Several methods, including the use of serology, are available for evaluating prey-predator relationships. Two basic methods involving precipitation and agglutination reactions have been utilised, both of which depend on the production of specific antisera with high titres. A critical account is presented of methods of preparing antisera, with particular reference to the amount of antigen required, the route of inoculation and testing antisera, together with a review of the five precipitation and two agglutination techniques available. The main limitations of serological methods are tje specificity of the arrtisera and the difficulties in quantifying results unless assumptions are made as to the number of prey eaten at each feed. Details of studies employing serological techniques to identify the predators of specific prey and the food od invertebrates are given intwo tables. The value of serological techniques is discussed in relation to the ecology of invertebrates by considering, as examples, te insect fauna on broon (Sarothamnus scoparius), predation of mosquitoes and the food of triclads. Errors in the quantification of predation may occur by including positive reactions resulting from carrion feeding or material ingested acidentally on plants by phytophagous arthropods.

The turnover of the radioisotope 137Cs is shown to be of a one-component nature and to be positively correlated with temperature for males of both Glossina morsitans Westw. and G. pallidipes Aust. A direct correlation with oxygen consumption is also demonstrated, and the relation for both species may be described by the same regression line. The feasibility of using 137Cs as a metabolic label for tsetse is therefore confirmed, and it is suggested that the predictive nature of the relationship between radioisotope turnover and metabolism may extend beyond closely related species.

The effects of wind speed, wind direction, strong moonlight and rainfall on hourly light-trap catches of adult Spodoptera exempta (Wlk.) made at Muguga, Kenya, between January and June in 1970 and 1971 were investigated. The highest catches occurred in winds of 2–3 m/s, but generally, fewer moths were caught as wind speed increased. In totally dark hours the geometric mean catch at wind speeds of 5–6 m/s was about one-tenth that at 0–1 m/s. The relationship between catch and wind speed changed between January and June. Wind direction and change in direction were not significantly related to catch. The geometric means of catches made in strong moonlight were about one-tenth those in total darkness at comparable wind speeds. Rainfall was associated with higher catches in seven out of eight months, but the differences were significant in only two months. Recognition of the association between light winds and large numbers of S. exempta should assist forecasting, but a fuller understanding of the relationship between light-trap catch and population requires a method of population assessment that is independent of the effects of weather and moonlight.

Collections of siricid-infested coniferous trees were made in 150 localities in 19 European countries, Turkey and North Africa to obtain parasites and parasitoids of siricids for use in the biological control of Sirex noctilio F. in Australia. During this work, information was obtained on the distribution and biology of 8 siricid species (S. noctilio, S. cyaneus F., S. juvencus L., Urocerus augur (Kiug), U. gigas. (L.), U. sah (Mocs.), U. fantoma (F.), Xeris spectrum (L.)) and 7 parasitoids (Rhyssa persu.asoria (L.), R. amoena. Gray., Pseudorhyssa maculicoxis (Krchb.), Megarhyssa emarginatoria (Thnb.), Ibalia leucospoides leucospoides (Hochenw.), I. rufipes drewseni Borries, Odontocolon geniculatum. (Krchb.)). Data are presented on distribution, flight periods and sexratios (determined from emergence records), factors leading to the susceptibility of timber to siricid infestation and the types of timber and host tree species infested. Levels of parasitism by the various parasitoid species, determined from emergence records, are given. Localities are assigned to bioclimatic categories, and their siricid and parasitoid species are classified in relation to the climatic criteria. The ecological status of S. noctilio is discussed in relation to its establishment in Australia.

Communication between adult male and female Diparopsis castanea Hmps. was disrupted by ultra-low-volume spraying of cotton in a 0·2-ha field cage and in an open-field plot in Malawi with a polyurea-based microencapsulated formulation of the mating inhibitor 80% (E)- and 20% (Z)-9-dodecenyl acetate (IIA). When sprays containing 38·7 or 105·3 g IIA/ha were applied at 6-day intervals within the cage, reductions in mating of 62–66% and in oviposition of 72–78% resulted. Larval infestation was reduced by an average of 61% over a 52-day period. Effective release rates during these experiments were 4–19 mg/IIA/ha. Spraying at 6-day intervals with 15·9 g IIA/ha, however, had no significant effect on mating, and applications of 25·8 g of IIA/ha at 12–14 day intervals in the presence of high moth populations produced a reduction in female mating of only 19% despite a release rate of 4·4–53·0 mg/ha/h. Physical and chemical evaluations of microcapsule deposition on cotton plants indicated a low application efficiency, with an ‘effective’ spray deposition on plants of only 3·25–20·05% between pre-flowering and maturity. In an open-field spraying trial, applications of 38·7 g IIA/ha at 14–15 day intervals reduced oviposition by 75% from expected levels. Application of 15·7 g IIA/ha, however, had no disruptive effect in the field. Gas-liquid chromatographic analysis revealed no chemical interaction or marked effect on the release rate of IIA when carbaryl and IIA were sprayed in combination. Indirect evidence indicated that the microencapsulated formulations used possessed a considerable ability to withstand rain when applied to plants.

The eleven Melanesian species of the genera Perisphincter Townes and Agrypon Foerster, endophagous parasites of Lepidoptera larvae, are revised, and a key to them is given. One species of Perisphincter, P. toxeres sp. n., and six species of Agrypon, A. augrhantum sp. n., A. ambomum sp. n., A. celenellum sp. n., A. rhamphidum sp. n., A. apistum sp. n. and A. phlogeum sp. n., are described. A. nigricans Szépligeti is placed as a synonym of A. caliginosum (Tosquinet).

In laboratory experiments in Australia under standard conditions, densities of the dung beetle Euoniticellus intermedius (Reiche) exceeding 150/1-litre pad of cattle dung were shown to suppress breeding of Musca vetustissima Wlk. The experiments also suggested that it was the effect of dung disturbance on the survival of eggs of the fly that led to suppression. Natural vaiation in the quality of cattle dung obscured but did not alter the effects of high beetle densities. The mobility of M. vetustissima in particular, obscured the relationship of its abundance to dung beetle numbers in the field in 1974–75 and 1975–77 an intial high level of flies was apparently reduced and suppressed by a seasonally late but otherwise similar level of beetle attack on dung pads.

Laboratory-bred males of Spodoptera exempta (Wlk.) required at least 48 h after emergence before responding to females, whereas wild-caught males matured in 24 to 36 h; laboratory-bred females took 60 h, whereas wild-caught females were sexually attractive to males 48 h after emergence. Mating only occurred between 00.30 and 03.00 h. Females exhibited a courtship behaviour involving ‘calling’, and the males exhibited a series of pre-mating behavioural responses, probably characteristic of physiological levels of excitement by the female's ‘calling’. Experiments showed that a male can mate with and inseminate only one female each night. The number of females inseminated by any male was related to the male's life-span and was very variable. The fertility of eggs laid by a female was not affected by the age of the male she mated with. A single mating was sufficient for the fertilisation of a life-time's production of eggs by a female.

Field collections in Bahia State, Brazil, of open cocoa flowers from an untreated plantation and one treated with insecticide and fungicide showed that Homoptera, including the cicadellid Xesrocephalus ancorifer Linnavuori, the aphidid Toxoptera aurantii (Boy.), and species of Pseudococcidae and Margarodidae (Coccoidea), constituted 96% of the total number of insects collected. In the untreated area, Wasmannia rochai Ford formed 22% of the ants collected and Brachymyrmex pictus Mayr, Crernatogaster ? parabiotica Forel,Iridomyrmex sp., Pheidole sp. and Solenopsis sp., a further 48%, whereas in the treated area, 47% were C. parabiotica, 14% W. rochai and 9% B. heeri Forel. There was evidence of a mosaic distribution pattern for the ant species. No cocoa pollen was found on any of the insects collected. Total pollination ranged between 7·4 and 8·1 % and effective pollination between 3·7 and 2·8 % in the treated and untreated areas, respectively. Approximately 76% of the pollen masses were stylar, with 38% of the ball type and 54% of the smear type, whereas the 16% stigmatic pollen masses consisted of 63% ball and 29% smear types; 44% of the stigmatic pollinations were effective, compared with only 33 % of the stylar ones. Some quadrats were more attractive to pollinators than others, and there was a significant positive correlation between percentage effective pollination and insolation, probably due to the favourable effect of sunshine on Forcipomyia activity.

Cerneura delonixia gen. et sp. n. is described from specimens collected on flamboyant trees (Delonix regia) in Mauritius and Reunion, where it causes severe damage. Attention is drawn to other leafhoppers causing similar damage to other trees elsewhere in the tropics.

Three suitable sex pheromone trap designs for trapping the red bofiworm of cotton, Diparopsis castanea Hmps., including a simple omnidirectional monitoring trap, are described. In trials in Malawi, Diparopsis was more readily trapped on open horizontal trapping surfaces (water or adhesive) than in enclosed types of traps. The presence of a roof above the trapping surface, at spacings of up to 20 cm, significantly reduced catches. White traps, or unpainted traps in the case of vane traps constructed from galvanised metal, caught more moths than traps of other colours. Catches were greatest when monitoring traps in cotton were placed at ground level or at a height of 0·5 m and, when dicastalure was released from polyethylene vials, by employing a trap 60 cm in diameter. Evidence was obtained that competition may exist between female-baited traps spaced up to 73 m apart, although catches in traps baited with dicastalure were not significantly different when traps were 40–60 m apart. The greatest catches of moths in cotton were in traps located in insecticide-sprayed fields, but moths were also trapped in considerable numbers in other crops and to a reduced extent in open areas 4·8 km from the nearest cotton. From about the end of February, catches in maize, groundnut and fallow areas frequently exceeded the catches recorded within cotton fields, which may indicate an increased dispersal flight from cotton by adult moths later in the season. Weekly replacement in monitoring traps of polyethylene vials containing dicastalure produced maximum moth catches, but there was no significant difference in catch between traps in which pheromone was replaced at intervals of 2, 3, 4 or 6 weeks.

During a large-scale air-spray trial using endosulfan against Glossina morsitans centralis Machado in the Okavango Delta area of Botswana, a programme of ageing all flies caught on fly-rounds was undertaken. The aim was to evaluate closely the effect of repeated sprays on the population and especially to determine the origin of the small residual population that often remains after spraying. Ageing males by the wing-fray method indicated that none survived the spraying. Ageing females by ovarian dissection showed that (a) no breeding occurred between sprays, (b) one pupal period was just covered by four spray applications, (c) the residual population was composed of females that had survived the spraying and (d) all survivors had been pregnant at the time of treatment. Dissections also showed a very low rate of insemination between sprays, but the few females that survived spraying were all inseminated. Larval and pupal periods under natural conditions of fluctuating temperature are discussed together with methods of improving air spraying results by eliminating pregnant females.

Glasshouse and field screening showed that several varieties of cowpea (Vigna unguiculata) in the germplasm collection at the International Institute of Tropical Agriculture at Ibadan, Nigeria, had promising levels of resistance to damage by larvae of Cydia ptychora (Meyr.). There was no preference between varieties for oviposition in the glasshouse, but varietal differences in damage to pods and seeds occurred due to differences in the pod-boring and seed-feeding success of larvae. Large numbers of seeds per pod in some varieties diluted the effects of a given larval density and resulted in low percentages of damaged seed. A measure of relative susceptibility was devised that overcame the problem of chance escape from attack by certain pods. Resistance in glasshouse screening was not necessarily related to resistance in the field, where plant growth habits and the ecological requirements of the adult moths are more fully expressed and play an important role in determining the outcome of the plant-insect interaction. The most resistant variety in the glasshouse, Vita-3, was least resistant in the field, partly because it was partially photosensitive and produced few flowers and pods in the early growing season in Ibadan. Two varieties, TVu 946 and TVu 2994, may have escaped severe attack by maturing quickly. The former is small-leaved, non-vigorous, carries its pods on long peduncles well above the foliage and consequently constitutes an unsuitable habitat for daytime sheltering by adults. It was the least damaged variety in the field trial. The latter was most attacked by other pod-feeding pests, and the consequent reduction in seed weight and quality appeared to enhance the level of damage caused by C. ptychora.

Newly emerged females of Euoniticellus intermedius (Reiche) have no differentiated oocytes in their single ovariole. The eggs mature sequentially during the maturation period, and at 27°C the first egg is laid 4–8 days after emergence. The rate of oviposition increases with temperature between 18 and 32°C. The threshold for oviposition is 19·6°C, and one egg is produced for every four day-degrees above this threshold. Most females can be sorted into the nulliparous or one of three parous categories, covering the period from emergence to the time when between 75 and 127 eggs have been deposited, on the basis of the quantity of yellow body in the ovariole. The hardness of the cuticle, the degree of oocyte development, and the presence or absence of fat-body in the abdomen can be used to subdivide the nulliparous category into three parts and to recognise old or ‘spent’ beetles. The degree of wear on the tibial teeth gives an age estimate that is independent of nutritionally induced delays and with which the ovarian age can be compared. Actual age cannot be estimated in field-caught-beetles, however, since many factors besides temperature alter the rate of brood production.

Approximately 300 000 larvae of Phthorimaea operculella (Zell.) infected with granulosis virus were collected from virus-treated potato crops in Western Australia. Modified crop culture and releases of laboratory-reared adults were used to boost the natural populations. Virus was applied as an aqueous suspension of pulverised diseased larvae. Infested foliage was collected into large polythene bags; the larvae were forced from their mines by heat and collected by washing in water. Collection and extraction took 100 h; field propagation of virus is thus inexpensive. The purification of the virus was carried out by differential centrifugation and separation on sucrose gradients. A total of 35 g of pure freeze-dried material containing approximately 1·35×1015 particles was obtained.

Zonocerus variegatus (L.) is a chronic but relatively minor pest of crops in West Africa, and expensive control measures are not generally warranted. Egg pods, which take approximately six months to develop, are deposited in highly aggregated sites found scattered throughout cultivated areas. To test the feasibility of reducing populations in large areas by digging up the egg pods, two areas, of 18·5 and 20 ha, were selected near Ibadan, Nigeria, for investigation. Egg-laying sites were identified by observation and the egg pods subsequently dug up. There were on average one or two sites, 5·7 m2 in area, per hectare. Counting the following season's hatching populations in the two areas showed that the potential hatches had been reduced by 83 and 91%, respectively. Control by community self-help is suggested, where individual farmers identify and dig up laying sites on their own land, exposing the egg pods to desiccation on the soil surface. If this was carried out by all the farmers in an area, populations of Zonocerus could be reduced and crop damage minimised. Such control can be carried out at little or no cost and with very little labour.

In studies in Nigeria, survival and weight increase of the larvae of Cydia ptychora (Meyr.) were affected by the variety of cowpea (Vigna unguiculata) on which they fed. The weights of fifth-instar larvae immediately prior to pupation and the amount of fresh food ingested were similar on three varieties when loose seeds were fed, but in a more natural situation, larvae appeared to face a manoeuvrability problem in small pods, which resulted in reduced weight gain. Differences in weight due to diet were less pronounced in emerging adults. Larval mortality was greatest on two varieties with large pods and may have been related to the nutritional quality of mature seeds or the presence of toxic chemicals. Some first-instar larvae died during the pod-boring process, particularly in the variety Vita-5. Two known susceptible varieties produced a moderate-to-small degree of mortality and large females. Significantly greater weight was attained when larvae fed for five days on 10-day-old seed followed by 15-day-old seed, or on 15-day-old seed throughout, than on 15-day-old seed followed by dried seed, or on 10-day-old seed throughout. Ovipositing females seemingly select pods of an age that minimises exposure of young larvae to drying or fully dried seed, which is a relatively unsuitable diet.

A silicone membrane was developed to meet the feeding requirements of Glossina palpalis palpalis (R.-D.). Starting with a total of 1050 females, a self-sustaining colony fed on defibrinated pig blood was established. The colony performance in terms of mean daily mortality, mean pupal weight and fecundity was evaluated. With the exception of June 1976, the mean daily mortality ranged between 0·40% and 1·20%. During June 1976, bacterial infections caused a sudden increase in mortality. Escherichia coli and Staphylococcus spp. were predominant in the gut of dead and diseased flies. Pure cultures of either organism caused the same symptoms in teneral flies within one week after uptake of an infected blood-meal. The weight of the offspring significantly decreased with increasing female age. Starting with a mean pupal weight of 30 mg there was a decrease of 4–6 mg over a period of 90 days. The innate capacity for increase in numbers (r-) was calculated based on data from 340 females. The value of rm = 0·0095 would result in a 32-fold increase of the colony in one year.

An investigation using modified Manitoba traps on a forest track in Scotland showed that carbon dioxide, coloured spheres, movement, heat, Haematopota pluvialis (L.) and a swarm of other adults of Hydrotaea irritans (Fall.) were attractive. Traps with coloured spheres attracted more flies than traps without spheres. Matt black, shiny black and shiny red spheres attracted more males and females than did shiny green, white or yellow spheres. Significant increases in the number of flies caught did not occur when carbon dioxide was released from a trap at rates above 2 litres/min. Carbon dioxide seems to act as a long-range attractant, with vision becoming important near the host. Manitoba traps were also used with three repellents for H. irritans in order to evaluate the trap's potential for testing repellents.

The flight activity of Hydrotaea irritans (Fall.) was investigated in western Scotland using an unbaited suction trap, a carbon-dioxide-baited suction trap and a Manitoba trap. Consistently more female flies were caught than males. Trapping experiments showed that carbon dioxide and visual or thermal stimuli influence long-range attraction and short-range orientation in host-seeking flies. The seasonal activity of adults was determined from the geometric means of catches from a suction trap baited with carbon dioxide and a Manitoba trap. H. irritans was shown to be univoltine. The activity of females was greatest in the middle of July and declined sharply in the first week of August. Male activity reached a peak at the same time as that of the females, then declined until no males were caught after mid-August. Females were most active between 10.00 and 18.00 h B.S.T., with a peak about 13.00 h. There was no variation in sex ratio during the day. Multiple regression equations of climatic and seasonal factors with log catches of flies were very similar for the two types of trap. Radiant temperature, illumination, wind speed and date were shown to influence activity of females and, with the exception of illumination, male activity also. Seasonal activity curves calculated from the regression equations were plotted for both sexes in the two traps.