The trend in the relative populations of Oryctes rhinoceros (L.) in two areas of the Gazelle Peninsula, New Britain, was studied by trapping adults searching for breeding sites. In a high rainfall area with 10-year-old palms and many possible breeding sites, there was a large initial population of beetles which declined over the next three years with the gradual disappearance of the breeding sites; weekly catches were higher when the undergrowth in the trapping area was slashed, and to some extent also at new moon; catches were depressed by heavy rain. The ♂/♂ sex ratio was 0·31; all females had mated and had mature eggs in the lower ends of the oviducts. These results were compared with those from a low rainfall area with 70-year-old palms and dispersed breeding sites. Catches were generally lower; they showed no long term trend and were not related to slashing or weekly rainfall, but were inversely related to the number of rainy days per week.

A survey for resistance to acaricides in Rhipicephalus appendiculatus Neumann, Amblyomma variegatum (F.), Boophilus decoloratus (Koch) and B. microplus (Canestrini) was carried out in three important cattle areas of Zambia during three consecutive rainy seasons (November-May) from 1981–82 to 1983–84 to determine the pattern and distribution of resistance to dieldrin, dimethoate, dioxathion and chlorfenvinphos. Resistance was assessed using the FAO resistance test kit. Resistance to dieldrin, dimethoate and dioxathion was found in a greater number of samples from Central and Southern Provinces than from Northern and Eastern Provinces. Relatively high resistance factors were recorded for R. appendiculatus against dimethoate (mean resistance factor (RF) 10·7 ± 3·8×) and dioxathion (mean RF 8·6 ± 1·9×). B. decoloratus from Central and Southern Provinces showed mixed responses to dieldrin and low resistance to dimethoate (mean RF 4·1 ± 2·3×) and dioxathion (6·4 ± 5·0×). Most samples of A. variegatum and B. microplus were susceptible to the four acaricides. Generally, most of the ticks tested showed high susceptibility to chlorfenvinphos.

The flight activity of adult Delia coarctata (Fall). was studied on Rothamsted Farm from 1969 to 1977 using light-traps. These catch, almost exclusively, dispersing mature females, more being caught at full moon than at new moon. Dispersal begins in response to an acceleration in the rate of decrease of daylength, and at Rothamsted begins on 10 July, soon after the rate of decrease accelerates. Maturation of eggs is controlled by temperature; at Rothamsted, the first mature females appear when temperature accumulation above 5° C has reached 314·5±10·5° after 12 June. Maturation usually coincides with dispersal, but females that have matured before 10 July do not disperse until after that date. Catches of females in light-traps are correlated with the numbers of emerging females per hectare and the numbers of eggs per hectare. Light-traps could be used as a simple way of forecasting numbers of eggs early enough to give advice on seed treatment for winter wheat on land subject to attack by D. coarctata.

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.

Resting site preferences of adult Glossina morsitans morsitans Westw., the dominant species in the Republic of Zambia, were observed during the cool (May–August) and hot (September–October) dry seasons in 1974 at the Chakwenga Game Reserve. Tanglefoot was used to trap resting flies on boles, branches, bushes (undergrowth), canopies, fallen logs and in ant-bear holes.

All resting flies were collected below 4 m and there was an inverse relationship between numbers of resting flies and height of resting sites on boles, branches and canopies. Most flies were collected betwen 06.00 and 09.00 h, except in ant-bear holes, where no flies were found. No significant differences existed between numbers of flies collected from the four cardinal positions on boles. Although more flies were found on shaded than unshaded fallen logs and bushes, the differences were only statistically significant for fallen logs. Numbers of flies on various tree species were generally not significantly different. Boles, bushes and fallen logs were the most preferred sites.

The red bollworm attacking cotton in Nigeria has recently been shown to be Diparopsis watersi (Roths.), distinct from D. castanea Hmps., the southern African species previously assumed to be that occurring on cotton throughout Africa. Earlier work on cotton pests, including Diparopsis, in southern Nigeria (1664) is briefly reviewed, and the discovery and definition of the problems of cotton pests in northern Nigeria is outlined, and the climatic and agricultural background of the northern areas described.

The main object of the present work, centred at Samaru, was to determine; the annual cycle of activity of Diparopsis in northern Nigeria. The methods employed are described. The insect passes the dry season in diapause as a pupa in the soil. In late May or June, emergence from these pupae commences, but this is completely interrupted during July-September. In October, after the end of the rains, emergence recommences, and the main attack occurs on the crop during October and November. The proportion of pupae entering diapause rises rapidly from mid-October onwards, and activity ceases in early December.

When diapause pupae were incubated at controlled (86°F.) or indoor air (74–86°F.) temperatures, emergence was unimodal, extending from June to October, with the peak in July or August, respectively. It is concluded that the bimodal emergence in the field is caused by waterlogging, or some other factor restricting aeration of the soil during July-September, when the emergence from diapause pupae is interrupted

Trials of dates of sowing laid down at Samaru and Daudawa showed that early sowings, made in mid-June or early July, may suffer heavier bollworm attack than those made in mid- or late July. The earlier sowings nevertheless outyielded later ones. It is suggested that this results from their benefiting from a longer growing season, in which a greater production of fruiting points more than offsets greater losses from bollworms and other insects.

Elimination of ratoon and standover cotton would prevent breeding by the early emergence of moths from diapause pupae, and consequent red-bollworm attack on early sowings of cotton.

The possibility of producing a unimodal emergence from diapause pupae is worth further attention. This might be achieved by altering the soil conditions during July-September, and if successful would result in the main crop escaping almost entirely any attack by Diparopsis.

There appear to be no fundamental differences biologically between Diparopsis castanea and D. watersi, as illustrated by previous work reported from South Africa and Nyasaland, and the observations recorded here.

Precipitin tests of the blood-meals of the non-anthropophilic population of Aedes simpsoni (Theo.) in Bwayise showed that at least 62% of the meals were mammalian; none was certainly avian or reptile. The remaining 38% were mostly too far digested for identification. Of the positive mammalian feeds, 84% were of rodents and only 5%; were of primates, probably human. In laboratory choice experiments, approximately two-thirds of a sample of the Bwayise strain fed on rodent in preference to monkey. Precipitin tests on blood-meals of the Bwamba strain of Ae. simpsoni confirmed earlier findings that this strain is strongly anthropophilic. At least 86% of wild-caught individuals had fed on mammals, 65% of these specifically identified: 28% of the feeds were of rodents and 72% were of primates, mostly human. During a five-month study at Bwayise in 1969, eleven species of rodents were caught; 91% of the rodents diurnally active were Arvicanthis niloticus which contributed 38% of the total collection and was twice as active during the afternoon as in the morning. The remaining species were predominantly nocturnal. A close relationship was found between the times of activity of A. niloticus and the biting cycle of Ae. simpsoni. In feeding tests using the three commonest rodent species, Ae. simpsoni selected A. niloticus as often as, or more often than, the nocturnal rodent species. This preference was maintained over one generation reared in culture. It is suggested that A. niloticus is the major natural host of the Bwayise strain by reason of the synchrony between rodent and mosquito activity rhythms. The Bwayise strain does not normally feed upon wild primates, so explaining further the almost total absence of human cases of yellow fever in areas of Uganda where this mosquito is non-anthropophilic.

The flight performance of three cytospecies from the West African complex of Simulium damnosum Theo. was tested under controlled laboratory conditions. A total of 293 individuals (174 of S. squamosum (End.), 65 of a new form of the subgroup of S. soubrense Vajime & Dunbar and S. sanctipauli Vajime & Dunbar and 54 of S. sirbanum Vajime & Dunbar) was tested on 526 occasions, of which 380 involved sucrose-fed insects, 65 water-only-fed insects, of both sexes, from laboratory-emerged stock and 81 blood-fed, wild-caught females. A high percentage of tests resulted in flights. Frequency distributions of both flight duration and distance flown were skewed, more flights being of short than of long duration. Sucrose-fed females and females caught wild at human bait generally flew well. Insects given access to water only made short flights, but S. sirbanum flew fairly well under these conditions. The recorded maximum flight durations and distances were 262 min (in a male) and 5·25 km (in a female) in S. squamosum, 282 min (in a male) and 6·15 km (in a male) in S. soubrense/sanctipauli, and 186 min (in a female) and 5 27 km (in a female) in S. sirbanum, all from sucrose-fed groups. Some insects were flown on several days up to 11 days after emergence. Some insects made long flights on one day but not on others. Further long flights could be induced on the same day if the insect was allowed access to sucrose solution prior to retesting. These results are discussed in relation to previous findings from S. ornatum Mg. s.l. and to the migration potential of the important vectors of onchocerciasis in West Africa.

A colony of Glossina morsitans morsitans Westw. was established in the laboratory in Tanga, Tanzania. After being expanded to the planned level of 60 000 flies, the stabilised colony was used to support a field trial using surplus males that were sterilised and released. The production system consisted of an adaptation of the in vivo rearing techniques developed at the Tsetse Research Laboratory, England. Goats were hosts for 90 % of the production; the balance was fed on rabbits. Techniques were developed to standardise the pupal off-take from stabilised colonies in each of three separate insectary units. Puparia were collected daily and kept separately until 52% emergence had occurred; these emerging flies, mostly females, were used to replenish the stock colony as needed. Further eclosion was prevented by chilling the remaining puparia (mostly males) quickly at 4°C and then storing at 10 ± 1°C for up to four days prior to irradiation and shipment to the field. About 68 % of the males produced were available for sterilisation. During the 15-month period of production in support of the field experiments, 1·3 million puparia were produced; 0·6 million of these puparia were released at a production cost of $220 per thousand.

The identity of the palm kernel borer in West Africa is established, its correct name being Pachymerus cardo (Fåhr.); a neotype is designated for P. bactris (L.), the type species of Pachymerus Thunberg; a new species, P. thoracicus, is described from Paraguay, and three new specific synonymies are made. A key in given to the species of Pachymerus, the definitive characters of all of which are described and illustrated.

Understanding herbivore diversity both at the species and genetic levels is a key to effective pest management. We examined moth samples from multiple locations from a major apple growing region in China. For specimen collection, we used a pheromone trap designed to attract Grapholita molesta (Busck) (Lepidoptera: Tortricidae). Surprisingly, we found a second species captured at high proportions. Its external morphology (e.g., male genitalia and forewing coloration) was the same as for Grapholita funebrana Treitschke (Lepidoptera: Tortricidae) specimens from Europe. However, the barcode sequence of the mitochondrial gene cytochrome oxidase I (COI) diverged markedly between specimens from China and Europe, and the genetic distance value between the specimens from the two regions as estimated using the Juke-Cantor (JC) model amounted to 0.067. These morphological and molecular findings together point to a cryptic species in G. funebrana from China. Further molecular analyses based on COI and COII genes revealed its extremely high genetic diversity, indicating that the origin of this species includes the sampling region. Moreover, molecular data suggest that this species passed through a recent population expansion. This is the first report on a cryptic species in G. funebrana, as well as the first report on its genetic diversity.

Observations were made on the behaviour of some Costa Rican species of Phyllophaga. Studies of oviposition and early larval survival under controlled conditions indicated that P. menetriesii (Blanchard) laid most eggs under a ground cover containing grasses and that the presence of living roots in the soil was important to the survival of the young larvae of the two most common species, P. menetriesii and P. vicina (Moser). At Turrialba, Costa Rica, the destruction of young maize plants by larvae of these two species and the consequent reduction in yield were significantly greater in land which was weedy or in close association with stands of old cassava plants, than where weeds had been effectively controlled and cassava was absent. Both plant loss and yields of maize were significantly correlated with larval densities. The best correlations were with numbers of second- and third-instar larvae sampled in July and with the total numbers of third-instar larvae sampled. Regression analyses established that 4·45 seedlings, or approximately 170 kg dry grain/ha, were lost per larva per square metre sampled during the seedling stage in July. An expression to calculate the economic threshold was determined. Significantly more larvae of P. vicina were found in maize growing on ridged than on unridged land, and where applications of lime and phosphate fertilizer had been made to an acid soil. The significance of weed control on infestation is discussed.

The history of tsetse-fly in Southern Rhodesia up to the present year (1918) continues on the whole to be one of expansion, although on the other hand one small, but important, belt appears to have become extinct. In addition, a fly area in the Moçambique Company's territory has extended up to our eastern border, with the result that serious losses of cattle from trypanosomiasis have occurred on the farms in that region. Detailed reports on the advance or retrogression of Glossina morsitans in other parts of Africa appear to be lacking, and it is felt that in view of the position of this territory in relation to tsetse-fly a review of the situation to the present day may not be without general interest.

The following notes on the various insects injurious to the economic crops of the Zanzibar Protectorate are based on investigations made during the last few years.

The shoot beetles Tomicus minor, Tomicus yunnanensis, and Tomicus brevipilosus have been decimating Pinus yunnanensis trees for more than 30 years in Southwestern China. To understand the chemical ecological relationship between pines and Tomicus, and among the three beetle species, we compared the attraction of these beetles to damaged shoots, extracts from damaged shoots, and volatiles from damaged shoots collected by the dynamic headspace sampling method. Experiments were performed using a modified open-arena olfactometer. The male T. minor and both sexes of T. brevipilosus were more strongly attracted to damaged shoots than to undamaged shoots and they showed attraction to shoots damaged by the same species. Female T. minor and both sexes of T. yunnanensis were attracted to shoots damaged by female T. brevipilosus. The three beetle species were attracted to shoot extracts and dynamic headspace volatiles from shoots damaged by the same species and sex. Female T. minor and male T. yunnanensis were also attracted to dynamic headspace volatiles from shoots damaged by both sexes of T. brevipilosus. The results suggested that specific semiochemicals that are induced or produced by T. brevipilosus also attract T. minor and T. yunnanensis. The semiochemicals in damaged shoots affect the attraction of the three beetle species and play an important chemical communication role in weakening the host trees during the beetles’ shoot-feeding phase.

Rhyssa persuasoria and Ibalia leucospoides, both parasitic on Sirex cyaneus, have been studied at Oxford.

Rhyssa lays its eggs in the burrow of and near to the almost or quite full-fed host larva or the pupa, by piercing the solid wood with itsovipositor. Feeding is entirely ectoparasitic and takes only a few weeks, during which the host larva may burrow a little further. The winter is passed by Rhyssa as a resting larva. Pupation takes place in the spring, and the whole life-cycle normally occupies one year.

Ibalia oviposits in the young larva just before ormore rarely just after hatching, utilising the oviposition-bores of the Sirex for this purpose. The first-stage larva is elongate, with sickle-shaped mandibles, and larval feeding seems wholly endoparasitic. Sirex larvae parasitised by Ibalia confine their boring largely to the outer portions of the trunk, and usually make their final cell just under and approximately parallel to the surface. The life-cycle of Ibalia requires at least two years.

Owing to the very different instars which they attack, there seems no risk of superparasitism of Ibalia by Rhyssa or vice versa, and it is therefore suggested that both species be introduced into New Zealand as a measure against Sirex juvencus, which is there very destructive to plantations of Pinus radiata.

Previous descriptions of the flight season of the Garden Chafer, Phyllopertha horticola (L.), are inadequate. From a study of five seasons, 1948–1952, the general or mass aspects may be outlined for the English Lake District as follows:—

The flight season starts in May or June, depending on soil temperature. When population is low the season lasts 3–4 weeks, when high it may last 5–6 weeks. Reasons for this are given.

The flight season has two overlapping phases. In Phase 1, beetles swarm close over the grass sward from which they emerged. As the season progresses, Phase 1 gradually gives way to Phase 2, in which the beetles now swarm closely on the bracken, hedges and trees surrounding the pasture. In the absence of bracken, the whole of Phase 2 takes place on hedges and/or trees. In the presence of bracken, phase-2 activity at first occurs on all three (bracken, hedges and trees) but, for some obscure reason, hedges and trees are forsaken in favour of bracken about halfway through the phase. Roughly speaking, phase-1 activity can be seen for the first two-thirds and Phase 2 for the last two-thirds of the flight season, i.e., there is about 50 per cent. overlap of the phases. The overlap is clearly due to earlier-emerging beetles entering phase-2 activity before later beetles have completed Phase 1.

Normal activity (i.e., flying closely over, or running or walking upon, the vegetation) is governed by weather. Both temperature and light are involved. Beetles are most active in warm bright conditions and, indeed, will fly and run only when the sun is shining. In warm bright-overcast conditions, they merely walk around. In cold, dull-overcast conditions (with or without wind or rain), they do not stir at all.

Activity starts any time between 8 a.m. and 2 p.m. (G.M.T.) according to weather (earliest recorded start being 7 a.m.). The first day of the flight season is usually marked by a short period of activity, 1–2 hours, in the forenoon, even when weather conditions continue favourable into late afternoon. As the days pass the period lengthens until beetles are active up to about 4 p.m. (latest recorded finish being 4.30 p.m.). The longest periods of activity, 8 a.m. to 4 p.m., occur when the sun shines all day after the first week of the season has passed. As the season draws to an end the activity period shortens until on the last day it is one hour or less. In general, rather more of the activity time occurs before noon than after.

The curve of numbers of beetles to be seen during the daily activity period is described for both phases. During the time of overlap of the phases, the curves are complicated by a certain amount of two-way traffic between grass sward and bracken (or hedges or trees). In addition, throughout Phase 2 a small proportion of individuals leaves the bracken flying high, straight and very fast, i.e., behaves abnormally; these individuals are termed “bee-liners” and will figure in a later paper.

For about the first week of the flight season all beetles disappear into the sward at the end of the day's activity. After that, a growing fraction of each day's active population spends the whole night in full view on the sward surface, bracken fringe, hedges and trees. All these “dormitories” begin to be used at the same time, i.e., about three days before Phase 2 starts. Passing the night on the sward surface ends with Phase 1. Roosting on hedges and trees ends simultaneously with activity there (first half of Phase 2). The bracken fringe alone is used right to the end of the season. Between sunset and sunrise, from 15 to 90 per cent, or more of resting beetles fall from bracken, hedges or trees to the ground. Reasons for this are given.

Beetles begin to feed when they stop spending the night below the sward surface. They feed after the day's activity is finished, and up to 8 p.m. at the latest. Their food is the herbage, bracken frondlets, leaves, blossoms, fruits, etc., on which they come to rest for the night.

The feeding penetrations of Myzus persicae (Sulz.) nymphs into tulip leaf epidermis, as shown by a study of stylets and tracks, may be intercellular, intracellular or stomatal with the former predominating. Contact between the stylet sheath or track and cell cytoplasm is at a maximum during intracellular entry but occurs to a limited extent during intercellular penetration due to partial rupture of the epidermal end walls. In the mesophyll, the stylet path is intercellular but a few cells were penetrated by tracks.Tracks vary in appearance according to the degree of confinement to which they have been subjected, the differing amounts of gelling saliva involved beingattributed to alterations in salivation rate or speed of penetration of the bundle. Seventypes of track were recognised, ranging from a thin membraneous to a thick lobular structure. The tracks have recognisable precursors in the stylet sheaths though differences between sheaths and tracks are evident, particularly where saliva is secreted during stylet withdrawal. In the vascular tissues, phloem and xylem are penetrated, often by repeatedlybranched tracks: the point of divergence of the arms of a branched track, in both mesophyll and vascular bundles, occurs only in large inter- or intracellular spaces where the lobular sheath or track is present. Three types of track are common in the vascular tissue:the lobular, the membraneous, and a saliva-filled type. The majority of stylet bundles terminate in the phloem. Rotation of the stylet bundle about its longitudal axis is generally absent.

The relations of the Strepsipterous parasite Halictophagus pontifex Fox to seven species of its Cercopid (Aphrophorinae) hosts were studied at a grassland site in Uganda. Dissections of weekly samples of the Cercopids collected by sweeping showed that the duration of the life-cycle of H. pontifex is 30–40 days. The parasite is found only in adult hosts which can support as many individuals (up to 7) in Poophilus costalis (Wlk.) as can develop in the space available in the body cavity. Both the maximum number of parasites per host and the rate of parasitism are related to the volume of the host. Parasitism arrests development of the ovaries of female hosts; they may reproduce after emergence of male parasites but not after exhaustion of females because of reinfection by triungulins. Graphical and regression analysis of the population data (no. individuals/1 000 sweeps) show that, for P. costalis, parasitism by H. pontifex is density dependent and the chief regulating factor. Rainfall 58–64 days before sampling also was correlated with P. costalis density, but multiple regression analysis showed it to be insignificant.

Anopheles aconitus Dön. has long been known as an important vector of malaria in Indonesia. More recently it has been shown to be the principal, if not the only vector in the inland areas of Java. A. maculatus Theo. has been regarded as an important vector in hilly regions.

The observations recorded in the present paper were carried out in an inland area in East Java between June 1957 and May 1958, and in a hilly one in West Java between April 1956 and March 1957, and were concerned, in particular, with the resting and feeding habits of these two species in so far as they might influence methods of control.

A. aconitus is found in great numbers throughout the year with a major peak of density from March to May, about harvest time of the first and more extensive rice crop.

In the areas studied, A. aconitus is largely exophilic and, where man is concerned, exophagous, nearly three times as many examples being taken biting man outdoors as indoors, and 17 per cent. of 359 examples taken outdoors were positive for human blood as compared with 5 per cent. of 1,438 examples from all situations. Of the remainder, 93·5 per cent. were positive for ox. On the whole, therefore, this species is highly, though not exclusively, zoophilic and readily enters cattle-sheds, built of bamboo matting, to feed, and, in those sheds that have walls as well as roofs, up to 75 per cent. may remain for at least two hours after having fed, and appreciable but variable numbers of fully fed individuals may remain during day-time.

Most of the feeding on man outdoors took place before midnight, and, on cattle in sheds, between midnight and 0600 hr., with peaks between midnight and 0100 hr. and between 0400 and 0500 hr., respectively. Peak periods of entry into an animal-baited trap were during the second and fourth quarters of the night.

These results differ somewhat from those reported from certain other localities in Java by other workers. There is, therefore, a need for careful repetition, in other areas, of studies of the bionomics and for experiments on the effect on a population of A. aconitus of applications of a residual insecticide.

A. maculatus occurs in the hilly area in considerable numbers throughout the year, and there seems to be no great seasonal fluctuation. This species rests mainly on coffee and palm plants both by day and by night, but readily enters cattle-sheds at night. No blood-meals from this species were subjected to the precipitin test. It is suggested that the importance of A. maculatus in the transmission of malaria needs further investigation.

Over 1,000 examples of A. maculatus and A. aconitus, taken in the hilly area, were dissected, but no malaria infection was found.

A. vagus Dön. is present in the inland area in large numbers during the greater part of the year, with its peak from November to February, during the rainy season. It is more endophilic and endophagous than A. aconitus but is not considered important in malaria transmission.

A. annularis Wulp has its peak in March, and A. kochi Dön. in May. A. barbirostris Wulp, A. subpictus malayensis Hack, and A. tessallatus Theo. were found only in small numbers. All these species are highly zoophilic in the areas studied; they are not considered important in malaria transmission.