In the laboratory, the trail pheromone methyl 4-methylpyrrole-2-carboxylate (M4MP2C) when added to bait particles acts as an attractant to leaf-cutting ants, increasing the pick-up of pheromone-impregnated bait compared with plain bait. However, field trials in Trinidad, Brazil and Paraguay were disappointing. Bait with and without pheromone was scattered in the foraging area, and the proportion of each taken to the nest by Atta sexdens rubropilosa Forel, A. cephalotes (L.) and Acromyrmex octospinosus (Reich) was assessed. In only one of the experiments (A. octospinosus foraging bait with 50 p.p.m. of M4MP2C) was increased pick-up detected. Four reasons for this are suggested: (1) small pheromone effects are difficult to measure as scattering bait produced a patchy distribution and heterogeneous replicates, whilst choice trials on plain and pheromone-impregnated bait placed close together were difficult to interpret, as the pheromone probably excited the ants, increasing pick-up of plain bait; (2) A. octospinosus workers, the subject of detailed studies, were less sensitive to M4MP2C in the field than in the laboratory; (3) as the pheromone only attracts, it does not produce a comparable increase in the number of pieces picked up, contact/pick-up ratios of sucroseimpregnated discs increasing from 2·26 at 5 pg pheromone to 16·39 at 50 ng; and (4) soyabean oil, citrus-pulp extract and orange juice were found to be attractive, and when pheromone was added, its effects were not additive. Early studies used sucrose-impregnated paper discs, and as these have no attractants of their own, the addition of M4MP2C had a more marked effect. It is concluded that M4MP2C is not a cost-effective addition to current leaf-cutting ant baits which possess food odours, a much cheaper source of attractiveness.

Behavioural responses of Triatoma infestans (Klug) to visual stimuli were analysed using a novel method involving remote monitoring of individual tethered bugs. T. infestans showed negative phototactic behaviour and a reduction in activity in response to a directional white light stimulus at an intensity of 1·2 /µW/cm2. A lower intensity of white light (0·6 µW/cm2) elicited a similar negative phototaxis but failed to induce a significant reduction in activity. The response to green light at 0·6 µW/cm2 was similar to that towards white light at 1·2 µW/cm2. Blue light did not induce any behavioural responses, whereas red light induced a significant reduction in activity at the lower intensity but did not affect phototaxis. Infrared radiation did not induce any significant behavioural effects, but there was an indication that T. infestans can detect near infrared radiation (750 nm). The activity response to the higher intensity white light appeared to be mediated primarily by the compound eyes. The dorsal ocelli, however, were involved in the directing of the phototactic response. T. infestans responded to moving objects by a marked reduction in activity. Slowly moving objects induced a following response, whereas more quickly moving objects did not.

Extracts from cultures of Pseudomonas aeruginosa, Bacillus subtilis, Proteus mirabilis and Enterobacter cloacae in samples of fleeces from sheep were incorporated into nutrient agar and exposed to females of Lucilia cuprina (Wied.) in cages. The blowflies often laid eggs in response to the odours emanating from the cultures of all bacteria. Pseudomonas aeruginosa and E. cloacae did not appear to utilise fleece components in the production of oviposition stimulants, whereas B. subtilis did, utilising compounds such as palmitic acid, and Proteus mirabilis degraded wool fibres to produce sulphurous compounds. The results are discussed in relation to the role of L. cuprina in cutaneous myiasis of sheep.

Flight activity characteristics of Chortoicetes terminifera (Wlk.) were recorded in adults suspended on a simple flight balance in a wind tunnel. Ninety-one per cent, of flights by post-teneral (>5-day-old) insects lasted less than 60 s, and only 11% of adults flew for a full 20-min test period at 30°C. The flight capacity ranged from a few or many short flights to continuous flights. Females flew for a greater proportion of the time than males. Flight activity increased with food-deprivation, and only fully hardened (>9-day-old) insects flew continuously throughout a 45-min test period at 26–41°C. Gravid females also made long flights. The frequencies of flight durations by laboratory-reared insects were strikingly similar to the day flight of milling field populations in eastern Australia. Flight performance observations indicated that lift declines with time in flight, wing-beat frequency initially being 33·2 Hz in males and 30·0 Hz in females. The results are discussed in relation to field studies.

Exposure of pregnant females of Glossina morsitans morsitans Westw. to a standard dose of 14·8 ng/fly of endosulfan confirmed that they acquire a higher level of tolerance of this insecticide than young unmated females. The development of tolerance was rapid, from threefold 48 h after larviposition, to eightfold midway through the pregnancy cycle at 4–5 days, and reaching 10- to 14-fold 24–28 h before the next larviposition. The acquisition of substantial tolerance preceded the periods of major growth of the larva in utero and of the developing oocyte, and it is suggested that the development of tolerance is associated with the diversion of insecticide by partitioning into lipid components of the milk as they are synthesised. The level of tolerance attained at equivalent stages of the pregnancy cycle appeared to be largely independent of the age of the fly between the second and fifth cycles, but that reached in the first cycle was lower. Some females survived repeated exposure to endosulfan in successive cycles. The offspring of treated females showed no apparent effects until shortly after adult eclosion, when substantial but variable delayed mortality occurred. However, surviving females and their offspring continued to reproduce normally. It is concluded that tolerance of the insecticide in pregnant flies accounts adequately for the observed survival following non-residual applications of endosulfan, and strategies for preventing this survival, and achieving eradication, are discussed.

External sexual characters are described for the larvae of Spodoptera littoralis (Boisd) and S. exempta (Wlk.). The characters on the female consist of two pairs of pits on the ventral surface of the eighth and ninth abdominal segments. These pits are visible under a light microscope and can therefore be used for the accurate sexing of live larvae from the third instar onwards. The first- and second-instar larvae of both species could not be sexed using external characters because of their small size. In the males of both species, there are no obvious external sexual characters until the last instar, and therefore the sexes are most easily separated by the presence or absence of the female characters. Third- to sixth-instar larvae of both species were examined for the presence or absence of the female pits and were then sexed by dissection. The accuracy of sexing using the external characters was 90–98% for S. littoralis and 100% in all cases for S. exempta. The histology of the female pits and their appearance under the scanning electron microscope is described. These pits in the female larvae give rise to the external openings of the adult reproductive system.

Diapause induction in Heliothis armigera (Hb.) from the Sudan Gezira was investigated under controlled conditions. A maximum incidence of diapause occurred in response to exposure to low temperature (22°C) and short daylength (12 h) during the larval stage. However, the prepupal and early pupal stages were also sensitive to temperature; if they were exposed to 26°C, diapause was averted. After more than two months at low temperature, some pupae remained in diapause for more than two months after transfer to high temperature (34°C) and only commenced developing when the temperature was lowered again. This may provide a mechanism to bridge the hot dry season and to synchronise emergence with the start of the rainy season. A high incidence of diapause in H. fletcheri (Hardwick) was observed to occur at the end of the rainy season under ambient conditions in the Sudan. Emergence from these diapause pupae occurred in the following rainy season. The different phenologies of diapause in the two species are discussed in relation to their distribution in rain-fed and irrigated vegetation in the Sudan.

Survival and wood consumption were measured for laboratory groups of Porotermes adamsoni (Frogg.) maintained over a range of constant temperatures from 8 to 29°C. The termites were fed on sound blocks of Pinus radiata, Eucalyptus regnans, decayed E. ?viminalis, and outer (sound) and inner (decayed) heartwood of E. pauciflora. Above 21 °C, diet influenced the pattern of survival, wood consumption and wood consumption adjusted for survival, resulting in a significant temperature × timber interaction. In the upper range of the temperatures used, the termites survived in larger numbers or for longer periods on decayed than on sound wood and ate more of it. From the results, it is clear that difficulties arise when employing laboratory data to estimate feeding activity of termite populations in the field. Knowledge of the correlation between the performance of termites in laboratory groups with that of members of a field colony is still sparse.

The identity of Chilo kanra (Fletcher), an obscure stem-borer of the wild and semi-cultivated grasses Saccharum fuscum and S. arundinaceum in northern India, is ratified on the basis of recently collected material from Bihar. A neotype is designated, and the adults and genitalia are illustrated. The species is differentiated from its congener C. partellus (Swinh.), a widely distributed pest of sugar-cane and other graminaceous crops in India and Africa. A neotype is also designated for C. saccharicola Fletcher, a stem-borer described at the same time as C. kanra and now found to be conspecific and a junior synonym.

After checking the identity of numerous mealybugs of the genus Planococcus from the south Pacific, many of which were previously recorded as P. citri (Risso), it was established that the most widespread is the recently described species P. pacificus Cox. P. citri is present in some islands, but the collection dates are recent, suggesting a recent introduction. Although P. pacificus is known from the area since the first quarter of the present century, it may have been introduced also. P. lilacinus (Ckll.) possibly arrived from southern Asia and P. dioscoreae Williams from the eastern part of the Oriental Region. The known host-plants are listed.

Zeteticontus utilis sp. n., an encyrtid parasite of larvae of Carpophilus hemipterus (L.) and Urophorus humeralis (F.) in pineapple fields in Kenya and of C. hemipterus larvae in decaying fruit in Israel, is described. The parasite has been released in an attempt to control C. hemipterus in pineapple fields in Hawaii and is to be released against the same pest in Ohio.

Resistance to carbaryl, lindane and methidathion was studied in field and laboratory strains of Dysdercus fasciatus Sign., D. nigrofasciatus Stål, D. superstitiosits (F.) and D. cardinalis Gerst. from Kenya. Four-day old fifth-instar female nymphs were found to be the most convenient for bioassay. The LC50s of carbaryl, lindane and methidathion for D. fasciatus were 372, 240, and 110 mg/litre, respectively, those for D. nigrofasciatus 337, 294, and 111 mg/litre, and that for carbaryl for D. cardinalis 147 mg/litre. The Meru and Ngwata strains of D. fasciatus had resistance factors of ×5·3 and ×6·1, respectively, to carbaryl. The field strains of all four species showed slight resistance (up to ×3·4) to lindane and methidathion. The poor control of Dysdercus spp. experienced in Eastern Province, Kenya, is probably due to the development of resistance to carbaryl. A laboratory and a field strain of each of D. fasciatus and D. nigrofasciatus were subjected to carbaryl selection pressure for six generations of doses equivalent to the LC50-LC70. The laboratory strain of D. fasciatus was also subjected to lindane selection for six generations. The laboratory and field strains of D. fasciatus developed resistance to carbaryl of ×3·7 and ×5·7, respectively, and cross-resistance to lindane of up to ×2·7. No significant increase in resistance was observed in D. nigrofasciatus after selection. The laboratory strain of D. fasciatus developed resistance to lindane of ×5·5 after selection and cross-resistance to carbaryl of ×4·3.

The African rice gall midge, Orseolia oryzivora sp. n., is described and illustrated from adults of both sexes, larvae and pupae collected in West Africa. This species had previously been misidentified as O. oryzae (Wood-Mason), which is a major pest of rice in Asia, but the two species are morphologically distinct in the larval, pupal and adult stages. All available African material has been examined, and O. oryzivora is recorded from cultivated rice in Senegal, Upper Volta, Ivory Coast, Nigeria and the Sudan. Larvae and pupae collected from Paspalum in Upper Volta differ from typical O. oryzivora in some morphological characters and probably represent an undescribed species of Orseolia

Three benzyl-l,3-benzodioxoles and three benzylphenols were tested for their ability to sterilise Glossina morsitans morsitans Westw. following topical application in acetone. Two of the former compounds, 5-ethoxy-6- (4-methoxyphenylmethyl)-l,3-benzodioxole and 5-ethoxy-6-[l-(4-meth-oxyphenyl)ethyl]-l,3-benzodioxole, caused total sterility in females at a dose of 10 μg per fly, and remained effective even after one year's storage at 4°C. Dose-fecundity data indicate a reduction to 50% fecundity (ED50) was achieved with 2·5 μg of the former or 0·5 μg of the latter per fly. An ED90 of 8·5 μg and 2·5 μg, respectively, is indicated. The latter compound reduced the survival of treated females and males and surviving males were incapable of inseminating even though copulation appeared normal. The effects on female survival and fecundity, of feeding the compounds at 0·25 and 1·0% in blood, were variable, owing to their low solubility and variations in the size of blood-meals. The highest doses of the former compound led to ovarian atrophy in females, which can be described as an effect on fecundity. Lower doses induced sterility through egg death and atrophy after ovulation. The latter compound acted more rapidly than the former, preventing ovulation of the first mature oocyte in a higher proportion of flies. The activity of these compounds, which were derived by modification of plant materials, and are non-mutagenic, renders them likely candidates for evaluation as contact insecticides for Glossina in the field.

In the Gambia, bed nets are often used for protection from mosquitoes although some of the nets are often in poor condition. In a village where the most abundant man-biting mosquito was Anopheles gambiae Giles s.s., nets in different condition were compared by assessing the success of mosquitoes in feeding. All the nets tested reduced mosquito feeding, and this reduction correlated with the number and size of holes in the nets. The experiments were conducted in purpose-built huts with verandah traps to sample the mosquito population leaving the hut. Although the majority of males and fed females of A. gambiae remained in the huts each morning, unfed females usually left the huts the same night, probably in search of alternative food sources.

The distribution of fed mosquitoes in a village in the Gambia where bed nets are widely used was studied. A total of 3470 blood-meals from Anopheles gambiae Giles s.s. and other mosquitoes was analysed to determine the human blood index (HBI). A. gambiae s.s. collected within nets gave an index of 0·99, whereas those within houses but outside nets gave an index of 0·70. The importance of distinguishing biotopes when presenting HBI values is stressed. By using a unique host, mosquitoes were ‘ marked ’ (with a blood-meal) and their dispersion was studied. Evidence was obtained for movement from house to house and from outside into houses before resting.

Flight initiation of adults of Triatoma infestans (Klug) was recorded in a laboratory apparatus. The proportion of individuals initiating flight depended on the nutritional status of the insects, and flight activity was greatest about 12–18 days after feeding. From measurements of the weight and length of the insects, it was possible to assign the probabilities of flight initiation and thus predict the proportion of an adult population likely to fly. The predictive model should be of use to field workers studying dispersion of T. infestans between infested houses.

Interference with reproduction in Glossina morsitans morsitans Westw. by diflubenzuron depends on a variety of factors that influence its uptake and loss from the female fly. The duration of its eftect depends on the site and method of application to the fly as well as the amount of material applied. In nulliparous females, loss of diflubenzuron was by excretion, but as the fly aged approximately 50% of the material remaining within the fly was lost with each larviposition. Following injection, the rate of loss of diflubenzuron by excretion was twice that from flies treated topically, but in neither was it directly related to the amount of diflubenzuron within the fly. Loss to the in utero larva, however, was governed by the amount of material within the fly, at least 9 ng diflubenzuron being necessary for production of an abnormal offspring. In injected flies, the overall loss was twice that from flies treated topically on the dorsal thorax and similar to those treated topically on the ventral abdomen. This difference in the rate of loss from topically-treated flies seems to be related to the amount of material available on the surface of the fly, the cuticle apparently acting as a storage site from which there is a gradual release of diflubenzuron into the fly.

Liothrips mikaniae (Priesn.) comb. n. is one of the most promising biological control agents for Mikania micrantha, a sprawling composite vine native to the Neotropics which is a serious weed of plantations in South-East Asia. A description and illustrations of the adult and larvae of this thrips is followed by details of the life-history, culture technique, host specificity (including laboratory studies demonstrating oligophagy) and natural enemies. It is recommended for introduction to South-East Asia.