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.

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.

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.

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.

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.

Adults of Zonocerus variegatus (L.) from the dry-season population in southern Nigeria were shown to exist in two forms, one with relatively long wings and the other with relatively short wings. The wet-season population normally existed as the short-winged form, but the insects had the capacity to develop long wings. Long-winged insects had welldeveloped flight muscles and were capable of flight. Flight in the field occurred before sexual maturation and may have led to downwind displacement of individuals over considerable distances.

Rhodnius prolixus Stȧl was successfully reared for three generations on a diet of defibrinated pig blood fed through Parafilm or silicone-rubber membranes. Reproduction in terms of the number and sizes of eggs produced was superior to, while survival from egg to adult was equal to that reported for, insects fed on live hosts. The technique appears equally applicable to the rearing of Panstrongylus megistus (Burm.), Triatoma infestans (Klug) and T. brasiliensis Neiva. The inadequacy of cow blood as a diet for R. prolixus was manifested in a decrease in adult size after two generations and in a reduction of egg weight from 30 to around 16 mg per female per week. This was accompanied by a corresponding reduction in egg hatch from 90 to about 50%.

A previously published method for determining the physiological age of female Lucilia cuprina (Wied.), based on a linear relationship between their rates of ovarian development and temperature, was tested under field-cage conditions. It was found that ovarian development was more rapid than that predicted by thermal summation based on ambient temperature. A re-examination of the rate of development-ambient temperature relationship, over a wider temperature range that that used previously, showed that the development threshold temperature was 8·2°C rather than 11·3°C. Thermal summation using the revised threshold also fell short of the observed day-degree totals. An effective temperature for ovarian development (ambient temperature plus a temperature excess proportional to the incoming solar radiation intensity) was fitted to the data from the field cage. This relationship gave accurate predictions of ovarian development (±8%) for flies that were released into the field.

In laboratory colonies of Atta cephalotes (L.) and Acromyrmex octospinosus (Reich), discs cut from young leaves of several plant species were picked up more readily than those from old leaves. Pith sections impregnated with whole extracts of young leaves were consistently picked up in preference to others with extracts of old leaves, and non-lipid extracts were consistently preferred to extracts containing lipids. Arrestive properties were confined to the non-lipid extracts, and inhibitory properties were mainly found in the lipids, but removal of lipids from the whole extracts did not necessarily make them more arrestive. In most cases, dewaxing of leaves with chloroform made them more acceptable, and heating and freezing of leaves had a similar effect. Leaf waxes showed inhibitory properties. Wax extract of young leaves was often preferred to that of old leaves, and differences in preferences were observed for wax extracts from different plant species. The implications of these findings for the relationship between leaf-cutting ants and the vegetation that they cut are discussed.

The leaf-cutting ants Atta cephalotes (L.) and Acromyrmex octospinosus (Reich) were tested in a moving-air olfactometer for their responses to a variety of odours from leaves, fruit, flowers, essential oils, other ants and a fungus garden. The line of a foraging trail established in still air tended to loop downwind in the presence of a laminar air flow. The ants exhibited positive, negative and neutral responses to the test odours, confirming the existence of attractants and repellents in substrate materials. Neutral responses to the odours of several of the materials that were acceptable for cutting showed that arrestive materials were not necessarily attractive. Ants orientating towards the source of an odour often secreted a pheromone trail. Atta and Acromyrmex responded differently to several of the materials tested, and the responses to odours of young and old leaves were not totally consistent with the observed cutting preferences. Removal of wax from non-attractive leaves made them attractive. Both species responded negatively to lemon-oil odour, but some Acromyrmex workers showed a hostile response. A hostile response was also elicited by the odour from other ants. Fungus-garden odour elicited a positive investigatory response, and no response was shown to queen odour. Laden Atta workers did not respond to an odour that was attractive to unladen ants, and laden examples of Acromyrmex responded in small numbers to such odours. The addition of attractive chemicals to baits for the control of leaf-cutting ants would improve pick-up by making the bait particle easier to find.

A comparison was made of the efficiencies of catching parties with hand nets and electric back-pack and screen traps for the capture of Glossina palpalis palpalis (R.-D.) and G. tachinoides Westw. in northern Nigeria. Whilst there was little to choose between the various devices during standing catches, one electric back-pack caught up to four times as many G. palpalis as two men with hand nets during moving catches on fly-rounds. Two reasons for the observed variation in success rate of the catching party with hand nets are suggested, and estimates are made of the relative efficiencies of each method at capturing flies during a single traverse of a fly-round. The combined use of the electric back-pack and screen drawn immediately behind the back-pack wearer recorded the arrival height of the flies, whilst hand-net catches tended to reflect the heights at which the flies spent most of their time after arrival. There were differences between the sexes both in arrival height, perhaps related to differences in resting heights on the vegetation, and in the fat and haematin levels of flies caught in hand nets above and below the waist. High ambient temperature reduced the average height of the visits of both sexes to human bait. The relevance of the results obtained in this study to sampling tsets populations is discussed in relation to various seasonal changes in hand-net samples recorded in the literature.

Glossina spp. were collected in south-western Ethiopia and were found to have a continuous distribution from the Sobat River Basin to the southern Rift Valley lakes of Chamo and Abaya. Their limits to the north and east of this range was not determined. Along the Omo River, Glossina inhabit a continuous band from 20 km above Lake Rudolf to at least as far as Abelti, 167 km south-west of Addis Ababa. The species collected were G. pallidipes Aust., G. fuscipes Newst., G. morsitans submorsitans Newst. and G. Iongipennis Corti. The ratio and numbers of G. pallidipes and G. fuscipes suggest a relationship between the latter and the number of hippopotamus along the Omo River. Both G. pallidipes and G. Iongipennis were caught biting at night.

Studies in Queensland showed that an outbreak of Austrosimulium pestilens Mack. & Mack. occurs if the water-level in a river rises enough to release eggs buried in the river-bed. Following such a rise, the larval development of A. pestilens was completed in 6–7 days in summer and 9–10 days in winter, and after a pupal period of 1·5–2 days in summer and 3 days in winter, adult eclosion began. Most flies emerging during the first 1–2 days were males, but females were slightly predominant later. A. pestilens emerged throughout the diel; at night there was a drop in the numbers emerging, and this was followed by a distinct early morning peak. Following a rapid rise and fall in river-levels, adult eclosion and mating occurred over a period of several days early in an outbreak, but after high river-levels of long duration, eclosion and mating occurred over a much longer period.

A total of 18 873 mosquitoes comprising 18 species in 4 genera was collected during a series of 12 monthly all-night collections on bovid baits near the village of Sattoki, Punjab Province, Pakistan. Anopheles pulcherrimus Theo. and usually An. Culicifacies Giles and An. Stephensi List. had unimodal biting rhythms. Mansonia uniformis (Theo.), An. Annularis Wulp and An. Nigerrimus Giles had essentially unimodal rhythms, with most feeding occurring early in the evening but with occasional very slight morning increases.Aedes caspius (Pall.), Culex pseudovishnui Colless, C. tritaeniorhynchus Giles and usually An. Subpictus Grassi had distinctly bimodal biting rhythms, with well-defined early evening and predawn peaks. An. culicifacies, An. Stephensi and An. Subpictus occasionally had multimodal rhythms or were arhythmic. Some species exhibited more than one type of biting curve. In species having a distinct bimodal curve, the amplitude of the predawn or dawn increase varied considerably from month to month. The anophelines, especially An. culicifacies, An. Stephensi and An. Subpictus, exhibited a marked seasonal shift in feeding times, with most biting occurring at dusk during the cold period and late at night during the warm period. However, all components of the biting curves for these species were maintained at varying magnitude throughout the year, perhaps suggesting seasonal variations in the relative frequency of more than one behavioural genome. The remaining species exhibited little or no seasonal change in biting rhythms

Males of Glossina morsitans Westw. and G. pallidipes Aust. labelled with radiocaesium (137Cs) were released in their natural habitat and later recovered on four occasions in the hot, hot wet and cold dry seasons in Rhodesia. The rate of excretion of the radioisotope was related to previous laboratory results to give estimates of activity, temperature regulation and energy utilisation in the field. It is considered that male G. morsitans are unlikely to fly for more than a few minutes per day. The hunger cycle duration is estimated as 3·5–4 days for G. morsitans males and 5·5 days for G. pallidipes males. Temperature regulation within the range 23–27°C was exhibited by both species, especially in the winter.