europe as part of a project to implement biological control of Chondrilla juncea in Australia.

A Cecidomyiid gall midge, Cystiphora schmidti (Rübsaamen), lives on several related Chondrilla spp. occurring from Greece and eastern Europe to Iran. Its biology and host specificity were studied in the eastern Mediterranean region as part of the biological control programme against the weed C. juncea (Compositae, Cichoriaceae) in Australia. The adult female oviposits into the lower epidermis of the plant where small circular to ovoid raised galls are produced on the rosette, stem leaves and the stem. All the immature stages are completed inside the gall in 24–44 days, allowing 6–7 generations per year in southern Greece before low temperatures prevent development of overwintering larvae. The midge is heavily parasitised in Greece by two species of Eulophidae. Particularly in southern Greece, dense gall populations cover the leaves and stems of C. juncea, causing death of leaves, stunting and less seeding. Tests against 76 species of plants including some Cichoriaceae closely related to Chondrilla showed that Cystiphora schmidti is specific to the genus Chondrilla. Comparative tests with Cystiphora schmidti from Greece against four forms of Chondrilla juncea showed that the midge was adapted to its usual Greek host but was less closely adapted to a western Mediterranean form. The Greek strain of the midge readily attacked and thrived on the main Australian form of C. juncea.

Hungry tsetse flies (Glossina morsitans Westw.) are confined individually on the stretched wing membrane of a bat. Only 10–20 s after the tarsi touch the membrane, the flies probe and salivate, the main saliva flow following after penetration. The clear colourless saliva is easily collected onto a microscope slide.

A total of 167 blood-fed mosquitoes of the genera Ficalbia, Mimomyia and Uranotaenia was collected from the Kisumu area of Kenya using Monks Wood light-traps under the outside eaves of houses, CDC light-traps inside houses and sweep-net catches. Precipitin tests were used to obtain 72 positive identifications of the hosts, 89% of which were amphibia. M. mediolineata (Theo.) and M. splendens Theo. were shown to feed occasionally on man while U. balfouri Theo. and M. hispida (Theo.) were shown to feed on other mammals, including cattle. No identification was effected from a single F. uniformis (Theo.) specimen collected resting in vegetation. The medical importance of these mosquitoes is uncertain but, since there is evidence for several arboviruses in amphibia, further study of these potential vectors should be undertaken.

Laboratory colonies of Monomorium pharaonis (L.) were given access only to food containing the juvenile hormone analogue isopropyl-11-methoxy-3, 7, 11-trimethyl-dodeca-2, 4-dienoate (Altosid). In contrast to control colonies all the brood died in 4–8 weeks and queens ceased to lay eggs at about this time. Comparison of ovaries dissected from treated and untreated queens showed the former to be atrophied and without developing oocytes. In treated colonies the worker caste became extinct between 9 and 20 weeks after treatment commenced but queens remained alive for more than 20 weeks. Treatments were lethal with exposure periods of one week only. Juvenile hormone analogues show real potential for the control of M. pharaonis.

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 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.

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.

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.

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.

The eggs of Aeneolamia varia saccharina (Dist.) were separated from samples of cane-field soils by means of a rotary sieve, hydrogen peroxide treatment and flotation; this method gave 76% extraction. Absolute population estimates of eggs were obtained from samples of soil (one-eighth of a cane stool) scraped from between the stems of 10 or 25 sugar-cane stools per field, the 25 pooled to give five sample groups. Relative population estimates, which took less time, were obtained from 20-g scoops of soil from between the stems of 25 stools, giving one composite sample. Taylor's power law was used to show that eggs were strongly aggregated in the dry season but less so in the wet season. The numbers of samples or sample groups needed for given levels of error were calculated from the indices of aggregation. Absolute and relative estimates of egg density were generally well correlated. The quicker relative method, suitably replicated and standardised, was considered suitable for extensive and intensive sampling.

Sturmiopsis parasitica (Curr.), an important larval pupal parasite of graminaceous borers in Africa south of the Sahara, was collected from Sesamia spp. and Eldana saccharina Wlk. in Ghana. Puparia were shipped to the CIBC station at Bangalore, where a rearing technique, using field-collected borers as hosts, was devised. At 26°C the larval period was 12–14 days, prepupal period 12 h, and the pupal period 12–19 days. In its 3–4 week life span a male could successfully inseminate 4–5 females, which each produced 500–900 maggots after a gestation period of 18–19 days. In the laboratory Sturmiopsis parasitica successfully parasitised Chilo auricilius Dudgn., C. partellus (Swinh.), C. infuscatellus Sn., C. sacchariphagus indicus (Kapur) and Sesamia inferens (Wlk.); it did not parasitise Tryporyza nivella (F.) or Corcyra cephalonica (Stnt.) and was only once recovered from Galleria mellonella (L.). Its potential as a biocontrol agent against graminaceous borers in the tropics is considered high.